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Joseph S, Haystead A, Robbins CB, Threlfall A, MacGillivray TJ, Stinnett S, Grewal DS, Fekrat S. Analysis of the Retinal and Choroidal Vasculature Using Ultrawidefield Fundus Imaging in Mild Cognitive Impairment and Normal Cognition. OPHTHALMOLOGY SCIENCE 2024; 4:100480. [PMID: 38827032 PMCID: PMC11141260 DOI: 10.1016/j.xops.2024.100480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 01/22/2024] [Accepted: 01/23/2024] [Indexed: 06/04/2024]
Abstract
Purpose To utilize ultrawidefield (UWF) imaging to evaluate retinal and choroidal vasculature and structure in individuals with mild cognitive impairment (MCI) compared with that of controls with normal cognition. Design Prospective cross sectional study. Participants One hundred thirty-one eyes of 82 MCI patients and 230 eyes of 133 cognitively normal participants from the Eye Multimodal Imaging in Neurodegenerative Disease Study. Methods A scanning laser ophthalmoscope (California, Optos Inc) was used to obtain UWF fundus color images. Images were analyzed with the Vasculature Assessment Platform for Images of the Retina UWF (VAMPIRE-UWF 2.0, Universities of Edinburgh and Dundee) software. Main outcome measures Imaging parameters included vessel width gradient, vessel width intercept, large vessel choroidal vascular density, vessel tortuosity, and vessel fractal dimension. Results Both retinal artery and vein width gradients were less negative in MCI patients compared with controls, demonstrating decreased rates of vessel thinning at the periphery (P < 0.001; P = 0.027). Retinal artery and vein width intercepts, a metric that extrapolates the width of the vessel at the center of the optic disc, were smaller in MCI patients compared with that of controls (P < 0.001; P = 0.017). The large vessel choroidal vascular density, which quantifies the vascular area versus the total choroidal area, was greater in MCI patients compared with controls (P = 0.025). Conclusions When compared with controls with normal cognition, MCI patients had thinner retinal vasculature manifested in both the retinal arteries and the veins. In MCI, these thinner arteries and veins attenuated at a lower rate when traveling toward the periphery. MCI patients also had increased choroidal vascular density. Financial Disclosures Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.
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Affiliation(s)
- Suzanna Joseph
- Department of Ophthalmology, Duke University School of Medicine, Durham, North Carolina
- iMIND Research Group, Duke University School of Medicine, Durham, North Carolina
| | - Alice Haystead
- iMIND Research Group, Duke University School of Medicine, Durham, North Carolina
| | - Cason B. Robbins
- Department of Ophthalmology, Duke University School of Medicine, Durham, North Carolina
- iMIND Research Group, Duke University School of Medicine, Durham, North Carolina
| | - Adam Threlfall
- Centre for Clinical Brain Science, University of Edinburgh, Scotland, United Kingdom
| | - Tom J. MacGillivray
- Centre for Clinical Brain Science, University of Edinburgh, Scotland, United Kingdom
| | - Sandra Stinnett
- Department of Ophthalmology, Duke University School of Medicine, Durham, North Carolina
- iMIND Research Group, Duke University School of Medicine, Durham, North Carolina
| | - Dilraj S. Grewal
- Department of Ophthalmology, Duke University School of Medicine, Durham, North Carolina
- iMIND Research Group, Duke University School of Medicine, Durham, North Carolina
| | - Sharon Fekrat
- Department of Ophthalmology, Duke University School of Medicine, Durham, North Carolina
- iMIND Research Group, Duke University School of Medicine, Durham, North Carolina
- Department of Neurology, Duke University School of Medicine, Durham, North Carolina
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Patterson EJ, Bounds AD, Wagner SK, Kadri-Langford R, Taylor R, Daly D. Oculomics: A Crusade Against the Four Horsemen of Chronic Disease. Ophthalmol Ther 2024; 13:1427-1451. [PMID: 38630354 PMCID: PMC11109082 DOI: 10.1007/s40123-024-00942-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Accepted: 03/25/2024] [Indexed: 05/22/2024] Open
Abstract
Chronic, non-communicable diseases present a major barrier to living a long and healthy life. In many cases, early diagnosis can facilitate prevention, monitoring, and treatment efforts, improving patient outcomes. There is therefore a critical need to make screening techniques as accessible, unintimidating, and cost-effective as possible. The association between ocular biomarkers and systemic health and disease (oculomics) presents an attractive opportunity for detection of systemic diseases, as ophthalmic techniques are often relatively low-cost, fast, and non-invasive. In this review, we highlight the key associations between structural biomarkers in the eye and the four globally leading causes of morbidity and mortality: cardiovascular disease, cancer, neurodegenerative disease, and metabolic disease. We observe that neurodegenerative disease is a particularly promising target for oculomics, with biomarkers detected in multiple ocular structures. Cardiovascular disease biomarkers are present in the choroid, retinal vasculature, and retinal nerve fiber layer, and metabolic disease biomarkers are present in the eyelid, tear fluid, lens, and retinal vasculature. In contrast, only the tear fluid emerged as a promising ocular target for the detection of cancer. The retina is a rich source of oculomics data, the analysis of which has been enhanced by artificial intelligence-based tools. Although not all biomarkers are disease-specific, limiting their current diagnostic utility, future oculomics research will likely benefit from combining data from various structures to improve specificity, as well as active design, development, and optimization of instruments that target specific disease signatures, thus facilitating differential diagnoses.
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Affiliation(s)
| | | | - Siegfried K Wagner
- Moorfields Eye Hospital NHS Trust, 162 City Road, London, EC1V 2PD, UK
- UCL Institute of Ophthalmology, University College London, 11-43 Bath Street, London, EC1V 9EL, UK
| | | | - Robin Taylor
- Occuity, The Blade, Abbey Square, Reading, Berkshire, RG1 3BE, UK
| | - Dan Daly
- Occuity, The Blade, Abbey Square, Reading, Berkshire, RG1 3BE, UK
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Kwapong WR, Tang F, Liu P, Zhang Z, Cao L, Feng Z, Yang S, Shu Y, Xu H, Lu Y, Zhao X, Chong B, Wu B, Liu M, Lei P, Zhang S. Choriocapillaris reduction accurately discriminates against early-onset Alzheimer's disease. Alzheimers Dement 2024; 20:4185-4198. [PMID: 38747519 PMCID: PMC11180859 DOI: 10.1002/alz.13871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 04/08/2024] [Accepted: 04/10/2024] [Indexed: 06/18/2024]
Abstract
INTRODUCTION This study addresses the urgent need for non-invasive early-onset Alzheimer's disease (EOAD) prediction. Using optical coherence tomography angiography (OCTA), we present a choriocapillaris model sensitive to EOAD, correlating with serum biomarkers. METHODS Eighty-four EOAD patients and 73 controls were assigned to swept-source OCTA (SS-OCTA) or the spectral domain OCTA (SD-OCTA) cohorts. Our hypothesis on choriocapillaris predictive potential in EOAD was tested and validated in these two cohorts. RESULTS Both cohorts revealed diminished choriocapillaris signals, demonstrating the highest discriminatory capability (area under the receiver operating characteristic curve: SS-OCTA 0.913, SD-OCTA 0.991; P < 0.001). A sparser SS-OCTA choriocapillaris correlated with increased serum amyloid beta (Aβ)42, Aβ42/40, and phosphorylated tau (p-tau)181 levels (all P < 0.05). Apolipoprotein E status did not affect choriocapillaris measurement. DISCUSSION The choriocapillaris, observed in both cohorts, proves sensitive to EOAD diagnosis, and correlates with serum Aβ and p-tau181 levels, suggesting its potential as a diagnostic tool for identifying and tracking microvascular changes in EOAD. HIGHLIGHTS Optical coherence tomography angiography may be applied for non-invasive screening of Alzheimer's disease (AD). Choriocapillaris demonstrates high sensitivity and specificity for early-onset AD diagnosis. Microvascular dynamics abnormalities are associated with AD.
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Affiliation(s)
| | - Fei Tang
- State Key Laboratory of Biotherapy, West China HospitalSichuan UniversityChengduP.R. China
| | - Peng Liu
- Department of EmergencyWest China Hospital of Sichuan UniversityChengduP.R. China
| | - Ziyi Zhang
- Department of NeurologyWest China HospitalSichuan UniversityChengduP.R. China
| | - Le Cao
- Department of NeurologyWest China HospitalSichuan UniversityChengduP.R. China
| | - Zijuan Feng
- Department of NeurologyWest China HospitalSichuan UniversityChengduP.R. China
| | - Shiyun Yang
- Department of NeurologyWest China HospitalSichuan UniversityChengduP.R. China
| | - Yang Shu
- State Key Laboratory of Biotherapy, West China HospitalSichuan UniversityChengduP.R. China
| | - Heng Xu
- State Key Laboratory of Biotherapy, West China HospitalSichuan UniversityChengduP.R. China
| | - Ying Lu
- State Key Laboratory of Biotherapy, West China HospitalSichuan UniversityChengduP.R. China
| | - Xinjun Zhao
- State Key Laboratory of Biotherapy, West China HospitalSichuan UniversityChengduP.R. China
| | - Baochen Chong
- State Key Laboratory of Biotherapy, West China HospitalSichuan UniversityChengduP.R. China
| | - Bo Wu
- Department of NeurologyWest China HospitalSichuan UniversityChengduP.R. China
| | - Ming Liu
- Department of NeurologyWest China HospitalSichuan UniversityChengduP.R. China
| | - Peng Lei
- Department of NeurologyWest China HospitalSichuan UniversityChengduP.R. China
- State Key Laboratory of Biotherapy, West China HospitalSichuan UniversityChengduP.R. China
| | - Shuting Zhang
- Department of NeurologyWest China HospitalSichuan UniversityChengduP.R. China
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Ho K, Bodi NE, Sharma TP. Normal-Tension Glaucoma and Potential Clinical Links to Alzheimer's Disease. J Clin Med 2024; 13:1948. [PMID: 38610712 PMCID: PMC11012506 DOI: 10.3390/jcm13071948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Revised: 03/21/2024] [Accepted: 03/25/2024] [Indexed: 04/14/2024] Open
Abstract
Glaucoma is a group of optic neuropathies and the world's leading cause of irreversible blindness. Normal-tension glaucoma (NTG) is a subtype of glaucoma that is characterized by a typical pattern of peripheral retinal loss, in which the patient's intraocular pressure (IOP) is considered within the normal range (<21 mmHg). Currently, the only targetable risk factor for glaucoma is lowering IOP, and patients with NTG continue to experience visual field loss after IOP-lowering treatments. This demonstrates the need for a better understanding of the pathogenesis of NTG and underlying mechanisms leading to neurodegeneration. Recent studies have found significant connections between NTG and cerebral manifestations, suggesting NTG as a neurodegenerative disease beyond the eye. Gaining a better understanding of NTG can potentially provide new Alzheimer's Disease diagnostics capabilities. This review identifies the epidemiology, current biomarkers, altered fluid dynamics, and cerebral and ocular manifestations to examine connections and discrepancies between the mechanisms of NTG and Alzheimer's Disease.
