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Ebrahimi M, Thompson P, Lauer AK, Sivaprasad S, Perry G. The retina-brain axis and diabetic retinopathy. Eur J Ophthalmol 2023; 33:2079-2095. [PMID: 37259525 DOI: 10.1177/11206721231172229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Diabetic retinopathy (DR) is a major contributor to permanent vision loss and blindness. Changes in retinal neurons, glia, and microvasculature have been the focus of intensive study in the quest to better understand DR. However, the impact of diabetes on the rest of the visual system has received less attention. There are reports of associations of changes in the visual system with preclinical and clinical manifestations of diabetes. Simultaneous investigation of the retina and the brain may shed light on the mechanisms underlying neurodegeneration in diabetics. Additionally, investigating the links between DR and other neurodegenerative disorders of the brain including Alzheimer's and Parkinson's disease may reveal shared mechanisms for neurodegeneration and potential therapy options.
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Affiliation(s)
- Moein Ebrahimi
- School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Network of Immunity in Infection, Malignancy, and Autoimmunity, Universal Scientific Education and Research Network (USERN), Tehran, Iran
| | - Paul Thompson
- Imaging Genetics Center, Mark and Mary Stevens Institute for Neuroimaging and Informatics, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Andreas K Lauer
- Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, USA
| | - Sobha Sivaprasad
- National Institute of Health and Care Research Moorfields Biomedical Research Centre, Moorfields Eye Hospital, London, UK
| | - George Perry
- Department of Neuroscience, Developmental and Regenerative Biology, University of Texas and San Antonio, San Antonio, TX, USA
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2
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Yoo TJ. Anti-Inflammatory Gene Therapy Improves Spatial Memory Performance in a Mouse Model of Alzheimer's Disease. J Alzheimers Dis 2021; 85:1001-1008. [PMID: 34897091 PMCID: PMC8925118 DOI: 10.3233/jad-215270] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The immune system plays a critical role in neurodegenerative processes involved in Alzheimer’s disease (AD). In this study, a gene-based immunotherapeutic method examined the effects of anti-inflammatory cellular immune response elements (CIREs) in the amyloid-β protein precursor (AβPP) mouse model. Bi-monthly intramuscular administration, beginning at either 4 or 6 months, and examined at 7.5 through 16 months, with plasmids encoding Interleukin (IL)-10, IL-4, TGF-β polynucleotides, or a combination thereof, into AβPP mice improved spatial memory performance. This work demonstrates an efficient gene therapy strategy to downregulate neuroinflammation, and possibly prevent or delay cognitive decline in AD.
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Affiliation(s)
- Tai June Yoo
- Korea Allergy Clinic, KangNam Gu, Seoul, South Korea.,University of Tennessee Health Science Center, Memphis, TN, USA
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3
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Zhang J, Gao F, Ma Y, Xue T, Shen Y. Identification of early-onset photoreceptor degeneration in transgenic mouse models of Alzheimer's disease. iScience 2021; 24:103327. [PMID: 34805789 PMCID: PMC8581578 DOI: 10.1016/j.isci.2021.103327] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 09/23/2021] [Accepted: 10/19/2021] [Indexed: 12/20/2022] Open
Abstract
Light sensitivity of the vertebrate retina relies on the integrity of photoreceptors, including rods and cones. Research in patients with Alzheimer's disease (AD) and in AD transgenic mice reports that accumulated amyloid-β (Aβ) plaques in the retina are toxic to retinal neurons. Moreover, Aβ plaques are deposited around the rods and cones, yet photoreceptor anomalies remain unclear in AD. Here, we identify the progressive degeneration of rods and cones characterized by impaired expression of phototransduction proteins, morphological alterations, functional deficits, and even cell loss. Furthermore, we demonstrate that cell senescence and necroptosis were involved in rod degeneration. Importantly, using in vivo scotopic electroretinogram, we detected rod degeneration in early-stage AD transgenic mice before Aβ plaques were observed in the brain. Moreover, we demonstrate that rod degeneration was among the earliest AD retinal manifestations compared with other types of retinal neurons. Overall, our study is the first to identify and detect in vivo, early-onset photoreceptor degeneration in AD. Progressive rod degeneration has been identified in AD transgenic mice Cell senescence and necroptosis were involved in rod degeneration Rod degeneration can be detected by in vivo scotopic electroretinogram Rod degeneration has earlier onset than amyloid-β plaques in the brain
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Affiliation(s)
- Jie Zhang
- Institute on Aging and Brain Disorders, The First Affiliated Hospital of USTC, Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Science, Division of Life Science and Medicine, University of Science and Technology of China, Hefei 230026, China
- Neurodegenerative Disorder Research Center, CAS Key Laboratory of Brain Function and Disease, University of Science and Technology of China, Hefei 230026, China
| | - Feng Gao
- Institute on Aging and Brain Disorders, The First Affiliated Hospital of USTC, Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Science, Division of Life Science and Medicine, University of Science and Technology of China, Hefei 230026, China
- Neurodegenerative Disorder Research Center, CAS Key Laboratory of Brain Function and Disease, University of Science and Technology of China, Hefei 230026, China
| | - Yuqian Ma
- Neurodegenerative Disorder Research Center, CAS Key Laboratory of Brain Function and Disease, University of Science and Technology of China, Hefei 230026, China
- Eye Center at The First Affiliated Hospital of USTC, Division of Life Science and Medicine, University of Science and Technology of China, Hefei 230026, China
| | - Tian Xue
- Institute on Aging and Brain Disorders, The First Affiliated Hospital of USTC, Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Science, Division of Life Science and Medicine, University of Science and Technology of China, Hefei 230026, China
- Neurodegenerative Disorder Research Center, CAS Key Laboratory of Brain Function and Disease, University of Science and Technology of China, Hefei 230026, China
- Eye Center at The First Affiliated Hospital of USTC, Division of Life Science and Medicine, University of Science and Technology of China, Hefei 230026, China
- Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China
| | - Yong Shen
- Institute on Aging and Brain Disorders, The First Affiliated Hospital of USTC, Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Science, Division of Life Science and Medicine, University of Science and Technology of China, Hefei 230026, China
- Neurodegenerative Disorder Research Center, CAS Key Laboratory of Brain Function and Disease, University of Science and Technology of China, Hefei 230026, China
- Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China
- Corresponding author
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4
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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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5
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Retinal hyperspectral imaging in the 5xFAD mouse model of Alzheimer's disease. Sci Rep 2021; 11:6387. [PMID: 33737550 PMCID: PMC7973540 DOI: 10.1038/s41598-021-85554-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 02/20/2021] [Indexed: 11/08/2022] Open
Abstract
Hyperspectral imaging of the retina has recently been posited as a potentially useful form of spectroscopy of amyloid-beta (Aβ) protein in the eyes of those with Alzheimer's disease (AD). The concept of using the retina as a biomarker for AD is an attractive one, as current screening tools for AD are either expensive or inaccessible. Recent studies have investigated hyperspectral imaging in Aβ models however these studies have been in younger mice. Here we characterised hyperspectral reflectance profile in 6 to 17 months old 5xFAD mice and compare this to Aβ in isolated preparations. Hyperspectral imaging was conducted across two preparations of Aβ using a custom built bench ophthalmoscope. In the in vitro condition, 1 mg of purified human Aβ42 was solubilised and left to aggregate for 72 h. This soluble/insoluble Aβ mixture was then imaged by suspending the solution at a pipette tip and compared against phosphate buffered saline (PBS) control (n = 10 ROIs / group). In the in vivo condition, a 5xFAD transgenic mouse model was used and retinae were imaged at the age of 6 (n = 9), 12 (n = 9) and 17 months (n = 8) with age matched wildtype littermates as control (n = 12, n = 13, n = 15 respectively). In the vitro condition, hyperspectral imaging of the solution showed greater reflectance compared with vehicle (p < 0.01), with the greatest differences occurring in the short visible spectrum (< 500 nm). In the in vivo preparation, 5xFAD showed greater hyperspectral reflectance at all ages (6, 12, 17 months, p < 0.01). These differences were noted most in the short wavelengths at younger ages, with an additional peak appearing at longer wavelengths (~ 550 nm) with advancing age. This study shows that the presence of Aβ (soluble/insoluble mixture) can increase the hyperspectral reflectance profile in vitro as well as in vivo. Differences were evident in the short wavelength spectrum (< 500 nm) in vitro and were preserved when imaged through the ocular media in the in vivo conditions. With advancing age a second hump around ~ 550 nm became more apparent. Hyperspectral imaging of the retina does not require the use of contrast agents and is a potentially useful and non-invasive biomarker for AD.
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6
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Latina V, Giacovazzo G, Cordella F, Balzamino BO, Micera A, Varano M, Marchetti C, Malerba F, Florio R, Ercole BB, La Regina F, Atlante A, Coccurello R, Di Angelantonio S, Calissano P, Amadoro G. Systemic delivery of a specific antibody targeting the pathological N-terminal truncated tau peptide reduces retinal degeneration in a mouse model of Alzheimer's Disease. Acta Neuropathol Commun 2021; 9:38. [PMID: 33750467 PMCID: PMC7942014 DOI: 10.1186/s40478-021-01138-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 02/26/2021] [Indexed: 12/28/2022] Open
Abstract
Retina and optic nerve are sites of extra-cerebral manifestations of Alzheimer's Disease (AD). Amyloid-β (Aβ) plaques and neurofibrillary tangles of hyperphosphorylated tau protein are detected in eyes from AD patients and transgenic animals in correlation with inflammation, reduction of synapses, visual deficits, loss of retinal cells and nerve fiber. However, neither the pathological relevance of other post-translational tau modifications-such as truncation with generation of toxic fragments-nor the potential neuroprotective action induced by their in vivo clearance have been investigated in the context of AD retinal degeneration. We have recently developed a monoclonal tau antibody (12A12mAb) which selectively targets the neurotoxic 20-22 kDa NH2-derived peptide generated from pathological truncation at the N-terminal domain of tau without cross-reacting with its full-length normal protein. Previous studies have shown that 12A12mAb, when intravenously (i.v.)-injected into 6-month-old Tg2576 animals, markedly improves their AD-like, behavioural and neuropathological syndrome. By taking advantage of this well-established tau-directed immunization regimen, we found that 12A12mAb administration also exerts a beneficial action on biochemical, morphological and metabolic parameters (i.e. APP/Aβ processing, tau hyperphosphorylation, neuroinflammation, synaptic proteins, microtubule stability, mitochondria-based energy production, neuronal death) associated with ocular injury in the AD phenotype. These findings prospect translational implications in the AD field by: (1) showing for the first time that cleavage of tau takes part in several pathological changes occurring in vivo in affected retinas and vitreous bodies and that its deleterious effects are successfully antagonized by administration of the specific 12A12mAb; (2) shedding further insights on the tight connections between neurosensory retina and brain, in particular following tau-based immunotherapy. In our view, the parallel response we detected in this preclinical animal model, both in the eye and in the hippocampus, following i.v. 12A12mAb injection opens novel diagnostic and therapeutic avenues for the clinical management of cerebral and extracerebral AD signs in human beings.
