1
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Gaire BP, Koronyo Y, Fuchs DT, Shi H, Rentsendorj A, Danziger R, Vit JP, Mirzaei N, Doustar J, Sheyn J, Hampel H, Vergallo A, Davis MR, Jallow O, Baldacci F, Verdooner SR, Barron E, Mirzaei M, Gupta VK, Graham SL, Tayebi M, Carare RO, Sadun AA, Miller CA, Dumitrascu OM, Lahiri S, Gao L, Black KL, Koronyo-Hamaoui M. Alzheimer's disease pathophysiology in the Retina. Prog Retin Eye Res 2024; 101:101273. [PMID: 38759947 DOI: 10.1016/j.preteyeres.2024.101273] [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: 02/11/2023] [Revised: 04/23/2024] [Accepted: 05/10/2024] [Indexed: 05/19/2024]
Abstract
The retina is an emerging CNS target for potential noninvasive diagnosis and tracking of Alzheimer's disease (AD). Studies have identified the pathological hallmarks of AD, including amyloid β-protein (Aβ) deposits and abnormal tau protein isoforms, in the retinas of AD patients and animal models. Moreover, structural and functional vascular abnormalities such as reduced blood flow, vascular Aβ deposition, and blood-retinal barrier damage, along with inflammation and neurodegeneration, have been described in retinas of patients with mild cognitive impairment and AD dementia. Histological, biochemical, and clinical studies have demonstrated that the nature and severity of AD pathologies in the retina and brain correspond. Proteomics analysis revealed a similar pattern of dysregulated proteins and biological pathways in the retina and brain of AD patients, with enhanced inflammatory and neurodegenerative processes, impaired oxidative-phosphorylation, and mitochondrial dysfunction. Notably, investigational imaging technologies can now detect AD-specific amyloid deposits, as well as vasculopathy and neurodegeneration in the retina of living AD patients, suggesting alterations at different disease stages and links to brain pathology. Current and exploratory ophthalmic imaging modalities, such as optical coherence tomography (OCT), OCT-angiography, confocal scanning laser ophthalmoscopy, and hyperspectral imaging, may offer promise in the clinical assessment of AD. However, further research is needed to deepen our understanding of AD's impact on the retina and its progression. To advance this field, future studies require replication in larger and diverse cohorts with confirmed AD biomarkers and standardized retinal imaging techniques. This will validate potential retinal biomarkers for AD, aiding in early screening and monitoring.
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Affiliation(s)
- Bhakta Prasad Gaire
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Yosef Koronyo
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Dieu-Trang Fuchs
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Haoshen Shi
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Altan Rentsendorj
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Ron Danziger
- Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Jean-Philippe Vit
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Nazanin Mirzaei
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Jonah Doustar
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Julia Sheyn
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Harald Hampel
- Sorbonne University, Alzheimer Precision Medicine (APM), AP-HP, Pitié-Salpêtrière Hospital, Paris, France
| | - Andrea Vergallo
- Sorbonne University, Alzheimer Precision Medicine (APM), AP-HP, Pitié-Salpêtrière Hospital, Paris, France
| | - Miyah R Davis
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Ousman Jallow
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Filippo Baldacci
- Sorbonne University, Alzheimer Precision Medicine (APM), AP-HP, Pitié-Salpêtrière Hospital, Paris, France; Department of Clinical and Experimental Medicine, Neurology Unit, University of Pisa, Pisa, Italy
| | | | - Ernesto Barron
- Department of Ophthalmology, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, CA, USA; Doheny Eye Institute, Los Angeles, CA, USA
| | - Mehdi Mirzaei
- Department of Clinical Medicine, Health and Human Sciences, Macquarie Medical School, Macquarie University, Sydney, NSW, Australia
| | - Vivek K Gupta
- Department of Clinical Medicine, Health and Human Sciences, Macquarie Medical School, Macquarie University, Sydney, NSW, Australia
| | - Stuart L Graham
- Department of Clinical Medicine, Health and Human Sciences, Macquarie Medical School, Macquarie University, Sydney, NSW, Australia; Department of Clinical Medicine, Macquarie University, Sydney, NSW, Australia
| | - Mourad Tayebi
- School of Medicine, Western Sydney University, Campbelltown, NSW, Australia
| | - Roxana O Carare
- Department of Clinical Neuroanatomy, University of Southampton, Southampton, UK
| | - Alfredo A Sadun
- Department of Ophthalmology, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, CA, USA; Doheny Eye Institute, Los Angeles, CA, USA
| | - Carol A Miller
- Department of Pathology Program in Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | | | - Shouri Lahiri
- Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Liang Gao
- Department of Bioengineering, University of California Los Angeles, Los Angeles, CA, USA
| | - Keith L Black
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Maya Koronyo-Hamaoui
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA; Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, CA, USA; Department of Biomedical Sciences, Division of Applied Cell Biology and Physiology, Cedars-Sinai Medical Center, Los Angeles, CA, USA.
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2
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Chow DJX, Tan TCY, Upadhya A, Lim M, Dholakia K, Dunning KR. Viewing early life without labels: optical approaches for imaging the early embryo†. Biol Reprod 2024; 110:1157-1174. [PMID: 38647415 PMCID: PMC11180623 DOI: 10.1093/biolre/ioae062] [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: 01/28/2024] [Revised: 03/26/2024] [Accepted: 04/18/2024] [Indexed: 04/25/2024] Open
Abstract
Embryo quality is an important determinant of successful implantation and a resultant live birth. Current clinical approaches for evaluating embryo quality rely on subjective morphology assessments or an invasive biopsy for genetic testing. However, both approaches can be inherently inaccurate and crucially, fail to improve the live birth rate following the transfer of in vitro produced embryos. Optical imaging offers a potential non-invasive and accurate avenue for assessing embryo viability. Recent advances in various label-free optical imaging approaches have garnered increased interest in the field of reproductive biology due to their ability to rapidly capture images at high resolution, delivering both morphological and molecular information. This burgeoning field holds immense potential for further development, with profound implications for clinical translation. Here, our review aims to: (1) describe the principles of various imaging systems, distinguishing between approaches that capture morphological and molecular information, (2) highlight the recent application of these technologies in the field of reproductive biology, and (3) assess their respective merits and limitations concerning the capacity to evaluate embryo quality. Additionally, the review summarizes challenges in the translation of optical imaging systems into routine clinical practice, providing recommendations for their future development. Finally, we identify suitable imaging approaches for interrogating the mechanisms underpinning successful embryo development.