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Affiliation(s)
- Kathleen Ho
- Eugene and Marilyn Glick Eye Institute, Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, IN 46202, USA;
| | - Nicole E. Bodi
- Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN 46202, USA;
| | - Tasneem P. Sharma
- Eugene and Marilyn Glick Eye Institute, Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, IN 46202, USA;
- Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN 46202, USA;
- Stark Neurosciences Research Institute, Indianapolis, IN 46202, USA
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Sun Y, Zhang L, Ye H, Leng L, Chen Y, Su Y, Ren P, Lu H, Peng G. Potential ocular indicators to distinguish posterior cortical atrophy and typical Alzheimer's disease: a cross-section study using optical coherence tomography angiography. Alzheimers Res Ther 2024; 16:64. [PMID: 38528626 DOI: 10.1186/s13195-024-01431-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Accepted: 03/18/2024] [Indexed: 03/27/2024]
Abstract
BACKGROUND Posterior cortical atrophy (PCA) is a form of dementia that frequently displays significant visual dysfunction and relatively preserved cognitive and executive functions, thus hindering early diagnosis and treatment. This study aimed to investigate possible fundus markers in PCA patients and compare them with those of typical Alzheimer's disease (AD) patients to seek potential diagnostic patterns. METHODS Age-matched PCA and AD patients and healthy controls (HC) completed optometry, intraocular pressure measurement, neuropsychologic assessments, optical coherence tomography (OCT), and optical coherence tomography angiography (OCTA) examination in one visit. Overall, six outcomes of thicknesses of various retinal layers and seven outcomes of the retinal microvascular network were calculated. After adjusting for age, sex, and years of education, the OCT and OCTA results were analyzed using analysis of covariance and generalized linear models. Correlation analyses were performed using Spearman correlation, and ROC curves were plotted. RESULTS Twelve PCA patients, nineteen AD patients, and thirty HC, aged 45-80 years were included. Fifty HC, thirty AD, and twenty PCA eyes were available for foveal avascular zone (FAZ) area analysis; forty-nine HC, thirty-four AD, and eighteen PCA eyes were available for OCT and OCTA assessments. PCA patients had thinner retinal nerve fiber layer and ganglion cell layer + inner plexiform layer than HC in the 0-3 mm circle and 1-3 mm ring. Few structural differences were observed between the AD group and the other two groups. The flow area of the superficial capillary plexus and the intermediate capillary plexus was smaller in the PCA group than in the HC group in the 0-1 mm circle, 0-3 mm circle. MMSE performed better than any combination of optical parameters in identifying AD and PCA from HC (AUC = 1), while the combination of MoCA, retinal thickness and vascular density of ICP in the 1-3 mm ring, with flow area of ICP in the 0-1 mm circle showed the strongest ability to distinguish PCA from AD (AUC = 0.944). CONCLUSIONS PCA patients exhibited similar impairment patterns to AD patients in the fundus structure and microvascular network. OCTA may aid in the non-invasive detection of AD and PCA, but still remains to be substantiated.
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Affiliation(s)
- Yan Sun
- Department of Neurology, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, People's Republic of China
| | - Lumi Zhang
- Department of Neurology, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, People's Republic of China
| | - Hui Ye
- Department of Ophthalmology, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, People's Republic of China
| | - Lumin Leng
- Department of Neurology, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, People's Republic of China
| | - Yi Chen
- Department of Neurology, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, People's Republic of China
| | - Yujie Su
- Department of Neurology, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, People's Republic of China
| | - Peifang Ren
- Department of Ophthalmology, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, People's Republic of China
| | - Hong Lu
- Department of Ophthalmology, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, People's Republic of China.
| | - Guoping Peng
- Department of Neurology, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, People's Republic of China.
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Goerdt L, Holz FG, Finger RP. [Retinal optical coherence tomography biomarkers in dementia]. DIE OPHTHALMOLOGIE 2024; 121:84-92. [PMID: 37847375 DOI: 10.1007/s00347-023-01947-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 09/25/2023] [Indexed: 10/18/2023]
Abstract
BACKGROUND Due to the general aging of society, the prevalence and incidence of dementia are expected to increase considerably. In order to timely identify patients and assess their need for treatment and/or supportive measures, comprehensive and easy access screening methods are required, which, however, are yet to be developed. To date, several biomarkers for the presence of dementia on high-resolution spectral domain optical coherence tomography (OCT) and OCT angiography (OCT-A) images were identified. AIM To summarize previously identified OCT biomarkers in dementia and to assess their suitability for comprehensive screening examinations. MATERIAL AND METHODS A literature search was conducted on PubMed until March 2023 for the keywords "dementia", "mild cognitive impairment", "OCT", "OCT angiography" and "retinal biomarkers". Relevant publications were identified and summarized. RESULTS Numerous unspecific alterations on OCT imaging and OCT‑A were identified in patients with (predementia) dementia according to many population and clinical studies. These include a reduced thickness of the peripapillary retinal nerve fiber layer, the ganglion cell complex and the central retinal region. Additionally, a reduced vascular density and an enlarged foveal avascular zone (FAZ) were identified on OCT‑A imaging. CONCLUSION The currently known OCT biomarkers are too unspecific, and there is to date no OCT or OCT-A-based signature distinguishing between different types of dementia. Further longitudinal studies with larger sample sizes are warranted to develop and evaluate such distinct OCT signatures for different types of dementia and their respective early disease stages and to assess their prognostic value. Only then is the inclusion in comprehensive screening investigations feasible.
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Affiliation(s)
- L Goerdt
- Universitäts-Augenklinik Bonn, Ernst-Abbe-Str. 2, 53127, Bonn, Deutschland.
| | - F G Holz
- Universitäts-Augenklinik Bonn, Ernst-Abbe-Str. 2, 53127, Bonn, Deutschland
| | - R P Finger
- Universitäts-Augenklinik Mannheim, Theodor-Kutzer-Ufer 1-3, 68167, Mannheim, Deutschland
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Shen Z, Zhang S, Yu W, Yue M, Hong C. Optical Coherence Tomography Angiography: Revolutionizing Clinical Diagnostics and Treatment in Central Nervous System Disease. Aging Dis 2024:AD.2024.0112. [PMID: 38300645 DOI: 10.14336/ad.2024.0112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Accepted: 01/12/2024] [Indexed: 02/02/2024] Open
Abstract
Optical coherence tomography angiography (OCTA), as a new generation of non-invasive and efficient fundus imaging technology, can provide non-invasive assessment of vascular lesions in the retina and choroid. In terms of anatomy and development, the retina is referred to as an extension of the central nervous system (CNS). CNS diseases are closely related to changes in fundus structure and blood vessels, and direct visualization of fundus structure and blood vessels provides an effective "window" for CNS research. This has important practical significance for identifying the characteristic changes of various CNS diseases on OCTA in the future, and plays a key role in promoting early screening, diagnosis, and monitoring of disease progression in CNS diseases. This article reviews relevant fundus studies by comparing and summarizing the unique advantages and existing limitations of OCTA in various CNS disease patients, in order to demonstrate the clinical significance of OCTA in the diagnosis and treatment of CNS diseases.
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Affiliation(s)
- Zeqi Shen
- Postgraduate training base Alliance of Wenzhou Medical University (Affiliated People's Hospital), Hangzhou, Zhejiang, China
| | - Sheng Zhang
- Center for Rehabilitation Medicine, Department of Neurology, Zhejiang Provincial People's Hospital (Affiliated People's Hospital), Hangzhou Medical College, Hangzhou, Zhejiang, China
| | - Weitao Yu
- The Second School of Clinical Medicine, Hangzhou Normal University, Hangzhou, Zhejiang, China
| | - Mengmeng Yue
- Postgraduate training base Alliance of Wenzhou Medical University (Affiliated People's Hospital), Hangzhou, Zhejiang, China
| | - Chaoyang Hong
- Center for Rehabilitation Medicine, Department of Ophthalmology, Zhejiang Provincial People's Hospital (Affiliated People's Hospital), Hangzhou Medical College, Hangzhou, Zhejiang, China
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Donato L, Mordà D, Scimone C, Alibrandi S, D’Angelo R, Sidoti A. Bridging Retinal and Cerebral Neurodegeneration: A Focus on Crosslinks between Alzheimer-Perusini's Disease and Retinal Dystrophies. Biomedicines 2023; 11:3258. [PMID: 38137479 PMCID: PMC10741418 DOI: 10.3390/biomedicines11123258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 12/02/2023] [Accepted: 12/07/2023] [Indexed: 12/24/2023] Open
Abstract
In the early stages of Alzheimer-Perusini's disease (AD), individuals often experience vision-related issues such as color vision impairment, reduced contrast sensitivity, and visual acuity problems. As the disease progresses, there is a connection with glaucoma and age-related macular degeneration (AMD) leading to retinal cell death. The retina's involvement suggests a link with the hippocampus, where most AD forms start. A thinning of the retinal nerve fiber layer (RNFL) due to the loss of retinal ganglion cells (RGCs) is seen as a potential AD diagnostic marker using electroretinography (ERG) and optical coherence tomography (OCT). Amyloid beta fragments (Aβ), found in the eye's vitreous and aqueous humor, are also present in the cerebrospinal fluid (CSF) and accumulate in the retina. Aβ is known to cause tau hyperphosphorylation, leading to its buildup in various retinal layers. However, diseases like AD are now seen as mixed proteinopathies, with deposits of the prion protein (PrP) and α-synuclein found in affected brains and retinas. Glial cells, especially microglial cells, play a crucial role in these diseases, maintaining immunoproteostasis. Studies have shown similarities between retinal and brain microglia in terms of transcription factor expression and morphotypes. All these findings constitute a good start to achieving better comprehension of neurodegeneration in both the eye and the brain. New insights will be able to bring the scientific community closer to specific disease-modifying therapies.
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Affiliation(s)
- Luigi Donato
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, Division of Medical Biotechnologies and Preventive Medicine, University of Messina, 98122 Messina, Italy; (L.D.); (C.S.); (R.D.); (A.S.)
- Department of Biomolecular Strategies, Genetics, Cutting-Edge Therapies, Euro-Mediterranean Institute of Science and Technology (I.E.ME.S.T.), 90139 Palermo, Italy;
| | - Domenico Mordà
- Department of Biomolecular Strategies, Genetics, Cutting-Edge Therapies, Euro-Mediterranean Institute of Science and Technology (I.E.ME.S.T.), 90139 Palermo, Italy;
- Department of Veterinary Sciences, University of Messina, 98122 Messina, Italy
| | - Concetta Scimone
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, Division of Medical Biotechnologies and Preventive Medicine, University of Messina, 98122 Messina, Italy; (L.D.); (C.S.); (R.D.); (A.S.)