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Affiliation(s)
- Valentina Latina
- European Brain Research Institute (EBRI), Viale Regina Elena 295, 00161 Rome, Italy
| | - Giacomo Giacovazzo
- IRCSS Santa Lucia Foundation, Via Fosso del Fiorano 64-65, 00143 Rome, Italy
| | - Federica Cordella
- Department of Physiology and Pharmacology, University of Rome La Sapienza, Piazzale Aldo Moro 5, 00185 Rome, Italy
- Center for Life Nanoscience, Istituto Italiano Di Tecnologia, Viale Regina Elena 291, 00161 Rome, Italy
| | - Bijorn Omar Balzamino
- Research Laboratories in Ophthalmology, IRCCS - Fondazione Bietti, Via Santo Stefano Rotondo, 6, 00184 Rome, Italy
| | - Alessandra Micera
- Research Laboratories in Ophthalmology, IRCCS - Fondazione Bietti, Via Santo Stefano Rotondo, 6, 00184 Rome, Italy
| | - Monica Varano
- Research Laboratories in Ophthalmology, IRCCS - Fondazione Bietti, Via Santo Stefano Rotondo, 6, 00184 Rome, Italy
| | - Cristina Marchetti
- European Brain Research Institute (EBRI), Viale Regina Elena 295, 00161 Rome, Italy
| | - Francesca Malerba
- European Brain Research Institute (EBRI), Viale Regina Elena 295, 00161 Rome, Italy
| | - Rita Florio
- European Brain Research Institute (EBRI), Viale Regina Elena 295, 00161 Rome, Italy
| | - Bruno Bruni Ercole
- European Brain Research Institute (EBRI), Viale Regina Elena 295, 00161 Rome, Italy
| | - Federico La Regina
- European Brain Research Institute (EBRI), Viale Regina Elena 295, 00161 Rome, Italy
| | - Anna Atlante
- Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM)-CNR, Via Amendola 122/O, 70126 Bari, Italy
| | - Roberto Coccurello
- IRCSS Santa Lucia Foundation, Via Fosso del Fiorano 64-65, 00143 Rome, Italy
- Institute for Complex System (ISC)-CNR, Via dei Taurini 19, 00185 Rome, Italy
| | - Silvia Di Angelantonio
- Department of Physiology and Pharmacology, University of Rome La Sapienza, Piazzale Aldo Moro 5, 00185 Rome, Italy
- Center for Life Nanoscience, Istituto Italiano Di Tecnologia, Viale Regina Elena 291, 00161 Rome, Italy
| | - Pietro Calissano
- European Brain Research Institute (EBRI), Viale Regina Elena 295, 00161 Rome, Italy
| | - Giuseppina Amadoro
- European Brain Research Institute (EBRI), Viale Regina Elena 295, 00161 Rome, Italy
- Institute of Translational Pharmacology (IFT), National Research Council (CNR), Via Fosso del Cavaliere 100, 00133 Rome, Italy
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7
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Salobrar-García E, López-Cuenca I, Sánchez-Puebla L, de Hoz R, Fernández-Albarral JA, Ramírez AI, Bravo-Ferrer I, Medina V, Moro MA, Saido TC, Saito T, Salazar JJ, Ramírez JM. Retinal Thickness Changes Over Time in a Murine AD Model APP NL-F/NL-F. Front Aging Neurosci 2021; 12:625642. [PMID: 33542683 PMCID: PMC7852550 DOI: 10.3389/fnagi.2020.625642] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 12/15/2020] [Indexed: 11/13/2022] Open
Abstract
Background: Alzheimer's disease (AD) may present retinal changes before brain pathology, suggesting the retina as an accessible biomarker of AD. The present work is a diachronic study using spectral domain optical coherence tomography (SD-OCT) to determine the total retinal thickness and retinal nerve fiber layer (RNFL) thickness in an APPNL−F/NL−F mouse model of AD at 6, 9, 12, 15, 17, and 20 months old compared to wild type (WT) animals. Methods: Total retinal thickness and RNFL thickness were determined. The mean total retinal thickness was analyzed following the Early Treatment Diabetic Retinopathy Study sectors. RNFL was measured in six sectors of axonal ring scans around the optic nerve. Results: In the APPNL−F/NL−F group compared to WT animals, the total retinal thickness changes observed were the following: (i) At 6-months-old, a significant thinning in the outer temporal sector was observed; (ii) at 15-months-old a significant thinning in the inner temporal and in the inner and outer inferior retinal sectors was noticed; (iii) at 17-months-old, a significant thickening in the inferior and nasal sectors was found in both inner and outer rings; and (iv) at 20-months-old, a significant thinning in the inner ring of nasal, temporal, and inferior retina and in the outer ring of superior and temporal retina was seen. In RNFL thickness, there was significant thinning in the global analysis and in nasal and inner-temporal sectors at 6 months old. Thinning was also found in the supero-temporal and nasal sectors and global value at 20 months old. Conclusions: In the APPNL−F/NL−F AD model, the retinal thickness showed thinning, possibly produced by neurodegeneration alternating with thickening caused by deposits and neuroinflammation in some areas of the retina. These changes over time are similar to those observed in the human retina and could be a biomarker for AD. The APPNL−F/NL−F AD model may help us better understand the different retinal changes during the progression of AD.
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Affiliation(s)
- Elena Salobrar-García
- Ramon Castroviejo Ophthalmological Research Institute, Complutense University of Madrid, Madrid, Spain.,Department of Immunology, Ophthalmology and Ear, Nose, and Throat, Faculty of Optics and Optometry, Complutense University of Madrid, Madrid, Spain
| | - Inés López-Cuenca
- Ramon Castroviejo Ophthalmological Research Institute, Complutense University of Madrid, Madrid, Spain
| | - Lídia Sánchez-Puebla
- Ramon Castroviejo Ophthalmological Research Institute, Complutense University of Madrid, Madrid, Spain
| | - Rosa de Hoz
- Ramon Castroviejo Ophthalmological Research Institute, Complutense University of Madrid, Madrid, Spain.,Department of Immunology, Ophthalmology and Ear, Nose, and Throat, Faculty of Optics and Optometry, Complutense University of Madrid, Madrid, Spain
| | - José A Fernández-Albarral
- Ramon Castroviejo Ophthalmological Research Institute, Complutense University of Madrid, Madrid, Spain
| | - Ana I Ramírez
- Ramon Castroviejo Ophthalmological Research Institute, Complutense University of Madrid, Madrid, Spain.,Department of Immunology, Ophthalmology and Ear, Nose, and Throat, Faculty of Optics and Optometry, Complutense University of Madrid, Madrid, Spain
| | - Isabel Bravo-Ferrer
- Department of Pharmacology and Toxicology, Faculty of Medicine, Complutense University of Madrid, Madrid, Spain.,Edinburgh Medical School, UK Dementia Research Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Violeta Medina
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
| | - María A Moro
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
| | - Takaomi C Saido
- Laboratory for Proteolytic Neuroscience, Brain Science Institute, RIKEN, Wako, Japan
| | - Takashi Saito
- Department of Neurocognitive Science, Institute of Brain Science, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Juan J Salazar
- Ramon Castroviejo Ophthalmological Research Institute, Complutense University of Madrid, Madrid, Spain.,Department of Immunology, Ophthalmology and Ear, Nose, and Throat, Faculty of Optics and Optometry, Complutense University of Madrid, Madrid, Spain
| | - José M Ramírez
- Ramon Castroviejo Ophthalmological Research Institute, Complutense University of Madrid, Madrid, Spain.,Department of Immunology, Ophthalmology and ENT, School of Medicine, Complutense University of Madrid, Madrid, Spain
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8
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Simons ES, Smith MA, Dengler-Crish CM, Crish SD. Retinal ganglion cell loss and gliosis in the retinofugal projection following intravitreal exposure to amyloid-beta. Neurobiol Dis 2021; 147:105146. [PMID: 33122075 DOI: 10.1016/j.nbd.2020.105146] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 10/09/2020] [Accepted: 10/23/2020] [Indexed: 01/07/2023] Open
Abstract
Pathological accumulations of amyloid-beta (Aβ) peptide are found in retina early in Alzheimer's disease, yet its effects on retinal neuronal structure remain unknown. To investigate this, we injected fibrillized Aβ1-42 protein into the eye of adult C57BL/6 J mice and analyzed the retina, optic nerve (ON), and the superior colliculus (SC), the primary retinal target in mice. We found that retinal Aβ exposure stimulated microglial activation and retinal ganglion cell (RGC) loss as early as 1-week post-injection. Pathology was not limited to the retina, but propagated into other areas of the central nervous system. Microgliosis spread throughout the retinal projection (retina, ON, and SC), with multiplex protein quantitation demonstrating an increase in endogenously produced Aβ in the ON and SC corresponding to the injected retinas. Surprisingly, this pathology spread to the opposite side, with unilateral Aβ eye injections driving increased Aβ levels, neuroinflammation, and RGC death in the opposite, un-injected retinal projection. As Aβ-mediated microglial activation has been shown to propagate Aβ pathology, we also investigated the role of the Aβ-binding microglial scavenger receptor CD36 in this pathology. Transgenic mice lacking the CD36 receptor were resistant to Aβ-induced inflammation and RGC death up to 2 weeks following exposure. These results indicate that Aβ pathology drives regional neuropathology in the retina and does not remain isolated to the affected eye, but spreads throughout the nervous system. Further, CD36 may serve as a promising target to prevent Aβ-mediated inflammatory damage.
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Affiliation(s)
- E S Simons
- Northeast Ohio Medical University, Rootstown, OH 44272, United States; Kent State Biomedical Sciences Graduate Program, Kent, OH 44240, United States
| | - M A Smith
- Northeast Ohio Medical University, Rootstown, OH 44272, United States; Kent State Biomedical Sciences Graduate Program, Kent, OH 44240, United States; Akron Children's Hospital, Rebecca D. Considine Research Institute, Akron, OH 44302, United States
| | - C M Dengler-Crish
- Northeast Ohio Medical University, Rootstown, OH 44272, United States; Kent State Biomedical Sciences Graduate Program, Kent, OH 44240, United States
| | - S D Crish
- Northeast Ohio Medical University, Rootstown, OH 44272, United States; Kent State Biomedical Sciences Graduate Program, Kent, OH 44240, United States.
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9
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Bajagai YS, Steel JC, Radovanovic A, Stanley D. Prolonged continual consumption of oregano herb interferes with the action of steroid hormones and several drugs, and effects signaling across the brain-gut axis. Food Funct 2020; 12:726-738. [PMID: 33349823 DOI: 10.1039/d0fo02988b] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Herbs and spices have been used throughout human history for their medicinal qualities. The advent of cheap and readily available medicines have lessened the need for herbs and spices as traditional medicines, however, they are rapidly regaining popularity with rising interest of the general population in health, natural products and nutrition. The need for alternative medicines with antimicrobial properties, such as herbs and spices, has also come to the forefront in light of the recent bans of antibiotic use in the livestock industry, including the poultry industry. This large scale use presents an opportunity to observe nutrigenomic effects of prolonged use of herbs on a substantial number of birds fed high concentrations of these products throughout the production cycle. In this manuscript, we investigated the transcriptional effect of continual prolonged oregano supplementation on chicken ileum gene expression. Based on ileum transcriptomics, we report that continual supplementation with 2% oregano altered microbiota-gut-brain axis signalling, rearranged cancer susceptibility towards reduced steroid hormone-related cancers and altered expression of genes targeted by many registered drugs, thus likely affecting their efficiency and side effects. Transcriptional toxicology analysis indicated significant activation of Ventricular Septal Defect and Congenital Heart Disease categories. Our results, counter the notion that natural products such as oregano have the potential for little to no side-effects as they are "natural". The nutrigenomic approach of understanding benefits and side effects of the food we eat, can revolutionize disease management and therapy and have special significance in designing the diets for individuals or livestock with known disease predispositions.
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Affiliation(s)
- Yadav S Bajagai
- Central Queensland University, Institute for Future Farming Systems, Rockhampton, Queensland 4702, Australia.
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10
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Lee S, Jiang K, McIlmoyle B, To E, Xu QA, Hirsch-Reinshagen V, Mackenzie IR, Hsiung GYR, Eadie BD, Sarunic MV, Beg MF, Cui JZ, Matsubara JA. Amyloid Beta Immunoreactivity in the Retinal Ganglion Cell Layer of the Alzheimer's Eye. Front Neurosci 2020; 14:758. [PMID: 32848548 PMCID: PMC7412634 DOI: 10.3389/fnins.2020.00758] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 06/29/2020] [Indexed: 01/04/2023] Open
Abstract
Alzheimer’s disease (AD) is the most prevalent form of dementia, accounting for 60–70% of all dementias. AD is often under-diagnosed and recognized only at a later, more advanced stage, and this delay in diagnosis has been suggested as a contributing factor in the numerous unsuccessful AD treatment trials. Although there is no known cure for AD, early diagnosis is important for disease management and care. A hallmark of AD is the deposition of amyloid-β (Aβ)-containing senile neuritic plaques and neurofibrillary tangles composed of hyperphosporylated tau in the brain. However, current in vivo methods to quantify Aβ in the brain are invasive, requiring radioactive tracers and positron emission tomography. Toward development of alternative methods to assess AD progression, we focus on the retinal manifestation of AD pathology. The retina is an extension of the central nervous system uniquely accessible to light-based, non-invasive ophthalmic imaging. However, earlier studies in human retina indicate that the literature is divided on the presence of Aβ in the AD retina. To help resolve this disparity, this study assessed retinal tissues from neuropathologically confirmed AD cases to determine the regional distribution of Aβ in retinal wholemounts and to inform on future retinal image studies targeting Aβ. Concurrent post-mortem brain tissues were also collected. Neuropathological cortical assessments including neuritic plaque (NP) scores and cerebral amyloid angiopathy (CAA) were correlated with retinal Aβ using immunohistochemistry, confocal microscopy, and quantitative image analysis. Aβ load was compared between AD and control (non-AD) eyes. Our results indicate that levels of intracellular and extracellular Aβ retinal deposits were significantly higher in AD than controls. Mid-peripheral Aβ levels were greater than central retina in both AD and control eyes. In AD retina, higher intracellular Aβ was associated with lower NP score, while higher extracellular Aβ was associated with higher CAA score. Our data support the feasibility of using the retinal tissue to assess ocular Aβ as a surrogate measure of Aβ in the brain of individuals with AD. Specifically, mid-peripheral retina possesses more Aβ deposition than central retina, and thus may be the optimal location for future in vivo ocular imaging.
