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Iezhitsa I, Lazaldin MM, Agarwal R, Agarwal P, Ismail N. Neuroprotective effects of exogenous brain-derived neurotrophic factor on amyloid-beta 1–40-induced retinal degeneration. Neural Regen Res 2023; 18:382-388. [PMID: 35900434 PMCID: PMC9396500 DOI: 10.4103/1673-5374.346546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Amyloid-beta (Aβ)-related alterations, similar to those found in the brains of patients with Alzheimer’s disease, have been observed in the retina of patients with glaucoma. Decreased levels of brain-derived neurotrophic factor (BDNF) are believed to be associated with the neurotoxic effects of Aβ peptide. To investigate the mechanism underlying the neuroprotective effects of BDNF on Aβ1–40-induced retinal injury in Sprague-Dawley rats, we treated rats by intravitreal administration of phosphate-buffered saline (control), Aβ1–40 (5 nM), or Aβ1–40 (5 nM) combined with BDNF (1 µg/mL). We found that intravitreal administration of Aβ1–40 induced retinal ganglion cell apoptosis. Fluoro-Gold staining showed a significantly lower number of retinal ganglion cells in the Aβ1–40 group than in the control and BDNF groups. In the Aβ1–40 group, low number of RGCs was associated with increased caspase-3 expression and reduced TrkB and ERK1/2 expression. BDNF abolished Aβ1–40-induced increase in the expression of caspase-3 at the gene and protein levels in the retina and upregulated TrkB and ERK1/2 expression. These findings suggest that treatment with BDNF prevents RGC apoptosis induced by Aβ1–40 by activating the BDNF-TrkB signaling pathway in rats.
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Boneva SK, Wolf J, Wieghofer P, Sebag J, Lange CAK. Hyalocyte functions and immunology. EXPERT REVIEW OF OPHTHALMOLOGY 2022. [DOI: 10.1080/17469899.2022.2100763] [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: 10/14/2022]
Affiliation(s)
- Stefaniya K Boneva
- Eye Center, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Julian Wolf
- Eye Center, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Peter Wieghofer
- Cellular Neuroanatomy, Institute of Theoretical Medicine, Medical Faculty, University of Augsburg, Augsburg, Germany
| | - J Sebag
- Doheny Eye Institute, UCLA, Pasadena, CA, USA
- UCLA Geffen School of Medicine, Los Angeles, CA, USA
- VMR Institute for Vitreous Macula Retina, Huntington Beach, California, USA
| | - Clemens AK Lange
- Eye Center, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Ophtha-Lab, Department of Ophthalmology at St. Franziskus Hospital, Muenster, Germany
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López-Higuera JM. Sensing Using Light: A Key Area of Sensors. SENSORS (BASEL, SWITZERLAND) 2021; 21:6562. [PMID: 34640881 PMCID: PMC8512037 DOI: 10.3390/s21196562] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 09/23/2021] [Accepted: 09/24/2021] [Indexed: 12/02/2022]
Abstract
This invited featured paper offers a Doctrinal Conception of sensing using Light (SuL) as an "umbrella" in which any sensing approach using Light Sciences and Technologies can be easily included. The key requirements of a sensing system will be quickly introduced by using a bottom-up methodology. Thanks to this, it will be possible to get a general conception of a sensor using Light techniques and know some related issues, such as its main constituted parts and types. The case in which smartness is conferred to the device is also considered. A quick "flight" over 10 significant cases using different principles, techniques, and technologies to detect diverse measurands in various sector applications is offered to illustrate this general concept. After reading this paper, any sensing approach using Light Sciences and Technologies may be easily included under the umbrella: sensing using Light or photonic sensors (PS).
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Affiliation(s)
- José Miguel López-Higuera
- Photonics Engineering Group, University of Cantabria, 39005 Santander, Spain;
- Instituto de Investigación Sanitaria Valdecilla (IDIVAL), 39011 Santander, Spain
- CIBER-BBN, Instituto de Salud Carlos III, 28029 Madrid, Spain
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Guo L, Ravindran N, Shamsher E, Hill D, Cordeiro MF. Retinal Changes in Transgenic Mouse Models of Alzheimer's Disease. Curr Alzheimer Res 2021; 18:89-102. [PMID: 33855942 DOI: 10.2174/1567205018666210414113634] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2020] [Revised: 02/09/2021] [Accepted: 04/05/2021] [Indexed: 11/22/2022]
Abstract
Alzheimer's disease (AD) is a neurodegenerative disorder, the most common form of dementia. AD is characterised by amyloid-β (Aβ) plaques and neurofibrillary tangles (NFT) in the brain, in association with neuronal loss and synaptic failure, causing cognitive deficits. Accurate and early diagnosis is currently unavailable in lifespan, hampering early intervention of potential new treatments. Visual deficits have been well documented in AD patients, and the pathological changes identified in the brain are also believed to be found in the retina, an integral part of the central nervous system. Retinal changes can be detected by real-time non-invasive imaging, due to the transparent nature of the ocular media, potentially allowing an earlier diagnosis as well as monitoring disease progression and treatment outcome. Animal models are essential for AD research, and this review has a focus on retinal changes in various transgenic AD mouse models with retinal imaging and immunohistochemical analysis as well as therapeutic effects in those models. We also discuss the limitations of transgenic AD models in clinical translations.
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Affiliation(s)
- Li Guo
- Glaucoma & Retinal Neurodegeneration Research Group, Institute of Ophthalmology, University College London, London, United Kingdom
| | - Nivedita Ravindran
- Glaucoma & Retinal Neurodegeneration Research Group, Institute of Ophthalmology, University College London, London, United Kingdom
| | - Ehtesham Shamsher
- Glaucoma & Retinal Neurodegeneration Research Group, Institute of Ophthalmology, University College London, London, United Kingdom
| | - Daniel Hill
- Glaucoma & Retinal Neurodegeneration Research Group, Institute of Ophthalmology, University College London, London, United Kingdom
| | - M Francesca Cordeiro
- Glaucoma & Retinal Neurodegeneration Research Group, Institute of Ophthalmology, University College London, London, United Kingdom
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Vandenabeele M, Veys L, Lemmens S, Hadoux X, Gelders G, Masin L, Serneels L, Theunis J, Saito T, Saido TC, Jayapala M, De Boever P, De Strooper B, Stalmans I, van Wijngaarden P, Moons L, De Groef L. The App NL-G-F mouse retina is a site for preclinical Alzheimer's disease diagnosis and research. Acta Neuropathol Commun 2021; 9:6. [PMID: 33407903 PMCID: PMC7788955 DOI: 10.1186/s40478-020-01102-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 12/13/2020] [Indexed: 12/13/2022] Open
Abstract
In this study, we report the results of a comprehensive phenotyping of the retina of the AppNL-G-F mouse. We demonstrate that soluble Aβ accumulation is present in the retina of these mice early in life and progresses to Aβ plaque formation by midlife. This rising Aβ burden coincides with local microglia reactivity, astrogliosis, and abnormalities in retinal vein morphology. Electrophysiological recordings revealed signs of neuronal dysfunction yet no overt neurodegeneration was observed and visual performance outcomes were unaffected in the AppNL-G-F mouse. Furthermore, we show that hyperspectral imaging can be used to quantify retinal Aβ, underscoring its potential as a biomarker for AD diagnosis and monitoring. These findings suggest that the AppNL-G-F retina mimics the early, preclinical stages of AD, and, together with retinal imaging techniques, offers unique opportunities for drug discovery and fundamental research into preclinical AD.
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Affiliation(s)
- Marjan Vandenabeele
- Neural Circuit Development and Regeneration Research Group, Department of Biology, University of Leuven (KU Leuven), Naamsestraat 61, Box 2464, 3000, Leuven, Belgium
- Leuven Brain Institute, Leuven, Belgium
| | - Lien Veys
- Neural Circuit Development and Regeneration Research Group, Department of Biology, University of Leuven (KU Leuven), Naamsestraat 61, Box 2464, 3000, Leuven, Belgium
- Leuven Brain Institute, Leuven, Belgium
| | - Sophie Lemmens
- Department of Ophthalmology, University Hospitals Leuven, Leuven, Belgium
- Research Group Ophthalmology, Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Xavier Hadoux
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia
- Ophthalmology, Department of Surgery, University of Melbourne, Parkville, Australia
| | - Géraldine Gelders
- Neural Circuit Development and Regeneration Research Group, Department of Biology, University of Leuven (KU Leuven), Naamsestraat 61, Box 2464, 3000, Leuven, Belgium
- Leuven Brain Institute, Leuven, Belgium
| | - Luca Masin
- Neural Circuit Development and Regeneration Research Group, Department of Biology, University of Leuven (KU Leuven), Naamsestraat 61, Box 2464, 3000, Leuven, Belgium
- Leuven Brain Institute, Leuven, Belgium
| | - Lutgarde Serneels
- Leuven Brain Institute, Leuven, Belgium
- Center for Brain and Disease Research, Flemish Institute for Biotechnology (VIB), Leuven, Belgium
- Laboratory for the Research of Neurodegenerative Diseases, Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Jan Theunis
- Health Unit, Flemish Institute for Technological Research (VITO), Mol, Belgium
| | - Takashi Saito
- Laboratory for Proteolytic Neuroscience, RIKEN Center for Brain Science, Saitama, Japan
- Department of Neurocognitive Science, Institute of Brain Science, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
- Interuniversity Microelectronics Centre (Imec), Leuven, Belgium
| | - Takaomi C Saido
- Laboratory for Proteolytic Neuroscience, RIKEN Center for Brain Science, Saitama, Japan
| | - Murali Jayapala
- Interuniversity Microelectronics Centre (Imec), Leuven, Belgium
| | - Patrick De Boever
- Center for Brain and Disease Research, Flemish Institute for Biotechnology (VIB), Leuven, Belgium
- Laboratory for the Research of Neurodegenerative Diseases, Department of Neurosciences, KU Leuven, Leuven, Belgium
- Center of Environmental Sciences, Hasselt University, Diepenbeek, Belgium
- Department of Biology, University of Antwerp, Wilrijk, Belgium
| | - Bart De Strooper
- Leuven Brain Institute, Leuven, Belgium
- Center for Brain and Disease Research, Flemish Institute for Biotechnology (VIB), Leuven, Belgium
- Laboratory for the Research of Neurodegenerative Diseases, Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Ingeborg Stalmans
- Department of Ophthalmology, University Hospitals Leuven, Leuven, Belgium
- Research Group Ophthalmology, Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Peter van Wijngaarden
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia
- Ophthalmology, Department of Surgery, University of Melbourne, Parkville, Australia
| | - Lieve Moons
- Neural Circuit Development and Regeneration Research Group, Department of Biology, University of Leuven (KU Leuven), Naamsestraat 61, Box 2464, 3000, Leuven, Belgium
- Leuven Brain Institute, Leuven, Belgium
| | - Lies De Groef
- Neural Circuit Development and Regeneration Research Group, Department of Biology, University of Leuven (KU Leuven), Naamsestraat 61, Box 2464, 3000, Leuven, Belgium.