- Department of Biomolecular Strategies, Genetics, Cutting-Edge Therapies, Euro-Mediterranean Institute of Science and Technology (I.E.ME.S.T.), 90139 Palermo, Italy;
| | - Simona Alibrandi
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, Division of Medical Biotechnologies and Preventive Medicine, University of Messina, 98122 Messina, Italy; (L.D.); (C.S.); (R.D.); (A.S.)
- Department of Biomolecular Strategies, Genetics, Cutting-Edge Therapies, Euro-Mediterranean Institute of Science and Technology (I.E.ME.S.T.), 90139 Palermo, Italy;
| | - Rosalia D’Angelo
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, Division of Medical Biotechnologies and Preventive Medicine, University of Messina, 98122 Messina, Italy; (L.D.); (C.S.); (R.D.); (A.S.)
| | - Antonina Sidoti
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, Division of Medical Biotechnologies and Preventive Medicine, University of Messina, 98122 Messina, Italy; (L.D.); (C.S.); (R.D.); (A.S.)
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Hussain A, Sheikh Z, Subramanian M. The Eye as a Diagnostic Tool for Alzheimer’s Disease. Life (Basel) 2023; 13:life13030726. [PMID: 36983883 PMCID: PMC10052959 DOI: 10.3390/life13030726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2023] [Revised: 02/23/2023] [Accepted: 03/04/2023] [Indexed: 03/10/2023] Open
Abstract
Alzheimer’s disease (AD) is a progressive neurodegenerative disorder impacting cognition, function, and behavior in the elderly population. While there are currently no disease-modifying agents capable of curing AD, early diagnosis and management in the preclinical stage can significantly improve patient morbidity and life expectancy. Currently, the diagnosis of Alzheimer’s disease is a clinical one, often supplemented by invasive and expensive biomarker testing. Over the last decade, significant advancements have been made in our understanding of AD and the role of ocular tissue as a potential biomarker. Ocular biomarkers hold the potential to provide noninvasive and easily accessible diagnostic and monitoring capabilities. This review summarizes current research for detecting biomarkers of Alzheimer’s disease in ocular tissue.
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Retinal Neurodegeneration Measured With Optical Coherence Tomography and Neuroimaging in Alzheimer Disease: A Systematic Review. J Neuroophthalmol 2023; 43:116-125. [PMID: 36255105 DOI: 10.1097/wno.0000000000001673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Optical coherence tomography (OCT) has enabled several retinal alterations to be detected in patients with Alzheimer disease (AD), alterations that could be potential biomarkers. However, the relationship between the retina and other biomarkers of AD has been underresearched. We gathered and analyzed the literature about the relationship between retinal and cerebral alterations detected via neuroimaging in patients with AD, mild cognitive impairment (MCI), and preclinical AD. METHODS This systematic review followed the PRISMA Statement guidelines through the 27 items on its checklist. We searched in PubMed, BVS, Scopus, and the Cochrane Library, using the keywords: Alzheimer's disease, optical coherence tomography, white matter, cortex, atrophy, cortical thickness, neuroimaging, magnetic resonance imaging, and positron emission tomography. We included articles that studied the retina in relation to neuroimaging in patients with AD, MCI, and preclinical AD. We excluded studies without OCT, without neuroimaging, clinical cases, opinion articles, systematic reviews, and animal studies. RESULTS Of a total of 35 articles found, 23 were finally included. Although mixed results were found, most of these corroborate the relationship between retinal and brain disorders. CONCLUSIONS More rigorous research is needed in the field, including homogenized, longitudinal, and prolonged follow-up studies, as well as studies that include all stages of AD. This will enable better understanding of the retina and its implications in AD, leading to the discovery of retinal biomarkers that reflect brain alterations in AD patients in an accessible and noninvasive manner.
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Vujosevic S, Parra MM, Hartnett ME, O'Toole L, Nuzzi A, Limoli C, Villani E, Nucci P. Optical coherence tomography as retinal imaging biomarker of neuroinflammation/neurodegeneration in systemic disorders in adults and children. Eye (Lond) 2023; 37:203-219. [PMID: 35428871 PMCID: PMC9012155 DOI: 10.1038/s41433-022-02056-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Revised: 03/10/2022] [Accepted: 03/31/2022] [Indexed: 01/28/2023] Open
Abstract
The retina and the optic nerve are considered extensions of the central nervous system (CNS) and thus can serve as the window for evaluation of CNS disorders. Spectral domain optical coherence tomography (OCT) allows for detailed evaluation of the retina and the optic nerve. OCT can non-invasively document changes in single retina layer thickness and structure due to neuronal and retinal glial cells (RGC) modifications in systemic and local inflammatory and neurodegenerative diseases. These can include evaluation of retinal nerve fibre layer and ganglion cell complex, hyper-reflective retinal spots (HRS, sign of activated microglial cells in the retina), subfoveal neuroretinal detachment, disorganization of the inner retinal layers (DRIL), thickness and integrity of the outer retinal layers and choroidal thickness. This review paper will report the most recent data on the use of OCT as a non invasive imaging biomarker for evaluation of the most common systemic neuroinflammatory and neurodegenerative/neurocognitive disorders in the adults and in paediatric population. In the adult population the main focus will be on diabetes mellitus, multiple sclerosis, optic neuromyelitis, neuromyelitis optica spectrum disorders, longitudinal extensive transverse myelitis, Alzheimer and Parkinson diseases, Amyotrophic lateral sclerosis, Huntington's disease and schizophrenia. In the paediatric population, demyelinating diseases, lysosomal storage diseases, Nieman Pick type C disease, hypoxic ischaemic encephalopathy, human immunodeficiency virus, leukodystrophies spinocerebellar ataxia will be addressed.
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Affiliation(s)
- Stela Vujosevic
- Department of Biomedical, Surgical and Dental Sciences, University of Milan, Milan, Italy.
- Eye Clinic, IRCCS MultiMedica, Milan, Italy.
| | - M Margarita Parra
- Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, University of Utah, Salt Lake City, UT, USA
| | - M Elizabeth Hartnett
- Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, University of Utah, Salt Lake City, UT, USA
| | - Louise O'Toole
- Department of Ophthalmology Mater Private Network, Dublin, Ireland
| | - Alessia Nuzzi
- Eye Clinic, IRCCS MultiMedica, Milan, Italy
- University of Milan, Milan, Italy
| | - Celeste Limoli
- Eye Clinic, IRCCS MultiMedica, Milan, Italy
- University of Milan, Milan, Italy
| | - Edoardo Villani
- Eye Clinic, IRCCS MultiMedica, Milan, Italy
- Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - Paolo Nucci
- Department of Biomedical, Surgical and Dental Sciences, University of Milan, Milan, Italy
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Moussa M, Falfoul Y, Nasri A, El Matri K, Kacem I, Mrabet S, Chebil A, Gharbi A, Gouider R, El Matri L. Optical coherence tomography and angiography in Alzheimer's disease and other cognitive disorders. Eur J Ophthalmol 2023:11206721221148952. [PMID: 36617984 DOI: 10.1177/11206721221148952] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
AIMS The aims of this study were to analyze retinal and choroidal changes on optical coherence tomography (OCT) and OCT-Angiography (OCT-A) in Alzheimer's disease (AD) patients and compare them to other forms of major dementia. We also aimed to analyze the correlation between clinical severity of global cognitive deficiency assessed by the mini-mental state exam (MMSE) score and OCT/OCT-A parameters. METHODS Retrospective cross-sectional evaluative study of AD, and age-and gender-matched patients with other dementias. Fundus examination, OCT and OCT-A were compared. RESULTS Ninety-one eyes of AD patients and 53 eyes of patients with other dementias were included. Retinal deposits were found in 6.59% of AD cases. OCT highlighted the presence of hyperreflective deposits and localized areas of outer retina and ellipsoid zone disruption, respectively in 20.87% and 15.38% of AD cases. Hyperreflective foci were noted within inner retinal layers in 4.39% of AD cases. Quantitative analysis revealed a thicker nasal retinal nerve fiber layer (p = 0.001) and ganglion cell complex in superior (p = 0.011) and temporal quadrants (p = 0.009) in eyes of AD patients, compared to other dementias. OCT-A showed a significantly higher fractal dimension of both superficial and deep capillary plexus (p = 0.005), with lower choriocapillaris density (p = 0.003) in AD patients. CONCLUSIONS Structural OCT could highlight the presence of hyperreflective deposits in AD, probably reflecting beta-amyloid deposits, associated to outer retinal disruptions. Quantitative OCT analysis showed structural differences between AD patients and other dementias, and combined OCT-A could identify microvascular changes in AD patients representing new potential differential diagnosis criteria.