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Affiliation(s)
- Darren J X Chow
- Robinson Research Institute, School of Biomedicine, The University of Adelaide, Adelaide, Australia
- Institute for Photonics and Advanced Sensing, The University of Adelaide, Adelaide, Australia
- Centre of Light for Life, The University of Adelaide, Adelaide, Australia
| | - Tiffany C Y Tan
- Robinson Research Institute, School of Biomedicine, The University of Adelaide, Adelaide, Australia
- Institute for Photonics and Advanced Sensing, The University of Adelaide, Adelaide, Australia
| | - Avinash Upadhya
- Institute for Photonics and Advanced Sensing, The University of Adelaide, Adelaide, Australia
- Centre of Light for Life, The University of Adelaide, Adelaide, Australia
- School of Biological Sciences, The University of Adelaide, Adelaide, Australia
| | - Megan Lim
- Robinson Research Institute, School of Biomedicine, The University of Adelaide, Adelaide, Australia
- Institute for Photonics and Advanced Sensing, The University of Adelaide, Adelaide, Australia
- Centre of Light for Life, The University of Adelaide, Adelaide, Australia
- School of Biological Sciences, The University of Adelaide, Adelaide, Australia
| | - Kishan Dholakia
- Centre of Light for Life, The University of Adelaide, Adelaide, Australia
- School of Biological Sciences, The University of Adelaide, Adelaide, Australia
- Scottish Universities Physics Alliance, School of Physics and Astronomy, University of St Andrews, St Andrews, United Kingdom
| | - Kylie R Dunning
- Robinson Research Institute, School of Biomedicine, The University of Adelaide, Adelaide, Australia
- Institute for Photonics and Advanced Sensing, The University of Adelaide, Adelaide, Australia
- Centre of Light for Life, The University of Adelaide, Adelaide, Australia
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3
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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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4
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Sonntag SR, Hamann M, Seifert E, Grisanti S, Brinkmann R, Miura Y. Detection sensitivity of fluorescence lifetime imaging ophthalmoscopy for laser-induced selective damage of retinal pigment epithelium. Graefes Arch Clin Exp Ophthalmol 2024:10.1007/s00417-024-06449-2. [PMID: 38587656 DOI: 10.1007/s00417-024-06449-2] [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: 11/05/2023] [Revised: 03/05/2024] [Accepted: 03/08/2024] [Indexed: 04/09/2024] Open
Abstract
PURPOSE To investigate the sensitivity of fluorescence lifetime imaging ophthalmoscopy (FLIO) to detect retinal laser spots by comparative analysis with other imaging modalities. METHODS A diode laser with a wavelength of 514 nm was applied with pulse durations of 5.2, 12, 20, and 50 µs. The laser pulse energy was increased so that the visibility of the laser spot by slit-lamp fundus examination (SL) under the irradiator's observation covers from the subvisible to visible range immediately after irradiation. The irradiated areas were then examined by fundus color photography (FC), optical coherence tomography (OCT), fundus autofluorescence (AF), FLIO, and fluorescein angiography (FA). The visibility of a total of over 2200 laser spots was evaluated by two independent researchers, and effective dose (ED) 50 laser pulse energy values were calculated for each imaging modality and compared. RESULTS Among examined modalities, FA showed the lowest mean of ED50 energy value and SL the highest, that is, they had the highest and lowest sensitivity to detect retinal pigment epithalium (RPE)-selective laser spots, respectively. FLIO also detected spots significantly more sensitively than SL at most laser pulse durations and was not significantly inferior to FA. AF was also often more sensitive than SL, but the difference was slightly less significant than FLIO. CONCLUSION Considering its high sensitivity in detecting laser spots and previously reported potential of indicating local wound healing and metabolic changes around laser spots, FLIO may be useful as a non-invasive monitoring tool during and after minimally invasive retinal laser treatment.
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Affiliation(s)
- Svenja Rebecca Sonntag
- Department of Ophthalmology, University Hospital Schleswig-Holstein, Campus Lübeck, Lübeck, Germany
| | - Maximilian Hamann
- Department of Ophthalmology, University Hospital Schleswig-Holstein, Campus Lübeck, Lübeck, Germany
- Department of Ophthalmology, Hannover Medical School, Hannover, Germany
| | | | - Salvatore Grisanti
- Department of Ophthalmology, University Hospital Schleswig-Holstein, Campus Lübeck, Lübeck, Germany
| | - Ralf Brinkmann
- Medical Laser Center Lübeck, Lübeck, Germany
- Institute of Biomedical Optics, University of Lübeck, Lübeck, Germany
| | - Yoko Miura
- Department of Ophthalmology, University Hospital Schleswig-Holstein, Campus Lübeck, Lübeck, Germany.
- Medical Laser Center Lübeck, Lübeck, Germany.
- Institute of Biomedical Optics, University of Lübeck, Lübeck, Germany.
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5
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Thiemann N, Sonntag SR, Kreikenbohm M, Böhmerle G, Stagge J, Grisanti S, Martinetz T, Miura Y. Artificial Intelligence in Fluorescence Lifetime Imaging Ophthalmoscopy (FLIO) Data Analysis-Toward Retinal Metabolic Diagnostics. Diagnostics (Basel) 2024; 14:431. [PMID: 38396470 PMCID: PMC10888399 DOI: 10.3390/diagnostics14040431] [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: 11/11/2023] [Revised: 01/30/2024] [Accepted: 02/06/2024] [Indexed: 02/25/2024] Open
Abstract
The purpose of this study was to investigate the possibility of implementing an artificial intelligence (AI) approach for the analysis of fluorescence lifetime imaging ophthalmoscopy (FLIO) data even with small data. FLIO data, including the fluorescence intensity and mean fluorescence lifetime (τm) of two spectral channels, as well as OCT-A data from 26 non-smokers and 28 smokers without systemic and ocular diseases were used. The analysis was performed with support vector machines (SVMs), a well-known AI method for small datasets, and compared with the results of convolutional neural networks (CNNs) and autoencoder networks. The SVM was the only tested AI method, which was able to distinguish τm between non-smokers and heavy smokers. The accuracy was about 80%. OCT-A data did not show significant differences. The feasibility and usefulness of the AI in analyzing FLIO and OCT-A data without any apparent retinal diseases were demonstrated. Although further studies with larger datasets are necessary to validate the results, the results greatly suggest that AI could be useful in analyzing FLIO-data even from healthy subjects without retinal disease and even with small datasets. AI-assisted FLIO is expected to greatly advance early retinal diagnosis.
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Affiliation(s)
- Natalie Thiemann
- Institute for Neuro- and Bioinformatics, University of Lübeck, 23538 Lübeck, Germany
| | - Svenja Rebecca Sonntag
- Department of Ophthalmology, University of Luebeck, University Hospital Schleswig-Holstein, Campus Lübeck, 23538 Lübeck, Germany
| | - Marie Kreikenbohm
- Department of Ophthalmology, University of Luebeck, University Hospital Schleswig-Holstein, Campus Lübeck, 23538 Lübeck, Germany
| | - Giulia Böhmerle
- Department of Ophthalmology, University of Luebeck, University Hospital Schleswig-Holstein, Campus Lübeck, 23538 Lübeck, Germany
| | - Jessica Stagge
- Department of Ophthalmology, University of Luebeck, University Hospital Schleswig-Holstein, Campus Lübeck, 23538 Lübeck, Germany
| | - Salvatore Grisanti
- Department of Ophthalmology, University of Luebeck, University Hospital Schleswig-Holstein, Campus Lübeck, 23538 Lübeck, Germany
| | - Thomas Martinetz
- Institute for Neuro- and Bioinformatics, University of Lübeck, 23538 Lübeck, Germany
| | - Yoko Miura
- Department of Ophthalmology, University of Luebeck, University Hospital Schleswig-Holstein, Campus Lübeck, 23538 Lübeck, Germany
- Institute of Biomedical Optics, University of Lübeck, 23538 Lübeck, Germany
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6
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Alber J, Bouwman F, den Haan J, Rissman RA, De Groef L, Koronyo‐Hamaoui M, Lengyel I, Thal DR. Retina pathology as a target for biomarkers for Alzheimer's disease: Current status, ophthalmopathological background, challenges, and future directions. Alzheimers Dement 2024; 20:728-740. [PMID: 37917365 PMCID: PMC10917008 DOI: 10.1002/alz.13529] [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: 08/07/2023] [Revised: 09/30/2023] [Accepted: 10/05/2023] [Indexed: 11/04/2023]
Abstract
There is emerging evidence that amyloid beta protein (Aβ) and tau-related lesions in the retina are associated with Alzheimer's disease (AD). Aβ and hyperphosphorylated (p)-tau deposits have been described in the retina and were associated with small amyloid spots visualized by in vivo imaging techniques as well as degeneration of the retina. These changes correlate with brain amyloid deposition as determined by histological quantification, positron emission tomography (PET) or clinical diagnosis of AD. However, the literature is not coherent on these histopathological and in vivo imaging findings. One important reason for this is the variability in the methods and the interpretation of findings across different studies. In this perspective, we indicate the critical methodological deviations among different groups and suggest a roadmap moving forward on how to harmonize (i) histopathologic examination of retinal tissue; (ii) in vivo imaging among different methods, devices, and interpretation algorithms; and (iii) inclusion/exclusion criteria for studies aiming at retinal biomarker validation.