- Leuven Brain Institute, Leuven, Belgium.
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Chua J, Hu Q, Ke M, Tan B, Hong J, Yao X, Hilal S, Venketasubramanian N, Garhöfer G, Cheung CY, Wong TY, Chen CLH, Schmetterer L. Retinal microvasculature dysfunction is associated with Alzheimer's disease and mild cognitive impairment. ALZHEIMERS RESEARCH & THERAPY 2020; 12:161. [PMID: 33276820 PMCID: PMC7718666 DOI: 10.1186/s13195-020-00724-0] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 11/10/2020] [Indexed: 12/20/2022]
Abstract
Background The retina and brain share many neuronal and vasculature characteristics. We investigated the retinal microvasculature in Alzheimer’s disease (AD) and mild cognitive impairment (MCI) using optical coherence tomography angiography (OCTA). Methods In this cross-sectional study, 24 AD participants, 37 MCI participants, and 29 controls were diagnosed according to internationally accepted criteria. OCTA images of the superficial and deep capillary plexus (SCP, DCP) of the retinal microvasculature were obtained using a commercial OCTA system (Zeiss Cirrus HD-5000 with AngioPlex, Carl Zeiss Meditec, Dublin, CA). The main outcome measures were vessel density (VD) and fractal dimension (FD) in the SCP and DCP within a 2.5-mm ring around the fovea which were compared between groups. Perfusion density of large vessels and foveal avascular zone (FAZ) area were additional outcome parameters. Results Age, gender, and race did not differ among groups. However, there was a significant difference in diabetes status (P = 0.039) and systolic blood pressure (P = 0.008) among the groups. After adjusting for confounders, AD participants showed significantly decreased VD in SCP and DCP (P = 0.006 and P = 0.015, respectively) and decreased FD in SCP (P = 0.006), compared to controls. MCI participants showed significantly decreased VD and FD only in SCP (P = 0.006 and P < 0.001, respectively) and not the DCP (P > 0.05) compared with controls. There was no difference in the OCTA variables between AD and MCI (P > 0.05). Perfusion density of large vessels and FAZ area did not differ significantly between groups (P > 0.05). Conclusions and relevance Eyes of patients with AD have significantly reduced macular VD in both plexuses whereas MCI participants only showed reduction in the superficial plexus. Changes in the retinal microvasculature and capillary network may offer a valuable insight on the brain in AD. Supplementary information The online version contains supplementary material available at 10.1186/s13195-020-00724-0.
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Affiliation(s)
- Jacqueline Chua
- Singapore Eye Research Institute, Singapore National Eye Centre, 20 College Road, The Academia, Level 6, Discovery Tower, Singapore, 169856, Singapore.,Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Medical School, National University of Singapore, Sha Tin, Singapore.,SERI-NTU Advanced Ocular Engineering (STANCE), Sha Tin, Singapore
| | - Qinglan Hu
- Singapore Eye Research Institute, Singapore National Eye Centre, 20 College Road, The Academia, Level 6, Discovery Tower, Singapore, 169856, Singapore.,SERI-NTU Advanced Ocular Engineering (STANCE), Sha Tin, Singapore
| | - Mengyuan Ke
- Singapore Eye Research Institute, Singapore National Eye Centre, 20 College Road, The Academia, Level 6, Discovery Tower, Singapore, 169856, Singapore.,SERI-NTU Advanced Ocular Engineering (STANCE), Sha Tin, Singapore
| | - Bingyao Tan
- Singapore Eye Research Institute, Singapore National Eye Centre, 20 College Road, The Academia, Level 6, Discovery Tower, Singapore, 169856, Singapore.,SERI-NTU Advanced Ocular Engineering (STANCE), Sha Tin, Singapore.,Institute for Health Technologies, Nanyang Technological University, Sha Tin, Singapore
| | - Jimmy Hong
- Singapore Eye Research Institute, Singapore National Eye Centre, 20 College Road, The Academia, Level 6, Discovery Tower, Singapore, 169856, Singapore
| | - Xinwen Yao
- Singapore Eye Research Institute, Singapore National Eye Centre, 20 College Road, The Academia, Level 6, Discovery Tower, Singapore, 169856, Singapore.,SERI-NTU Advanced Ocular Engineering (STANCE), Sha Tin, Singapore.,Institute for Health Technologies, Nanyang Technological University, Sha Tin, Singapore
| | - Saima Hilal
- Memory Aging and Cognition Centre, Departments of Pharmacology and Psychological Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Sha Tin, Singapore.,Saw Swee Hock School of Public Health, National University of Singapore, Sha Tin, Singapore.,Department of Pharmacology, National University of Singapore, Singapore, Singapore
| | - Narayanaswamy Venketasubramanian
- Memory Aging and Cognition Centre, Departments of Pharmacology and Psychological Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Sha Tin, Singapore.,Raffles Neuroscience Centre, Raffles Hospital, Singapore, Singapore
| | - Gerhard Garhöfer
- Department of Clinical Pharmacology, Medical University Vienna, Vienna, Austria
| | - Carol Y Cheung
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Sha Tin, Hong Kong
| | - Tien Yin Wong
- Singapore Eye Research Institute, Singapore National Eye Centre, 20 College Road, The Academia, Level 6, Discovery Tower, Singapore, 169856, Singapore.,Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Medical School, National University of Singapore, Sha Tin, Singapore
| | - Christopher Li-Hsian Chen
- Memory Aging and Cognition Centre, Departments of Pharmacology and Psychological Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Sha Tin, Singapore
| | - Leopold Schmetterer
- Singapore Eye Research Institute, Singapore National Eye Centre, 20 College Road, The Academia, Level 6, Discovery Tower, Singapore, 169856, Singapore. .,Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Medical School, National University of Singapore, Sha Tin, Singapore. .,SERI-NTU Advanced Ocular Engineering (STANCE), Sha Tin, Singapore. .,Institute for Health Technologies, Nanyang Technological University, Sha Tin, Singapore. .,Department of Clinical Pharmacology, Medical University Vienna, Vienna, Austria. .,Center for Medical Physics and Biomedical Engineering, Medical University Vienna, Vienna, Austria. .,Institute of Molecular and Clinical Ophthalmology, Basel, Switzerland.
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Ganglion Cell Layer Thinning in Alzheimer's Disease. ACTA ACUST UNITED AC 2020; 56:medicina56100553. [PMID: 33096909 PMCID: PMC7590216 DOI: 10.3390/medicina56100553] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 10/08/2020] [Accepted: 10/19/2020] [Indexed: 12/13/2022]
Abstract
The main advantages of optical retinal imaging may allow researchers to achieve deeper analysis of retinal ganglion cells (GC) in vivo using optical coherence tomography (OCT). Using this device to elucidate the impact of Alzheimer’s disease (AD) on retinal health with the aim to identify a new AD biomarker, a large amount of studies has analyzed GC in different stages of the disease. Our review highlights recent knowledge into measuring retinal morphology in AD making distinctive between whether those studies included patients with clinical dementia stage or also mild cognitive impairment (MCI), which selection criteria were applied to diagnosed patients included, and which device of OCT was employed. Despite several differences, previous works found a significant thinning of GC layer in patients with AD and MCI. In the long term, an important future direction is to achieve a specific ocular biomarker with enough sensitivity to reveal preclinical AD disorder and to monitor progression.
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Evaluation of choroidal thickness in prodromal Alzheimer's disease defined by amyloid PET. PLoS One 2020; 15:e0239484. [PMID: 32956392 PMCID: PMC7505462 DOI: 10.1371/journal.pone.0239484] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 09/07/2020] [Indexed: 12/27/2022] Open
Abstract
Objective To assess and compare the involvement of choroidal thickness (CT) in patients with mild cognitive impairment (MCI) and dementia due to Alzheimer’s disease (AD) defined by amyloid PET and healthy controls (HC). Methods Sixty-three eyes from 34 AD patients [12 eyes (19.0%) with dementia and 51 eyes (80.9%) with MCI], positive to 11C-labelled Pittsburgh Compound-B with positron emission tomography (11C-PiB PET/CT), and the same number of sex- and age-paired HC were recruited. All participants underwent enhanced depth imaging optical coherence tomography (EDI-OCT) assessing CT at 14 measurements from 2 B-scans. Paired Student t-test was used to compare CT measurements between MCI, dementia and sex- and age-paired HC. A univariate generalized estimating equations model (GEE) test was performed to compare MCI and dementia individually with all HC included. Results Compared with HC, eyes from patients with positive 11C-PiB PET/CT showed a significant CT thinning in 5 selected locations (in foveal thickness in vertical scan, in temporal scan at 1500μm, in superior scan at 500μm and in inferior scan at 1000μm and 1500μm, p = 0.020–0.045) whilst few significant CT reduction data was reported in MCI or dementia individually versus HC. However, the GEE test identified significant CT thinning in AD compared with all HC included (p = 0.015–0.046). Conclusions To our knowledge, the present study is the first measuring CT in eyes from MCI and dementia eyes positive to 11C-PiB PET/CT reporting a significant trend towards CT thinning in MCI patients which became more pronounced in dementia stage. We support further investigation involving larger and prospective OCT studies in AD population characterized with available biomarkers to describe whether choroidal vascular damage occurs specifically in prodromal stages of AD.