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Affiliation(s)
- Sieun Lee
- Department of Ophthalmology and Visual Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, BC, Canada.,School of Engineering Science, Simon Fraser University, Burnaby, BC, Canada
| | - Kailun Jiang
- Department of Surgery, Division of Ophthalmology, University of Calgary, Calgary, AB, Canada
| | - Brandon McIlmoyle
- Department of Family Medicine, Queen's University, Kingston, ON, Canada
| | - Eleanor To
- Department of Ophthalmology and Visual Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, BC, Canada
| | - Qinyuan Alis Xu
- Department of Ophthalmology and Visual Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, BC, Canada
| | - Veronica Hirsch-Reinshagen
- Department of Pathology, Vancouver General Hospital, The University of British Columbia, Vancouver, BC, Canada
| | - Ian R Mackenzie
- Department of Pathology, Vancouver General Hospital, The University of British Columbia, Vancouver, BC, Canada
| | - Ging-Yuek R Hsiung
- Division of Neurology, Department of Medicine, Faculty of Medicine, The University of British Columbia, Vancouver, BC, Canada
| | - Brennan D Eadie
- Department of Ophthalmology and Visual Sciences, Dalhousie University, Halifax, NS, Canada
| | - Marinko V Sarunic
- School of Engineering Science, Simon Fraser University, Burnaby, BC, Canada
| | - Mirza Faisal Beg
- School of Engineering Science, Simon Fraser University, Burnaby, BC, Canada
| | - Jing Z Cui
- Department of Ophthalmology and Visual Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, BC, Canada
| | - Joanne A Matsubara
- Department of Ophthalmology and Visual Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, BC, Canada
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11
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Sidiqi A, Wahl D, Lee S, Ma D, To E, Cui J, To E, Beg MF, Sarunic M, Matsubara JA. In vivo Retinal Fluorescence Imaging With Curcumin in an Alzheimer Mouse Model. Front Neurosci 2020; 14:713. [PMID: 32719582 PMCID: PMC7350785 DOI: 10.3389/fnins.2020.00713] [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: 04/27/2020] [Accepted: 06/12/2020] [Indexed: 12/04/2022] Open
Abstract
Alzheimer’s disease (AD) is characterized by amyloid beta (Aβ) plaques in the brain detectable by highly invasive in vivo brain imaging or in post-mortem tissues. A non-invasive and inexpensive screening method is needed for early diagnosis of asymptomatic AD patients. The shared developmental origin and similarities with the brain make the retina a suitable surrogate tissue to assess Aβ load in AD. Using curcumin, a FluoroProbe that binds to Aβ, we labeled and measured the retinal fluorescence in vivo and compared with the immunohistochemical measurements of the brain and retinal Aβ load in the APP/PS1 mouse model. In vivo retinal images were acquired every 2 months using custom fluorescence scanning laser ophthalmoscopy (fSLO) after tail vein injections of curcumin in individual mice followed longitudinally from ages 5 to 19 months. At the same time points, 1–2 mice from the same cohort were sacrificed and immunohistochemistry was performed on their brain and retinal tissues. Results demonstrated cortical and retinal Aβ immunoreactivity were significantly greater in Tg than WT groups. Age-related increase in retinal Aβ immunoreactivity was greater in Tg than WT groups. Retinal Aβ immunoreactivity was present in the inner retinal layers and consisted of small speck-like extracellular deposits and intracellular labeling in the cytoplasm of a subset of retinal ganglion cells. In vivo retinal fluorescence with curcumin injection was significantly greater in older mice (11–19 months) than younger mice (5–9 months) in both Tg and WT groups. In vivo retinal fluorescence with curcumin injection was significantly greater in Tg than WT in older mice (ages 11–19 months). Finally, and most importantly, the correlation between in vivo retinal fluorescence with curcumin injection and Aβ immunoreactivity in the cortex was stronger in Tg compared to WT groups. Our data reveal that retina and brain of APP/PS1 Tg mice increasingly express Aβ with age. In vivo retinal fluorescence with curcumin correlated strongly with cortical Aβ immunohistochemistry in Tg mice. These findings suggest that using in vivo fSLO imaging of AD-susceptible retina may be a useful, non-invasive method of detecting Aβ in the retina as a surrogate indicator of Aβ load in the brain.
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Affiliation(s)
- Ahmad Sidiqi
- Department of Ophthalmology & Visual Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Daniel Wahl
- School of Engineering Science, Simon Fraser University, Burnaby, BC, Canada
| | - Sieun Lee
- Department of Ophthalmology & Visual Sciences, University of British Columbia, Vancouver, BC, Canada.,School of Engineering Science, Simon Fraser University, Burnaby, BC, Canada
| | - Da Ma
- School of Engineering Science, Simon Fraser University, Burnaby, BC, Canada
| | - Elliott To
- Department of Ophthalmology & Visual Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Jing Cui
- Department of Ophthalmology & Visual Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Eleanor To
- Department of Ophthalmology & Visual Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Mirza Faisal Beg
- School of Engineering Science, Simon Fraser University, Burnaby, BC, Canada
| | - Marinko Sarunic
- School of Engineering Science, Simon Fraser University, Burnaby, BC, Canada
| | - Joanne A Matsubara
- Department of Ophthalmology & Visual Sciences, University of British Columbia, Vancouver, BC, Canada
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12
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Harper MM, Hedberg-Buenz A, Herlein J, Abrahamson EE, Anderson MG, Kuehn MH, Kardon RH, Poolman P, Ikonomovic MD. Blast-Mediated Traumatic Brain Injury Exacerbates Retinal Damage and Amyloidosis in the APPswePSENd19e Mouse Model of Alzheimer's Disease. Invest Ophthalmol Vis Sci 2019; 60:2716-2725. [PMID: 31247112 PMCID: PMC6735799 DOI: 10.1167/iovs.18-26353] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Purpose Traumatic brain injury (TBI) is a risk factor for developing chronic neurodegenerative conditions including Alzheimer's disease (AD). The purpose of this study was to examine chronic effects of blast TBI on retinal ganglion cells (RGC), optic nerve, and brain amyloid load in a mouse model of AD amyloidosis. Methods Transgenic (TG) double-mutant APPswePSENd19e (APP/PS1) mice and nontransgenic (Non-TG) littermates were exposed to a single blast TBI (20 psi) at age 2 to 3 months. RGC cell structure and function was evaluated 2 months later (average age at endpoint = 4.5 months) using pattern electroretinogram (PERG), optical coherence tomography (OCT), and the chromatic pupil light reflex (cPLR), followed by histologic analysis of retina, optic nerve, and brain amyloid pathology. Results APP/PS1 mice exposed to blast TBI (TG-Blast) had significantly lower PERG and cPLR responses 2 months after injury compared to preblast values and compared to sham groups of APP/PS1 (TG-Sham) and nontransgenic (Non-TG-Sham) mice as well as nontransgenic blast-exposed mice (Non-TG-Blast). The TG-Blast group also had significantly thinner RGC complex and more optic nerve damage compared to all groups. No amyloid-β (Aβ) deposits were detected in retinas of APP/PS1 mice; however, increased amyloid precursor protein (APP)/Aβ-immunoreactivity was seen in TG-Blast compared to TG-Sham mice, particularly near blood vessels. TG-Blast and TG-Sham groups exhibited high variability in pathology severity, with a strong, but not statistically significant, trend for greater cerebral cortical Aβ plaque load in the TG-Blast compared to TG-Sham group. Conclusions When combined with a genetic susceptibility for developing amyloidosis of AD, blast TBI exposure leads to earlier RGC and optic nerve damage associated with modest but detectable increase in cerebral cortical Aβ pathology. These findings suggest that genetic risk factors for AD may increase the sensitivity of the retina to blast-mediated damage.
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Affiliation(s)
- Matthew M Harper
- Department of Ophthalmology and Visual Sciences, The University of Iowa, Iowa City, Iowa, United States.,The Iowa City VA Center for the Prevention and Treatment of Visual Loss, Iowa City, Iowa, United States
| | - Adam Hedberg-Buenz
- The Iowa City VA Center for the Prevention and Treatment of Visual Loss, Iowa City, Iowa, United States.,Department of Molecular Physiology and Biophysics, The University of Iowa, Iowa City, Iowa, United States
| | - Judith Herlein
- The Iowa City VA Center for the Prevention and Treatment of Visual Loss, Iowa City, Iowa, United States
| | - Eric E Abrahamson
- Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States.,Geriatric Research Education and Clinical Center, Pittsburgh VA Healthcare System, Pittsburgh, Pennsylvania, United States
| | - Michael G Anderson
- Department of Ophthalmology and Visual Sciences, The University of Iowa, Iowa City, Iowa, United States.,The Iowa City VA Center for the Prevention and Treatment of Visual Loss, Iowa City, Iowa, United States.,Department of Molecular Physiology and Biophysics, The University of Iowa, Iowa City, Iowa, United States
| | - Markus H Kuehn
- Department of Ophthalmology and Visual Sciences, The University of Iowa, Iowa City, Iowa, United States.,The Iowa City VA Center for the Prevention and Treatment of Visual Loss, Iowa City, Iowa, United States
| | - Randy H Kardon
- Department of Ophthalmology and Visual Sciences, The University of Iowa, Iowa City, Iowa, United States.,The Iowa City VA Center for the Prevention and Treatment of Visual Loss, Iowa City, Iowa, United States
| | - Pieter Poolman
- Department of Ophthalmology and Visual Sciences, The University of Iowa, Iowa City, Iowa, United States.,The Iowa City VA Center for the Prevention and Treatment of Visual Loss, Iowa City, Iowa, United States
| | - Milos D Ikonomovic
- Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States.,Geriatric Research Education and Clinical Center, Pittsburgh VA Healthcare System, Pittsburgh, Pennsylvania, United States.,Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States
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13
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Chiquita S, Campos EJ, Castelhano J, Ribeiro M, Sereno J, Moreira PI, Castelo-Branco M, Ambrósio AF. Retinal thinning of inner sub-layers is associated with cortical atrophy in a mouse model of Alzheimer's disease: a longitudinal multimodal in vivo study. ALZHEIMERS RESEARCH & THERAPY 2019; 11:90. [PMID: 31722748 PMCID: PMC6854691 DOI: 10.1186/s13195-019-0542-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Accepted: 09/22/2019] [Indexed: 12/26/2022]
Abstract
BACKGROUND It has been claimed that the retina can be used as a window to study brain disorders. However, concerning Alzheimer's disease (AD), it still remains controversial whether changes occurring in the brain and retina are associated. We aim to understand when changes start appearing in the retina and brain, how changes progress, and if they are correlated. METHODS We carried out a unique longitudinal study, at 4, 8, 12, and 16 months of age, in a triple transgenic mouse model of AD (3×Tg-AD), which mimics pathological and neurobehavioral features of AD, as we have already shown. Retinal structure and physiology were evaluated in vivo using optical coherence tomography and electroretinography. Brain visual cortex structure was evaluated in vivo using magnetic resonance imaging. RESULTS The retinal thickness of 3×Tg-AD decreased, at all time points, except for the outer nuclear layer, where the opposite alteration was observed. Amplitudes in scotopic and photopic responses were increased throughout the study. Similarly, higher amplitude and lower phase values were observed in the photopic flicker response. No differences were found in the activity of retinal ganglion cells. Visual cortex gray matter volume was significantly reduced. CONCLUSIONS Our results show that this animal model shows similar neural changes in the retina and brain visual cortex, i.e., retinal and brain thinning. Moreover, since similar changes occur in the retina and brain visual cortex, these observations support the possibility of using the eye as an additional tool (noninvasive) for early AD diagnosis and therapeutic monitoring.