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Affiliation(s)
- Jessica Alber
- George and Anne Ryan Institute for Neuroscience, Department of Biomedical and Pharmaceutical SciencesUniversity of Rhode IslandKingstonRhode IslandUSA
- Butler Hospital Memory & Aging ProgramProvidenceRhode IslandUSA
| | - Femke Bouwman
- Amsterdam UMC, location VUmcAlzheimer Center, Department of NeurologyAmsterdamThe Netherlands
| | - Jurre den Haan
- Amsterdam UMC, location VUmcAlzheimer Center, Department of NeurologyAmsterdamThe Netherlands
| | - Robert A. Rissman
- Alzheimer's Therapeutic Research InstituteKeck School of Medicine of the University of Southern CaliforniaSan DiegoCaliforniaUSA
| | - Lies De Groef
- Cellular Communication and Neurodegeneration Research Group, Animal Physiology and Neurobiology Division, Department of BiologyLeuven Brain InstituteKU LeuvenLeuvenBelgium
| | - Maya Koronyo‐Hamaoui
- Departments of Neurosurgery, Neurology, and Biomedical SciencesMaxine Dunitz Neurosurgical Research Institute, Cedars‐Sinai Medical CenterLos AngelesCaliforniaUSA
| | - Imre Lengyel
- The Wellcome‐Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical ScienceQueen's University BelfastBelfastUK
| | - Dietmar Rudolf Thal
- Laboratory of NeuropathologyDepartment of Imaging and Pathology, and Leuven Brain Institute, KU LeuvenLeuvenBelgium
- Department of PathologyUZ LeuvenLeuvenBelgium
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7
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Morizet J, Chow D, Wijesinghe P, Schartner E, Dwapanyin G, Dubost N, Bruce GD, Anckaert E, Dunning K, Dholakia K. UVA Hyperspectral Light-Sheet Microscopy for Volumetric Metabolic Imaging: Application to Preimplantation Embryo Development. ACS PHOTONICS 2023; 10:4177-4187. [PMID: 38145166 PMCID: PMC10739996 DOI: 10.1021/acsphotonics.3c00900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 10/16/2023] [Accepted: 10/17/2023] [Indexed: 12/26/2023]
Abstract
Cellular metabolism is a key regulator of energetics, cell growth, regeneration, and homeostasis. Spatially mapping the heterogeneity of cellular metabolic activity is of great importance for unraveling the overall cell and tissue health. In this regard, imaging the endogenous metabolic cofactors, nicotinamide adenine dinucleotide (phosphate) (NAD(P)H) and flavin adenine dinucleotide (FAD), with subcellular resolution and in a noninvasive manner would be useful to determine tissue and cell viability in a clinical environment, but practical use is limited by current imaging techniques. In this paper, we demonstrate the use of phasor-based hyperspectral light-sheet (HS-LS) microscopy using a single UVA excitation wavelength as a route to mapping metabolism in three dimensions. We show that excitation solely at a UVA wavelength of 375 nm can simultaneously excite NAD(P)H and FAD autofluorescence, while their relative contributions can be readily quantified using a hardware-based spectral phasor analysis. We demonstrate the potential of our HS-LS system by capturing dynamic changes in metabolic activity during preimplantation embryo development. To validate our approach, we delineate metabolic changes during preimplantation embryo development from volumetric maps of metabolic activity. Importantly, our approach overcomes the need for multiple excitation wavelengths, two-photon imaging, or significant postprocessing of data, paving the way toward clinical translation, such as in situ, noninvasive assessment of embryo viability.
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Affiliation(s)
- Josephine Morizet
- SUPA,
School of Physics and Astronomy, University
of St Andrews, North Haugh, St Andrews Fife KY16, U.K.
| | - Darren Chow
- Robinson
Research Institute, School of Biomedicine, The University of Adelaide, Adelaide 5501, Australia
- Australian
Research Council Centre of Excellence for Nanoscale Biophotonics, The University of Adelaide, Adelaide 5505, Australia
- Institute
for Photonics and Advanced Sensing, The
University of Adelaide, Adelaide 5505, Australia
| | - Philip Wijesinghe
- SUPA,
School of Physics and Astronomy, University
of St Andrews, North Haugh, St Andrews Fife KY16, U.K.
| | - Erik Schartner
- Robinson
Research Institute, School of Biomedicine, The University of Adelaide, Adelaide 5501, Australia
- Institute
for Photonics and Advanced Sensing, The
University of Adelaide, Adelaide 5505, Australia
- Centre
of Light for Life, The University of Adelaide, Adelaide 5005, Australia
| | - George Dwapanyin
- SUPA,
School of Physics and Astronomy, University
of St Andrews, North Haugh, St Andrews Fife KY16, U.K.
| | - Nicolas Dubost
- SUPA,
School of Physics and Astronomy, University
of St Andrews, North Haugh, St Andrews Fife KY16, U.K.
| | - Graham D. Bruce
- SUPA,
School of Physics and Astronomy, University
of St Andrews, North Haugh, St Andrews Fife KY16, U.K.
| | - Ellen Anckaert
- Faculty of
Medicine and Pharmacy, Vrije Universiteit
Brussel, Brussels 1070, Belgium
| | - Kylie Dunning
- Robinson
Research Institute, School of Biomedicine, The University of Adelaide, Adelaide 5501, Australia
- Australian
Research Council Centre of Excellence for Nanoscale Biophotonics, The University of Adelaide, Adelaide 5505, Australia
- Institute
for Photonics and Advanced Sensing, The
University of Adelaide, Adelaide 5505, Australia
| | - Kishan Dholakia
- SUPA,
School of Physics and Astronomy, University
of St Andrews, North Haugh, St Andrews Fife KY16, U.K.
- Centre
of Light for Life, The University of Adelaide, Adelaide 5005, Australia
- School
of Biological Sciences, The University of
Adelaide, Adelaide 5005, Australia
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8
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Suh A, Ong J, Kamran SA, Waisberg E, Paladugu P, Zaman N, Sarker P, Tavakkoli A, Lee AG. Retina Oculomics in Neurodegenerative Disease. Ann Biomed Eng 2023; 51:2708-2721. [PMID: 37855949 DOI: 10.1007/s10439-023-03365-0] [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: 07/13/2023] [Accepted: 09/05/2023] [Indexed: 10/20/2023]
Abstract
Ophthalmic biomarkers have long played a critical role in diagnosing and managing ocular diseases. Oculomics has emerged as a field that utilizes ocular imaging biomarkers to provide insights into systemic diseases. Advances in diagnostic and imaging technologies including electroretinography, optical coherence tomography (OCT), confocal scanning laser ophthalmoscopy, fluorescence lifetime imaging ophthalmoscopy, and OCT angiography have revolutionized the ability to understand systemic diseases and even detect them earlier than clinical manifestations for earlier intervention. With the advent of increasingly large ophthalmic imaging datasets, machine learning models can be integrated into these ocular imaging biomarkers to provide further insights and prognostic predictions of neurodegenerative disease. In this manuscript, we review the use of ophthalmic imaging to provide insights into neurodegenerative diseases including Alzheimer Disease, Parkinson Disease, Amyotrophic Lateral Sclerosis, and Huntington Disease. We discuss recent advances in ophthalmic technology including eye-tracking technology and integration of artificial intelligence techniques to further provide insights into these neurodegenerative diseases. Ultimately, oculomics opens the opportunity to detect and monitor systemic diseases at a higher acuity. Thus, earlier detection of systemic diseases may allow for timely intervention for improving the quality of life in patients with neurodegenerative disease.