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Means JC, Lopez AA, Koulen P. Resveratrol Protects Optic Nerve Head Astrocytes from Oxidative Stress-Induced Cell Death by Preventing Caspase-3 Activation, Tau Dephosphorylation at Ser 422 and Formation of Misfolded Protein Aggregates. Cell Mol Neurobiol 2020; 40:911-926. [PMID: 31919747 PMCID: PMC7299779 DOI: 10.1007/s10571-019-00781-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Accepted: 12/23/2019] [Indexed: 12/19/2022]
Abstract
Optic nerve head astrocytes (ONHAs) are the major cell type within the optic nerve head, providing both structural and nutrient support to the optic nerve. Astrocytes are necessary for the survival of neurons with controlled activation of astrocytes being beneficial to neurons. However, overactive astrocytes can be harmful and the loss of normal astrocyte function can be a primary contributor to neurodegeneration. The neuroprotective properties of reactive astrocytes can be lost or they might gain neurotoxic properties in neurodegenerative diseases. The activated astrocytes are crucial in the development of glaucoma, where they serve as a source for cytotoxic substances that participate in ganglion apoptosis. There is increasing evidence indicating that neuroinflammation is an important process in glaucoma. Under pathological conditions, astrocytes can induce an inflammatory response. Extensive evidence shows that inflammatory responses mediated by astrocytes can also influence pathology development, synapse health, and neurodegeneration. The elimination of activated astrocytes by apoptosis is also expected in unfavorable conditions. In neurodegenerative diseases, a common feature is the presence of aggregates found in astrocytes, which can disrupt astrocyte function in such a way as to be detrimental to the viability of neurons. The biological processes involved in vision loss in glaucoma are not well understood. Despite the rapid advances in our understanding of optic nerve head (ONH) structure and function, numerous potential contributions of the ONHAs to optic nerve damage remain unanswered. The present study investigated the role of ONHAs during oxidative stress in order to determine novel cell biological processes underlying glaucoma pathogenesis. ONHAs were exposed to chemically induced oxidative stress using tert-butyl hydroperoxide (tBHP) in order to model extracellular oxidative stress as it occurs in the glaucomatous retina and ONH. In order to determine the impact of an intervention approach employing potential glioprotective treatments for central nervous system tissue we pretreated cells with the polyphenolic phytostilbene and antioxidant trans-resveratrol (3,5,4'-trihydroxy-trans-stilbene). ONHAs exposed to tBHP-mediated oxidative stress displayed decreased viability and underwent apoptosis. In addition, increased levels of activated caspases, dephosphorylation of Tau protein at Ser422, an important site adjacent to the caspase cleavage site controlling Tau cleavage, caspase-mediated Tau cleavage, and cytoskeletal changes, specifically formation of neurofibrillary tangles (NFTs) were detected in ONHAs undergoing oxidative stress. When cells were pretreated with resveratrol cell viability increased along with a significant decrease in activated caspases, cleaved Tau, and NFT formation. Taken together, ONHAs appear to act similar to neurons when undergoing oxidative stress, where proteolytic cleavage of Tau by caspases leads to NFT formation. In addition, resveratrol appears to have promise as a potential protective treatment preventing ONHA dysfunction and degeneration. There is currently no cure for glaucoma or a neuro- and glioprotective treatment that directly targets the pathogenic mechanisms in the glaucomatous retina and optic nerve. The present study identified a potential mechanism underlying degeneration of astrocytes that is susceptible to pharmaco-therapeutic intervention in the eye and potentially elsewhere in the central nervous system. Identification of such mechanisms involved in glaucoma and other disorders of the eye and brain is critical to determine novel targets for effective therapies.
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Affiliation(s)
- John C Means
- Vision Research Center, Department of Ophthalmology, School of Medicine, University of Missouri -Kansas City, 2411 Holmes St, Kansas City, MO, 64108, USA
| | - Adam A Lopez
- Vision Research Center, Department of Ophthalmology, School of Medicine, University of Missouri -Kansas City, 2411 Holmes St, Kansas City, MO, 64108, USA
| | - Peter Koulen
- Vision Research Center, Department of Ophthalmology, School of Medicine, University of Missouri -Kansas City, 2411 Holmes St, Kansas City, MO, 64108, USA.
- Department of Biomedical Sciences, School of Medicine, University of Missouri -Kansas City, 2411 Holmes St, Kansas City, MO, 64108, USA.
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Microglial Activation in the Retina of a Triple-Transgenic Alzheimer's Disease Mouse Model (3xTg-AD). Int J Mol Sci 2020; 21:ijms21030816. [PMID: 32012676 PMCID: PMC7038053 DOI: 10.3390/ijms21030816] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 01/24/2020] [Accepted: 01/25/2020] [Indexed: 12/26/2022] Open
Abstract
Alzheimer’s disease (AD) is the most common type of dementia in the world. The main biomarkers associated with AD are protein amyloid-β (Aβ) plaques and protein tau neurofibrillary tangles, which are responsible for brain neuroinflammation mediated by microglial cells. Increasing evidence has shown that the retina can also be affected in AD, presenting some molecular and cellular changes in the brain, such as microglia activation. However, there are only a few studies assessing such changes in the retinal microglia in animal models of AD. These studies use retinal sections, which have some limitations. In this study, we performed, for the first time in a triple-transgenic AD mouse model (3xTg-AD), a quantitative morphometric analysis of microglia activation (using the anti-Iba-1 antibody) in retinal whole-mounts, allowing visualization of the entire microglial cell, as well as its localization along the extension of the retina in different layers. Compared to age-matched animals, the retina of 3xTg-AD mice presents a higher number of microglial cells and a thicker microglial cell body area. Moreover, the microglia migrate, reorient, and retract their processes, changing their localization from a parallel to a perpendicular position relative to the retinal surface. These findings demonstrate clear microglia remodeling in the retina of 3xTg-AD mice.
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11
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Kwak DE, Ko T, Koh HS, Ji YW, Shin J, Kim K, Kim HY, Lee HK, Kim Y. Alterations of aqueous humor Aβ levels in Aβ-infused and transgenic mouse models of Alzheimer disease. PLoS One 2020; 15:e0227618. [PMID: 31923257 PMCID: PMC6953883 DOI: 10.1371/journal.pone.0227618] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 12/23/2019] [Indexed: 12/17/2022] Open
Abstract
Alzheimer's disease (AD) is an ageing-related neurodegenerative disease characterized and diagnosed by deposition of insoluble amyloid-β (Aβ) plaques in the brain. The plaque accumulation in the brain directly affects reduced levels of Aβ in cerebrospinal fluid (CSF) and blood, as Aβ can freely transport the blood-brain barrier, and clinical investigations have suggested these two biofluids as promising samples for in vitro diagnosis. Given that the human eye structurally resembles the brain and Aβ accumulation often observed in the ocular region of AD patients, in this study, we examined aqueous humor Aβ as another possible surrogate biomarker. First, using the acute Aβ-infused AD mouse model by injecting Aβ to the CSF in intracerebroventricular region of normal ICR mice, we investigated whether Aβ concentration in the aqueous humor in AD models is positively correlated with the concentration in the CSF. Then, we examined the correlation of aqueous humor Aβ levels with increased plaque deposition in the brain and reduced Aβ levels in both CSF and blood in adult and aged 5XFAD Alzheimer transgenic mice. Collectively, the synthetic Aβ injected into CSF immediately migrate to the aqueous humor, however, the age-dependently reducing pattern of Aβ levels in CSF and blood was not observed in the aqueous humor.
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Affiliation(s)
- Da Eun Kwak
- Department of Pharmacy, Yonsei University, Incheon, Republic of Korea
- Yonsei Institute of Pharmaceutical Sciences, Yonsei University, Incheon, Republic of Korea
| | - Taeho Ko
- Department of Pharmacy, Yonsei University, Incheon, Republic of Korea
- Industrial Pharmaceutical Sciences, Yonsei University, Incheon, Republic of Korea
| | - Han Seok Koh
- Department of Ophthalmology, Institute of Vision Research, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Yong Woo Ji
- Department of Ophthalmology, Institute of Vision Research, Yonsei University College of Medicine, Seoul, Republic of Korea
- Department of Ophthalmology, National Health Insurance Service Ilsan Hospital, Goyang, Republic of Korea
| | - Jisu Shin
- Department of Pharmacy, Yonsei University, Incheon, Republic of Korea
- Yonsei Institute of Pharmaceutical Sciences, Yonsei University, Incheon, Republic of Korea
| | - Kyeonghwan Kim
- Department of Pharmacy, Yonsei University, Incheon, Republic of Korea
- Yonsei Institute of Pharmaceutical Sciences, Yonsei University, Incheon, Republic of Korea
| | - Hye Yun Kim
- Department of Pharmacy, Yonsei University, Incheon, Republic of Korea
- Yonsei Institute of Pharmaceutical Sciences, Yonsei University, Incheon, Republic of Korea
| | - Hyung-Keun Lee
- Department of Ophthalmology, Institute of Vision Research, Yonsei University College of Medicine, Seoul, Republic of Korea
- * E-mail: (HKL); (YSK)
| | - YoungSoo Kim
- Department of Pharmacy, Yonsei University, Incheon, Republic of Korea
- Yonsei Institute of Pharmaceutical Sciences, Yonsei University, Incheon, Republic of Korea
- Industrial Pharmaceutical Sciences, Yonsei University, Incheon, Republic of Korea
- Integrated Science and Engineering Division, Yonsei University, Incheon, Republic of Korea
- * E-mail: (HKL); (YSK)
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12
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Georgevsky D, Retsas S, Raoufi N, Shimoni O, Golzan SM. A longitudinal assessment of retinal function and structure in the APP/PS1 transgenic mouse model of Alzheimer's disease. Transl Neurodegener 2019; 8:30. [PMID: 31592131 PMCID: PMC6774218 DOI: 10.1186/s40035-019-0170-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Accepted: 08/19/2019] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND A great body of evidence suggests that there are retinal functional and structural changes that occur in Alzheimer's disease (AD). However, whether such changes are primary or secondary remains to be elucidated. We studied a range of retinal functional and structural parameters in association with AD- specific pathophysiological markers in the double transgenic APP/PS1 and control mice across age. METHODS Electroretinogram (ERG) and optical coherence tomography (OCT) was performed in APP/PS1 and wild type (WT) control mice every 3 months from 3 to 12 months of age. For functional assessment, the a- and b-wave of the ERG, amplitude of oscillatory potentials (OP) and the positive scotopic threshold response (pSTR) were quantified at each time point. For structural assessment, the inner and outer retinal thickness was segmented and measured from OCT scans. Episodic memory was evaluated at 6, 9 and 12 months of age using the novel object recognition test. Amyloid beta (Aβ) distribution in the hippocampus and the retina were visualised at 3, 6 and 12 months of age. Inter- and intra- group analysis was performed to study rate of change for each parameter between the two groups. RESULTS Inter-group analysis revealed a significant difference in b-wave and OPs of APP/PS1 compared to WT controls starting from 3 months (p < 0.001). There was also a significant difference in the amplitude of pSTR between the two groups starting from 6 months (p < 0.001). Furthermore, a significant difference in the inner retinal thickness, between the two groups, was observed starting from 9 months (p < 0.001). CONCLUSIONS We observed an age-related decline in retinal functional and structural parameters in both APP/PS1 and WT controls, however, inter-group analysis revealed that inner retinal functional and structural decline is exacerbated in APP/PS1 mice, and that retinal functional changes precede structural changes in this strain. Further studies are required to confirm whether such phenomenon occurs in humans and if studying retinal functional changes can aid-in early assessment of AD.