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Affiliation(s)
- Samuel Chiquita
- Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, University of Coimbra, 3000-548, Coimbra, Portugal.,CNC.IBILI Consortium, University of Coimbra, 3004-504, Coimbra, Portugal
| | - Elisa J Campos
- Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, University of Coimbra, 3000-548, Coimbra, Portugal.,CNC.IBILI Consortium, University of Coimbra, 3004-504, Coimbra, Portugal
| | - João Castelhano
- CNC.IBILI Consortium, University of Coimbra, 3004-504, Coimbra, Portugal.,Coimbra Institute for Biomedical Imaging and Translational Research (CIBIT), University of Coimbra, 3000-548, Coimbra, Portugal.,Institute for Nuclear Sciences Applied to Health (ICNAS), University of Coimbra, 3000-548, Coimbra, Portugal
| | - Mário Ribeiro
- CNC.IBILI Consortium, University of Coimbra, 3004-504, Coimbra, Portugal.,Coimbra Institute for Biomedical Imaging and Translational Research (CIBIT), University of Coimbra, 3000-548, Coimbra, Portugal.,Institute for Nuclear Sciences Applied to Health (ICNAS), University of Coimbra, 3000-548, Coimbra, Portugal
| | - José Sereno
- CNC.IBILI Consortium, University of Coimbra, 3004-504, Coimbra, Portugal.,Coimbra Institute for Biomedical Imaging and Translational Research (CIBIT), University of Coimbra, 3000-548, Coimbra, Portugal.,Institute for Nuclear Sciences Applied to Health (ICNAS), University of Coimbra, 3000-548, Coimbra, Portugal
| | - Paula I Moreira
- CNC.IBILI Consortium, University of Coimbra, 3004-504, Coimbra, Portugal.,Center for Neuroscience and Cell Biology (CNC), University of Coimbra, 3004-517, Coimbra, Portugal.,Institute of Physiology, Faculty of Medicine, University of Coimbra, 3004-517, Coimbra, Portugal
| | - Miguel Castelo-Branco
- CNC.IBILI Consortium, University of Coimbra, 3004-504, Coimbra, Portugal. .,Coimbra Institute for Biomedical Imaging and Translational Research (CIBIT), University of Coimbra, 3000-548, Coimbra, Portugal. .,Institute for Nuclear Sciences Applied to Health (ICNAS), University of Coimbra, 3000-548, Coimbra, Portugal.
| | - António Francisco Ambrósio
- Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, University of Coimbra, 3000-548, Coimbra, Portugal. .,CNC.IBILI Consortium, University of Coimbra, 3004-504, Coimbra, Portugal.
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14
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Yan B, Wang H, Tan Y, Fu W. microRNAs in Cardiovascular Disease: Small Molecules but Big Roles. Curr Top Med Chem 2019; 19:1918-1947. [PMID: 31393249 DOI: 10.2174/1568026619666190808160241] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 06/01/2019] [Accepted: 07/25/2019] [Indexed: 01/01/2023]
Abstract
microRNAs (miRNAs) are an evolutionarily conserved class of small single-stranded noncoding RNAs. The aberrant expression of specific miRNAs has been implicated in the development and progression of diverse cardiovascular diseases. For many decades, miRNA therapeutics has flourished, taking advantage of the fact that miRNAs can modulate gene expression and control cellular phenotypes at the posttranscriptional level. Genetic replacement or knockdown of target miRNAs by chemical molecules, referred to as miRNA mimics or inhibitors, has been used to reverse their abnormal expression as well as their adverse biological effects in vitro and in vivo in an effort to fully implement the therapeutic potential of miRNA-targeting treatment. However, the limitations of the chemical structure and delivery systems are hindering progress towards clinical translation. Here, we focus on the regulatory mechanisms and therapeutic trials of several representative miRNAs in the context of specific cardiovascular diseases; from this basic perspective, we evaluate chemical modifications and delivery vectors of miRNA-based chemical molecules and consider the underlying challenges of miRNA therapeutics as well as the clinical perspectives on their applications.
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Affiliation(s)
- Bingqian Yan
- Institute of Pediatric Translational Medicine, Shanghai Children's Medical Center, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China
| | - Huijing Wang
- Institute of Pediatric Translational Medicine, Shanghai Children's Medical Center, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China
| | - Yao Tan
- Institute of Pediatric Translational Medicine, Shanghai Children's Medical Center, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China
| | - Wei Fu
- Institute of Pediatric Translational Medicine, Shanghai Children's Medical Center, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China.,Department of Pediatric Cardiothoracic Surgery, Shanghai Children's Medical Center, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China.,Shanghai Key Laboratory of Tissue Engineering, Shanghai 9th People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200011, China
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15
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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: 23] [Impact Index Per Article: 4.6] [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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16
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King JL, Wong AA, Brown RE. Age-Related Changes in the Spatial Frequency Threshold of Male and Female 3xTg-AD Mice Using OptoMotry. J Alzheimers Dis 2019; 62:591-596. [PMID: 29480178 DOI: 10.3233/jad-170805] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Visual impairments and retinal abnormalities occur in patients with Alzheimer's disease (AD) and in mouse models of AD. It is important to know the visual ability of mouse models of AD to ensure that age-related cognitive deficits are not confounded by visual impairments. Using OptoMotry, the spatial frequency thresholds of male and female 3xTg-AD mice did not differ from their B6129SF2 wildtype controls between 1-18 months of age, but females had higher spatial frequency thresholds than males. However, the differences were quite small, and the visual ability of all mice was comparable to that of C57BL/6 mice.
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Affiliation(s)
- Jillian L King
- Department of Psychology and Neuroscience, Dalhousie University, Halifax, NS, Canada
| | - Aimée A Wong
- Department of Psychology and Neuroscience, Dalhousie University, Halifax, NS, Canada
| | - Richard E Brown
- Department of Psychology and Neuroscience, Dalhousie University, Halifax, NS, Canada
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17
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Chiquita S, Rodrigues-Neves AC, Baptista FI, Carecho R, Moreira PI, Castelo-Branco M, Ambrósio AF. The Retina as a Window or Mirror of the Brain Changes Detected in Alzheimer's Disease: Critical Aspects to Unravel. Mol Neurobiol 2019; 56:5416-5435. [PMID: 30612332 DOI: 10.1007/s12035-018-1461-6] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 12/17/2018] [Indexed: 11/24/2022]
Abstract
Alzheimer's disease is the most frequent cause of dementia worldwide, representing a global health challenge, with a massive impact on the quality of life of Alzheimer's disease patients and their relatives. The diagnosis of Alzheimer's disease constitutes a real challenge, because the symptoms manifest years after the first degenerative changes occurring in the brain and the diagnosis is based on invasive and/or expensive techniques. Therefore, there is an urgent need to identify new reliable biomarkers to detect Alzheimer's disease at an early stage. Taking into account the evidence for visual deficits in Alzheimer's disease patients, sometimes even before the appearance of the first disease symptoms, and that the retina is an extension of the brain, the concept of the retina as a window to look into the brain or a mirror of the brain has received increasing interest in recent years. However, only a few studies have assessed the changes occurring in the retina and the brain at the same time points. Unlike previous reviews on this subject, which are mainly focused on brain changes, we organized this review by comprehensively summarizing findings related with structural, functional, cellular, and molecular parameters in the retina reported in both Alzheimer's disease patients and animal models. Moreover, we separated the studies that assessed only the retina, and those that assessed both the retina and brain, which are few but allow establishing correlations between the retina and brain. This review also highlights some inconsistent results in the literature as well as relevant missing gaps in this field.
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Affiliation(s)
- Samuel Chiquita
- iCBR, Coimbra Institute for Clinical and Biomedical Research, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
- CNC.IBILI Consortium, University of Coimbra, Coimbra, Portugal
| | - Ana C Rodrigues-Neves
- iCBR, Coimbra Institute for Clinical and Biomedical Research, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
- CNC.IBILI Consortium, University of Coimbra, Coimbra, Portugal
| | - Filipa I Baptista
- iCBR, Coimbra Institute for Clinical and Biomedical Research, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
- CNC.IBILI Consortium, University of Coimbra, Coimbra, Portugal
| | - Rafael Carecho
- iCBR, Coimbra Institute for Clinical and Biomedical Research, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
- CNC.IBILI Consortium, University of Coimbra, Coimbra, Portugal
| | - Paula I Moreira
- CNC.IBILI Consortium, University of Coimbra, Coimbra, Portugal
- CNC, Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- Institute of Physiology, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Miguel Castelo-Branco
- CNC.IBILI Consortium, University of Coimbra, Coimbra, Portugal
- CIBIT, Coimbra Institute for Biomedical Imaging and Translational Research, ICNAS, Institute of Nuclear Sciences Applied to Health, University of Coimbra, Coimbra, Portugal
| | - António F Ambrósio
- iCBR, Coimbra Institute for Clinical and Biomedical Research, Faculty of Medicine, University of Coimbra, Coimbra, Portugal.
- CNC.IBILI Consortium, University of Coimbra, Coimbra, Portugal.
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18
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Zhang G, Wang X, Gillette TG, Deng Y, Wang ZV. Unfolded Protein Response as a Therapeutic Target in Cardiovascular Disease. Curr Top Med Chem 2019; 19:1902-1917. [PMID: 31109279 PMCID: PMC7024549 DOI: 10.2174/1568026619666190521093049] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2019] [Revised: 04/09/2019] [Accepted: 05/02/2019] [Indexed: 12/15/2022]
Abstract
Cardiovascular disease is the leading cause of death worldwide. Despite overwhelming socioeconomic impact and mounting clinical needs, our understanding of the underlying pathophysiology remains incomplete. Multiple forms of cardiovascular disease involve an acute or chronic disturbance in cardiac myocytes, which may lead to potent activation of the Unfolded Protein Response (UPR), a cellular adaptive reaction to accommodate protein-folding stress. Accumulation of unfolded or misfolded proteins in the Endoplasmic Reticulum (ER) elicits three signaling branches of the UPR, which otherwise remain quiescent. This ER stress response then transiently suppresses global protein translation, augments production of protein-folding chaperones, and enhances ER-associated protein degradation, with an aim to restore cellular homeostasis. Ample evidence has established that the UPR is strongly induced in heart disease. Recently, the mechanisms of action and multiple pharmacological means to favorably modulate the UPR are emerging to curb the initiation and progression of cardiovascular disease. Here, we review the current understanding of the UPR in cardiovascular disease and discuss existing therapeutic explorations and future directions.
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Affiliation(s)
- Guangyu Zhang
- Division of Cardiology, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Xiaoding Wang
- Division of Cardiology, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Thomas G. Gillette
- Division of Cardiology, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Yingfeng Deng
- Touchstone Diabetes Center, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Zhao V. Wang
- Division of Cardiology, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, United States
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19
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Dong Z, Luo A, Gan Y, Li J. Amyloid Beta Deposition Could Cause Corneal Epithelial Cell Degeneration Associated with Increasing Apoptosis in APPswePS1 Transgenic Mice. Curr Eye Res 2018; 43:1326-1333. [PMID: 30015526 DOI: 10.1080/02713683.2018.1501070] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
OBJECTIVE To investigate the expression of amyloid precursor protein (APP) and amyloid beta (Aβ) in cornea and further explore the pathological and ultrastructural changes in corneal epithelium in APPswePS1 transgenic mice. METHODS Twelve wild type mice were grouped into control group and twelve TgAPPswePS1 mice at least 8 months old were grouped into the young experiment group (Tg-8M group), and another twelve transgenic mice at least 15 months old were selected into the aged experiment group (Tg-15M group). The pathological degeneration, ultrastructural changes, and the expression of APP, Aβ deposition, and the TUNEL reaction in corneal epithelial cells were observed. Western blot analysis was performed to determine expression levels of APP and Aβ with scraped epithelial debridement. All the results were quantified and analyzed. RESULTS In transgenic mice, the H&E-stained cornea sections demonstrated histopathological changes in corneal epithelial cells with irregular arrangement and the number of cell layers decreased, while normal structure observed in controls. In Tg-15M group, the corneal epithelial cell displaced a significant number of intracellular vacuoles with 1-2 cell layers left. Transmission electron microscopy (TEM) further confirmed the dramatic degeneration in corneal epithelium, the microvilli suffered degenerative changes and found with typical fingerpoint-like morphology in controls; however, microspike-like in Tg-15M group, and the number of microvilli decreased considerabely. An APP-positive immunoreaction was detected with a diffuse pattern in the corneal epithelial cells layer, about 3.122 ± 0.596 and 7.372 ± 0.936 fold changes in Tg-8M and Tg-15M groups, respectively, as compared with controls. On corneal flatmount, Aβ deposition found a diffuse pattern in the cytoplasm by fluorescence staining in TgAPPswePS1 with significantly increasing as compared with the controls, but no plaque was found. The apoptosis of TUNEL cells were observed in TgAPPswePS1 mice and increased 16.329 ± 3.542 fold changes in Tg-15M group as compared with controls. CONCLUSION The APP expression and Aβ deposition might cause cornea epithelial cells degeneration in TgAPPswePS1 mice, associated with apoptosis in basal lamina cells.