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Affiliation(s)
- Mohamed Moussa
- Department of Ophthalmology B, 383447Hedi Raies Institute of Ophthalmology, Tunis, Tunisia
- Faculty of Medicine of Tunis, 37964University of Tunis El Manar, Tunis, Tunisia
| | - Yousra Falfoul
- Department of Ophthalmology B, 383447Hedi Raies Institute of Ophthalmology, Tunis, Tunisia
- Faculty of Medicine of Tunis, 37964University of Tunis El Manar, Tunis, Tunisia
| | - Amina Nasri
- Faculty of Medicine of Tunis, 37964University of Tunis El Manar, Tunis, Tunisia
- Department of Neurology, LR18SP03, Clinical Investigation Center "Neurosciences and Mental Health", Razi University Hospital, Tunis, Manouba, Tunisia
| | - Khaled El Matri
- Department of Ophthalmology B, 383447Hedi Raies Institute of Ophthalmology, Tunis, Tunisia
- Faculty of Medicine of Tunis, 37964University of Tunis El Manar, Tunis, Tunisia
| | - Imen Kacem
- Faculty of Medicine of Tunis, 37964University of Tunis El Manar, Tunis, Tunisia
- Department of Neurology, LR18SP03, Clinical Investigation Center "Neurosciences and Mental Health", Razi University Hospital, Tunis, Manouba, Tunisia
| | - Saloua Mrabet
- Faculty of Medicine of Tunis, 37964University of Tunis El Manar, Tunis, Tunisia
- Department of Neurology, LR18SP03, Clinical Investigation Center "Neurosciences and Mental Health", Razi University Hospital, Tunis, Manouba, Tunisia
| | - Ahmed Chebil
- Department of Ophthalmology B, 383447Hedi Raies Institute of Ophthalmology, Tunis, Tunisia
- Faculty of Medicine of Tunis, 37964University of Tunis El Manar, Tunis, Tunisia
| | - Alya Gharbi
- Faculty of Medicine of Tunis, 37964University of Tunis El Manar, Tunis, Tunisia
- Department of Neurology, LR18SP03, Clinical Investigation Center "Neurosciences and Mental Health", Razi University Hospital, Tunis, Manouba, Tunisia
| | - Riadh Gouider
- Faculty of Medicine of Tunis, 37964University of Tunis El Manar, Tunis, Tunisia
- Department of Neurology, LR18SP03, Clinical Investigation Center "Neurosciences and Mental Health", Razi University Hospital, Tunis, Manouba, Tunisia
| | - Leila El Matri
- Department of Ophthalmology B, 383447Hedi Raies Institute of Ophthalmology, Tunis, Tunisia
- Faculty of Medicine of Tunis, 37964University of Tunis El Manar, Tunis, Tunisia
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13
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Ma X, Xie Z, Wang H, Tian Z, Bi Y, Li Y, Zhang L. A cross-sectional study of retinal vessel changes based on optical coherence tomography angiography in Alzheimer's disease and mild cognitive impairment. Front Aging Neurosci 2023; 15:1101950. [PMID: 37113575 PMCID: PMC10126258 DOI: 10.3389/fnagi.2023.1101950] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2022] [Accepted: 03/20/2023] [Indexed: 04/29/2023] Open
Abstract
Background The involvement of retina and its vasculature has been recently described in Alzheimer's disease (AD). Optical coherence tomography angiography (OCTA) is noninvasively used to assess the retinal blood flow. Objective This study was to compare vessel density (VD) and blood perfusion density (PD) of the macular in AD patients, mild cognitive impairment (MCI) patients and healthy controls by OCTA, which may provide new ideas for diagnosis of AD or MCI. Methods AD patients, MCI patients and healthy controls underwent a comprehensive ophthalmic and neurological evaluations, including cognitive function assessments as well as visual acuity, intraocular pressure (IOP), slit lamp examinations, and OCTA. General demographic data, cognitive function, retinal VD and PD were compared among three groups. The correlations among retinal VD, PD and cognitive function, amyloid-beta (Aβ) protein and phosphorylated Tau (p-Tau) protein were further evaluated. The correlations between retinal superficial capillary plexus and cognitive function, Aβ protein and p-Tau protein were also explored. Results A total of 139 participants were recruited into this study, including 43 AD patients, 62 MCI patients, and 34 healthy controls. After adjusting for sex, age, history of smoking, history of alcohol intake, hypertension, hyperlipidemia, best corrected visual acuity, and IOP, VD and PD in the nasal and inferior regions of the inner ring, superior and inferior regions of outer ring in the AD group were significantly lower than in the control group (p < 0.05). PD in nasal region of outer ring also significantly decreased in the AD group. VD and PD in superior and inferior regions of inner ring, superior and temporal regions of outer ring in the MCI group were markedly lower than in the control group (p < 0.05). After adjusting for sex and age, VD and PD were correlated with Montreal Cognitive Assessment Basic score, Mini-mental State Examination score, visuospatial function and executive function (p < 0.05), while Aβ protein and p-Tau protein had no relationship with VD and PD. Conclusion Our findings suggest that superficial retinal VD and PD in macula may be potential non-invasive biomarkers for AD and MCI, and these vascular parameters correlate with cognitive function.
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Affiliation(s)
- Xiaoyu Ma
- Department of Ophthalmology, Tongji Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Zengmai Xie
- Department of Neurology, Tongji Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Huan Wang
- Clinical Research Center, Tongji Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Zhongping Tian
- Department of Ophthalmology, Tongji Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Yanlong Bi
- Department of Ophthalmology, Tongji Hospital, School of Medicine, Tongji University, Shanghai, China
- Tongji Eye Institute, School of Medicine, Tongji University, Shanghai, China
- *Correspondence: Yanlong Bi,
| | - Yunxia Li
- Department of Neurology, Tongji Hospital, School of Medicine, Tongji University, Shanghai, China
- Yunxia Li,
| | - Li Zhang
- Department of Ophthalmology, Tongji Hospital, School of Medicine, Tongji University, Shanghai, China
- Li Zhang,
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Vij R, Arora S. A systematic survey of advances in retinal imaging modalities for Alzheimer's disease diagnosis. Metab Brain Dis 2022; 37:2213-2243. [PMID: 35290546 DOI: 10.1007/s11011-022-00927-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 02/04/2022] [Indexed: 01/06/2023]
Abstract
Recent advances in retinal imaging pathophysiology have shown a new function for biomarkers in Alzheimer's disease diagnosis and prognosis. The significant improvements in Optical coherence tomography (OCT) retinal imaging have led to significant clinical translation, particularly in Alzheimer's disease detection. This systematic review will provide a comprehensive overview of retinal imaging in clinical applications, with a special focus on biomarker analysis for use in Alzheimer's disease detection. Articles on OCT retinal imaging in Alzheimer's disease diagnosis were identified in PubMed, Google Scholar, IEEE Xplore, and Research Gate databases until March 2021. Those studies using simultaneous retinal imaging acquisition were chosen, while those using sequential techniques were rejected. "Alzheimer's disease" and "Dementia" were searched alone and in combination with "OCT" and "retinal imaging". Approximately 1000 publications were searched, and after deleting duplicate articles, 145 relevant studies focused on the diagnosis of Alzheimer's disease utilizing retinal imaging were chosen for study. OCT has recently been demonstrated to be a valuable technique in clinical practice as according to this survey, 57% of the researchers employed optical coherence tomography, 19% used ocular fundus imaging, 13% used scanning laser ophthalmoscopy, and 11% have used multimodal imaging to diagnose Alzheimer disease. Retinal imaging has become an important diagnostic technique for Alzheimer's disease. Given the scarcity of available literature, it is clear that future prospective trials involving larger and more homogeneous groups are necessary, and the work can be expanded by evaluating its significance utilizing a machine-learning platform rather than simply using statistical methodologies.
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Affiliation(s)
- Richa Vij
- School of Computer Science & Engineering, Shri Mata Vaishno Devi University, Katra, Jammu and Kashmir, 182320, India
| | - Sakshi Arora
- School of Computer Science & Engineering, Shri Mata Vaishno Devi University, Katra, Jammu and Kashmir, 182320, India.
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15
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Amy Y, Lee CS. Retinal Biomarkers for Alzheimer Disease: The Facts and the Future. Asia Pac J Ophthalmol (Phila) 2022; 11:140-148. [PMID: 35533333 PMCID: PMC9889204 DOI: 10.1097/apo.0000000000000505] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
ABSTRACT Alzheimer disease (AD) is a significant cause of morbidity and mortality worldwide, with limited treatment options and considerable diagnostic challenges. Identification and validation of retinal changes that correlate with clinicopathologic features of AD could provide a noninvasive method of screening and monitoring progression of disease, with notable implications for developing new therapies, particularly in its preclinical stages. Retinal biomarkers that have been studied to date include structural changes in neurosensory retinal layers, alterations in vascular architecture and function, and pathologic deposition of proteins within the retina, which have all demonstrated variable correlation with the presence of preclinical or clinical AD. Evolution of specialized retinal imaging modalities and advances in artificial intelligence hold great promise for future study in this burgeoning field. The current status of research in retinal biomarkers, and some of the challenges that will need to be addressed in future work, are reviewed herein.
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Affiliation(s)
- Yuan Amy
- Department of Ophthalmology, University of Washington, Seattle WA, US
| | - Cecilia S. Lee
- Department of Ophthalmology, University of Washington, Seattle WA, US
- Karalis Johnson Retina Center, Seattle WA, US
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16
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Majeed A, Marwick B, Yu H, Fadavi H, Tavakoli M. Ophthalmic Biomarkers for Alzheimer's Disease: A Review. Front Aging Neurosci 2021; 13:720167. [PMID: 34566623 PMCID: PMC8461312 DOI: 10.3389/fnagi.2021.720167] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Accepted: 08/11/2021] [Indexed: 11/13/2022] Open
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disease characterized by neuronal loss, extracellular amyloid-β (Aβ) plaques, and intracellular neurofibrillary tau tangles. A diagnosis is currently made from the presenting symptoms, and the only definitive diagnosis can be done post-mortem. Over recent years, significant advances have been made in using ocular biomarkers to diagnose various neurodegenerative diseases, including AD. As the eye is an extension of the central nervous system (CNS), reviewing changes in the eye's biology could lead to developing a series of non-invasive, differential diagnostic tests for AD that could be further applied to other diseases. Significant changes have been identified in the retinal nerve fiber layer (RNFL), cornea, ocular vasculature, and retina. In the present paper, we review current research and assess some ocular biomarkers' accuracy and reliability that could potentially be used for diagnostic purposes. Additionally, we review the various imaging techniques used in the measurement of these biomarkers.
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Affiliation(s)
- Ayesha Majeed
- Medical School, University of Exeter, Exeter, United Kingdom
| | - Ben Marwick
- Medical School, University of Exeter, Exeter, United Kingdom
| | - Haoqing Yu
- Medical School, University of Exeter, Exeter, United Kingdom
| | | | - Mitra Tavakoli
- Medical School, University of Exeter, Exeter, United Kingdom
- Exeter Centre of Excellence for Diabetes Research, University of Exeter, Exeter, United Kingdom
- National Institute for Health Research, Exeter Clinical Research Facility, Exeter, United Kingdom
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17
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Liu K, Li J, Raghunathan R, Zhao H, Li X, Wong STC. The Progress of Label-Free Optical Imaging in Alzheimer's Disease Screening and Diagnosis. Front Aging Neurosci 2021; 13:699024. [PMID: 34366828 PMCID: PMC8341907 DOI: 10.3389/fnagi.2021.699024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 07/02/2021] [Indexed: 01/13/2023] Open
Abstract
As the major neurodegenerative disease of dementia, Alzheimer's disease (AD) has caused an enormous social and economic burden on society. Currently, AD has neither clear pathogenesis nor effective treatments. Positron emission tomography (PET) and magnetic resonance imaging (MRI) have been verified as potential tools for diagnosing and monitoring Alzheimer's disease. However, the high costs, low spatial resolution, and long acquisition time limit their broad clinical utilization. The gold standard of AD diagnosis routinely used in research is imaging AD biomarkers with dyes or other reagents, which are unsuitable for in vivo studies owing to their potential toxicity and prolonged and costly process of the U.S. Food and Drug Administration (FDA) approval for human use. Furthermore, these exogenous reagents might bring unwarranted interference to mechanistic studies, causing unreliable results. Several label-free optical imaging techniques, such as infrared spectroscopic imaging (IRSI), Raman spectroscopic imaging (RSI), optical coherence tomography (OCT), autofluorescence imaging (AFI), optical harmonic generation imaging (OHGI), etc., have been developed to circumvent this issue and made it possible to offer an accurate and detailed analysis of AD biomarkers. In this review, we present the emerging label-free optical imaging techniques and their applications in AD, along with their potential and challenges in AD diagnosis.