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Affiliation(s)
- Dana Georgevsky
- Vision Science group, Graduate School of Health (Orthoptics Discipline), University of Technology Sydney, 15 Broadway, Ultimo, Sydney, NSW 2007 Australia
| | - Stephanie Retsas
- Vision Science group, Graduate School of Health (Orthoptics Discipline), University of Technology Sydney, 15 Broadway, Ultimo, Sydney, NSW 2007 Australia
| | - Newsha Raoufi
- Vision Science group, Graduate School of Health (Orthoptics Discipline), University of Technology Sydney, 15 Broadway, Ultimo, Sydney, NSW 2007 Australia
- Institute of Biomedical Materials & Devices (IBMD), Faculty of Science, University of Technology Sydney, 15 Broadway, Ultimo, Sydney, NSW 2007 Australia
| | - Olga Shimoni
- Institute of Biomedical Materials & Devices (IBMD), Faculty of Science, University of Technology Sydney, 15 Broadway, Ultimo, Sydney, NSW 2007 Australia
| | - S. Mojtaba Golzan
- Vision Science group, Graduate School of Health (Orthoptics Discipline), University of Technology Sydney, 15 Broadway, Ultimo, Sydney, NSW 2007 Australia
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13
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Yap T, Shamsher E, Guo L, Cordeiro M. Ophthalmic Research Lecture 2018: DARC as a Potential Surrogate Marker. Ophthalmic Res 2019; 63:1-7. [DOI: 10.1159/000500527] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 04/15/2019] [Indexed: 11/19/2022]
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14
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Fernández-Albarral JA, Salobrar-García E, Martínez-Páramo R, Ramírez AI, de Hoz R, Ramírez JM, Salazar JJ. Retinal glial changes in Alzheimer's disease - A review. JOURNAL OF OPTOMETRY 2019; 12:198-207. [PMID: 30377086 PMCID: PMC6612028 DOI: 10.1016/j.optom.2018.07.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 07/11/2018] [Accepted: 07/13/2018] [Indexed: 05/17/2023]
Abstract
Alzheimer's disease (AD) is a neurodegenerative dementia characterized by the deposition of extracellular β-amyloid (Aβ) plaques and the presence of neurofibrillary tangles. Until now, the techniques used to analyze these deposits have been difficult to access, invasive, and expensive. This leads us to consider new access routes to the central nervous system (CNS), allowing us to diagnose the disease before the first symptoms appear. Recent studies have shown that microglial and macroglial cell activation could play a role in the development of this disease. Glial cells in the CNS can respond to various damages, such as neurodegenerative pathologies, with morphological and functional changes. These changes are a common feature in neurodegenerative diseases, including AD. The retina is considered an extension of the CNS and has a population of glial cells similar to that of the CNS. When glial cells are activated, various molecules are released and changes in glial cell expression occur, which can be indicators of neuronal damage. The objective of this review is to compile the most relevant findings in the last 10 years relating to alterations in the eye in AD, and the role that glial cells play in the degenerative process in the retina in the context of neurodegeneration.
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Affiliation(s)
- José A Fernández-Albarral
- Instituto de Investigaciones Oftalmológicas Ramón Castroviejo, Universidad Complutense de Madrid, Spain
| | - Elena Salobrar-García
- Instituto de Investigaciones Oftalmológicas Ramón Castroviejo, Universidad Complutense de Madrid, Spain
| | - Rebeca Martínez-Páramo
- Instituto de Investigaciones Oftalmológicas Ramón Castroviejo, Universidad Complutense de Madrid, Spain
| | - Ana I Ramírez
- Instituto de Investigaciones Oftalmológicas Ramón Castroviejo, Universidad Complutense de Madrid, Spain; Facultad de Óptica y Optometría, Departamento de Inmunología, Oftalmología y ORL, Universidad Complutense de Madrid, Spain
| | - Rosa de Hoz
- Instituto de Investigaciones Oftalmológicas Ramón Castroviejo, Universidad Complutense de Madrid, Spain; Facultad de Óptica y Optometría, Departamento de Inmunología, Oftalmología y ORL, Universidad Complutense de Madrid, Spain
| | - José M Ramírez
- Instituto de Investigaciones Oftalmológicas Ramón Castroviejo, Universidad Complutense de Madrid, Spain; Facultad de Medicina, Departamento de Inmunología, Oftalmología y ORL, Universidad Complutense de Madrid, Spain.
| | - Juan J Salazar
- Instituto de Investigaciones Oftalmológicas Ramón Castroviejo, Universidad Complutense de Madrid, Spain; Facultad de Óptica y Optometría, Departamento de Inmunología, Oftalmología y ORL, Universidad Complutense de Madrid, Spain.
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15
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Ocular amyloid imaging at the crossroad of Alzheimer's disease and age-related macular degeneration: implications for diagnosis and therapy. J Neurol 2018; 266:1566-1577. [PMID: 30155741 DOI: 10.1007/s00415-018-9028-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 08/18/2018] [Accepted: 08/20/2018] [Indexed: 12/17/2022]
Abstract
Alzheimer's disease (AD) and age-related macular degeneration (AMD) are important disorders of aging, but significant challenges remain in diagnosis and therapy. Amyloid-beta (Aβ), found in the brain and a defining feature of AD, has also been observed in the retina in both AD and AMD. While current diagnostic modalities for detecting Aβ in the brain are costly or invasive, Aβ in the retina can be noninvasively and conveniently imaged using modern photonic imaging systems such as optical coherence tomography (OCT). Moreover, since many of these retinal changes occur before degenerative changes can be detected in the brain, ocular amyloid biomarkers could be utilized to detect AD as well as AMD in their earliest stages when therapy may be most effective in halting disease progression. Novel technologies to quantify retinal biomarkers have the potential to facilitate early diagnosis and noninvasive monitoring of disease progression with important therapeutic implications.
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16
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Rodriguez L, Mdzomba JB, Joly S, Boudreau-Laprise M, Planel E, Pernet V. Human Tau Expression Does Not Induce Mouse Retina Neurodegeneration, Suggesting Differential Toxicity of Tau in Brain vs. Retinal Neurons. Front Mol Neurosci 2018; 11:293. [PMID: 30197586 PMCID: PMC6117378 DOI: 10.3389/fnmol.2018.00293] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 08/03/2018] [Indexed: 02/03/2023] Open
Abstract
The implication of the microtubule-associated protein (MAP) Tau in the ocular manifestations of Alzheimer’s disease (AD) is elusive due to the lack of relevant animal model. However, signs of AD have been reported in the brain of transgenic mice expressing human Tau (hTau). To assess whether hTau is sufficient to induce AD pathogenesis in the retina as well, in the present study, we compared the retinal structure and function of KO mice deprived of Tau (mTKO) with those of transgenic mice expressing hTau. Our results revealed that hTau is particularly abundant in the inner nuclear layer (INL) cells of the retina. By electroretinogram (ERG) recording, light-induced retinal cell activation was not altered in hTau compared with mTKO littermates. Surprisingly, the ERG response mediated by cone photoreceptor stimulation was even stronger in hTau than in mTKO retinae. Immunofluorescent analysis of retinal sections allowed us to observe thicker inner retina in hTau than in mTKO eyes. By Western Blotting (WB), the upregulation of mTOR that was found in hTau mice may underlie retinal structure and function increases. Taken together, our results not only indicate that hTau expression is not toxic for retinal cells but they also suggest that it may play a positive role in visual physiology. The use of hTau may be envisaged to improve visual recovery in ocular diseases affecting the retinal function such as glaucoma or diabetic retinopathy.