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Affiliation(s)
- Zhizhang Dong
- a Department of Ophthalmology , The second Affiliated Hospital and Yuying Children' s Hospital of Wenzhou Medical University , Wenzhou , Zhejiang Province , China
| | - Ali Luo
- b Department of Pathology , the Chest Hospital of Xi 'an , Xi'an , Shaanxi Province , China
| | - Yifeng Gan
- c Physical Emergency Department , The second Affiliated Hospital and Yuying Children' s Hospital of Wenzhou Medical University , Wenzhou , Zhejiang Province , China
| | - Juan Li
- d Shaanxi Ophthalmic Medical Center, Xi'an No. 4 Hospital , Guangren Hospital Affiliated to School of Medicine of Xi'an Jiaotong University , Xi'an , Shaanxi Province , China
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20
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Chidlow G, Wood JPM, Manavis J, Finnie J, Casson RJ. Investigations into Retinal Pathology in the Early Stages of a Mouse Model of Alzheimer's Disease. J Alzheimers Dis 2018; 56:655-675. [PMID: 28035930 PMCID: PMC5271427 DOI: 10.3233/jad-160823] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
There is increasing recognition that visual performance is impaired in early stages of Alzheimer’s disease (AD); however, no consensus exists as to the mechanisms underlying this visual dysfunction, in particular regarding the timing, nature, and extent of retinal versus cortical pathology. If retinal pathology presents sufficiently early, it offers great potential as a source of novel biomarkers for disease diagnosis. The current project utilized an array of immunochemical and molecular tools to perform a characterization of retinal pathology in the early stages of disease progression using a well-validated mouse model of AD (APPSWE/PS1ΔE9). Analytical endpoints included examination of aberrant amyloid and tau in the retina, quantification of any neuronal degeneration, delineation of cellular stress responses of neurons and particularly glial cells, and investigation of oxidative stress. Brain, eyes, and optic nerves were taken from transgenic and wild-type mice of 3 to 12 months of age and processed for immunohistochemistry, qPCR, or western immunoblotting. The results revealed robust expression of the human APP transgene in the retinas of transgenic mice, but a lack of identifiable retinal pathology during the period when amyloid deposits were dramatically escalating in the brain. We were unable to demonstrate the presence of amyloid plaques, dystrophic neurites, neuronal loss, macro- or micro-gliosis, aberrant cell cycle re-entry, oxidative stress, tau hyperphosphorylation, or upregulations of proinflammatory cytokines or stress signaling molecules in the retina. The overall results do not support the hypothesis that detectable retinal pathology occurs concurrently with escalating amyloid deposition in the brains of APPSWE/PS1ΔE9 mice.
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Affiliation(s)
- Glyn Chidlow
- Ophthalmic Research Laboratories, Hanson Institute Centre for Neurological Diseases, Adelaide, SA, Australia.,Department of Ophthalmology and Visual Sciences, University of Adelaide, Adelaide, SA, Australia
| | - John P M Wood
- Ophthalmic Research Laboratories, Hanson Institute Centre for Neurological Diseases, Adelaide, SA, Australia.,Department of Ophthalmology and Visual Sciences, University of Adelaide, Adelaide, SA, Australia
| | - Jim Manavis
- School of Medicine, University of Adelaide, Adelaide, SA, Australia
| | - John Finnie
- School of Medicine, University of Adelaide, Adelaide, SA, Australia.,SA Pathology, Hanson Institute Centre for Neurological Diseases, Adelaide, SA, Australia
| | - Robert J Casson
- Ophthalmic Research Laboratories, Hanson Institute Centre for Neurological Diseases, Adelaide, SA, Australia.,Department of Ophthalmology and Visual Sciences, University of Adelaide, Adelaide, SA, Australia
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21
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Li Y, Chang L, Song Y, Gao X, Roselli F, Liu J, Zhou W, Fang Y, Ling W, Li H, Almeida OFX, Wu Y. Astrocytic GluN2A and GluN2B Oppose the Synaptotoxic Effects of Amyloid-β1-40 in Hippocampal Cells. J Alzheimers Dis 2018; 54:135-48. [PMID: 27497478 DOI: 10.3233/jad-160297] [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] [Indexed: 01/25/2023]
Abstract
Early-stage Alzheimer's disease (AD) is characterized by synaptic dysfunction, a phenomenon in which soluble oligomers of amyloid-beta (Aβ) and N-methyl-D-aspartate receptor (NMDAR) are implicated. Here, we demonstrated that astrocytes express NMDARs and therefore have the potential to modulate the synaptotoxic actions of Aβ. We found that specific pharmacological antagonism of two of the major NMDAR subunits, GluN2A and GluN2B, exacerbates Aβ-induced synaptotoxicity suggesting, for the first time, that astrocytic GluN2A and GluN2B mediate synaptoprotection. From the perspective of the pathogenic mechanisms of Alzheimer's disease, in which Aβ and NMDAR play significant roles, these observations are striking since neuronal GluN2A and GluN2B are well known modulators of neurodegeneration. We did initial studies to understand the basis for the differential effects of astrocytic and neuronal GluN2A and GluN2B in the promotion of synapse survival, and identified a neurotrophin produced by astrocytes, nerve growth factor β (β-NGF), as a likely mediator of the synaptoprotective effects of astrocytic GluN2A and GluN2B activation. The results presented suggest that astrocytes may be suitable druggable targets for the prevention and/or delay of the synaptic loss that occurs during early stages of AD.
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Affiliation(s)
- Yan Li
- Department of Anatomy, Ministry of Science and Technology Laboratory of Brain Disorders, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China
| | - Lirong Chang
- Department of Anatomy, Ministry of Science and Technology Laboratory of Brain Disorders, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China
| | - Yizhi Song
- Department of Anatomy, Ministry of Science and Technology Laboratory of Brain Disorders, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China
| | - Xianghong Gao
- Department of Anatomy, Ministry of Science and Technology Laboratory of Brain Disorders, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China
| | - Francesco Roselli
- Departments of Neurology and Anatomy, University of Ulm School of Medicine, Germany.,Max Planck Institute of Psychiatry, Munich, Germany
| | - Jinping Liu
- School of Medicine, Tsinghua University, Beijing, China
| | - Wei Zhou
- Department of Anatomy, Ministry of Science and Technology Laboratory of Brain Disorders, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China
| | - Yuan Fang
- Department of Anatomy, Ministry of Science and Technology Laboratory of Brain Disorders, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China
| | - Wei Ling
- Department of Anatomy, Ministry of Science and Technology Laboratory of Brain Disorders, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China
| | - Hui Li
- Department of Anatomy, Ministry of Science and Technology Laboratory of Brain Disorders, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China
| | | | - Yan Wu
- Department of Anatomy, Ministry of Science and Technology Laboratory of Brain Disorders, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China
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22
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Pelak VS, Hills W. Vision in Alzheimer's disease: a focus on the anterior afferent pathway. Neurodegener Dis Manag 2018; 8:49-67. [PMID: 29359625 DOI: 10.2217/nmt-2017-0030] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Visual dysfunction has long been recognized as a manifestation of Alzheimer's disease (AD), particularly in the form of visuospatial impairment during all stages of disease. However, investigations have revealed findings within the anterior (i.e., pregeniculate) afferent visual pathways that rely on retinal imaging and electrophysiologic methodologies for detection. Here we focus on the anterior afferent visual pathways in AD and the measures used for assessment, including optical coherence tomography, electrophysiology, color vision testing and threshold visual field perimetry. A brief summary of higher order visual dysfunction is also included to allow the reader to keep in context the broader findings of afferent visual dysfunction in AD.
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Affiliation(s)
- Victoria S Pelak
- Departments of Neurology & Ophthalmology, The Rocky Mountain Lions Eye Institute, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - William Hills
- Departments of Ophthalmology & Neurology, Casey Eye Institute, Oregon Health & Science University, Portland, OR 97239, USA
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23
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Beta-amyloid sequelae in the eye: a critical review on its diagnostic significance and clinical relevance in Alzheimer's disease. Mol Psychiatry 2017; 22:353-363. [PMID: 28093567 DOI: 10.1038/mp.2016.251] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Revised: 10/31/2016] [Accepted: 11/22/2016] [Indexed: 01/14/2023]
Abstract
Alzheimer's disease (AD) is a progressive and fatal neurodegenerative disorder. There is no test for its definitive diagnosis in routine clinical practice. Although phase III clinical trials have failed, only symptomatic treatment is currently available; a possible reason for these failed trials is that intervention commenced at an advanced stage of the disease. The hallmarks of an AD brain include plaques comprising of extracellular beta-amyloid (Aβ) protein aggregates and intracellular hyperphosphorylated neurofibrillary tangles of tau. Research into the preclinical diagnosis of AD has provided considerable evidence regarding early neuropathological changes using brain Aβ imaging and the cerebrospinal fluid biomarkers, Aβ and tau. Both these approaches have limitations that are expensive, invasive or time consuming and thus preclude them from screening at-risk population. Recent studies have demonstrated the presence of Aβ plaques in the eyes of AD subjects, which is positively associated with their brain Aβ burden. Thus ocular biomarkers point to a potential avenue for an earlier, relatively low-cost diagnosis in order for therapeutic interventions to be effective. Here we review the literature that spans the investigation for the presence of Aβ in aging eyes and the significance of its deposition in relation to AD pathology. We discuss clinical studies investigating in vivo imaging of Aβ in the eye and its association with brain Aβ burden and therapies that target ocular Aβ. Finally, we focus on the need to characterize AD-specific retinal Aβ to differentiate Aβ found in some eye diseases. Based on the current evidence, we conclude that integration of ocular biomarkers that can correctly predict brain Aβ burden would have an important role as a non-invasive, yet economical surrogate marker in the diagnostic process of AD.
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24
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Nguyen CTO, Hui F, Charng J, Velaedan S, van Koeverden AK, Lim JKH, He Z, Wong VHY, Vingrys AJ, Bui BV, Ivarsson M. Retinal biomarkers provide "insight" into cortical pharmacology and disease. Pharmacol Ther 2017; 175:151-177. [PMID: 28174096 DOI: 10.1016/j.pharmthera.2017.02.009] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The retina is an easily accessible out-pouching of the central nervous system (CNS) and thus lends itself to being a biomarker of the brain. More specifically, the presence of neuronal, vascular and blood-neural barrier parallels in the eye and brain coupled with fast and inexpensive methods to quantify retinal changes make ocular biomarkers an attractive option. This includes its utility as a biomarker for a number of cerebrovascular diseases as well as a drug pharmacology and safety biomarker for the CNS. It is a rapidly emerging field, with some areas well established, such as stroke risk and multiple sclerosis, whereas others are still in development (Alzheimer's, Parkinson's, psychological disease and cortical diabetic dysfunction). The current applications and future potential of retinal biomarkers, including potential ways to improve their sensitivity and specificity are discussed. This review summarises the existing literature and provides a perspective on the strength of current retinal biomarkers and their future potential.
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Affiliation(s)
- Christine T O Nguyen
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, 3010, Victoria, Australia.
| | - Flora Hui
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, 3010, Victoria, Australia
| | - Jason Charng
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, 3010, Victoria, Australia
| | - Shajan Velaedan
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, 3010, Victoria, Australia
| | - Anna K van Koeverden
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, 3010, Victoria, Australia
| | - Jeremiah K H Lim
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, 3010, Victoria, Australia
| | - Zheng He
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, 3010, Victoria, Australia
| | - Vickie H Y Wong
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, 3010, Victoria, Australia
| | - Algis J Vingrys
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, 3010, Victoria, Australia
| | - Bang V Bui
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, 3010, Victoria, Australia
| | - Magnus Ivarsson
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, 3010, Victoria, Australia
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25
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Leinonen H, Lipponen A, Gurevicius K, Tanila H. Normal Amplitude of Electroretinography and Visual Evoked Potential Responses in AβPP/PS1 Mice. J Alzheimers Dis 2016; 51:21-6. [PMID: 26836173 DOI: 10.3233/jad-150798] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Alzheimer's disease has been shown to affect vision in human patients and animal models. This may pose the risk of bias in behavior studies and therefore requires comprehensive investigation. We recorded electroretinography (ERG) under isoflurane anesthesia and visual evoked potentials (VEP) in awake amyloid expressing AβPPswe/PS1dE9 (AβPP/PS1) and wild-type littermate mice at a symptomatic age. The VEPs in response to patterned stimuli were normal in AβPP/PS1 mice. They also showed normal ERG amplitude but slightly shortened ERG latency in dark-adapted conditions. Our results indicate subtle changes in visual processing in aged male AβPP/PS1 mice specifically at a retinal level.
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26
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Chang L, Zhang Y, Liu J, Song Y, Lv A, Li Y, Zhou W, Yan Z, Almeida OFX, Wu Y. Differential Regulation of N-Methyl-D-Aspartate Receptor Subunits is an Early Event in the Actions of Soluble Amyloid-β(1-40) Oligomers on Hippocampal Neurons. J Alzheimers Dis 2016; 51:197-212. [PMID: 26836185 DOI: 10.3233/jad-150942] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Synaptic dysfunction during early stages of Alzheimer's disease (AD) is triggered by soluble amyloid-β (Aβ) oligomers that interact with NMDA receptors (NMDARs). We previously showed that Aβ induces synaptic protein loss through NMDARs, albeit through undefined mechanisms. Accordingly, we here examined the contribution of individual NMDAR subunits to synaptotoxicity and demonstrate that Aβ exerts differential effects on the levels and distribution of GluN2A and GluN2B subunits of NMDAR in dendrites. Treatment of cultured hippocampal neurons with Aβ1-40 (10 μM, 1 h) induced a significant increase of dendritic and synaptic GluN2B puncta densities with parallel decreases in the puncta densities of denritic and synaptic pTyr1472-GluN2B. Conversely, Aβ significantly decreased dendritic and synaptic GluN2A and dendritic pTyr1325-GluN2A puncta densities and increased synaptic pTyr1325-GluN2A puncta densities. Unexpectedly, Aβ treatment resulted in a significant reduction of GluN2B and pTyr1472-GluN2B protein levels but did not influence GluN2A and pTyr1325-GluN2A levels. These results show that Aβ exerts complex and distinct regulatory effects on the trafficking and phosphorylation of GluN2A and GluN2B, as well as on their localization within synaptic and non-synaptic sites. Increased understanding of these early events in Aβ-induced synaptic dysfunction is likely to be important for the development of timely preventive and therapeutic interventions.