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Affiliation(s)
- Kai Liu
- Translational Biophotonics Laboratory, Systems Medicine and Bioengineering Department, Houston Methodist Cancer Center, Houston, TX, United States
- Department of Gastrointestinal Surgery, The Third Xiangya Hospital of Central South University, Changsha, China
| | - Jiasong Li
- Translational Biophotonics Laboratory, Systems Medicine and Bioengineering Department, Houston Methodist Cancer Center, Houston, TX, United States
- T. T. and W. F. Chao Center for BRAIN, Houston Methodist Hospital, Houston, TX, United States
| | - Raksha Raghunathan
- Translational Biophotonics Laboratory, Systems Medicine and Bioengineering Department, Houston Methodist Cancer Center, Houston, TX, United States
- T. T. and W. F. Chao Center for BRAIN, Houston Methodist Hospital, Houston, TX, United States
| | - Hong Zhao
- Translational Biophotonics Laboratory, Systems Medicine and Bioengineering Department, Houston Methodist Cancer Center, Houston, TX, United States
| | - Xuping Li
- T. T. and W. F. Chao Center for BRAIN, Houston Methodist Hospital, Houston, TX, United States
| | - Stephen T. C. Wong
- Translational Biophotonics Laboratory, Systems Medicine and Bioengineering Department, Houston Methodist Cancer Center, Houston, TX, United States
- T. T. and W. F. Chao Center for BRAIN, Houston Methodist Hospital, Houston, TX, United States
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18
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Past, present and future role of retinal imaging in neurodegenerative disease. Prog Retin Eye Res 2021; 83:100938. [PMID: 33460813 PMCID: PMC8280255 DOI: 10.1016/j.preteyeres.2020.100938] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 12/11/2020] [Accepted: 12/17/2020] [Indexed: 02/08/2023]
Abstract
Retinal imaging technology is rapidly advancing and can provide ever-increasing amounts of information about the structure, function and molecular composition of retinal tissue in humans in vivo. Most importantly, this information can be obtained rapidly, non-invasively and in many cases using Food and Drug Administration-approved devices that are commercially available. Technologies such as optical coherence tomography have dramatically changed our understanding of retinal disease and in many cases have significantly improved their clinical management. Since the retina is an extension of the brain and shares a common embryological origin with the central nervous system, there has also been intense interest in leveraging the expanding armamentarium of retinal imaging technology to understand, diagnose and monitor neurological diseases. This is particularly appealing because of the high spatial resolution, relatively low-cost and wide availability of retinal imaging modalities such as fundus photography or OCT compared to brain imaging modalities such as magnetic resonance imaging or positron emission tomography. The purpose of this article is to review and synthesize current research about retinal imaging in neurodegenerative disease by providing examples from the literature and elaborating on limitations, challenges and future directions. We begin by providing a general background of the most relevant retinal imaging modalities to ensure that the reader has a foundation on which to understand the clinical studies that are subsequently discussed. We then review the application and results of retinal imaging methodologies to several prevalent neurodegenerative diseases where extensive work has been done including sporadic late onset Alzheimer's Disease, Parkinson's Disease and Huntington's Disease. We also discuss Autosomal Dominant Alzheimer's Disease and cerebrovascular small vessel disease, where the application of retinal imaging holds promise but data is currently scarce. Although cerebrovascular disease is not generally considered a neurodegenerative process, it is both a confounder and contributor to neurodegenerative disease processes that requires more attention. Finally, we discuss ongoing efforts to overcome the limitations in the field and unmet clinical and scientific needs.
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Foveal Avascular Zone and Choroidal Thickness Are Decreased in Subjects with Hard Drusen and without High Genetic Risk of Developing Alzheimer's Disease. Biomedicines 2021; 9:biomedicines9060638. [PMID: 34199664 PMCID: PMC8229973 DOI: 10.3390/biomedicines9060638] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 06/01/2021] [Accepted: 06/01/2021] [Indexed: 01/08/2023] Open
Abstract
A family history (FH+) of Alzheimer’s disease (AD) and ɛ4 allele of the ApoE gene are the main genetic risk factors for developing AD, whereas ɛ4 allele plays a protective role in age-related macular degeneration. Ocular vascular changes have been reported in both pathologies. We analyzed the choroidal thickness using optical coherence tomography (OCT) and the foveal avascular zone (FAZ) using OCT-angiography and compared the results with ApoE gene expression, AD FH+, and the presence or absence of hard drusen (HD) in 184 cognitively healthy subjects. Choroidal thickness was statistically significantly different in the (FH−, ɛ4−, HD+) group compared with (i) both the (FH−, ɛ4−, HD−) and the (FH+, ɛ4+, HD+) groups in the superior and inferior points at 1500 μm, and (ii) the (FH+, ɛ4−, HD+) group in the superior point at 1500 μm. There were statistically significant differences in the superficial FAZ between the (FH+, ɛ4−, HD+) group and (i) the (FH+, ɛ4−, HD−) group and (ii) the (FH+, ɛ4+, HD−) group. In conclusion, ocular vascular changes are not yet evident in participants with a genetic risk of developing AD.
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20
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Fereshetian S, Agranat JS, Siegel N, Ness S, Stein TD, Subramanian ML. Protein and Imaging Biomarkers in the Eye for Early Detection of Alzheimer's Disease. J Alzheimers Dis Rep 2021; 5:375-387. [PMID: 34189409 PMCID: PMC8203283 DOI: 10.3233/adr-210283] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/26/2021] [Indexed: 12/28/2022] Open
Abstract
Alzheimer's disease (AD) is one of the most common causes of dementia worldwide. Although no formal curative therapy exists for the treatment of AD, considerable research has been performed to identify biomarkers for early detection of this disease, and thus improved subsequent management. Given that the eye can be examined and imaged non-invasively with relative ease, it has emerged as an exciting area of research for evidence of biomarkers and to aid in the early diagnosis of AD. This review explores the current understanding of both protein and retinal imaging biomarkers in the eye. Herein, primary findings in the literature regarding AD biomarkers associated with the lens, retina, and other ocular structures are reviewed.
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Affiliation(s)
- Shaunt Fereshetian
- Boston University School of Medicine, Department of Ophthalmology, Boston, MA, USA
| | - Joshua S. Agranat
- Boston University School of Medicine, Department of Ophthalmology, Boston, MA, USA
- Boston Medical Center, Boston, MA, USA
| | - Nicole Siegel
- Boston University School of Medicine, Department of Ophthalmology, Boston, MA, USA
- Boston Medical Center, Boston, MA, USA
| | - Steven Ness
- Boston University School of Medicine, Department of Ophthalmology, Boston, MA, USA
- Boston Medical Center, Boston, MA, USA
| | - Thor D. Stein
- Boston University Alzheimer’s Disease and CTE Center, Boston University School of Medicine, Boston, MA, USA
- Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, MA, USA
- VA Boston Healthcare System, Boston, MA, USA
- Department of Veterans Affairs Medical Center, Bedford, MA, USA
| | - Manju L. Subramanian
- Boston University School of Medicine, Department of Ophthalmology, Boston, MA, USA
- Boston Medical Center, Boston, MA, USA
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21
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Zhang S, Kwapong WR, Yang T, Liu P, Tuo Q, Cheng Y, Li X, Liu M, Lei P, Wu B. Choriocapillaris Changes Are Correlated With Disease Duration and MoCA Score in Early-Onset Dementia. Front Aging Neurosci 2021; 13:656750. [PMID: 33927609 PMCID: PMC8076507 DOI: 10.3389/fnagi.2021.656750] [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] [Received: 01/21/2021] [Accepted: 03/24/2021] [Indexed: 02/05/2023] Open
Abstract
Purpose: Imaging of the choroid may detect the microvascular changes associated with early-onset dementia (EOD) and may represent an indicator for detection of the disease. We aimed to analyze the in vivo choriocapillaris (CC) flow density in EOD patients using optical coherence tomography angiography (OCTA) and evaluate the association with its clinical measures. Methods: This cross-sectional study used the OCTA to image and analyze the choriocapillaris (CC) of 25 EOD patients and 20 healthy controls. Choriocapillaris flow density in the 3 mm area and 6 mm area was measured by an inbuilt algorithm in the OCT tool. Brain volume using magnetic resonance imaging and cognitive assessment was done and recorded. Results: Significantly reduced capillary flow density of the choriocapillaris was seen in EOD patients when compared to healthy controls in the 3.0 mm (P = 0.001) and 6.0 mm (P < 0.001) area respectively. Montreal Cognitive Assessment (MoCA) scores in EOD patients positively correlated with choriocapillaris flow density in the 3 mm area (Rho = 0.466, P = 0.021). Disease duration of EOD patients also negatively correlated with choriocapillaris density in the 3 mm area (Rho = -0.497, P = 0.008). Discussion: Our report suggests that choriocapillaris damage may be a potential indicator of early-onset dementia. Microvascular impairment may be involved in the early phase of dementia without aging playing a role in its impairment. Clinical Trial Registration: www.ClinicalTrials.gov, ChiCTR2000041386.
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Affiliation(s)
- Shuting Zhang
- Department of Neurology, West China Hospital, Sichuan University, Chengdu, China
| | | | - Tang Yang
- Department of Neurology, West China Hospital, Sichuan University, Chengdu, China
| | - Peng Liu
- Department of Emergency, West China Hospital, Sichuan University, Chengdu, China
| | - Qingzhang Tuo
- State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Yajun Cheng
- Department of Neurology, West China Hospital, Sichuan University, Chengdu, China
| | - Xue Li
- Department of Neurology, West China Hospital, Sichuan University, Chengdu, China
| | - Ming Liu
- Department of Neurology, West China Hospital, Sichuan University, Chengdu, China
| | - Peng Lei
- Department of Neurology, West China Hospital, Sichuan University, Chengdu, China.,State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Bo Wu
- Department of Neurology, West China Hospital, Sichuan University, Chengdu, China
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22
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Robbins CB, Grewal DS, Thompson AC, Powers JH, Soundararajan S, Koo HY, Yoon SP, Polascik BW, Liu A, Agrawal R, Fekrat S. Choroidal Structural Analysis in Alzheimer Disease, Mild Cognitive Impairment, and Cognitively Healthy Controls. Am J Ophthalmol 2021; 223:359-367. [PMID: 33039373 DOI: 10.1016/j.ajo.2020.09.049] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 09/09/2020] [Accepted: 09/28/2020] [Indexed: 12/22/2022]
Abstract
PURPOSE To assess choroidal structural parameters in symptomatic Alzheimer disease (AD), mild cognitive impairment (MCI), and cognitively healthy control subjects. DESIGN Prospective cross-sectional study. METHODS This study took place in an outpatient neurological disorders clinic. Participants included 67 patients (112 eyes) with AD, 74 patients (143 eyes) with MCI, and 137 (248 eyes) control subjects. Subjects with diabetes, glaucoma, or retinal pathology were excluded. High-definition enhanced depth imaging foveal scans were obtained using Zeiss Cirrus HD-5000 AngioPlex. Subfoveal choroidal thickness (SFCT) was measured by 2 masked graders with a third adjudicator. Total choroidal area (TCA), luminal area (LA), and the choroidal vascularity index (CVI) were calculated after image binarization. Association of choroidal parameters with AD, MCI, or control subjects was assessed using multivariable generalized estimating equations, adjusted for age, sex, and visual acuity. RESULTS After adjustment for age, sex, and visual acuity, TCA was significantly greater in patients with AD (ß = 2.73; p = .001) and MCI (ß = 4.38; p < .001) compared with control subjects. LA was significantly greater in patients with AD (ß = 1.68; p = .001) and MCI (ß = 2.69; p < .001) compared with control subjects, and CVI was significantly lower in patients with MCI (ß = -0.58; p = .002) compared with control subjects. SFCT was similar among patients with AD and MCI and control subjects on multivariable analysis (p > .05). CONCLUSIONS TCA, LA, and CVI may differ between patients with AD, MCI, and healthy cognition, whereas SFCT may not differ among these groups. TCA, LA, and CVI deserve further study in subjects on the Alzheimer continuum.