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Affiliation(s)
- Alex Suh
- Tulane University School of Medicine, New Orleans, LA, USA.
| | - Joshua Ong
- Michigan Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Sharif Amit Kamran
- Human-Machine Perception Laboratory, Department of Computer Science and Engineering, University of Nevada, Reno, Reno, NV, USA
| | - Ethan Waisberg
- University College Dublin School of Medicine, Belfield, Dublin, Ireland
| | - Phani Paladugu
- Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
- Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA
| | - Nasif Zaman
- Human-Machine Perception Laboratory, Department of Computer Science and Engineering, University of Nevada, Reno, Reno, NV, USA
| | - Prithul Sarker
- Human-Machine Perception Laboratory, Department of Computer Science and Engineering, University of Nevada, Reno, Reno, NV, USA
| | - Alireza Tavakkoli
- Human-Machine Perception Laboratory, Department of Computer Science and Engineering, University of Nevada, Reno, Reno, NV, USA
| | - Andrew G Lee
- Center for Space Medicine, Baylor College of Medicine, Houston, TX, USA
- Department of Ophthalmology, Blanton Eye Institute, Houston Methodist Hospital, 6560 Fannin St #450, Houston, TX, 77030, USA
- The Houston Methodist Research Institute, Houston Methodist Hospital, Houston, TX, USA
- Departments of Ophthalmology, Neurology and Neurosurgery, Weill Cornell Medicine, New York, NY, USA
- Department of Ophthalmology, University of Texas Medical Branch, Galveston, TX, USA
- University of Texas MD Anderson Cancer Center, Houston, TX, USA
- Texas A&M College of Medicine, Bryan, TX, USA
- Department of Ophthalmology, The University of Iowa Hospitals and Clinics, Iowa City, IA, USA
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9
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Sonntag SR, Kreikenbohm M, Böhmerle G, Stagge J, Grisanti S, Miura Y. Impact of cigarette smoking on fluorescence lifetime of ocular fundus. Sci Rep 2023; 13:11484. [PMID: 37460627 DOI: 10.1038/s41598-023-37484-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 06/22/2023] [Indexed: 07/20/2023] Open
Abstract
Cigarette smoking is known to adversely affect cellular metabolism and is a risk factor for various retinal diseases. Fluorescence lifetime imaging ophthalmoscopy (FLIO) has the potential to detect metabolic changes in the ocular fundus. Aim of this study was to analyze the influence of cigarette smoking on fluorescence lifetime (FLT) of healthy eyes using FLIO. Twenty-six non-smokers and 28 smokers aged between 20 and 37 years without systemic and ocular diseases were investigated by FLIO (excitation: 473 nm, emission: short spectral channel (SSC) 498-560 nm, long spectral channel (LSC) 560-720 nm). The FLT at the ETDRS grid regions were analyzed and compared. In SSC, the mean FLT (τm) of smokers was significantly longer in the ETDRS inner ring region, whereas the τm in LSC was significantly shorter in the outer ring. For the long component (τ2), smokers with pack year < 7.11 showed significantly shorter τ2 in SSC than non-smokers and the smokers with pack year ≥ 7.11. There were no significant differences in retinal thickness. The lack of obvious structural differences implies that the observed FLT changes are likely related to smoking-induced metabolic changes. These results suggest that FLIO may be useful in assessing retinal conditions related to lifestyle and systemic metabolic status.
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Affiliation(s)
- Svenja Rebecca Sonntag
- Department of Ophthalmology, University of Lübeck, Ratzeburger Allee 160, 23538, Lübeck, Germany
| | - Marie Kreikenbohm
- Department of Ophthalmology, University of Lübeck, Ratzeburger Allee 160, 23538, Lübeck, Germany
| | - Giulia Böhmerle
- Department of Ophthalmology, University of Lübeck, Ratzeburger Allee 160, 23538, Lübeck, Germany
| | - Jessica Stagge
- Department of Ophthalmology, University of Lübeck, Ratzeburger Allee 160, 23538, Lübeck, Germany
| | - Salvatore Grisanti
- Department of Ophthalmology, University of Lübeck, Ratzeburger Allee 160, 23538, Lübeck, Germany
| | - Yoko Miura
- Department of Ophthalmology, University of Lübeck, Ratzeburger Allee 160, 23538, Lübeck, Germany.
- Institute of Biomedical Optics, University of Lübeck, Lübeck, Germany.
- Medical Laser Center Lübeck, Lübeck, Germany.
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10
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Ashraf G, McGuinness M, Khan MA, Obtinalla C, Hadoux X, van Wijngaarden P. Retinal imaging biomarkers of Alzheimer's disease: A systematic review and meta-analysis of studies using brain amyloid beta status for case definition. ALZHEIMER'S & DEMENTIA (AMSTERDAM, NETHERLANDS) 2023; 15:e12421. [PMID: 37250908 PMCID: PMC10210353 DOI: 10.1002/dad2.12421] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 03/03/2023] [Accepted: 03/07/2023] [Indexed: 05/31/2023]
Abstract
Introduction We performed a systematic review and meta-analysis of the association between retinal imaging parameters and Alzheimer's disease (AD). Methods PubMed, EMBASE, and Scopus were systematically searched for prospective and observational studies. Included studies had AD case definition based on brain amyloid beta (Aβ) status. Study quality assessment was performed. Random-effects meta-analyses of standardized mean difference, correlation, and diagnostic accuracy were conducted. Results Thirty-eight studies were included. There was weak evidence of peripapillary retinal nerve fiber layer thinning on optical coherence tomography (OCT) (p = 0.14, 11 studies, n = 828), increased foveal avascular zone area on OCT-angiography (p = 0.18, four studies, n = 207), and reduced arteriole and venule vessel fractal dimension on fundus photography (p < 0.001 and p = 0.08, respectively, three studies, n = 297) among AD cases. Discussion Retinal imaging parameters appear to be associated with AD. Small study sizes and heterogeneity in imaging methods and reporting make it difficult to determine utility of these changes as AD biomarkers. Highlights We performed a systematic review on retinal imaging and Alzheimer's disease (AD).We only included studies in which cases were based on brain amyloid beta status.Several retinal biomarkers were associated with AD but clinical utility is uncertain.Studies should focus on biomarker-defined AD and use standardized imaging methods.