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Affiliation(s)
- Lirong Chang
- Department of Anatomy, Ministry of Science and Technology Laboratory of Brain Disorders, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China
| | - Yali Zhang
- Department of Anatomy, Ministry of Science and Technology Laboratory of Brain Disorders, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China
| | - Jinping Liu
- School of Medicine, Tsinghua University, Beijing, China
| | - Yizhi Song
- Department of Anatomy, Ministry of Science and Technology Laboratory of Brain Disorders, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China
| | - Angchu Lv
- Department of Anatomy, Ministry of Science and Technology Laboratory of Brain Disorders, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China
| | - Yan Li
- Department of Anatomy, Ministry of Science and Technology Laboratory of Brain Disorders, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China
| | - Wei Zhou
- Department of Anatomy, Ministry of Science and Technology Laboratory of Brain Disorders, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China
| | - Zhen Yan
- Department of Anatomy, Ministry of Science and Technology Laboratory of Brain Disorders, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China.,Department of Physiology and Biophysics, State University of New York at Buffalo, School of Medicine and Biomedical Sciences, Buffalo, NY, USA
| | | | - Yan Wu
- Department of Anatomy, Ministry of Science and Technology Laboratory of Brain Disorders, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China
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27
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Lim JKH, Li QX, He Z, Vingrys AJ, Wong VHY, Currier N, Mullen J, Bui BV, Nguyen CTO. The Eye As a Biomarker for Alzheimer's Disease. Front Neurosci 2016; 10:536. [PMID: 27909396 PMCID: PMC5112261 DOI: 10.3389/fnins.2016.00536] [Citation(s) in RCA: 113] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Accepted: 11/03/2016] [Indexed: 01/08/2023] Open
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disorder resulting in dementia and eventual death. It is the leading cause of dementia and the number of cases are projected to rise in the next few decades. Pathological hallmarks of AD include the presence of hyperphosphorylated tau and amyloid protein deposition. Currently, these pathological biomarkers are detected either through cerebrospinal fluid analysis, brain imaging or post-mortem. Though effective, these methods are not widely available due to issues such as the difficulty in acquiring samples, lack of infrastructure or high cost. Given that the eye possesses clear optics and shares many neural and vascular similarities to the brain, it offers a direct window to cerebral pathology. These unique characteristics lend itself to being a relatively inexpensive biomarker for AD which carries the potential for wide implementation. The development of ocular biomarkers can have far implications in the discovery of treatments which can improve the quality of lives of patients. In this review, we consider the current evidence for ocular biomarkers in AD and explore potential future avenues of research in this area.
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Affiliation(s)
- Jeremiah K H Lim
- Department of Optometry and Vision Sciences, University of Melbourne Melbourne, VIC, Australia
| | - Qiao-Xin Li
- Melbourne Brain Centre, The Florey Institute of Neuroscience and Mental Health Parkville, VIC, Australia
| | - Zheng He
- Department of Optometry and Vision Sciences, University of Melbourne Melbourne, VIC, Australia
| | - Algis J Vingrys
- Department of Optometry and Vision Sciences, University of Melbourne Melbourne, VIC, Australia
| | - Vickie H Y Wong
- Department of Optometry and Vision Sciences, University of Melbourne Melbourne, VIC, Australia
| | | | | | - Bang V Bui
- Department of Optometry and Vision Sciences, University of Melbourne Melbourne, VIC, Australia
| | - Christine T O Nguyen
- Department of Optometry and Vision Sciences, University of Melbourne Melbourne, VIC, Australia
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28
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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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29
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Kristofikova Z, Ricny J, Sirova J, Ripova D, Lubitz I, Schnaider-Beeri M. Differences Between Tg2576 and Wild Type Mice in the NMDA Receptor-Nitric Oxide Pathway After Prolonged Application of a Diet High in Advanced Glycation End Products. Neurochem Res 2015; 40:1709-18. [PMID: 26189181 DOI: 10.1007/s11064-015-1654-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 06/25/2015] [Accepted: 06/28/2015] [Indexed: 10/23/2022]
Abstract
It has been suggested that advanced glycation end (AGE) products, via cognate receptor activation, are implicated in several diseases, including Alzheimer's disease. The NMDA receptor-nitric oxide pathway appears to be influenced by AGE products and involved in the pathogenesis of this type of dementia. In this study, C57BL/6J (WT) and transgenic (Tg2576) mice expressing human mutant amyloid precursor protein were kept on prolonged (8 months) diets containing regular or high amounts of AGE products. After the decapitation of 11-months old mice, brain tissue analyses were performed [expressions of the NR1, NR2A and NR2B subunits of NMDA receptors, activities of neuronal, endothelial and inducible nitric oxide synthase (nNOS, eNOS and iNOS)]. Moreover, levels of malondialdehyde and of human amyloid β 1-42 were estimated. We found increased activity of nNOS in WT mice maintained on a high compared to regular AGE diet; however, no similar differences were found in Tg2576 mice. In addition, we observed an increase in NR1 expression in Tg2576 compared to WT mice, both kept on a diet high in AGE products. Correlation analyses performed on mice kept on the regular AGE diet supported close links between particular subunits (NR2A-NR2B, in WT as well as in Tg2576 mice), between subunits and synthase (NR2A/NR2B-nNOS, only in WT mice) or between particular synthases (nNOS-iNOS, only in WT). Correlation analysis also revealed differences between WT mice kept on both diets (changed correlations between NR2A/NR2B-nNOS, between nNOS-eNOS and between eNOS-iNOS). Malondialdehyde levels were increased in both Tg2576 groups when compared to the corresponding WT mice, but no effects of the diets were observed. Analogously, no significant effects of diets were found in the levels of soluble or insoluble amyloid β 1-42 in Tg2576 mice. Our results demonstrate that prolonged ingestion of AGE products can influence the NMDA receptor-nitric oxide pathway in the brain and that only WT mice, not Tg2576 mice, are able to maintain homeostasis among subunits and synthases or among particular synthases. The prolonged application of AGE products enhanced differences between 11-months old Tg2576 and WT mice regarding this pathway. Observed differences in the pathway between WT mice kept on regular or high AGE diets suggest that the prolonged application of a diet low in AGE products could have beneficial effects in older or diabetic people and perhaps also in people with Alzheimer's disease.
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Affiliation(s)
- Zdena Kristofikova
- Alzheimer's Disease Center, National Institute of Mental Health, Topolova 748, 250 67, Klecany, Czech Republic,
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30
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Dehabadi MH, Davis BM, Wong TK, Cordeiro MF. Retinal manifestations of Alzheimer's disease. Neurodegener Dis Manag 2015; 4:241-52. [PMID: 25095818 DOI: 10.2217/nmt.14.19] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Alzheimer's disease (AD) is neurodegenerative condition and most common cause of dementia worldwide. Current criteria for its diagnosis and monitoring rely on subjective, expensive or invasive methods that lack sufficient sensitivity, such that a concrete diagnosis of AD can only be made postmortem. Given the structural similarities of the neuro-retina and central nervous system, researchers have shown many manifestations of AD to be detectible in the retinae of humans and transgenic models of AD. Due to the eye's unique optical properties allowing noninvasive in vivo imaging, the retina could provide a window for the early diagnosis and monitoring of AD long before symptom manifestation.
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Affiliation(s)
- Mohammad H Dehabadi
- Glaucoma & Retinal Neurodegeneration Research Group, Visual Neuroscience, UCL Institute of Ophthalmology, London, UK
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31
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Ho WL, Leung Y, Cheng SSY, Lok CKM, Ho YS, Baum L, Yang X, Chiu K, Chang RCC. Investigating degeneration of the retina in young and aged tau P301L mice. Life Sci 2015; 124:16-23. [PMID: 25592136 DOI: 10.1016/j.lfs.2014.12.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Revised: 12/15/2014] [Accepted: 12/20/2014] [Indexed: 10/24/2022]
Abstract
AIMS Tau is a microtubule-binding protein facilitating the stability of the cytoskeleton. It is important for neurons as several neurodegenerative diseases involve hyperphosphorylation and aggregation of tau. It is known that mutated tau P301L results in aggregation of tau proteins, leading to neuronal loss in the brain. The aim of this study was to investigate the effect of tau mutation on the retina using a transgenic tau P301L mouse model. MAIN METHODS Morphometric analysis was utilized to quantify the neurodegenerative changes, including the thickness of the inner nuclear layer (INL), and the density and size of retinal ganglion cells (RGCs). Sections of retina tissue stained by hematoxylin and eosin (H&E) and immunohistochemistry were analyzed. Comparisons were made between the tau P301L mice and control mice, as well as between different age groups. KEY FINDINGS A significant decrease in the thickness of the INL in tau P301L mice was found when compared with that of control mice. The effect was more pronounced in the peripheral area, and the effect increased with age. Regarding density of RGCs, tau P301L mice showed a similar age-related decline as in control mice. Furthermore, the RGCs from tau P301L mice increased in size with age, and the RGCs from control mice decreased in size with age. SIGNIFICANCE Tau may be an age-independent factor of accelerated neurodegeneration, with effects differing by types of neurons and regions of the retina.
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Affiliation(s)
- Wing Lau Ho
- Laboratory of Neurodegenerative Diseases, Department of Anatomy, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Yen Leung
- Laboratory of Neurodegenerative Diseases, Department of Anatomy, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Sally Shuk Yee Cheng
- Laboratory of Neurodegenerative Diseases, Department of Anatomy, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Carmen Ka Ming Lok
- Laboratory of Neurodegenerative Diseases, Department of Anatomy, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Yuen-Shan Ho
- Laboratory of Neurodegenerative Diseases, Department of Anatomy, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, China; School of Nursing, Faculty of Health and Social Sciences, Hong Kong Polytechnic University, Hunghom, Kowloon, Hong Kong, China
| | - Larry Baum
- School of Pharmacy, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Xifei Yang
- Shenzhen Center of Disease Control and Prevention, Shenzhen, China
| | - Kin Chiu
- Laboratory of Neurodegenerative Diseases, Department of Anatomy, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, China; Department of Ophthalmology, LKS Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong, China.
| | - Raymond Chuen-Chung Chang
- Laboratory of Neurodegenerative Diseases, Department of Anatomy, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, China; Research Centre of Heart, Brain, Hormone and Healthy Aging, LKS Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong, China; State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China.
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32
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At the interface of sensory and motor dysfunctions and Alzheimer's disease. Alzheimers Dement 2015; 11:70-98. [PMID: 25022540 PMCID: PMC4287457 DOI: 10.1016/j.jalz.2014.04.514] [Citation(s) in RCA: 360] [Impact Index Per Article: 40.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Revised: 03/13/2014] [Accepted: 04/09/2014] [Indexed: 11/21/2022]
Abstract
Recent evidence indicates that sensory and motor changes may precede the cognitive symptoms of Alzheimer's disease (AD) by several years and may signify increased risk of developing AD. Traditionally, sensory and motor dysfunctions in aging and AD have been studied separately. To ascertain the evidence supporting the relationship between age-related changes in sensory and motor systems and the development of AD and to facilitate communication between several disciplines, the National Institute on Aging held an exploratory workshop titled "Sensory and Motor Dysfunctions in Aging and AD." The scientific sessions of the workshop focused on age-related and neuropathologic changes in the olfactory, visual, auditory, and motor systems, followed by extensive discussion and hypothesis generation related to the possible links among sensory, cognitive, and motor domains in aging and AD. Based on the data presented and discussed at this workshop, it is clear that sensory and motor regions of the central nervous system are affected by AD pathology and that interventions targeting amelioration of sensory-motor deficits in AD may enhance patient function as AD progresses.