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Song A, Johnson N, Ayala A, Thompson AC. Optical Coherence Tomography in Patients with Alzheimer's Disease: What Can It Tell Us? Eye Brain 2021; 13:1-20. [PMID: 33447120 PMCID: PMC7802785 DOI: 10.2147/eb.s235238] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2020] [Accepted: 12/09/2020] [Indexed: 12/17/2022] Open
Abstract
PURPOSE Although Alzheimer's disease (AD) is a leading cause of dementia worldwide, its clinical diagnosis remains a challenge. Optical coherence tomography (OCT) and OCT with angiography (OCTA) are non-invasive ophthalmic imaging tools with the potential to detect retinal structural and microvascular changes in patients with AD, which may serve as biomarkers for the disease. In this systematic review, we evaluate whether certain OCT and OCTA parameters are significantly associated with AD and mild cognitive impairment (MCI). METHODS PubMed database was searched using a combination of MeSH terms to identify studies for review. Studies were organized by participant diagnostic groups, type of imaging modality, and OCT/OCTA parameters of interest. Participant demographic data was also collected and baseline descriptive statistics were calculated for the included studies. RESULTS Seventy-one studies were included for review, representing a total of 6757 patients (2350 AD, 793 MCI, 2902 healthy controls (HC), and 841 others with a range of other neurodegenerative diagnoses). The mean baseline ages were 72.78±3.69, 71.52±2.88, 70.55±3.85 years for AD, MCI and HC groups, respectively. The majority of studies noted significant structural and functional decline in AD patients when compared to HC. Although analysis of MCI groups yielded more mixed results, a similar pattern of decline was often noted amongst patients with MCI relative to HC. OCT and OCTA measurements were also shown to correlate with established measures of AD such as neuropsychological testing or neuroimaging. CONCLUSION OCT and OCTA show great potential as non-invasive technologies for the diagnosis of AD. However, further research is needed to determine whether there are AD-specific patterns of structural or microvascular change in the retina and optic nerve that distinguish AD from other neurodegenerative diseases. Development of sensitive and specific OCT/OCTA parameters will be necessary before they can be used to detect AD in clinical settings.
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Affiliation(s)
- Ailin Song
- Duke University School of Medicine, Durham, NC, USA
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Ocular Vascular Changes in Mild Alzheimer's Disease Patients: Foveal Avascular Zone, Choroidal Thickness, and ONH Hemoglobin Analysis. J Pers Med 2020; 10:jpm10040231. [PMID: 33203157 PMCID: PMC7712569 DOI: 10.3390/jpm10040231] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 11/04/2020] [Accepted: 11/13/2020] [Indexed: 12/17/2022] Open
Abstract
In Alzheimer’s disease (AD), vascular changes could be caused by amyloid beta (Aβ) aggregates replacing the contractile smooth musculature of the arteriole walls. These changes happen in the brain vascular network, but also in the eye, and are related to decreased vascular density and low blood flow. In patients with Alzheimer’s disease, thinning of the choroid and the retina has been shown. The aim of this prospective study was to assess the retinal and choroidal vascular systems, analyzing the choroidal thickness with optical coherence tomography (OCT), the foveal avascular zone (FAZ) with OCT-angiography (OCTA), and the optic nerve head (ONH) hemoglobin with the Laguna ONhE program, to evaluate which of the two ocular vascular systems shows earlier changes in mild AD patients. These patients, compared to controls, showed a significantly thinner choroid at all the analyzed points, with the exception of the temporal macula (at 1000 and 1500 µm from the fovea). On the other hand, the FAZ and ONH hemoglobin did not show significant differences. In conclusion, a thinner choroid was the main ocular vascular change observed in mild AD patients, while the retinal vessels were not yet affected. Therefore, choroidal thickness could be used an early biomarker in AD.
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25
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Alber J, Goldfarb D, Thompson LI, Arthur E, Hernandez K, Cheng D, DeBuc DC, Cordeiro F, Provetti-Cunha L, den Haan J, Van Stavern GP, Salloway SP, Sinoff S, Snyder PJ. Developing retinal biomarkers for the earliest stages of Alzheimer's disease: What we know, what we don't, and how to move forward. Alzheimers Dement 2020; 16:229-243. [PMID: 31914225 DOI: 10.1002/alz.12006] [Citation(s) in RCA: 80] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 10/23/2019] [Accepted: 11/18/2019] [Indexed: 12/12/2022]
Abstract
The last decade has seen a substantial increase in research focused on the identification, development, and validation of diagnostic and prognostic retinal biomarkers for Alzheimer's disease (AD). Sensitive retinal biomarkers may be advantageous because they are cost and time efficient, non-invasive, and present a minimal degree of patient risk and a high degree of accessibility. Much of the work in this area thus far has focused on distinguishing between symptomatic AD and/or mild cognitive impairment (MCI) and cognitively normal older adults. Minimal work has been done on the detection of preclinical AD, the earliest stage of AD pathogenesis characterized by the accumulation of cerebral amyloid absent clinical symptoms of MCI or dementia. The following review examines retinal structural changes, proteinopathies, and vascular alterations that have been proposed as potential AD biomarkers, with a focus on studies examining the earliest stages of disease pathogenesis. In addition, we present recommendations for future research to move beyond the discovery phase and toward validation of AD risk biomarkers that could potentially be used as a first step in a multistep screening process for AD risk detection.
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Affiliation(s)
- Jessica Alber
- Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, Rhode Island, USA.,George and Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, Rhode Island, USA.,Department of Psychiatry and Human Behavior, Alpert Medical School of Brown University, Providence, Rhode Island, USA.,Butler Hospital Memory & Aging Program, Providence, Rhode Island, USA
| | | | - Louisa I Thompson
- Department of Psychiatry and Human Behavior, Alpert Medical School of Brown University, Providence, Rhode Island, USA.,Butler Hospital Memory & Aging Program, Providence, Rhode Island, USA
| | - Edmund Arthur
- Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, Rhode Island, USA.,George and Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, Rhode Island, USA.,Butler Hospital Memory & Aging Program, Providence, Rhode Island, USA
| | | | - Derrick Cheng
- Alpert Medical School of Brown University, Providence, Rhode Island, USA
| | - Delia Cabrera DeBuc
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami, Miami, Florida, USA
| | - Francesca Cordeiro
- Imperial College London, London, UK.,University College London, London, UK.,Western Eye Hospital, London, UK
| | - Leonardo Provetti-Cunha
- Federal University of Juiz de Fora Medical School, Juiz de Fora, Minas Gerais, Brazil.,Juiz de Fora Eye Hospital, Juiz de Fora, Minas Gerais, Brazil.,University of São Paulo Medical School, São Paulo, Brazil
| | - Jurre den Haan
- Alzheimer Center Amsterdam, Department of Neurology, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam UMC, Amsterdam, the Netherlands
| | - Gregory P Van Stavern
- Department of Ophthalmology and Visual Sciences, Washington University in St. Louis School of Medicine, St. Louis, Missouri, USA
| | - Stephen P Salloway
- Department of Psychiatry and Human Behavior, Alpert Medical School of Brown University, Providence, Rhode Island, USA.,Butler Hospital Memory & Aging Program, Providence, Rhode Island, USA.,Department of Neurology, Alpert Medical School of Brown University, Providence, Rhode Island, USA
| | | | - Peter J Snyder
- Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, Rhode Island, USA.,George and Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, Rhode Island, USA.,Department of Neurology and Department of Surgery (Ophthalmology), Alpert Medical School of Brown University, Providence, Rhode Island, USA
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Retinal Degeneration and Alzheimer's Disease: An Evolving Link. Int J Mol Sci 2020; 21:ijms21197290. [PMID: 33023198 PMCID: PMC7582766 DOI: 10.3390/ijms21197290] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Revised: 09/15/2020] [Accepted: 09/25/2020] [Indexed: 12/13/2022] Open
Abstract
Age-related macular degeneration (AMD) and glaucoma are degenerative conditions of the retina and a significant cause of irreversible blindness in developed countries. Alzheimer’s disease (AD), the most common dementia of the elderly, is often associated with AMD and glaucoma. The cardinal features of AD include extracellular accumulation of amyloid β (Aβ) and intracellular deposits of hyper-phosphorylated tau (p-tau). Neuroinflammation and brain iron dyshomeostasis accompany Aβ and p-tau deposits and, together, lead to progressive neuronal death and dementia. The accumulation of Aβ and iron in drusen, the hallmark of AMD, and Aβ and p-tau in retinal ganglion cells (RGC), the main retinal cell type implicated in glaucoma, and accompanying inflammation suggest overlapping pathology. Visual abnormalities are prominent in AD and are believed to develop before cognitive decline. Some are caused by degeneration of the visual cortex, while others are due to RGC loss or AMD-associated retinal degeneration. Here, we review recent information on Aβ, p-tau, chronic inflammation, and iron dyshomeostasis as common pathogenic mechanisms linking the three degenerative conditions, and iron chelation as a common therapeutic option for these disorders. Additionally discussed is the role of prion protein, infamous for prion disorders, in Aβ-mediated toxicity and, paradoxically, in neuroprotection.