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Affiliation(s)
- Léa Rodriguez
- CUO-Recherche, Centre de Recherche du CHU de Québec, Quebec, QC, Canada.,Département d'ophtalmologie, Faculté de Médecine, Université Laval, Quebec, QC, Canada
| | - Julius Baya Mdzomba
- CUO-Recherche, Centre de Recherche du CHU de Québec, Quebec, QC, Canada.,Département d'ophtalmologie, Faculté de Médecine, Université Laval, Quebec, QC, Canada
| | - Sandrine Joly
- CUO-Recherche, Centre de Recherche du CHU de Québec, Quebec, QC, Canada.,Département d'ophtalmologie, Faculté de Médecine, Université Laval, Quebec, QC, Canada
| | - Mélissa Boudreau-Laprise
- CUO-Recherche, Centre de Recherche du CHU de Québec, Quebec, QC, Canada.,Département d'ophtalmologie, Faculté de Médecine, Université Laval, Quebec, QC, Canada
| | - Emmanuel Planel
- Axe Neurosciences, Centre de Recherche du CHU de Québec, Quebec, QC, Canada.,Département de Psychiatrie et de Neurosciences, Faculté de Médecine, Université Laval, Quebec, QC, Canada
| | - Vincent Pernet
- CUO-Recherche, Centre de Recherche du CHU de Québec, Quebec, QC, Canada.,Département d'ophtalmologie, Faculté de Médecine, Université Laval, Quebec, QC, Canada
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17
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Liao H, Zhu Z, Peng Y. Potential Utility of Retinal Imaging for Alzheimer's Disease: A Review. Front Aging Neurosci 2018; 10:188. [PMID: 29988470 PMCID: PMC6024140 DOI: 10.3389/fnagi.2018.00188] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2018] [Accepted: 06/05/2018] [Indexed: 01/18/2023] Open
Abstract
The ensuing upward shift in demographic distribution due to the increase in life expectancy has resulted in a rising prevalence of Alzheimer's disease (AD). The heavy public burden of AD, along with the urgent to prevent and treat the disease before the irreversible damage to the brain, calls for a sensitive and specific screening technology to identify high-risk individuals before cognitive symptoms arise. Even though current modalities, such as positron emission tomography (PET) and cerebrospinal fluid (CSF) biomarker, showed their potential clinical uses in early detection of AD, the high cost, narrow isotope availability of PET probes and invasive characteristics of CSF biomarker limited their broad utility. Therefore, additional tools for detection of AD are needed. As a projection of the central nervous system (CNS), the retina has been described as a "window to the brain" and a novel marker for AD. Low cost, easy accessibility and non-invasive features make retina tests suitable for large-scale population screening and investigations of preclinical AD. Furthermore, a number of novel approaches in retina imaging, such as optical coherence tomography (OCT), have been developed and made it possible to visualize changes in the retina at a very fine resolution. In this review, we outline the background for AD to accelerate the adoption of retina imaging for the diagnosis and management of AD in clinical practice. Then, we focus on recent findings on the application of retina imaging to investigate AD and provide suggestions for future research directions.
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Affiliation(s)
- Huan Liao
- Department of Neurology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
| | - Zhuoting Zhu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Ying Peng
- Department of Neurology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
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18
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Abstract
Glaucoma is one of the leading causes of irreversible visual loss, which has been estimated to affect 3.5% of those over 40 years old and projected to affect a total of 112 million people by 2040. Such a dramatic increase in affected patients demonstrates the need for continual improvement in the way we diagnose and treat this condition. Annexin A5 is a 36 kDa protein that is ubiquitously expressed in humans and is studied as an indicator of apoptosis in several fields. This molecule has a high calcium-dependent affinity for phosphatidylserine, a cell membrane phospholipid externalized to the outer cell membrane in early apoptosis. The DARC (Detection of Apoptosing Retinal Cells) project uses fluorescently-labelled annexin A5 to assess glaucomatous degeneration, the inherent process of which is the apoptosis of retinal ganglion cells. Furthermore, this project has conducted investigation of the retinal apoptosis in the neurodegenerative conditions of the eye and brain. In this present study, we summarized the use of annexin A5 as a marker of apoptosis in the eye. We also relayed the progress of the DARC project, developing real-time imaging of retinal ganglion cell apoptosis in vivo from the experimental models of disease and identifying mechanisms underlying neurodegeneration and its treatments, which has been applied to the first human clinical trials. DARC has potential as a biomarker in neurodegeneration, especially in the research of novel treatments, and could be a useful tool for the diagnosis and monitoring of glaucoma.
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19
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Lad EM, Mukherjee D, Stinnett SS, Cousins SW, Potter GG, Burke JR, Farsiu S, Whitson HE. Evaluation of inner retinal layers as biomarkers in mild cognitive impairment to moderate Alzheimer's disease. PLoS One 2018; 13:e0192646. [PMID: 29420642 PMCID: PMC5805310 DOI: 10.1371/journal.pone.0192646] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Accepted: 01/26/2018] [Indexed: 12/12/2022] Open
Abstract
Inner retina in Alzheimer's Disease (AD) may experience neuroinflammation resulting in atrophy. The objective of our study was to determine whether retinal GCIPL (ganglion cell-inner plexiform layer) or nerve fiber layer (NFL) thickness may serve as noninvasive biomarkers to diagnose AD. This cross-sectional case-control study enrolled 15 mild cognitive impairment (MCI) patients, 15 mild-moderate AD patients, and 18 cognitively normal adults. NFL and GCIPL thicknesses on optical coherence tomography (OCT) were measured using Duke Optical Coherence Tomography Retinal Analysis Program (DOCTRAP) and Spectralis software. We demonstrated that regional thicknesses of NFL or GCIPL on macular or nerve OCTs did not differ between groups. However, a multi-variate regression analysis identified macular areas with a significant thickening or thinning in NFL and GCIPL in MCI and AD patients. Our primary findings controvert previous reports of thinner NFL in moderate-to-severe AD. The areas of thickening of GCIPL and NFL in the macula adjacent to areas of thinning, as revealed by a more complex statistical model, suggest that NFL and GCIPL may undergo dynamic changes during AD progression.
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Affiliation(s)
- Eleonora M. Lad
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Dibyendu Mukherjee
- Department of Biomedical Engineering, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Sandra S. Stinnett
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Scott W. Cousins
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Guy G. Potter
- Joseph and Kathleen Bryan Alzheimer's Disease Research Center, Durham, North Carolina, United States of America
| | - James R. Burke
- Joseph and Kathleen Bryan Alzheimer's Disease Research Center, Durham, North Carolina, United States of America
| | - Sina Farsiu
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina, United States of America
- Department of Biomedical Engineering, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Heather E. Whitson
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina, United States of America
- Department of Medicine, Duke University Medical Center, Durham, North Carolina, United States of America
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20
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Kusne Y, Wolf AB, Townley K, Conway M, Peyman GA. Visual system manifestations of Alzheimer's disease. Acta Ophthalmol 2017; 95:e668-e676. [PMID: 27864881 DOI: 10.1111/aos.13319] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 10/07/2016] [Indexed: 12/13/2022]
Abstract
Alzheimer's disease (AD) is an increasingly common disease with massive personal and economic costs. While it has long been known that AD impacts the visual system, there has recently been an increased focus on understanding both pathophysiological mechanisms that may be shared between the eye and brain and how related biomarkers could be useful for AD diagnosis. Here, were review pertinent cellular and molecular mechanisms of AD pathophysiology, the presence of AD pathology in the visual system, associated functional changes, and potential development of diagnostic tools based on the visual system. Additionally, we discuss links between AD and visual disorders, including possible pathophysiological mechanisms and their relevance for improving our understanding of AD.
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Affiliation(s)
- Yael Kusne
- University of Arizona College of Medicine; Phoenix Arizona USA
| | - Andrew B. Wolf
- University of Colorado School of Medicine; Aurora Colorado USA
| | - Kate Townley
- University of Arizona College of Medicine; Phoenix Arizona USA
| | - Mandi Conway
- University of Arizona College of Medicine; Phoenix Arizona USA
- Arizona Retinal Specialists; Sun City Arizona USA
| | - Gholam A. Peyman
- University of Arizona College of Medicine; Phoenix Arizona USA
- Arizona Retinal Specialists; Sun City Arizona USA
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21
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Ramirez AI, de Hoz R, Salobrar-Garcia E, Salazar JJ, Rojas B, Ajoy D, López-Cuenca I, Rojas P, Triviño A, Ramírez JM. The Role of Microglia in Retinal Neurodegeneration: Alzheimer's Disease, Parkinson, and Glaucoma. Front Aging Neurosci 2017; 9:214. [PMID: 28729832 PMCID: PMC5498525 DOI: 10.3389/fnagi.2017.00214] [Citation(s) in RCA: 297] [Impact Index Per Article: 42.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 06/16/2017] [Indexed: 12/12/2022] Open
Abstract
Microglia, the immunocompetent cells of the central nervous system (CNS), act as neuropathology sensors and are neuroprotective under physiological conditions. Microglia react to injury and degeneration with immune-phenotypic and morphological changes, proliferation, migration, and inflammatory cytokine production. An uncontrolled microglial response secondary to sustained CNS damage can put neuronal survival at risk due to excessive inflammation. A neuroinflammatory response is considered among the etiological factors of the major aged-related neurodegenerative diseases of the CNS, and microglial cells are key players in these neurodegenerative lesions. The retina is an extension of the brain and therefore the inflammatory response in the brain can occur in the retina. The brain and retina are affected in several neurodegenerative diseases, including Alzheimer's disease (AD), Parkinson's disease (PD), and glaucoma. AD is an age-related neurodegeneration of the CNS characterized by neuronal and synaptic loss in the cerebral cortex, resulting in cognitive deficit and dementia. The extracellular deposits of beta-amyloid (Aβ) and intraneuronal accumulations of hyperphosphorylated tau protein (pTau) are the hallmarks of this disease. These deposits are also found in the retina and optic nerve. PD is a neurodegenerative locomotor disorder with the progressive loss of dopaminergic neurons in the substantia nigra. This is accompanied by Lewy body inclusion composed of α-synuclein (α-syn) aggregates. PD also involves retinal dopaminergic cell degeneration. Glaucoma is a multifactorial neurodegenerative disease of the optic nerve, characterized by retinal ganglion cell loss. In this pathology, deposition of Aβ, synuclein, and pTau has also been detected in retina. These neurodegenerative diseases share a common pathogenic mechanism, the neuroinflammation, in which microglia play an important role. Microglial activation has been reported in AD, PD, and glaucoma in relation to protein aggregates and degenerated neurons. The activated microglia can release pro-inflammatory cytokines which can aggravate and propagate neuroinflammation, thereby degenerating neurons and impairing brain as well as retinal function. The aim of the present review is to describe the contribution in retina to microglial-mediated neuroinflammation in AD, PD, and glaucomatous neurodegeneration.