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Affiliation(s)
- Gizem Ashraf
- Centre for Eye Research AustraliaRoyal Victorian Eye and Ear HospitalMelbourneVictoriaAustralia
- OphthalmologyDepartment of SurgeryUniversity of MelbourneMelbourneVictoriaAustralia
| | - Myra McGuinness
- Centre for Eye Research AustraliaRoyal Victorian Eye and Ear HospitalMelbourneVictoriaAustralia
- Centre for Epidemiology and BiostatisticsMelbourne School of Population and Global HealthUniversity of MelbourneMelbourneVictoriaAustralia
| | - Muhammad Azaan Khan
- Faculty of Medicine and HealthUniversity of New South WalesSydneyNew South WalesAustralia
| | - Czarina Obtinalla
- Discipline of OrthopticsSchool of Allied HealthHuman Services & SportCollege of ScienceHealth & EngineeringLa Trobe UniversityMelbourneVictoriaAustralia
| | - Xavier Hadoux
- Centre for Eye Research AustraliaRoyal Victorian Eye and Ear HospitalMelbourneVictoriaAustralia
| | - Peter van Wijngaarden
- Centre for Eye Research AustraliaRoyal Victorian Eye and Ear HospitalMelbourneVictoriaAustralia
- OphthalmologyDepartment of SurgeryUniversity of MelbourneMelbourneVictoriaAustralia
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11
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Feldman TB, Dontsov AE, Yakovleva MA, Ostrovsky MA. Photobiology of lipofuscin granules in the retinal pigment epithelium cells of the eye: norm, pathology, age. Biophys Rev 2022; 14:1051-1065. [PMID: 36124271 PMCID: PMC9481861 DOI: 10.1007/s12551-022-00989-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 07/26/2022] [Indexed: 01/10/2023] Open
Abstract
Lipofuscin granules (LGs) are accumulated in the retinal pigment epithelium (RPE) cells. The progressive LG accumulation can somehow lead to pathology and accelerate the aging process. The review examines composition, spectral properties and photoactivity of LGs isolated from the human cadaver eyes. By use of atomic force microscopy and near-field microscopy, we have revealed the fluorescent heterogeneity of LGs. We have discovered the generation of reactive oxygen species by LGs, and found that LGs and melanolipofuscin granules are capable of photoinduced oxidation of lipids. It was shown that A2E, as the main fluorophore (bisretinoid) of LGs, is much less active as an oxidation photosensitizer than other fluorophores (bisretinoids) of LGs. Photooxidized products of bisretinoids pose a much greater danger to the cell than non-oxidized one. Our studies of the fluorescent properties of LGs and their fluorophores (bisretinoids) showed for the first time that their spectral characteristics change (shift to the short-wavelength region) in pathology and after exposure to ionizing radiation. By recording the fluorescence spectra and fluorescence decay kinetics of oxidized products of LG fluorophores, it is possible to improve the methods of early diagnosis of degenerative diseases. Lipofuscin ("aging pigment") is not an inert "slag". The photoactivity of LGs can pose a significant danger to the RPE cells. Fluorescence characteristics of LGs are a tool to detect early stages of degeneration in the retina and RPE.
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Affiliation(s)
- T. B. Feldman
- Department of Biology, Lomonosov Moscow State University, Moscow, Russia
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow, Russia
| | - A. E. Dontsov
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow, Russia
| | - M. A. Yakovleva
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow, Russia
| | - M. A. Ostrovsky
- Department of Biology, Lomonosov Moscow State University, Moscow, Russia
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow, Russia
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12
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Jeevakumar V, Sefton R, Chan J, Gopinath B, Liew G, Shah TM, Siette J. Association between retinal markers and cognition in older adults: a systematic review. BMJ Open 2022; 12:e054657. [PMID: 35728906 PMCID: PMC9214387 DOI: 10.1136/bmjopen-2021-054657] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
OBJECTIVES To appraise the existing literature reporting an association between retinal markers and cognitive impairment in adults aged 65 years and over and to provide directions for future use of retinal scanning as a potential tool for dementia diagnosis. DESIGN Systematic review of peer-reviewed empirical articles investigating the association of retinal markers in assessing cognitive impairment. DATA SOURCES Three electronic databases, Medline, PsycINFO and EMBASE were searched from inception until March 2022. ELIGIBILITY CRITERIA All empirical articles in English investigating the association between retinal markers and cognition in humans aged ≥65 years using various retinal scanning methodologies were included. Studies with no explicit evaluation of retinal scanning and cognitive outcomes were excluded. Risk of bias was assessed using the Quality Assessment of Diagnostic Accuracy Studies tool. DATA EXTRACTION AND SYNTHESIS Data extraction was conducted by two authors (VJ, RS) and reviewed by another author (JS). Results were synthesised and described narratively. RESULTS Sixty-seven eligible studies examining 6815 older adults were included. Majority of studies were cross-sectional (n=60; 89.6%). Optical coherence tomography (OCT) was the most commonly used retinal scanning methodology to measure the thickness of retinal nerve fibre layer, the ganglion cell complex, choroid and macula. 51.1% of cross-sectional studies using OCT reported an association between the thinning of at least one retinal parameter and poor cognition. Longitudinal studies (n=6) using OCT also mostly identified significant reductions in retinal nerve fibre layer thickness with cognitive decline. Study quality was overall moderate. CONCLUSION Retinal nerve fibre layer thickness is linked with cognitive performance and therefore may have the potential to detect cognitive impairment in older adults. Further longitudinal studies are required to validate our synthesis and understand underlying mechanisms before recommending implementation of OCT as a dementia screening tool in clinical practice. PROSPERO REGISTRATION NUMBER CRD42020176757.
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Affiliation(s)
- Varshanie Jeevakumar
- Australian Institute of Health Innovation, Macquarie University, Macquarie Park, New South Wales, Australia
| | - Rebekah Sefton
- Australian Institute of Health Innovation, Macquarie University, Macquarie Park, New South Wales, Australia
| | - Joyce Chan
- New Look Eyewear, Maitland, New South Wales, Australia
| | - Bamini Gopinath
- Department of Linguistics, Australian Hearing Hub, Macquarie University, Macquarie Park, New South Wales, Australia
| | - Gerald Liew
- Centre for Vision Research, The University of Sydney, Sydney, New South Wales, Australia
| | - Tejal M Shah
- Macquarie Medical School, Macquarie University, North Ryde, New South Wales, Australia
| | - Joyce Siette
- Australian Institute of Health Innovation, Macquarie University, Macquarie Park, New South Wales, Australia
- MARCS Institute for Brain, Behaviour and Development, Western Sydney University, Westmead, New South Wales, Australia
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13
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Christinaki E, Kulenovic H, Hadoux X, Baldassini N, Van Eijgen J, De Groef L, Stalmans I, van Wijngaarden P. Retinal imaging biomarkers of neurodegenerative diseases. Clin Exp Optom 2022; 105:194-204. [PMID: 34751086 DOI: 10.1080/08164622.2021.1984179] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The timely detection of neurodegenerative diseases is central to improving clinical care as well as enabling the development and deployment of disease-modifying therapies. Retinal imaging is emerging as a method to detect features of a number of neurodegenerative diseases, given the anatomical and functional similarities between the retina and the brain. This review provides an overview of the current status of retinal imaging biomarkers of neurodegenerative diseases including Alzheimer's disease, Parkinson's disease, Lewy body dementia, frontotemporal dementia, Huntington's disease and multiple sclerosis. Whilst research findings are promising, efforts to harmonise study designs and imaging methods will be important in translating these findings into clinical care. Doing so may mean that eye care providers will play important roles in the detection of a variety of neurodegenerative diseases in future.