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Nagai N, Ito Y, Tanino T. Effect of High Glucose Levels on Amyloid β Production in Retinas of Spontaneous Diabetes Mellitus Otsuka Long-Evans Tokushima Fatty Rats. Biol Pharm Bull 2015; 38:601-10. [DOI: 10.1248/bpb.b14-00819] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Li JB, Lu ZG, Xu L, Wang Q, Zhang ZH, Fang JH. Neuroprotective effects of bis(7)-tacrine in a rat model of pressure-induced retinal ischemia. Cell Biochem Biophys 2014; 68:275-82. [PMID: 23832279 DOI: 10.1007/s12013-013-9707-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The retinal ischemia-reperfusion model has been studied extensively and is an ideal animal model for studying clinical situations such as acute glaucoma and optic neuropathy. Our previous reports showed that bis(7)-tacrine had neuroprotective effects against glutamate-induced retinal ganglion cells damage through the drug's anti-NMDA receptor effects. Here, we investigated whether bis(7)-tacrine protects the retina from ischemic injury in a rat model. Retinal ischemia was induced by raising the intraocular pressure to 120 mmHg for 90 min. Rats received intraperitoneal injections of 0.2 mg/kg bis(7)-tacrine or saline at 30 min before ischemia, and then twice a day after retinal ischemia. Morphometric evaluation showed that bis(7)-tacrine dramatically reduced the retinal damage compared with the control group. Moreover, bis(7)-tacrine suppressed ischemia-induced reductions in a- and b-wave amplitudes of electroretinography. Protein levels of p53, the tumor suppressor gene known to induce apoptosis, were increased after ischemic injury, and treatment with bis(7)-tacrine reduced the expression of the protein. Our results suggest that bis(7)-tacrine has a neuroprotective effect against ischemic injury in the rat retina, possibly through the drug's anti-apoptotic effects. Bis(7)-tacrine may potentially be useful as a therapeutic drug in the management of ischemic retinal diseases.
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Affiliation(s)
- Jing-bo Li
- Department of Ophthalmology, First Hospital of Jingzhou, Yangtze University, Jingzhou, 434000, Hubei, China
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Edwards MM, Rodríguez JJ, Gutierrez-Lanza R, Yates J, Verkhratsky A, Lutty GA. Retinal macroglia changes in a triple transgenic mouse model of Alzheimer's disease. Exp Eye Res 2014; 127:252-60. [PMID: 25149907 DOI: 10.1016/j.exer.2014.08.006] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Revised: 08/06/2014] [Accepted: 08/11/2014] [Indexed: 11/18/2022]
Abstract
The retinas of Alzheimer's disease (AD) patients and transgenic AD animal models display amyloid beta deposits and degeneration of ganglion cells. Little is known, however, about the glial changes in the AD retina. The present study used a triple transgenic mouse model (3xTG-AD), which carries mutated human amyloid precursor protein, tau, and presenilin 1 genes and closely mimics the human brain pathology, to investigate retinal glial changes in AD. AD cognitive symptoms are known to begin in the 3xTG-AD mice at four months of age but plaques and tangles are not seen until six to twelve months. Müller cells in 3xTG-AD animals were GFAP-positive, indicating activation, at the earliest time point investigated, nine months. Astrocyte activation was also suggested in the 3xTG-AD mice by an apparent increase in size and process number. Another glial marker, S100, was expressed by astrocytes in both the non-transgenic (NTG) controls and 3xTG-AD retinas. Labeling was predominantly nuclear in nine month non-transgenic (NTG) control mice but was also seen in the cytoplasm and processes at 18 months of age. Interestingly, the nuclear localization was not as prominent in the 3xTG-AD retina even at nine months with labeling observed in astrocyte processes. The diffusion of S100 suggests the possible secretion of this protein, as is seen in the brain, with age and, more profoundly, associated with AD. Several dense, abnormally shaped, opaque structures were noted in all 3xTG-AD mice investigated. These structures, which were enveloped by GFAP and S100-positive astrocytes and Müller cells, were positive for amyloid beta, suggesting that they are amyloid plaques. Staining control retinas with amyloid showed similar structures in 30% of NTG animals but these were fewer in number and not associated with glial activation. The results herein indicate retinal glia activation in the 3xTG-AD mouse retina.
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Affiliation(s)
- Malia M Edwards
- Wilmer Eye Institute, Johns Hopkins Hospital, M023 Smith Building, 400 N. Broadway, Baltimore, MD 21287, USA.
| | - José J Rodríguez
- Department of Neurosciences, University of Basque Country, UPV/EHU, Leioa, Spain; IKERBASQUE, Basque Foundation for Science, Bilbao, Spain.
| | | | - Joseph Yates
- Wilmer Eye Institute, Johns Hopkins Hospital, M023 Smith Building, 400 N. Broadway, Baltimore, MD 21287, USA.
| | - Alexei Verkhratsky
- Department of Neurosciences, University of Basque Country, UPV/EHU, Leioa, Spain; IKERBASQUE, Basque Foundation for Science, Bilbao, Spain; Faculty of Life Sciences, The University of Manchester, Oxford Road, Manchester M13 9PT, UK.
| | - Gerard A Lutty
- Wilmer Eye Institute, Johns Hopkins Hospital, M023 Smith Building, 400 N. Broadway, Baltimore, MD 21287, USA.
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Wang ZC, Zhao J, Li S. Dysregulation of synaptic and extrasynaptic N-methyl-D-aspartate receptors induced by amyloid-β. Neurosci Bull 2013; 29:752-60. [PMID: 24136243 DOI: 10.1007/s12264-013-1383-2] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2012] [Accepted: 02/25/2013] [Indexed: 02/07/2023] Open
Abstract
The toxicity of amyloid-beta (Aβ) is strongly associated with Alzheimer's disease (AD), which has a high incidence in the elderly worldwide. Recent evidence showed that alteration in the activity of N-methyl-D-aspartate receptors (NMDARs) plays a key role in Aβ-induced neurotoxicity. However, the activation of synaptic and extrasynaptic NMDARs has distinct consequences for plasticity, gene regulation, neuronal death, and Aβ production. This review focuses on the dysregulation of synaptic and extrasynaptic NMDARs induced by Aβ. On one hand, Aβ downregulates the synaptic NMDAR response by promoting NMDAR endocytosis, leading to either neurotoxicity or neuroprotection. On the other hand, Aβ enhances the activation of extrasynaptic NMDARs by decreasing neuronal glutamate uptake and inducing glutamate spillover, subsequently causing neurotoxicity. In addition, selective enhancement of synaptic activity by low doses of NMDA, or reduction of extrasynaptic activity by memantine, a non-competitive NMDAR antagonist, halts Aβ-induced neurotoxicity. Therefore, future neuroprotective drugs for AD should aim at both the enhancement of synaptic activity and the disruption of extrasynaptic NMDAR-dependent death signaling.
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Affiliation(s)
- Zhi-Cong Wang
- Department of Physiology, Dalian Medical University, Dalian, 116044, China
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Nagai N, Ito Y. Excessive hydrogen peroxide enhances the attachment of amyloid β1-42 in the lens epithelium of UPL rats, a hereditary model for cataracts. Toxicology 2013; 315:55-64. [PMID: 23941810 DOI: 10.1016/j.tox.2013.08.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Revised: 08/03/2013] [Accepted: 08/03/2013] [Indexed: 01/09/2023]
Abstract
Several studies have reported that hydrogen peroxide (H2O2) is related to the toxicity of amyloid β (Aβ), and that the accumulation of Aβ in the lenses of humans causes lens opacification. In this study, we investigate the accumulation of Aβ1-42 in the lenses of UPL rats, which then leads to lens opacification. In addition, we demonstrate the effect of disulfiram eye drops (DSF), a potent radical scavenger, on Aβ1-42 accumulation in the lenses of UPL rats. The H2O2 levels in 46- to 60-day-old UPL rat lenses are significantly higher than in normal rats, and the Aβ1-42 levels in 53- and 60-day-old UPL rats are also increased only in lens epithelium containing capsules (capsule-epithelium), not in the lens cortex and nucleus. However, no increases in amyloid precursor protein (APP), β- or γ-secretase mRNA were observed in lenses of the corresponding ages. It has been thought that Aβ1-42 that accumulates in the lenses of UPL rats is actually produced in another tissue containing neuronal cells, such as brain or retina. Aβ1-42 levels in the brain and retina rise with aging, and the levels of APP, β- and γ-secretase mRNA in the retinas of 53-day-old UPL rats with opaque lenses are significantly higher than in 25-day-old UPL rats with transparent lenses. In contrast to the results in retinas, the levels of APP, β- and γ-secretase mRNA in the brains of 25- and 53-day-old UPL rats are similar. On the other hand, in an in vitro study, Aβ1-42 attachment in the lens capsule-epithelium of UPL rats was found to increase in H2O2. In addition, in an in vivo study, the inhibition of H2O2 by DSF was found to attenuate the increase in Aβ1-42 in the lens capsule-epithelium of 60-day-old UPL rats. Taken together, we hypothesize that excessive H2O2 in the lens enhances the attachment of Aβ1-42 in the lens capsule-epithelium of UPL rats, and that the instillation of DSF has the ability to attenuate the attachment of Aβ1-42 by inhibiting H2O2 production in lens. These findings provide significant information that can be used to design further studies aimed at developing anti-cataract drugs.
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Affiliation(s)
- Noriaki Nagai
- Faculty of Pharmacy, Kinki University, 3-4-1 Kowakae, Higashi-Osaka, Osaka 577-8502, Japan
| | - Yoshimasa Ito
- Faculty of Pharmacy, Kinki University, 3-4-1 Kowakae, Higashi-Osaka, Osaka 577-8502, Japan.
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Jindal V. Glaucoma: An Extension of Various Chronic Neurodegenerative Disorders. Mol Neurobiol 2013; 48:186-9. [DOI: 10.1007/s12035-013-8416-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2012] [Accepted: 01/29/2013] [Indexed: 10/27/2022]
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Gorbatyuk MS, Gorbatyuk OS. The Molecular Chaperone GRP78/BiP as a Therapeutic Target for Neurodegenerative Disorders: A Mini Review. ACTA ACUST UNITED AC 2013; 4. [PMID: 23750325 DOI: 10.4172/2157-7412.1000128] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The glucose regulated protein 78 (GRP78), also known as BiP, is the endoplasmatic reticulum (ER) homologue of HSP70, which plays a dual role in the ER by controlling protein folding, in order to prevent aggregation, and by regulating the signaling of the unfolded protein response (UPR). Most neurodegenerative disorders including Parkinson's, Alzheimer's diseases and progressive retinal degeneration are characterized by activation of the UPR and modified expression of GRP78. The expression levels and activity of GRP78 are altered with age raising the question of whether the lack of GRP78 could be a predisposing factor for many neurodegenerative disorders associated with age including PD, Alzheimer and Age-related macular degeneration. Attempts to induce or upregulate GRP78 in animal models of neurodegeneration have recently been made with the help of pharmacological BiP protein Inducer X (BIX) and GRP78 cDNA delivery via adeno-associated virus (AAV) vectors. The results of these studies validate GRP78 as a new therapeutic target for treatments of forebrain ischemia, Parkinson disease and retinal degeneration. These data, together with the results from age-related studies, highlight the importance for developing drugs to induce elevation of endogenous GRP78 in order to increase cellular survival and extend functional longevity.
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Affiliation(s)
- Marina S Gorbatyuk
- Department of Visual Sciences, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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Cao K, Farahi M, Dakanali M, Chang WM, Sigurdson CJ, Theodorakis EA, Yang J. Aminonaphthalene 2-cyanoacrylate (ANCA) probes fluorescently discriminate between amyloid-β and prion plaques in brain. J Am Chem Soc 2012; 134:17338-41. [PMID: 22866977 DOI: 10.1021/ja3063698] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
A major challenge for diagnosing and monitoring the progression of amyloid-based diseases is the capability to distinguish between amyloid deposits that are associated with related, but distinctly different, diseases. Here, we demonstrate that aminonaphthalenyl 2-cyanoacrylate-based probes can fluorescently discriminate between different types of amyloid deposits in brain. The discriminating capability of these molecular rotors is due to the stabilization of the ground versus excited states of these probes as a function of the polarity of their microenvironment (i.e., within the binding pocket on the amyloid). This property makes it possible, for the first time, to estimate the inherent static relative permittivity (ε(0)) of the binding pocket of each amyloid within tissue. The capability to selectively follow the deposition of specific amyloids in tissue may provide important information for therapeutic development that is not readily accessible from currently available technology.