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Affiliation(s)
- Ana I. Ramirez
- Instituto de Investigaciones Oftalmológicas Ramón Castroviejo. Universidad Complutense de MadridMadrid, Spain
- Departamento de Oftalmología y ORL, Facultad de Óptica y Optometría, Universidad Complutense de Madrid (UCM)Madrid, Spain
| | - Rosa de Hoz
- Instituto de Investigaciones Oftalmológicas Ramón Castroviejo. Universidad Complutense de MadridMadrid, Spain
- Departamento de Oftalmología y ORL, Facultad de Óptica y Optometría, Universidad Complutense de Madrid (UCM)Madrid, Spain
| | - Elena Salobrar-Garcia
- Instituto de Investigaciones Oftalmológicas Ramón Castroviejo. Universidad Complutense de MadridMadrid, Spain
- Departamento de Oftalmología y ORL, Facultad de Medicina, Universidad Complutense de Madrid (UCM)Madrid, Spain
| | - Juan J. Salazar
- Instituto de Investigaciones Oftalmológicas Ramón Castroviejo. Universidad Complutense de MadridMadrid, Spain
- Departamento de Oftalmología y ORL, Facultad de Óptica y Optometría, Universidad Complutense de Madrid (UCM)Madrid, Spain
| | - Blanca Rojas
- Instituto de Investigaciones Oftalmológicas Ramón Castroviejo. Universidad Complutense de MadridMadrid, Spain
- Departamento de Oftalmología y ORL, Facultad de Medicina, Universidad Complutense de Madrid (UCM)Madrid, Spain
| | - Daniel Ajoy
- Instituto de Investigaciones Oftalmológicas Ramón Castroviejo. Universidad Complutense de MadridMadrid, Spain
| | - Inés López-Cuenca
- Instituto de Investigaciones Oftalmológicas Ramón Castroviejo. Universidad Complutense de MadridMadrid, Spain
| | - Pilar Rojas
- Instituto de Investigaciones Oftalmológicas Ramón Castroviejo. Universidad Complutense de MadridMadrid, Spain
- Servicio de Oftalmología, Hospital Gregorio MarañónMadrid, Spain
| | - Alberto Triviño
- Instituto de Investigaciones Oftalmológicas Ramón Castroviejo. Universidad Complutense de MadridMadrid, Spain
- Departamento de Oftalmología y ORL, Facultad de Medicina, Universidad Complutense de Madrid (UCM)Madrid, Spain
| | - José M. Ramírez
- Instituto de Investigaciones Oftalmológicas Ramón Castroviejo. Universidad Complutense de MadridMadrid, Spain
- Departamento de Oftalmología y ORL, Facultad de Medicina, Universidad Complutense de Madrid (UCM)Madrid, Spain
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22
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Hart NJ, Koronyo Y, Black KL, Koronyo-Hamaoui M. Ocular indicators of Alzheimer's: exploring disease in the retina. Acta Neuropathol 2016; 132:767-787. [PMID: 27645291 PMCID: PMC5106496 DOI: 10.1007/s00401-016-1613-6] [Citation(s) in RCA: 173] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 08/29/2016] [Accepted: 09/01/2016] [Indexed: 12/11/2022]
Abstract
Although historically perceived as a disorder confined to the brain, our understanding of Alzheimer's disease (AD) has expanded to include extra-cerebral manifestation, with mounting evidence of abnormalities in the eye. Among ocular tissues, the retina, a developmental outgrowth of the brain, is marked by an array of pathologies in patients suffering from AD, including nerve fiber layer thinning, degeneration of retinal ganglion cells, and changes to vascular parameters. While the hallmark pathological signs of AD, amyloid β-protein (Aβ) plaques and neurofibrillary tangles (NFT) comprising hyperphosphorylated tau (pTau) protein, have long been described in the brain, identification of these characteristic biomarkers in the retina has only recently been reported. In particular, Aβ deposits were discovered in post-mortem retinas of advanced and early stage cases of AD, in stark contrast to non-AD controls. Subsequent studies have reported elevated Aβ42/40 peptides, morphologically diverse Aβ plaques, and pTau in the retina. In line with the above findings, animal model studies have reported retinal Aβ deposits and tauopathy, often correlated with local inflammation, retinal ganglion cell degeneration, and functional deficits. This review highlights the converging evidence that AD manifests in the eye, especially in the retina, which can be imaged directly and non-invasively. Visual dysfunction in AD patients, traditionally attributed to well-documented cerebral pathology, can now be reexamined as a direct outcome of retinal abnormalities. As we continue to study the disease in the brain, the emerging field of ocular AD warrants further investigation of how the retina may faithfully reflect the neurological disease. Indeed, detection of retinal AD pathology, particularly the early presenting amyloid biomarkers, using advanced high-resolution imaging techniques may allow large-scale screening and monitoring of at-risk populations.
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Affiliation(s)
- Nadav J Hart
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, 127 S. San Vicente Blvd., Los Angeles, 90048, CA, USA
| | - Yosef Koronyo
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, 127 S. San Vicente Blvd., Los Angeles, 90048, CA, USA
| | - Keith L Black
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, 127 S. San Vicente Blvd., Los Angeles, 90048, CA, USA
| | - Maya Koronyo-Hamaoui
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, 127 S. San Vicente Blvd., Los Angeles, 90048, CA, USA.
- Department of Biomedical Sciences, Cedars-Sinai Medical Center, 110 George Burns Rd., Los Angeles, CA, 90048, USA.
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Choi SH, Park SJ, Kim NR. Macular Ganglion Cell -Inner Plexiform Layer Thickness Is Associated with Clinical Progression in Mild Cognitive Impairment and Alzheimers Disease. PLoS One 2016; 11:e0162202. [PMID: 27598262 PMCID: PMC5012569 DOI: 10.1371/journal.pone.0162202] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 08/18/2016] [Indexed: 01/30/2023] Open
Abstract
PURPOSE We investigated the association of the macular ganglion cell-inner plexiform layer (GCIPL) and peripapillary retinal nerve fiber layer (RNFL) thicknesses with disease progression in mild cognitive impairment (MCI) and Alzheimer's disease (AD). METHODS We recruited 42 patients with AD, 26 with MCI, and 66 normal elderly controls. The thicknesses of the RNFL and GCIPL were measured via spectral-domain optic coherent tomography in all participants at baseline. The patients with MCI or AD underwent clinical and neuropsychological tests at baseline and once every year thereafter for 2 years. RESULTS The Clinical Dementia Rating scale-Sum of Boxes (CDR-SB) score exhibited significant negative relationships with the average GCIPL thickness (β = -0.15, p < 0.05) and the GCIPL thickness in the superotemporal, superonasal, and inferonasal sectors. The composite memory score exhibited significant positive associations with the average GCIPL thickness and the GCIPL thickness in the superotemporal, inferonasal, and inferotemporal sectors. The temporal RNFL thickness, the average and minimum GCIPL thicknesses, and the GCIPL thickness in the inferonasal, inferior, and inferotemporal sectors at baseline were significantly reduced in MCI patients who were converted to AD compared to stable MCI patients. The change of CDR-SB from baseline to 2 years exhibited significant negative associations with the average (β = -0.150, p = 0.006) and minimum GCIPL thicknesses as well as GCIPL thickness in the superotemporal, superior, superonasal, and inferonasal sectors at baseline. CONCLUSIONS Our data suggest that macular GCIPL thickness represents a promising biomarker for monitoring the progression of MCI and AD.
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Affiliation(s)
- Seong Hye Choi
- Department of Neurology, Inha University School of Medicine, Incheon, Korea
| | - Sang Jun Park
- Department of Ophthalmology and Inha Vision Science Laboratory, Inha University School of Medicine, Incheon, Korea
| | - Na Rae Kim
- Department of Ophthalmology and Inha Vision Science Laboratory, Inha University School of Medicine, Incheon, Korea
- * E-mail:
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Masuzzo A, Dinet V, Cavanagh C, Mascarelli F, Krantic S. Amyloidosis in Retinal Neurodegenerative Diseases. Front Neurol 2016; 7:127. [PMID: 27551275 PMCID: PMC4976396 DOI: 10.3389/fneur.2016.00127] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Accepted: 07/27/2016] [Indexed: 01/18/2023] Open
Abstract
As a part of the central nervous system, the retina may reflect both physiological processes and abnormalities related to pathologies that affect the brain. Amyloidosis due to the accumulation of amyloid-beta (Aβ) was initially regarded as a specific and exclusive characteristic of neurodegenerative alterations seen in the brain of Alzheimer's disease (AD) patients. More recently, it was discovered that amyloidosis-related alterations, similar to those seen in the brain of Alzheimer's patients, also occur in the retina. Remarkably, these alterations were identified not only in primary retinal pathologies, such as age-related macular degeneration (AMD) and glaucoma, but also in the retinas of Alzheimer's patients. In this review, we first briefly discuss the biogenesis of Aβ, a peptide involved in amyloidosis. We then discuss some pathological aspects (synaptic dysfunction, mitochondrial failure, glial activation, and vascular abnormalities) related to the neurotoxic effects of Aβ. We finally highlight common features shared by AD, AMD, and glaucoma in the context of Aβ amyloidosis and further discuss why the retina, due to the transparency of the eye, can be considered as a "window" to the brain.