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27
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Evaluation of choroidal thickness in prodromal Alzheimer's disease defined by amyloid PET. PLoS One 2020; 15:e0239484. [PMID: 32956392 PMCID: PMC7505462 DOI: 10.1371/journal.pone.0239484] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 09/07/2020] [Indexed: 12/27/2022] Open
Abstract
Objective To assess and compare the involvement of choroidal thickness (CT) in patients with mild cognitive impairment (MCI) and dementia due to Alzheimer’s disease (AD) defined by amyloid PET and healthy controls (HC). Methods Sixty-three eyes from 34 AD patients [12 eyes (19.0%) with dementia and 51 eyes (80.9%) with MCI], positive to 11C-labelled Pittsburgh Compound-B with positron emission tomography (11C-PiB PET/CT), and the same number of sex- and age-paired HC were recruited. All participants underwent enhanced depth imaging optical coherence tomography (EDI-OCT) assessing CT at 14 measurements from 2 B-scans. Paired Student t-test was used to compare CT measurements between MCI, dementia and sex- and age-paired HC. A univariate generalized estimating equations model (GEE) test was performed to compare MCI and dementia individually with all HC included. Results Compared with HC, eyes from patients with positive 11C-PiB PET/CT showed a significant CT thinning in 5 selected locations (in foveal thickness in vertical scan, in temporal scan at 1500μm, in superior scan at 500μm and in inferior scan at 1000μm and 1500μm, p = 0.020–0.045) whilst few significant CT reduction data was reported in MCI or dementia individually versus HC. However, the GEE test identified significant CT thinning in AD compared with all HC included (p = 0.015–0.046). Conclusions To our knowledge, the present study is the first measuring CT in eyes from MCI and dementia eyes positive to 11C-PiB PET/CT reporting a significant trend towards CT thinning in MCI patients which became more pronounced in dementia stage. We support further investigation involving larger and prospective OCT studies in AD population characterized with available biomarkers to describe whether choroidal vascular damage occurs specifically in prodromal stages of AD.
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28
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Subramanian ML, Vig V, Chung J, Fiorello MG, Xia W, Zetterberg H, Blennow K, Zetterberg M, Shareef F, Siegel NH, Ness S, Jun GR, Stein TD. Neurofilament light chain in the vitreous humor of the eye. Alzheimers Res Ther 2020; 12:111. [PMID: 32943089 PMCID: PMC7500015 DOI: 10.1186/s13195-020-00677-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 09/01/2020] [Indexed: 12/13/2022]
Abstract
BACKGROUND Neurofilament light chain (NfL) is a promising biomarker of neurodegeneration in the cerebrospinal fluid and blood. This study investigated the presence of NfL in the vitreous humor and its associations with amyloid beta, tau, inflammatory cytokines and vascular proteins, apolipoprotein E (APOE) genotypes, Mini-Mental State Examination (MMSE) scores, systemic disease, and ophthalmic diseases. METHODS This is a single-site, prospective, cross-sectional cohort study. Undiluted vitreous fluid (0.5-1.0 mL) was aspirated during vitrectomy, and whole blood was drawn for APOE genotyping. NfL, amyloid beta (Aβ), total Tau (t-Tau), phosphorylated Tau (p-Tau181), inflammatory cytokines, chemokines, and vascular proteins in the vitreous were quantitatively measured by immunoassay. The main outcome measures were the detection of NfL levels in the vitreous humor and its associations with the aforementioned proteins. Linear regression was used to test the associations of NfL with other proteins, APOE genotypes, MMSE scores, and ophthalmic and systemic diseases after adjustment for age, sex, education level, and other eye diseases. RESULTS NfL was detected in all 77 vitreous samples. NfL was not found to be associated with ophthalmic conditions, APOE genotypes, MMSE scores, or systemic disease (p > 0.05). NfL levels were positively associated with increased vitreous levels of Aβ40 (p = 7.7 × 10-5), Aβ42 (p = 2.8 × 10-4), and t-tau (p = 5.5 × 10-7), but not with p-tau181 (p = 0.53). NfL also had significant associations with inflammatory cytokines such as interleukin-15 (IL-15, p = 5.3 × 10-4), IL-16 (p = 2.2 × 10-4), monocyte chemoattractant protein-1 (MCP1, p = 4.1 × 10-4), and vascular proteins such as vascular endothelial growth factor receptor-1 (VEGFR1, p = 2.9 × 10-6), Vegf-C (p = 8.6 × 10-6), vascular cell adhesion molecule-1 (VCAM-1, p = 5.0 × 10-4), Tie-2 (p = 6.3 × 10-4), and intracellular adhesion molecular-1 (ICAM-1, p = 1.6 × 10-4). CONCLUSION NfL is detectable in the vitreous humor of the eye and significantly associated with amyloid beta, t-tau, and select inflammatory and vascular proteins in the vitreous. Additionally, NfL was not associated with patients' clinical eye condition. Our results serve as a foundation for further investigation of NfL in the ocular fluids to inform us about the potential utility of its presence in the eye.
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Affiliation(s)
- Manju L Subramanian
- Department of Ophthalmology, Boston Medical Center, Boston University School of Medicine, 85 E Concord St. #8813, Boston, MA, 02118, USA.
| | - Viha Vig
- Department of Ophthalmology, Boston Medical Center, Boston University School of Medicine, 85 E Concord St. #8813, Boston, MA, 02118, USA
| | - Jaeyoon Chung
- Department of Medicine (Biomedical Genetics Section), Boston University School of Medicine, Boston, MA, USA
| | - Marissa G Fiorello
- Department of Ophthalmology, Boston Medical Center, Boston University School of Medicine, 85 E Concord St. #8813, Boston, MA, 02118, USA
| | - Weiming Xia
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA, USA
- Geriatric Research Education and Clinical Center, Bedford Veterans Affairs Medical Center, Bedford, MA, USA
| | - Henrik Zetterberg
- Department of Psychiatry and Neurochemistry at Institute of Neuroscience and Physiology, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
- Department of Neurodegenerative Diseases, UCL Institute of Neurology, London, UK
- UK Dementia Research Institute at UCL, London, UK
| | - Kaj Blennow
- Department of Psychiatry and Neurochemistry at Institute of Neuroscience and Physiology, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
| | - Madeleine Zetterberg
- Department of Clinical Neuroscience at Institute of Neuroscience and Physiology, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden
| | - Farah Shareef
- Department of Ophthalmology, University of Illinois at Chicago School of Medicine, Chicago, IL, USA
| | - Nicole H Siegel
- Department of Ophthalmology, Boston Medical Center, Boston University School of Medicine, 85 E Concord St. #8813, Boston, MA, 02118, USA
| | - Steven Ness
- Department of Ophthalmology, Boston Medical Center, Boston University School of Medicine, 85 E Concord St. #8813, Boston, MA, 02118, USA
| | - Gyungah R Jun
- Department of Medicine (Biomedical Genetics Section), Boston University School of Medicine, Boston, MA, USA
| | - Thor D Stein
- Boston University Alzheimer's Disease and CTE Center, Boston University School of Medicine, Boston, MA, USA
- Department of Pathology and Laboratory Medicine, Boston Medical Center, Boston University School of Medicine, Boston, MA, USA
- Department of Veterans Affairs Medical Center, VA Boston Healthcare System, Boston, MA, USA
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Asanad S, Ross-Cisneros FN, Barron E, Nassisi M, Sultan W, Karanjia R, Sadun AA. The retinal choroid as an oculovascular biomarker for Alzheimer's dementia: A histopathological study in severe disease. ALZHEIMER'S & DEMENTIA: DIAGNOSIS, ASSESSMENT & DISEASE MONITORING 2019; 11:775-783. [PMID: 31737776 PMCID: PMC6849152 DOI: 10.1016/j.dadm.2019.08.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Introduction Previous in vivo optical coherence tomography studies have proposed the retinal choroid as a potential oculovascular biomarker for Alzheimer's disease (AD). However, the clinical use of the choroid as a purported surrogate marker remains poorly understood. We pursued a histopathological approach to assess choroidal thickness and vascular morphology in severe disease. Methods Human postmortem tissues from 8 patients with AD (mean age: 80.1 ± 12.7 years) and from 11 age-matched controls (mean age: 78.4 ± 16.57 years) were analyzed. Thickness, area, and vascularity of the retinal choroid and its sublayers were measured from the nasal and temporal quadrants of the superior retina. Results Nasally, the choroid was thinner in the patients with AD than in the controls (22% thickness reduction; P < .001), but to our surprise, the choroid was thicker in the patients with AD than in the controls (~60% increase; P < .03) within the macula, temporally. The choroidal area was also significantly greater in the patients with AD than in the controls (~60% increase; P < .03). Choroidal thickening in AD was strongly correlated with the stromal vessel number (R2 = 0.96, P < .001). Discussion We found significant differences in the retinal choroid by layer and by region, nasally and temporally with respect to the optic nerve. Intriguingly, the choroid was markedly thicker in the central macular region and was strongly associated with vessel number in the stromal vascular layer. These quantified histological findings in severe disease expand our understanding of vascular pathology in AD and suggest vascularity as a potential biomarker supplementary to thickness when evaluating the retinal choroid in AD.
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Affiliation(s)
- Samuel Asanad
- Doheny Eye Institute, Los Angeles, CA, USA.,Department of Ophthalmology, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, CA, USA
| | | | | | | | | | - Rustum Karanjia
- Doheny Eye Institute, Los Angeles, CA, USA.,Department of Ophthalmology, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, CA, USA.,Department of Ophthalmology, University of Ottawa, Ottawa, Ontario, Canada.,Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
| | - Alfredo A Sadun
- Doheny Eye Institute, Los Angeles, CA, USA.,Department of Ophthalmology, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, CA, USA
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30
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Cabrera DeBuc D, Gaca-Wysocka M, Grzybowski A, Kanclerz P. Identification of Retinal Biomarkers in Alzheimer's Disease Using Optical Coherence Tomography: Recent Insights, Challenges, and Opportunities. J Clin Med 2019; 8:jcm8070996. [PMID: 31323964 PMCID: PMC6678943 DOI: 10.3390/jcm8070996] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2019] [Revised: 06/30/2019] [Accepted: 07/04/2019] [Indexed: 12/20/2022] Open
Abstract
This review will highlight recent insights into measuring retinal structure in Alzheimer’s disease (AD). A growing body of evidence indicates that disturbances in retinal blood flow and structure are related to cognitive function, which can severely impair vision. Optical coherence tomography (OCT) is an optical imaging technology that may allow researchers and physicians to gain deeper insights into retinal morphology and clarify the impact of AD on retinal health and function. Direct and noninvasive measurement of retinal morphology using OCT has provided useful diagnostic and therapeutic indications in several central nervous system (CNS) diseases, including AD, multiple sclerosis, and Parkinson disease. Despite several limitations, morphology assessment in the retinal layers is a significant advancement in the understanding of ocular diseases. Nevertheless, additional studies are required to validate the use of OCT in AD and its complications in the eye.