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Affiliation(s)
- Eirini Christinaki
- Research Group Ophthalmology, Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Hana Kulenovic
- Research Group Ophthalmology, Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Xavier Hadoux
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia
| | - Nicole Baldassini
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia
| | - Jan Van Eijgen
- Research Group Ophthalmology, Department of Neurosciences, KU Leuven, Leuven, Belgium.,Department of Ophthalmology, University Hospitals Leuven, Leuven, Belgium
| | - Lies De Groef
- Neural Circuit Development and Regeneration Research Group, Department of Biology, University of Leuven (KU Leuven), Leuven, Belgium.,Leuven Brain Institute, Leuven, Belgium
| | - Ingeborg Stalmans
- Research Group Ophthalmology, Department of Neurosciences, KU Leuven, Leuven, Belgium.,Department of Ophthalmology, University Hospitals Leuven, Leuven, Belgium.,Neural Circuit Development and Regeneration Research Group, Department of Biology, University of Leuven (KU Leuven), Leuven, Belgium
| | - Peter van Wijngaarden
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia.,Ophthalmology, Department of Surgery, University of Melbourne, Parkville, Australia
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14
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Attiku Y, He Y, Nittala MG, Sadda SR. Current status and future possibilities of retinal imaging in diabetic retinopathy care applicable to low- and medium-income countries. Indian J Ophthalmol 2021; 69:2968-2976. [PMID: 34708731 PMCID: PMC8725126 DOI: 10.4103/ijo.ijo_1212_21] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Diabetic retinopathy (DR) is a leading cause of blindness among adults and the numbers are projected to rise. There have been dramatic advances in the field of retinal imaging since the first fundus image was captured by Jackman and Webster in 1886. The currently available imaging modalities in the management of DR include fundus photography, fluorescein angiography, autofluorescence imaging, optical coherence tomography, optical coherence tomography angiography, and near-infrared reflectance imaging. These images are obtained using traditional fundus cameras, widefield fundus cameras, handheld fundus cameras, or smartphone-based fundus cameras. Fluorescence lifetime ophthalmoscopy, adaptive optics, multispectral and hyperspectral imaging, and multicolor imaging are the evolving technologies which are being researched for their potential applications in DR. Telemedicine has gained popularity in recent years as remote screening of DR has been made possible. Retinal imaging technologies integrated with artificial intelligence/deep-learning algorithms will likely be the way forward in the screening and grading of DR. We provide an overview of the current and upcoming imaging modalities which are relevant to the management of DR.
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Affiliation(s)
- Yamini Attiku
- Doheny Image Reading Center, Doheny Eye Institute, Los Angeles, California
| | - Ye He
- Doheny Image Reading Center, Doheny Eye Institute, Los Angeles, California; Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin Branch of National Clinical Research Center for Ocular Disease, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin, China
| | | | - SriniVas R Sadda
- Doheny Image Reading Center, Doheny Eye Institute; Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
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15
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Santangelo R, Huang SC, Bernasconi MP, Falautano M, Comi G, Magnani G, Leocani L. Neuro-Retina Might Reflect Alzheimer's Disease Stage. J Alzheimers Dis 2021; 77:1455-1468. [PMID: 32925026 DOI: 10.3233/jad-200043] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Alzheimer's disease (AD) pathological hallmarks were found in retinas of AD patients. Several studies showed a significant reduction of neuro-retina thickness measured through optical coherence tomography (OCT) in AD patients, but possible correlations between retina morphology, cognition, and cerebrospinal fluid (CSF) AD biomarkers (Aβ42, t-tau, and p-tau) have been poorly investigated so far. OBJECTIVE In the present cross-sectional study, we measured the thickness of neuro-retinal layers through OCT searching for possible correlations with patients' cognitive performances and CSF AD biomarkers. METHODS 137 consecutive subjects [43 with AD, 37 with mild cognitive impairment (MCI), and 57 healthy controls (HC)], received an OCT scan acquisition to measure the peripapillary retinal nerve fiber layer (RNFL) thickness. In a subsample of 21 AD, 18 MCI, and 18 HC, the macular volume of ganglion cell layer (GCL), inner plexiform layer (IPL), and inner nuclear layer was computed. A comprehensive neuropsychological assessment and CSF AD biomarkers' concentrations were available in AD and MCI patients. RESULTS Peripapillary RNFL, global, and in superior quadrant was significantly thinner in AD and MCI patients when compared to HC, while macular GCL volume was significantly reduced only in AD. RNFL thickness in nasal and inferior quadrants was correlated with single CSF AD biomarker concentrations, but no differences were found in retina morphology depending on the presence of a CSF profile typical for AD. Memory performances were positively associated with GCL and IPL volume. CONCLUSION Our findings might propose OCT as a reliable and easy to handle tool able to detect neuro-retinal atrophy in AD in relation with cognitive performances.
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Affiliation(s)
- Roberto Santangelo
- Experimental Neurophysiology Unit, Institute of Experimental Neurology-INSPE, IRCCS San Raffaele Hospital, Milan, Italy.,Vita-Salute San Raffaele University, Milan, Italy
| | - Su-Chun Huang
- Experimental Neurophysiology Unit, Institute of Experimental Neurology-INSPE, IRCCS San Raffaele Hospital, Milan, Italy.,Vita-Salute San Raffaele University, Milan, Italy
| | | | | | - Giancarlo Comi
- Experimental Neurophysiology Unit, Institute of Experimental Neurology-INSPE, IRCCS San Raffaele Hospital, Milan, Italy.,Vita-Salute San Raffaele University, Milan, Italy
| | | | - Letizia Leocani
- Experimental Neurophysiology Unit, Institute of Experimental Neurology-INSPE, IRCCS San Raffaele Hospital, Milan, Italy.,Vita-Salute San Raffaele University, Milan, Italy.,Neuropsychology Unit, IRCCS San Raffaele Hospital, Milan, Italy.,Neurorehabilitation Unit, IRCCS San Raffaele Hospital, Milan, Italy
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16
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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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17
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Kim TH, Son T, Klatt D, Yao X. Concurrent OCT and OCT angiography of retinal neurovascular degeneration in the 5XFAD Alzheimer's disease mice. NEUROPHOTONICS 2021; 8:035002. [PMID: 34277888 PMCID: PMC8271351 DOI: 10.1117/1.nph.8.3.035002] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 06/25/2021] [Indexed: 05/15/2023]
Abstract
Significance: As one part of the central nervous system, the retina manifests neurovascular defects in Alzheimer's disease (AD). Quantitative imaging of retinal neurovascular abnormalities may promise a new method for early diagnosis and treatment assessment of AD. Previous imaging studies of transgenic AD mouse models have been limited to the central part of the retina. Given that the pathological hallmarks of AD frequently appear in different peripheral quadrants, a comprehensive regional investigation is needed for a better understanding of the retinal degeneration associated with AD-like pathology. Aim: We aim to demonstrate concurrent optical coherence tomography (OCT) and OCT angiography (OCTA) of retinal neuronal and vascular abnormalities in the 5XFAD mouse model and to investigate region-specific retinal degeneration. Approach: A custom-built OCT system was used for retinal imaging. Retinal thickness, vessel width, and vessel density were quantitatively measured. The artery and vein (AV) were classified for differential AV analysis, and trilaminar vascular plexuses were segmented for depth-resolved density measurement. Results: It was observed that inner and outer retinal thicknesses were explicitly reduced in the dorsal and temporal quadrants, respectively, in 5XFAD mice. A significant arterial narrowing in 5XFAD mice was also observed. Moreover, overall capillary density consistently showed a decreasing trend in 5XFAD mice, but regional specificity was not identified. Conclusions: Quadrant- and layer-specific neurovascular degeneration was observed in 5XFAD mice. Concurrent OCT and OCTA promise a noninvasive method for quantitative monitoring of AD progression and treatment assessment.
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Affiliation(s)
- Tae-Hoon Kim
- University of Illinois at Chicago, Department of Bioengineering, Chicago, Illinois, United States
| | - Taeyoon Son
- University of Illinois at Chicago, Department of Bioengineering, Chicago, Illinois, United States
| | - Dieter Klatt
- University of Illinois at Chicago, Department of Bioengineering, Chicago, Illinois, United States
| | - Xincheng Yao
- University of Illinois at Chicago, Department of Bioengineering, Chicago, Illinois, United States
- University of Illinois at Chicago, Department of Ophthalmology and Visual Sciences, Chicago, Illinois, United States
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18
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Abstract
The eye and brain share common mechanisms of aging and disease, thus the retina is an essential source of accessible information about neurodegenerative processes occurring in the brain. Advances in retinal imaging have led to the discovery of many potential biomarkers of Alzheimer's disease, although further research is needed to validate these associations. Understanding the mechanisms of retinal disease in the context of aging will extend our knowledge of AD and may enable advancements in diagnosis, monitoring, and treatment.