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Affiliation(s)
- Ambra Masuzzo
- Centre de Recherche des Cordeliers, Institut national de la santé et de la recherche médicale (INSERM), Université Paris Descartes, Sorbonne Paris Cité, UMR_S 1138, Université Pierre et Marie Curie Université Paris 06, Sorbonne Universités , Paris , France
| | - Virginie Dinet
- Centre de Recherche des Cordeliers, Institut national de la santé et de la recherche médicale (INSERM), Université Paris Descartes, Sorbonne Paris Cité, UMR_S 1138, Université Pierre et Marie Curie Université Paris 06, Sorbonne Universités , Paris , France
| | - Chelsea Cavanagh
- Department of Neuroscience, Douglas Hospital Research Center , Montreal, QC , Canada
| | - Frederic Mascarelli
- Centre de Recherche des Cordeliers, Institut national de la santé et de la recherche médicale (INSERM), Université Paris Descartes, Sorbonne Paris Cité, UMR_S 1138, Université Pierre et Marie Curie Université Paris 06, Sorbonne Universités , Paris , France
| | - Slavica Krantic
- Centre de Recherche des Cordeliers, Institut national de la santé et de la recherche médicale (INSERM), Université Paris Descartes, Sorbonne Paris Cité, UMR_S 1138, Université Pierre et Marie Curie Université Paris 06, Sorbonne Universités , Paris , France
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25
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Longitudinal live imaging of retinal α-synuclein::GFP deposits in a transgenic mouse model of Parkinson's Disease/Dementia with Lewy Bodies. Sci Rep 2016; 6:29523. [PMID: 27389831 PMCID: PMC4937425 DOI: 10.1038/srep29523] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 06/17/2016] [Indexed: 01/20/2023] Open
Abstract
Abnormal α-synuclein (α-syn) accumulation in the CNS may underlie neuronal cell and synaptic dysfunction leading to motor and cognitive deficits in synucleinopathies including Parkinson’s disease (PD) and Dementia with Lewy Bodies (DLB). Multiple groups demonstrated α-syn accumulation in CNS accessory structures, including the eyes and olfactory terminals, as well as in peripheral organs of Parkinsonian patients. Retinal imaging studies of mice overexpressing fused α-syn::GFP were conducted to evaluate the presence and progression of retinal pathology in a PD/DLB transgenic mouse model. Bright-field image retinal maps and fluorescent images were acquired at 1-month intervals for 3 months. Retinal imaging revealed the accumulation of GFP-tagged α-syn in retinal ganglion cell layer and in the edges of arterial blood vessels in the transgenic mice. Double labeling studies confirmed that the α-syn::GFP-positive cells were retinal ganglion cells containing α-syn. Accumulation of α-syn persisted in the same cells and increased with age. Accumulation of α-syn::GFP was reduced by immunization with single chain antibodies against α-syn. In conclusion, longitudinal live imaging of the retina in the PDGF-α-syn::GFP mice might represent a useful, non-invasive tool to monitor the fate of α-syn accumulation in the CNS and to evaluate the therapeutic effects of compounds targeting α-syn.
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26
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Javaid FZ, Brenton J, Guo L, Cordeiro MF. Visual and Ocular Manifestations of Alzheimer's Disease and Their Use as Biomarkers for Diagnosis and Progression. Front Neurol 2016; 7:55. [PMID: 27148157 PMCID: PMC4836138 DOI: 10.3389/fneur.2016.00055] [Citation(s) in RCA: 106] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 03/29/2016] [Indexed: 12/21/2022] Open
Abstract
Alzheimer's disease (AD) is the most common form of dementia affecting the growing aging population today, with prevalence expected to rise over the next 35 years. Clinically, patients exhibit a progressive decline in cognition, memory, and social functioning due to deposition of amyloid β (Aβ) protein and intracellular hyperphosphorylated tau protein. These pathological hallmarks of AD are measured either through neuroimaging, cerebrospinal fluid analysis, or diagnosed post-mortem. Importantly, neuropathological progression occurs in the eye as well as the brain, and multiple visual changes have been noted in both human and animal models of AD. The eye offers itself as a transparent medium to cerebral pathology and has thus potentiated the development of ocular biomarkers for AD. The use of non-invasive screening, such as retinal imaging and visual testing, may enable earlier diagnosis in the clinical setting, minimizing invasive and expensive investigations. It also potentially improves disease management and quality of life for AD patients, as an earlier diagnosis allows initiation of medication and treatment. In this review, we explore the evidence surrounding ocular changes in AD and consider the biomarkers currently in development for early diagnosis.
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Affiliation(s)
- Fatimah Zara Javaid
- Glaucoma and Retinal Degeneration Research Group, Visual Neurosciences, UCL Institute of Ophthalmology, London, UK
| | - Jonathan Brenton
- Glaucoma and Retinal Degeneration Research Group, Visual Neurosciences, UCL Institute of Ophthalmology, London, UK
| | - Li Guo
- Glaucoma and Retinal Degeneration Research Group, Visual Neurosciences, UCL Institute of Ophthalmology, London, UK
| | - Maria F. Cordeiro
- Glaucoma and Retinal Degeneration Research Group, Visual Neurosciences, UCL Institute of Ophthalmology, London, UK
- Western Eye Hospital, Imperial College Healthcare NHS Trust, London, UK
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27
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Choroidal Thickness in Patients with Mild Cognitive Impairment and Alzheimer's Type Dementia. J Ophthalmol 2016; 2016:7291257. [PMID: 26925259 PMCID: PMC4748862 DOI: 10.1155/2016/7291257] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Accepted: 12/08/2015] [Indexed: 02/02/2023] Open
Abstract
Aim. To asses both choroidal thickness differences among Alzheimer's type dementia (ATD) patients, mild cognitive impairment (MCI) patients, and healthy control (C) subjects and choroidal thickness relationships with cognitive performance. Methods. A total of 246 eyes of 123 people (41 ATD, 38 MCI, and 44 healthy C subjects) were included in this study. Complete ophthalmological and neurological examination was performed in all subjects. Choroidal thicknesses (CT) were measured at seven locations: the fovea, 500-1500-3000 μm temporal and 500-1500-3000 μm nasal to the fovea by enhanced depth imaging optical coherence tomography (EDI-OCT). Detailed neurological examination including mini mental state examination (MMSE) test which evaluates the cognitive function was applied to all participants. Results. The ages and genders of all participants were similar in all groups. Compared with healthy C subjects, the CT measurements at all regions were significantly thinner both in patients with ATD and in patients with MCI than in healthy C subjects (p < 0.05). The MMSE scores were significantly different among ATD patients, MCI patients, and healthy C subjects. They were 19.3 ± 1.8, 24.8 ± 0.9, and 27.6 ± 1.2 in ATD, MCI, and healthy controls, respectively (p < 0.001). There were also significant correlation between MMSE score and choroidal thickness at each location (p < 0.05). Conclusions. CT was reduced in ATD patients and MCI patients. Since vascular structures were affected in ATD patients and MCI patients, they had thin CT. Besides CT was correlated with degree of cognitive impairment. Therefore CT may be a new biomarker in diagnosis and follow-up of MCI and ATD patients.
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Kerbage C, Sadowsky CH, Tariot PN, Agronin M, Alva G, Turner FD, Nilan D, Cameron A, Cagle GD, Hartung PD. Detection of Amyloid β Signature in the Lens and Its Correlation in the Brain to Aid in the Diagnosis of Alzheimer's Disease. Am J Alzheimers Dis Other Demen 2015; 30:738-45. [PMID: 24526759 PMCID: PMC10852881 DOI: 10.1177/1533317513520214] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2024]
Abstract
We report the findings from a clinical trial in which a group of patients clinically diagnosed with probable Alzheimer's disease (AD) were discriminated from an age-matched group of healthy volunteers (HVs) with statistical significance (P<.001). The results from 20 patients with AD and 20 HVs were obtained by a Fluorescent Ligand Eye Scanning (FLES) technique that measures a fluorescent signature specific to an exogenous ligand bound to amyloid-β in the lens of the eye. Sensitivity and specificity of 85% and 95%, respectively, have been achieved in predicting clinical diagnosis. Additionally, amyloid brain imaging using florbetapir F18 positron emission tomography shows significant correlation with the results obtained in the eye. Results of the study demonstrate the safety of the FLES system.
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Affiliation(s)
| | - Carl H Sadowsky
- Premiere Research Institute and Nova Southeastern University, West Palm Beach, FL, USA
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29
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Jones-Odeh E, Hammond CJ. How strong is the relationship between glaucoma, the retinal nerve fibre layer, and neurodegenerative diseases such as Alzheimer's disease and multiple sclerosis? Eye (Lond) 2015; 29:1270-84. [PMID: 26337943 DOI: 10.1038/eye.2015.158] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Accepted: 07/27/2015] [Indexed: 01/09/2023] Open
Abstract
Glaucoma is a neurodegenerative disorder with established relationships with ocular structures such as the retinal nerve fibre layer (RNFL) and the ganglion cell layer (GCL). Ocular imaging techniques such as optical coherence tomography (OCT) allow for quantitative measurement of these structures. OCT has been used in the monitoring of glaucoma, as well as investigating other neurodegenerative conditions such as Alzheimer's disease (AD) and multiple sclerosis (MS). In this review, we highlight the association between these disorders and ocular structures (RNFL and GCL), examining their usefulness as biomarkers of neurodegeneration. The average RNFL thickness loss in patients with AD is 11 μm, and 7 μm in MS patients. Most of the studies investigating these changes are cross-sectional. Further longitudinal studies are required to assess sensitivity and specificity of these potential ocular biomarkers to neurodegenerative disease progression.
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Affiliation(s)
- E Jones-Odeh
- Department of Ophthalmology, King's College London, London, UK
| | - C J Hammond
- Department of Ophthalmology, King's College London, London, UK.,Department of Twin Research and Genetic Epidemiology, King's College London, London, UK
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30
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Ermilov VV, Nesterova AA. [Beta-amyloidopathy as a manifestation of proteinopathy in age-related macular degeneration]. Vestn Oftalmol 2015; 131:26-31. [PMID: 26080579 DOI: 10.17116/oftalma2015131226-31] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
AIM To investigate clinical and morphological features of amyloidogenesis in age-related macular degeneration (AMD), which is thought to be associated with proteinopathy, namely beta-amyloidopathy. MATERIAL AND METHODS A total of 111 eyes with morphological signs of AMD as well as brain samples from 56 cadavers (aged at death 60 and over) were assessed with selective methods of amyloid detection. RESULTS Amyloid deposits were present in 39% of eyes with dry AMD and 80% of eyes with wet AMD. Combined accumulation of amyloid (that is both in eyes and the brain) was found in 50.6% of cases. CONCLUSION The results allow to suggest that common etiopathogenetic and morphological features of AMD and Alzheimer's disease (AD) are due to the same metabolic pathway of the transmembrane amyloid precursor protein (APP) responsible for aggregation of beta-amyloid (Aβ), an abnormal fibrillar protein, and the development of beta-amyloidopathy in eyes and brains. It has been demonstrated that beta-amyloidopathy is the keynote of both AMD and AD pathogenesis leading to cytotoxicity, neurodegeneration and pathological apoptosis. Such views on the problem may promote the development of neuroprotective and ophthalmic geriatric medications effective at all stages of pathogenesis, including beta-amyloid formation and aggregation.