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Affiliation(s)
- Delia Cabrera DeBuc
- Bascom Palmer Eye Institute, Department of Ophthalmology, Miller School of Medicine, University of Miami, Miami, FL 33136, USA.
| | | | - Andrzej Grzybowski
- Department of Ophthalmology, University of Warmia and Mazury, 10-082 Olsztyn, Poland
- Institute for Research in Ophthalmology, Foundation for Ophthalmology Development, 60-554 Poznan, Poland
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31
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Cerquera-Jaramillo MA, Nava-Mesa MO, González-Reyes RE, Tellez-Conti C, de-la-Torre A. Visual Features in Alzheimer's Disease: From Basic Mechanisms to Clinical Overview. Neural Plast 2018; 2018:2941783. [PMID: 30405709 PMCID: PMC6204169 DOI: 10.1155/2018/2941783] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Accepted: 08/07/2018] [Indexed: 12/16/2022] Open
Abstract
Alzheimer's disease (AD) is the leading cause of dementia worldwide. It compromises patients' daily activities owing to progressive cognitive deterioration, which has elevated direct and indirect costs. Although AD has several risk factors, aging is considered the most important. Unfortunately, clinical diagnosis is usually performed at an advanced disease stage when dementia is established, making implementation of successful therapeutic interventions difficult. Current biomarkers tend to be expensive, insufficient, or invasive, raising the need for novel, improved tools aimed at early disease detection. AD is characterized by brain atrophy due to neuronal and synaptic loss, extracellular amyloid plaques composed of amyloid-beta peptide (Aβ), and neurofibrillary tangles of hyperphosphorylated tau protein. The visual system and central nervous system share many functional components. Thus, it is plausible that damage induced by Aβ, tau, and neuroinflammation may be observed in visual components such as the retina, even at an early disease stage. This underscores the importance of implementing ophthalmological examinations, less invasive and expensive than other biomarkers, as useful measures to assess disease progression and severity in individuals with or at risk of AD. Here, we review functional and morphological changes of the retina and visual pathway in AD from pathophysiological and clinical perspectives.
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Affiliation(s)
| | - Mauricio O. Nava-Mesa
- Grupo de Investigación en Neurociencias (NeURos), Escuela de Medicina y Ciencias de la Salud, Universidad del Rosario, Bogotá, Colombia
| | - Rodrigo E. González-Reyes
- Grupo de Investigación en Neurociencias (NeURos), Escuela de Medicina y Ciencias de la Salud, Universidad del Rosario, Bogotá, Colombia
| | - Carlos Tellez-Conti
- Escuela Superior de Oftalmología-Instituto Barraquer de América, Bogotá, Colombia
| | - Alejandra de-la-Torre
- Grupo de Investigación en Neurociencias (NeURos), Escuela de Medicina y Ciencias de la Salud, Universidad del Rosario, Bogotá, Colombia
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32
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Chan VTT, Sun Z, Tang S, Chen LJ, Wong A, Tham CC, Wong TY, Chen C, Ikram MK, Whitson HE, Lad EM, Mok VCT, Cheung CY. Spectral-Domain OCT Measurements in Alzheimer's Disease: A Systematic Review and Meta-analysis. Ophthalmology 2018; 126:497-510. [PMID: 30114417 DOI: 10.1016/j.ophtha.2018.08.009] [Citation(s) in RCA: 204] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2018] [Revised: 08/02/2018] [Accepted: 08/06/2018] [Indexed: 02/07/2023] Open
Abstract
TOPIC OCT is a noninvasive tool to measure specific retinal layers in the eye. The relationship of retinal spectral-domain (SD) OCT measurements with Alzheimer's disease (AD) and mild cognitive impairment (MCI) remains unclear. Hence, we conducted a systematic review and meta-analysis to examine the SD OCT measurements in AD and MCI. CLINICAL RELEVANCE Current methods of diagnosing early AD are expensive and invasive. Retinal measurements of SD OCT, which are noninvasive, technically simple, and inexpensive, are potential biomarkers of AD. METHODS We conducted a literature search in PubMed and Excerpta Medica Database to identify studies published before December 31, 2017, that assessed the associations between AD, MCI, and measurements of SD OCT: ganglion cell-inner plexiform layer (GC-IPL), ganglion cell complex (GCC), macular volume, and choroidal thickness, in addition to retinal nerve fiber layer (RNFL) and macular thickness. We used a random-effects model to examine these relationships. We also conducted meta-regression and assessed heterogeneity, publication bias, and study quality. RESULTS We identified 30 eligible studies, involving 1257 AD patients, 305 MCI patients, and 1460 controls, all of which were cross-sectional studies. In terms of the macular structure, AD patients showed significant differences in GC-IPL thickness (standardized mean difference [SMD], -0.46; 95% confidence interval [CI], -0.80 to -0.11; I2 = 71%), GCC thickness (SMD, -0.84; 95% CI, -1.10 to -0.57; I2 = 0%), macular volume (SMD, -0.58; 95% CI, -1.03 to -0.14; I2 = 80%), and macular thickness of all inner and outer sectors (SMD range, -0.52 to -0.74; all P < 0.001) when compared with controls. Peripapillary RNFL thickness (SMD, -0.67; 95% CI, -0.95 to -0.38; I2 = 89%) and choroidal thickness (SMD range, -0.88 to -1.03; all P < 0.001) also were thinner in AD patients. CONCLUSIONS Our results confirmed the associations between retinal measurements of SD OCT and AD, highlighting the potential usefulness of SD OCT measurements as biomarkers of AD.
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Affiliation(s)
- Victor T T Chan
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China; Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong, China
| | - Zihan Sun
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Shumin Tang
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Li Jia Chen
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Adrian Wong
- Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong, China
| | - Clement C Tham
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Tien Y Wong
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Republic of Singapore; Duke-NUS Medical School, National University of Singapore, Singapore, Republic of Singapore
| | - Christopher Chen
- Memory Aging and Cognition Centre, National University Health System, Singapore, Republic of Singapore; Department of Pharmacology, National University of Singapore, Singapore, Republic of Singapore
| | - M Kamran Ikram
- Departments of Neurology and Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Heather E Whitson
- Duke University Medical Center, Durham, North Carolina; Geriatrics Research Education and Clinical Center (GRECC), Durham VA Medical Center, Durham, North Carolina
| | | | - Vincent C T Mok
- Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong, China; Therese Pei Fong Chow Research Centre for Prevention of Dementia, The Chinese University of Hong Kong, Hong Kong, China
| | - Carol Y Cheung
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China.
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33
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Colligris P, Perez de Lara MJ, Colligris B, Pintor J. Ocular Manifestations of Alzheimer's and Other Neurodegenerative Diseases: The Prospect of the Eye as a Tool for the Early Diagnosis of Alzheimer's Disease. J Ophthalmol 2018; 2018:8538573. [PMID: 30151279 PMCID: PMC6091327 DOI: 10.1155/2018/8538573] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 06/07/2018] [Accepted: 06/26/2018] [Indexed: 12/20/2022] Open
Abstract
Dementia, including Alzheimer's disease (AD), is a major disorder, leading to several ocular manifestations amongst the elderly population. These visual disorders may be due to retinal nerve degenerative changes, including nerve fibre layer thinning, degeneration of retinal ganglion cells, and changes to vascular parameters. There is no cure for Alzheimer's, but medicines can slow down the development of many of the classic symptoms, such as loss of memory and communication skills, mood swings, and depression. The disease diagnosis is difficult, and it is only possible through PET scans of the brain, detecting evidence of the accumulation of amyloid and tau. PET is expensive and invasive, requiring the injection of radioactive tracers, which bind with these proteins and glow during scanning. Recently, scientists developed promising eye-scan techniques that may detect Alzheimer's disease at its earliest stage, before major symptoms appear, leading to improved management of the disease symptoms. In this review, we are discussing the visual abnormalities of Alzheimer's and other neurodegenerative diseases, focused on ocular functional-visual-structural biomarkers, retinal pathology, and potential novel diagnostic tools.
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Affiliation(s)
- Pade Colligris
- Universidad Alfonso X, Madrid, Spain
- Ocupharm Diagnostics SL, Madrid, Spain
| | | | - Basilio Colligris
- Ocupharm Diagnostics SL, Madrid, Spain
- Universidad Complutense de Madrid, Madrid, Spain
| | - Jesus Pintor
- Ocupharm Diagnostics SL, Madrid, Spain
- Universidad Complutense de Madrid, Madrid, Spain
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Afonso JM, Falcão M, Schlichtenbrede F, Falcão-Reis F, Silva SE, Schneider TM. Spectral Domain-Optical Coherence Tomography As a New Diagnostic Marker for Idiopathic Normal Pressure Hydrocephalus. Front Neurol 2017; 8:172. [PMID: 28507532 PMCID: PMC5410594 DOI: 10.3389/fneur.2017.00172] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2017] [Accepted: 04/12/2017] [Indexed: 11/13/2022] Open
Abstract
PURPOSE Characterized by a progressive onset of gait disturbances, dementia, and urinary incontinence, idiopathic normal pressure hydrocephalus (iNPH) is considered a rare, but under-diagnosed disease. Non-invasive diagnostic markers are still insufficient to enable the diagnosis of iNPH with certainty and yet early treatment with ventriculoperitoneal (VP) shunting can reverse symptoms and stop disease progression. Vascular circulation abnormalities in iNPH may be reflected by changes in subfoveal and peripapillary choroidal thickness (PPChT). This study uses spectral domain-optical coherence tomography (SD-OCT)-based measures of retinal and choroidal thickness to test this hypothesis and to assess ophthalmological non-invasive markers for iNPH. METHODS Twelve patients who displayed neurological and neuroradiological characteristics of iNPH were subject to a full ophthalmological examination including enhanced depth imaging (EDI) SD-OCT. Of the 12 included iNPH patients, 6 had undergone VP shunting with beneficial outcome. Parameters studied with EDI SD-OCT were macular retinal thickness (MT), subfoveal choroidal thickness (SFChT), retinal nerve fiber layer thickness (RNFL), and PPChT. Results were compared with 13 healthy, age-matched controls. RESULTS Macular thickness and RNFL and MT values of iNPH patients did not reflect atrophy. Non-shunted iNPH patients showed significantly lowered median PPChT and SFChT values compared to healthy controls. Shunted iNPH patients displayed a significantly higher median PPChT and SFChT compared to non-shunted iNPH patients. SFChT and PPChT values in shunted patients were not significantly different to values in healthy controls. CONCLUSION Although limited by small sample size, SD-OCT measures in this study reveal significant changes of choroidal thickness and support the hypothesis of choroidal susceptibility to hemodynamic alterations in iNPH. Non-shunted iNPH patients in this study show choroidal thinning in combination with normal RNFL and MT values. In addition to neurological and neuroradiological exams, this pattern may aid in the challenging diagnosis of iNPH.
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Affiliation(s)
- Joana M Afonso
- Department of Ophthalmology, São João University Hospital, Porto, Portugal.,Department of Ophthalmology, University Hospital Mannheim, Mannheim, Germany
| | - Manuel Falcão
- Department of Ophthalmology, São João University Hospital, Porto, Portugal.,Faculty of Medicine, Department of Sense Organs, University of Porto, Porto, Portugal
| | | | - Fernando Falcão-Reis
- Department of Ophthalmology, São João University Hospital, Porto, Portugal.,Faculty of Medicine, Department of Sense Organs, University of Porto, Porto, Portugal
| | | | - Till M Schneider
- Department of Neuroradiology, University Hospital Heidelberg, Heidelberg, Germany
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