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Affiliation(s)
- Kevin Cao
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093-0358, USA
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Parnell M, Guo L, Abdi M, Cordeiro MF. Ocular manifestations of Alzheimer's disease in animal models. Int J Alzheimers Dis 2012; 2012:786494. [PMID: 22666623 PMCID: PMC3362039 DOI: 10.1155/2012/786494] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2012] [Accepted: 03/11/2012] [Indexed: 12/29/2022] Open
Abstract
Alzheimer's disease (AD) is the most common form of dementia, and the pathological changes of senile plaques (SPs) and neurofibrillary tangles (NFTs) in AD brains are well described. Clinically, a diagnosis remains a postmortem one, hampering both accurate and early diagnosis as well as research into potential new treatments. Visual deficits have long been noted in AD patients, and it is becoming increasingly apparent that histopathological changes already noted in the brain also occur in an extension of the brain; the retina. Due to the optically transparent nature of the eye, it is possible to image the retina at a cellular level noninvasively and thus potentially allow an earlier diagnosis as well as a way of monitoring progression and treatment effects. Transgenic animal models expressing amyloid precursor protein (APP) presenilin (PS) and tau mutations have been used successfully to recapitulate the pathological findings of AD in the brain. This paper will cover the ocular abnormalities that have been detected in these transgenic AD animal models.
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Affiliation(s)
- Miles Parnell
- Glaucoma & Retinal Neurodegeneration Research Group, Visual Neuroscience, UCL Institute of Ophthalmology, London EC1V 9EL, UK
- Sutton Eye Unit, Epsom and St. Helier NHS Trust, Cotswold Road, Sutton, Surry, London, UK
| | - Li Guo
- Glaucoma & Retinal Neurodegeneration Research Group, Visual Neuroscience, UCL Institute of Ophthalmology, London EC1V 9EL, UK
| | - Mohamed Abdi
- St. Georges Healthcare NHS Trust, Blackshaw Road, Tooting, London, UK
| | - M. Francesca Cordeiro
- Glaucoma & Retinal Neurodegeneration Research Group, Visual Neuroscience, UCL Institute of Ophthalmology, London EC1V 9EL, UK
- Western Eye Hospital, Imperial College Healthcare Trust, London, UK
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Kur J, Newman EA, Chan-Ling T. Cellular and physiological mechanisms underlying blood flow regulation in the retina and choroid in health and disease. Prog Retin Eye Res 2012; 31:377-406. [PMID: 22580107 DOI: 10.1016/j.preteyeres.2012.04.004] [Citation(s) in RCA: 438] [Impact Index Per Article: 36.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2012] [Revised: 04/17/2012] [Accepted: 04/22/2012] [Indexed: 02/06/2023]
Abstract
We review the cellular and physiological mechanisms responsible for the regulation of blood flow in the retina and choroid in health and disease. Due to the intrinsic light sensitivity of the retina and the direct visual accessibility of fundus blood vessels, the eye offers unique opportunities for the non-invasive investigation of mechanisms of blood flow regulation. The ability of the retinal vasculature to regulate its blood flow is contrasted with the far more restricted ability of the choroidal circulation to regulate its blood flow by virtue of the absence of glial cells, the markedly reduced pericyte ensheathment of the choroidal vasculature, and the lack of intermediate filaments in choroidal pericytes. We review the cellular and molecular components of the neurovascular unit in the retina and choroid, techniques for monitoring retinal and choroidal blood flow, responses of the retinal and choroidal circulation to light stimulation, the role of capillaries, astrocytes and pericytes in regulating blood flow, putative signaling mechanisms mediating neurovascular coupling in the retina, and changes that occur in the retinal and choroidal circulation during diabetic retinopathy, age-related macular degeneration, glaucoma, and Alzheimer's disease. We close by discussing issues that remain to be explored.
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Affiliation(s)
- Joanna Kur
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA
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Amyloid precursor protein is required for normal function of the rod and cone pathways in the mouse retina. PLoS One 2012; 7:e29892. [PMID: 22279552 PMCID: PMC3261162 DOI: 10.1371/journal.pone.0029892] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2011] [Accepted: 12/07/2011] [Indexed: 01/01/2023] Open
Abstract
Amyloid precursor protein (APP) is a transmembrane glycoprotein frequently studied for its role in Alzheimer's disease. Our recent study in APP knockout (KO) mice identified an important role for APP in modulating normal neuronal development in the retina. However the role APP plays in the adult retina and whether it is required for vision is unknown. In this study we evaluated the role of APP in retinal function and morphology comparing adult wildtype (WT) and APP-KO mice. APP was expressed on neuronal cells of the inner retina, including horizontal, cone bipolar, amacrine and ganglion cells in WT mice. The function of the retina was assessed using the electroretinogram and although the rod photoreceptor responses were similar in APP-KO and WT mice, the post-photoreceptor, inner retinal responses of both the rod and cone pathways were reduced in APP-KO mice. These changes in inner retinal function did not translate to a substantial change in visual acuity as assessed using the optokinetic response or to changes in the gross cellular structure of the retina. These findings indicate that APP is not required for basic visual function, but that it is involved in modulating inner retinal circuitry.
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Baltmr A, Duggan J, Nizari S, Salt TE, Cordeiro MF. Neuroprotection in glaucoma - Is there a future role? Exp Eye Res 2010; 91:554-66. [PMID: 20800593 DOI: 10.1016/j.exer.2010.08.009] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2010] [Revised: 07/26/2010] [Accepted: 08/06/2010] [Indexed: 02/06/2023]
Abstract
In glaucoma, the major cause of global irreversible blindness, there is an urgent need for treatment modalities that directly target the RGCs. The discovery of an alternative therapeutic approach, independent of IOP reduction, is highly sought after, due to the indirect nature and limited effectiveness of IOP lowering therapy in preventing RGC loss. Several mechanisms have been implicated in initiating the apoptotic cascade in glaucomatous retinopathy and numerous drugs have been shown to be neuroprotective in animal models of glaucoma. These mechanisms and their potential treatment include excitotoxicity, protein misfolding, mitochondrial dysfunction, oxidative stress, inflammation and neurotrophin deprivation. All of these mechanisms ultimately lead to programmed cell death with loss of RGCs. In this article we summarize the mechanisms involved in glaucomatous disease, highlight the rationale for neuroprotection in glaucoma management and review current potential neuroprotective strategies targeting RGCs from the laboratory to the clinic.
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Affiliation(s)
- Abeir Baltmr
- Glaucoma and Retinal Neurodegeneration Research Group, Visual Neurosciences Department, University College London Institute of Ophthalmology, Bath Street, London EC1V 9EL, United Kingdom
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Tsuruma K, Tanaka Y, Shimazawa M, Hara H. Induction of amyloid precursor protein by the neurotoxic peptide, amyloid-beta 25-35, causes retinal ganglion cell death. J Neurochem 2010; 113:1545-54. [PMID: 20374419 DOI: 10.1111/j.1471-4159.2010.06724.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Patients with Alzheimer's disease (AD) show a significantly increased incidence of glaucoma. AD is also associated with the occurrence of the neurotoxic peptide amyloid beta (Abeta). Therefore, we investigated whether Abeta is associated with retinal cell death in a retinal ganglion cell line (RGC-5). Treatment with Abeta(25-35), a neurotoxic fragment of Abeta, induced cell death in RGC-5 in both a concentration- and time-dependent manner. The amount of amyloid precursor protein was increased by treatment of RGC-5 and primary culture of mouse cortical neurons with fibril Abeta(25-35) and Abeta(1-42), which is a putative physiological neurotoxic fragment of Abeta present in AD. Amyloid precursor protein knockdown inhibited the cell death induced by Abeta(25-35). Treatment with Abeta(25-35) increased the amount of intracellular Abeta(1-40) and Abeta(1-42), while beta- and gamma-secretase inhibitors reduced cell death. Thus, the regulation of Abeta can be viewed as a new therapeutic target for glaucoma, especially in patients with coincident AD.
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Affiliation(s)
- Kazuhiro Tsuruma
- Department of Biofunctional Evaluation, Molecular Pharmacology, Gifu Pharmaceutical University, Gifu, Japan
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Cordeiro MF, Guo L, Coxon KM, Duggan J, Nizari S, Normando EM, Sensi SL, Sillito AM, Fitzke FW, Salt TE, Moss SE. Imaging multiple phases of neurodegeneration: a novel approach to assessing cell death in vivo. Cell Death Dis 2010; 1:e3. [PMID: 21364622 PMCID: PMC3032512 DOI: 10.1038/cddis.2009.3] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2009] [Revised: 10/02/2009] [Accepted: 10/02/2009] [Indexed: 11/29/2022]
Abstract
Nerve cell death is the key event in all neurodegenerative disorders, with apoptosis and necrosis being central to both acute and chronic degenerative processes. However, until now, it has not been possible to study these dynamically and in real time. In this study, we use spectrally distinct, well-recognised fluorescent cell death markers to enable the temporal resolution and quantification of the early and late phases of apoptosis and necrosis of single nerve cells in different disease models. The tracking of single-cell death profiles in the same living eye over hours, days, weeks and months is a significant advancement on currently available techniques. We identified a numerical preponderance of late-phase versus early-phase apoptotic cells in chronic models, reinforcing the commonalities between cellular mechanisms in different disease models. We showed that MK801 effectively inhibited both apoptosis and necrosis, but our findings support the use of our technique to investigate more specific anti-apoptotic and anti-necrotic strategies with well-defined targets, with potentially greater clinical application. The optical properties of the eye provide compelling opportunities for the quantitative monitoring of disease mechanisms and dynamics in experimental neurodegeneration. Our findings also help to directly observe retinal nerve cell death in patients as an adjunct to refining diagnosis, tracking disease status and assessing therapeutic intervention.
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Affiliation(s)
- M F Cordeiro
- UCL Institute of Ophthalmology, University College London, London, UK.
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48
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Shimazawa M, Hara H. [Current therapeutic approaches and involvement of amyloid-beta in retinal diseases]. Nihon Yakurigaku Zasshi 2009; 134:309-314. [PMID: 20009363 DOI: 10.1254/fpj.134.309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
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Isas JM, Luibl V, Johnson LV, Kayed R, Wetzel R, Glabe CG, Langen R, Chen J. Soluble and mature amyloid fibrils in drusen deposits. Invest Ophthalmol Vis Sci 2009; 51:1304-10. [PMID: 19892876 DOI: 10.1167/iovs.09-4207] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Drusen are a hallmark of eyes affected by age-related macular degeneration. In previous study, a conformational-specific antibody showed drusen to contain nonfibrillar amyloid structures. The current study was undertaken to assess the presence of additional amyloid structures in drusen. METHODS Sections from human donor eyes were reacted with M204, a monoclonal antibody that recognizes nonfibrillar oligomers; OC, a polyclonal antibody that recognizes amyloid fibrils of various molecular weights; and WO1 and WO2, monoclonal antibodies that are specifically reactive to mature amyloid fibrils. Electron microscopy was used as an independent means of investigating the presence of amyloid fibrils in drusen. RESULTS The presence of nonfibrillar oligomers was verified using the M204 antibody. OC and WO antibodies stained a wide spectrum of vesicular structures. OC reactivity showed extensive overlap with Abeta immunoreactivity, whereas a partial overlap was seen between Abeta reactivity and that of the WO antibodies. The presence of amyloid fibrils was also visualized by electron microscopy. CONCLUSIONS These data reveal the presence of a wide spectrum of amyloid structures in drusen. The results are significant, given that specific conformational forms of amyloid are known to be pathogenic in a variety of neurodegenerative diseases. Deposition of these structures may lead to local toxicity of the retinal pigmented epithelium or induction of local inflammatory events that contribute to drusen biogenesis and the pathogenesis of AMD.
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Affiliation(s)
- J Mario Isas
- Department of Biochemistry and Molecular Biology, University of Southern California, Los Angeles, California, USA
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50
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Induction of cerebral beta-amyloidosis: intracerebral versus systemic Abeta inoculation. Proc Natl Acad Sci U S A 2009; 106:12926-31. [PMID: 19622727 DOI: 10.1073/pnas.0903200106] [Citation(s) in RCA: 211] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Despite the importance of the aberrant polymerization of Abeta in the early pathogenic cascade of Alzheimer's disease, little is known about the induction of Abeta aggregation in vivo. Here we show that induction of cerebral beta-amyloidosis can be achieved in many different brain areas of APP23 transgenic mice through the injection of dilute Abeta-containing brain extracts. Once the amyloidogenic process has been exogenously induced, the nature of the induced Abeta-deposition is determined by the brain region of the host. Because these observations are reminiscent of a prion-like mechanism, we then investigated whether cerebral beta-amyloidosis also can be induced by peripheral and systemic inoculations or by the intracerebral implantation of stainless steel wires previously coated with minute amounts of Abeta-containing brain extract. Results reveal that oral, intravenous, intraocular, and intranasal inoculations yielded no detectable induction of cerebral beta-amyloidosis in APP23 transgenic mice. In contrast, transmission of cerebral beta-amyloidosis through the Abeta-contaminated steel wires was demonstrated. Notably, plasma sterilization, but not boiling of the wires before implantation, prevented the induction of beta-amyloidosis. Our results suggest that minute amounts of Abeta-containing brain material in direct contact with the CNS can induce cerebral beta-amyloidosis, but that systemic cellular mechanisms of prion uptake and transport to the CNS may not apply to Abeta.
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