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Affiliation(s)
- V V Ermilov
- Volgograd State Medical University, 1 Pavshikh Bortsov Sq., Volgograd, Russian Federation, 400131
| | - A A Nesterova
- Volgograd State Medical University, 1 Pavshikh Bortsov Sq., Volgograd, Russian Federation, 400131
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31
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Williams MA, McGowan AJ, Cardwell CR, Cheung CY, Craig D, Passmore P, Silvestri G, Maxwell AP, McKay GJ. Retinal microvascular network attenuation in Alzheimer's disease. ALZHEIMER'S & DEMENTIA: DIAGNOSIS, ASSESSMENT & DISEASE MONITORING 2015; 1:229-235. [PMID: 26634224 PMCID: PMC4629099 DOI: 10.1016/j.dadm.2015.04.001] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
INTRODUCTION Cerebral small-vessel disease has been implicated in the development of Alzheimer's disease (AD). The retinal microvasculature enables the noninvasive visualization and evaluation of the systemic microcirculation. We evaluated retinal microvascular parameters in a case-control study of AD patients and cognitively normal controls. METHODS Retinal images were computationally analyzed and quantitative retinal parameters (caliber, fractal dimension, tortuosity, and bifurcation) measured. Regression models were used to compute odds ratios (OR) and confidence intervals (CI) for AD with adjustment for confounders. RESULTS Retinal images were available in 213 AD participants and 294 cognitively normal controls. Persons with lower venular fractal dimension (OR per standard deviation [SD] increase, 0.77 [CI: 0.62-0.97]) and lower arteriolar tortuosity (OR per SD increase, 0.78 [CI: 0.63-0.97]) were more likely to have AD after appropriate adjustment. DISCUSSION Patients with AD have a sparser retinal microvascular network and retinal microvascular variation may represent similar pathophysiological events within the cerebral microvasculature of patients with AD.
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Affiliation(s)
| | - Amy J McGowan
- Centre for Public Health, Queen's University Belfast, Belfast, UK
| | - Chris R Cardwell
- Centre for Public Health, Queen's University Belfast, Belfast, UK
| | - Carol Y Cheung
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore ; Ophthalmology and Visual Sciences Academic Clinical Programme, Duke-NUS Graduate Medical School, National University of Singapore, Singapore, Singapore
| | - David Craig
- Southern Health and Social Care Trust, Craigavon Hospital, Craigavon, UK
| | - Peter Passmore
- Centre for Public Health, Queen's University Belfast, Belfast, UK
| | - Giuliana Silvestri
- Centre for Experimental Medicine, Queen's University Belfast, Belfast, UK
| | | | - Gareth J McKay
- Centre for Public Health, Queen's University Belfast, Belfast, UK
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32
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Gatta C, Castaldo L, Cellerino A, de Girolamo P, Lucini C, D'Angelo L. Brain derived neurotrophic factor in the retina of the teleost N. furzeri. Ann Anat 2014; 196:192-6. [PMID: 24629406 DOI: 10.1016/j.aanat.2014.01.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Revised: 01/02/2014] [Accepted: 01/08/2014] [Indexed: 12/27/2022]
Abstract
BDNF plays an important role in the development and maintenance of visual circuitries in the retina and brain visual centers. In adulthood, BDNF signaling is involved in neural protection and regeneration of retina. In this survey, we investigated the expression of BDNF in the retina of adult Nothobranchius furzeri, a teleost fish employed for age research. After describing the retina of N. furzeri and confirming that the structure is organized in layers as in all vertebrates, we have studied the localization of BDNF mRNA and protein throughout the retinal layers. BDNF mRNA is detectable in all layers, whereas the protein is lacking in the photoreceptors. The occurrence of BDNF provides new insights on its role in the retina, particularly in view of age-related disease of retina.
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Affiliation(s)
- Claudia Gatta
- Department of Veterinary Medicine and Animal Productions, University of Naples Federico II, via Veterinaria, 1, I-80137 Napoli, Italy
| | - Luciana Castaldo
- Department of Veterinary Medicine and Animal Productions, University of Naples Federico II, via Veterinaria, 1, I-80137 Napoli, Italy
| | - Alessandro Cellerino
- Scuola Normale Superiore of Pisa, Laboratory of Biology, c/o Institute of Biophysics of CNR, via Moruzzi, 1, I-56100 Pisa, Italy
| | - Paolo de Girolamo
- Department of Veterinary Medicine and Animal Productions, University of Naples Federico II, via Veterinaria, 1, I-80137 Napoli, Italy
| | - Carla Lucini
- Department of Veterinary Medicine and Animal Productions, University of Naples Federico II, via Veterinaria, 1, I-80137 Napoli, Italy
| | - Livia D'Angelo
- Department of Veterinary Medicine and Animal Productions, University of Naples Federico II, via Veterinaria, 1, I-80137 Napoli, Italy.
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Ho CY, Troncoso JC, Knox D, Stark W, Eberhart CG. Beta-amyloid, phospho-tau and alpha-synuclein deposits similar to those in the brain are not identified in the eyes of Alzheimer's and Parkinson's disease patients. Brain Pathol 2014; 24:25-32. [PMID: 23714377 PMCID: PMC3976129 DOI: 10.1111/bpa.12070] [Citation(s) in RCA: 114] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Accepted: 05/17/2013] [Indexed: 11/27/2022] Open
Abstract
Alzheimer's disease (AD) and Parkinson's disease (PD) are the two most common neurodegenerative disorders, and are characterized by deposition of specific proteins in the brain. If similar abnormal protein deposits are present in the eye, it would facilitate noninvasive diagnosis and monitoring of disease progression. We therefore evaluated expression of proteins associated with AD and PD pathology in postmortem eyes and brains in a case-control study. Eyes from 11 cases of AD, 6 cases of PD or PD with dementia, and 6 age-matched controls were retrieved from the autopsy archives of The Johns Hopkins Hospital. Immunostains for β-amyloid, phospho-tau and α-synuclein and Congo red stains were performed in the same laboratory in both brains and eyes. No amyloid deposits or abnormal tau accumulations were detected in the lens, retina or other structures in the eyes of AD patients. Eyes also lacked definite Lewy bodies or Lewy neurites in either PD or AD cases. Patchy cytoplasmic α-synuclein positivity was seen in the retina of AD, PD and control cases, but did not correlate with the presence or extent of Lewy body pathology in the brain. Abnormal protein aggregations characteristic of AD and PD are thus not commonly present in the retinas or lens of affected patients when assayed using the same protocols as in the brain. This suggests that β-amyloid, phospho-tau and α-synuclein either do not deposit in the eye in a manner analogous to brain, or are present at lower levels or in different forms.
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Affiliation(s)
- Cheng-Ying Ho
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD
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34
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Kerbage C, Sadowsky CH, Jennings D, Cagle GD, Hartung PD. Alzheimer's disease diagnosis by detecting exogenous fluorescent signal of ligand bound to Beta amyloid in the lens of human eye: an exploratory study. Front Neurol 2013; 4:62. [PMID: 23750151 PMCID: PMC3664322 DOI: 10.3389/fneur.2013.00062] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2013] [Accepted: 05/12/2013] [Indexed: 11/13/2022] Open
Abstract
We report results of a clinical exploratory human trial involving 10 participants using a combination of a fluorescent ligand and a laser scanning device, SAPPHIRE System, as an aid in the diagnosis of Probable Alzheimer's disease (AD). To the best of our knowledge, this is the first time that such a technique has been used in vivo of a human lens. The primary goal of the clinical trial, in addition to safety assessment, was to evaluate efficacy of the system. By detecting specific fluorescent signature of ligand bound beta amyloid in the supranucleus (SN) region of the human lens, a twofold differentiation factor between AD patients and Control groups is achieved. Data from our studies indicates that deeper regions of the SN provide the highest measures of ligand bound fluorescence signal from both controls and patients with AD. In addition, we present preclinical studies that were performed to investigate the binding affinity of the ligand to beta amyloid and evaluate the pharmacokinetics of the ligand in rabbit eyes. Further studies are underway involving a larger population for statistical evaluation of the method.
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35
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Microtubule-associated protein tau in bovine retinal photoreceptor rod outer segments: comparison with brain tau. Biochim Biophys Acta Mol Basis Dis 2013; 1832:1549-59. [PMID: 23712071 DOI: 10.1016/j.bbadis.2013.05.021] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2013] [Revised: 05/09/2013] [Accepted: 05/17/2013] [Indexed: 01/09/2023]
Abstract
Recent studies have suggested a possible involvement of abnormal tau in some retinal degenerative diseases. The common view in these studies is that these retinal diseases share the mechanism of tau-mediated degenerative diseases in brain and that information about these brain diseases may be directly applied to explain these retinal diseases. Here we collectively examine this view by revealing three basic characteristics of tau in the rod outer segment (ROS) of bovine retinal photoreceptors, i.e., its isoforms, its phosphorylation mode and its interaction with microtubules, and by comparing them with those of brain tau. We find that ROS contains at least four isoforms: three are identical to those in brain and one is unique in ROS. All ROS isoforms, like brain isoforms, are modified with multiple phosphate molecules; however, ROS isoforms show their own specific phosphorylation pattern, and these phosphorylation patterns appear not to be identical to those of brain tau. Interestingly, some ROS isoforms, under the normal conditions, are phosphorylated at the sites identical to those in Alzheimer's patient isoforms. Surprisingly, a large portion of ROS isoforms tightly associates with a membranous component(s) other than microtubules, and this association is independent of their phosphorylation states. These observations strongly suggest that tau plays various roles in ROS and that some of these functions may not be comparable to those of brain tau. We believe that knowledge about tau in the entire retinal network and/or its individual cells are also essential for elucidation of tau-mediated retinal diseases, if any.
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