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19
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Sauer L, Vitale AS, Modersitzki NK, Bernstein PS. Fluorescence lifetime imaging ophthalmoscopy: autofluorescence imaging and beyond. Eye (Lond) 2021; 35:93-109. [PMID: 33268846 PMCID: PMC7852552 DOI: 10.1038/s41433-020-01287-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 10/20/2020] [Accepted: 11/04/2020] [Indexed: 12/14/2022] Open
Abstract
Fluorescence lifetime imaging ophthalmoscopy, FLIO, has gained large interest in the scientific community in the recent years. It is a noninvasive imaging modality that has been shown to provide additional information to conventional imaging modalities. The FLIO device is based on a Heidelberg Engineering Spectralis system. Autofluorescence lifetimes are excited at 473 nm and recorded in two spectral wavelength channels, a short spectral channel (SSC, 498-560 nm) and a long spectral channel (LSC, 560-720 nm). Typically, mean autofluorescence lifetimes in a 30° retinal field are investigated. FLIO shows a clear benefit for imaging different retinal diseases. For example, in age-related macular degeneration (AMD), ring patterns of prolonged FLIO lifetimes 1.5-3.0 mm from the fovea can be appreciated. Macular telangiectasia type 2 (MacTel) shows a different pattern, with prolonged FLIO lifetimes within the typical MacTel zone. In Stargardt disease, retinal flecks can be appreciated even before they are visible with other imaging modalities. Early hydroxychloroquine toxicity appears to be detectable with FLIO. This technique has more potential that has yet to be discovered. This review article focuses on current knowledge as well as pitfalls of this technology. It highlights clinical benefits of FLIO imaging in different ophthalmic and systemic diseases, and provides an outlook with perspectives from the authors.
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Affiliation(s)
- Lydia Sauer
- Department of Ophthalmology and Visual Sciences, Moran Eye Center, University of Utah School of Medicine, 65 Mario Capecchi Drive, Salt Lake City, UT, 84132, USA
| | - Alexandra S Vitale
- Department of Ophthalmology and Visual Sciences, Moran Eye Center, University of Utah School of Medicine, 65 Mario Capecchi Drive, Salt Lake City, UT, 84132, USA
| | - Natalie K Modersitzki
- Department of Ophthalmology and Visual Sciences, Moran Eye Center, University of Utah School of Medicine, 65 Mario Capecchi Drive, Salt Lake City, UT, 84132, USA
| | - Paul S Bernstein
- Department of Ophthalmology and Visual Sciences, Moran Eye Center, University of Utah School of Medicine, 65 Mario Capecchi Drive, Salt Lake City, UT, 84132, USA.
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20
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Snyder PJ, Alber J, Alt C, Bain LJ, Bouma BE, Bouwman FH, DeBuc DC, Campbell MC, Carrillo MC, Chew EY, Cordeiro MF, Dueñas MR, Fernández BM, Koronyo-Hamaoui M, La Morgia C, Carare RO, Sadda SR, van Wijngaarden P, Snyder HM. Retinal imaging in Alzheimer's and neurodegenerative diseases. Alzheimers Dement 2021; 17:103-111. [PMID: 33090722 PMCID: PMC8062064 DOI: 10.1002/alz.12179] [Citation(s) in RCA: 83] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 07/26/2020] [Accepted: 07/27/2020] [Indexed: 12/22/2022]
Abstract
In the last 20 years, research focused on developing retinal imaging as a source of potential biomarkers for Alzheimer's disease and other neurodegenerative diseases, has increased significantly. The Alzheimer's Association and the Alzheimer's & Dementia: Diagnosis, Assessment, Disease Monitoring editorial team (companion journal to Alzheimer's & Dementia) convened an interdisciplinary discussion in 2019 to identify a path to expedite the development of retinal biomarkers capable of identifying biological changes associated with AD, and for tracking progression of disease severity over time. As different retinal imaging modalities provide different types of structural and/or functional information, the discussion reflected on these modalities and their respective strengths and weaknesses. Discussion further focused on the importance of defining the context of use to help guide the development of retinal biomarkers. Moving from research to context of use, and ultimately to clinical evaluation, this article outlines ongoing retinal imaging research today in Alzheimer's and other brain diseases, including a discussion of future directions for this area of study.
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Affiliation(s)
- Peter J. Snyder
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, Rhode Island
| | - Jessica Alber
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, Rhode Island
| | - Clemens Alt
- Wellman Center for Photomedicine and Center for Systems Biology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Lisa J. Bain
- Independent Science Writer, Elverson, Pennsylvania
| | - Brett E. Bouma
- Harvard Medical School, Massachusetts General Hospital and Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Massachusetts
| | - Femke H. Bouwman
- Neurologist, Alzheimer Center Amsterdam UMC, Amsterdam, The Netherlands
| | | | - Melanie C.W. Campbell
- Physics and Astronomy, Optometry and Vision Science and Systems Design Engineering, University of Waterloo, Waterloo, Ontario, Canada
| | - Maria C. Carrillo
- Medical & Scientific Relations, Alzheimer’s Association, Chicago, Illinois
| | - Emily Y. Chew
- Division of Epidemiology and Clinical Applications, National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - M. Francesca Cordeiro
- Imperial College London, UCL Institute of Ophthalmology, ICORG Western Eye Hospital, London, UK
| | - Michael R. Dueñas
- Chief Public Health Officer (Ret.), American Optometric Association, Washington, D.C
| | | | - Maya Koronyo-Hamaoui
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute and Department of Biomedical Sciences, Division of Applied Cell Biology and Physiology, Cedars-Sinai Medical Center, Los Angeles, California
| | - Chiara La Morgia
- IRCCS Istituto delle Scienze Neurologiche di Bologna, UOC Clinica Neurologica, Bologna, Italy
- Dipartimento di Scienze Biomediche e Neuromotorie, University of Bologna, Italy
| | | | - Srinivas R. Sadda
- Doheny Eye Institute, Los Angeles, California
- Department of Ophthalmology, UCLA, Los Angeles, California
| | - Peter van Wijngaarden
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia
- Ophthalmology, Department of Surgery, University of Melbourne, Parkville, Australia
| | - Heather M. Snyder
- Medical & Scientific Relations, Alzheimer’s Association, Chicago, Illinois
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21
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Lee CS, Apte RS. Retinal Biomarkers of Alzheimer Disease. Am J Ophthalmol 2020; 218:337-341. [PMID: 32387435 DOI: 10.1016/j.ajo.2020.04.040] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 04/28/2020] [Accepted: 04/28/2020] [Indexed: 01/06/2023]
Abstract
PURPOSE To address challenges associated with identifying retinal biomarkers for Alzheimer's disease (AD) and strategies for future investigation of novel ophthalmologic biomarkers. DESIGN Perspective. METHODS Summarization of the current understanding of retinal changes that have been identified using advances in imaging technology, analysis of current research into how these changes reflect neurodegenerative pathology, and recommendations for further research in this area that will allow for the identification of unique biomarkers for early AD. RESULTS Some retinal changes detectable using various imaging modalities may reflect neurodegeneration or other AD-related pathology on a cellular level. Structural changes in both the peripapillary and macular retina and changes in vascular parameters have been identified. Some imaging findings correlate with known histopathologic findings, and some are associated with cognitive decline. However, multiple challenges exist, such as identifying retinal biomarkers that are specific to biomarker-positive AD, clinical syndrome of AD, and/or pathologic AD brain, finding features that are highly sensitive and specific to AD in patients with other eye diseases, and validating potential biomarkers in population-based longitudinal cohorts. CONCLUSIONS Further research is needed to validate retinal biomarkers for AD, with accurate classification of patients according to diagnosis and cognitive symptoms. Advances in imaging technology, big data, and machine learning, as well as carefully designed studies, will help to identify and confirm potential biomarkers and may lead to novel treatment approaches.
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22
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Schweitzer D, Haueisen J, Brauer JL, Hammer M, Klemm M. Comparison of algorithms to suppress artifacts from the natural lens in fluorescence lifetime imaging ophthalmoscopy (FLIO). BIOMEDICAL OPTICS EXPRESS 2020; 11:5586-5602. [PMID: 33149973 PMCID: PMC7587265 DOI: 10.1364/boe.400059] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 08/08/2020] [Accepted: 08/08/2020] [Indexed: 06/11/2023]
Abstract
Fluorescence lifetime imaging ophthalmoscopy (FLIO) has developed as a new diagnostic tool in ophthalmology. FLIO measurements are taken from 30° retinal fields in two spectral channels (short spectral channel (SSC): 498-560 nm, long spectral channel (LSC): 560-720 nm). Because of the layered structure of the eye, the detected signal is an interaction of the fluorescence decay of the anterior part and of the fundus. By comparing FLIO measurements before and after cataract surgery, the impact of the natural lens was proven, despite the application of a confocal laser scanning (cSLO) technique. The goal of this work was to determine the best algorithmic solution to isolate the sole fundus fluorescence lifetime from the measured signal, suppressing artifacts from the natural lens. Three principles based on a tri-exponential model were investigated: a tailfit, a layer-based approach with a temporally shifted component, and the inclusion of a separately measured fluorescence decay of the natural lens. The mean fluorescence lifetime τm,12 is calculated using only the shortest and the intermediate exponential component. τm,all is calculated using all three exponential components. The results of tri-exponential tailfit after cataract surgery were considered as a reference, because the implanted artificial lens can be assumed as non-fluorescent. In SSC, the best accordance of τm,all of the reference was determined with τm,12 of the tailfit before surgery. If high-quality natural lens measurements are available, the correspondence of τm,12 is best with τm,all of the reference. In LSC, there is a good accordance for all models between τm,12 before and after surgery. To study the pure fundus fluorescence decay in eyes with natural lenses, we advise to utilize fluorescence lifetime τm,12 of a triple-exponential tailfit, as it corresponds well with the mean fluorescence lifetime τm,all of eyes with fluorescence-less artificial intraocular lenses.
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Affiliation(s)
- D. Schweitzer
- Department of Ophthalmology, University Hospital Jena, Am Klinikum 1, 07747 Jena, Germany
| | - J. Haueisen
- Institute of Biomedical Engineering and Informatics, POB 100565, 98694 Ilmenau, Germany
| | - J. L. Brauer
- Department of Ophthalmology, University Hospital Jena, Am Klinikum 1, 07747 Jena, Germany
| | - M. Hammer
- Department of Ophthalmology, University Hospital Jena, Am Klinikum 1, 07747 Jena, Germany
| | - M. Klemm
- Institute of Biomedical Engineering and Informatics, POB 100565, 98694 Ilmenau, Germany
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23
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The Retinal Inner Plexiform Synaptic Layer Mirrors Grey Matter Thickness of Primary Visual Cortex with Increased Amyloid β Load in Early Alzheimer's Disease. Neural Plast 2020; 2020:8826087. [PMID: 33014034 PMCID: PMC7525303 DOI: 10.1155/2020/8826087] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 08/19/2020] [Accepted: 08/24/2020] [Indexed: 11/17/2022] Open
Abstract
The retina may serve as putative window into neuropathology of synaptic loss in Alzheimer's disease (AD). Here, we investigated synapse-rich layers versus layers composed by nuclei/cell bodies in an early stage of AD. In addition, we examined the associations between retinal changes and molecular and structural markers of cortical damage. We recruited 20 AD patients and 17 healthy controls (HC). Combining optical coherence tomography (OCT), magnetic resonance (MR), and positron emission tomography (PET) imaging, we measured retinal and primary visual cortex (V1) thicknesses, along with V1 amyloid β (Aβ) retention ([11C]-PiB PET tracer) and neuroinflammation ([11C]-PK11195 PET tracer). We found that V1 showed increased amyloid-binding potential, in the absence of neuroinflammation. Although thickness changes were still absent, we identified a positive association between the synapse-rich inner plexiform layer (IPL) and V1 in AD. This retinocortical interplay might reflect changes in synaptic function resulting from Aβ deposition, contributing to early visual loss.
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24
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Mirzaei N, Shi H, Oviatt M, Doustar J, Rentsendorj A, Fuchs DT, Sheyn J, Black KL, Koronyo Y, Koronyo-Hamaoui M. Alzheimer's Retinopathy: Seeing Disease in the Eyes. Front Neurosci 2020; 14:921. [PMID: 33041751 PMCID: PMC7523471 DOI: 10.3389/fnins.2020.00921] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 08/10/2020] [Indexed: 01/18/2023] Open
Abstract
The neurosensory retina emerges as a prominent site of Alzheimer's disease (AD) pathology. As a CNS extension of the brain, the neuro retina is easily accessible for noninvasive, high-resolution imaging. Studies have shown that along with cognitive decline, patients with mild cognitive impairment (MCI) and AD often suffer from visual impairments, abnormal electroretinogram patterns, and circadian rhythm disturbances that can, at least in part, be attributed to retinal damage. Over a decade ago, our group identified the main pathological hallmark of AD, amyloid β-protein (Aβ) plaques, in the retina of patients including early-stage clinical cases. Subsequent histological, biochemical and in vivo retinal imaging studies in animal models and in humans corroborated these findings and further revealed other signs of AD neuropathology in the retina. Among these signs, hyperphosphorylated tau, neuronal degeneration, retinal thinning, vascular abnormalities and gliosis were documented. Further, linear correlations between the severity of retinal and brain Aβ concentrations and plaque pathology were described. More recently, extensive retinal pericyte loss along with vascular platelet-derived growth factor receptor-β deficiency were discovered in postmortem retinas of MCI and AD patients. This progressive loss was closely associated with increased retinal vascular amyloidosis and predicted cerebral amyloid angiopathy scores. These studies brought excitement to the field of retinal exploration in AD. Indeed, many questions still remain open, such as queries related to the temporal progression of AD-related pathology in the retina compared to the brain, the relations between retinal and cerebral changes and whether retinal signs can predict cognitive decline. The extent to which AD affects the retina, including the susceptibility of certain topographical regions and cell types, is currently under intense investigation. Advances in retinal amyloid imaging, hyperspectral imaging, optical coherence tomography, and OCT-angiography encourage the use of such modalities to achieve more accurate, patient- and user-friendly, noninvasive detection and monitoring of AD. In this review, we summarize the current status in the field while addressing the many unknowns regarding Alzheimer's retinopathy.
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Affiliation(s)
- Nazanin Mirzaei
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States
| | - Haoshen Shi
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States
| | - Mia Oviatt
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States
| | - Jonah Doustar
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States
| | - Altan Rentsendorj
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States
| | - Dieu-Trang Fuchs
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States
| | - Julia Sheyn
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States
| | - Keith L. Black
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States
| | - Yosef Koronyo
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States
| | - Maya Koronyo-Hamaoui
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States
- Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, United States
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25
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Schmitz-Valckenberg S, Pfau M, Fleckenstein M, Staurenghi G, Sparrow JR, Bindewald-Wittich A, Spaide RF, Wolf S, Sadda SR, Holz FG. Fundus autofluorescence imaging. Prog Retin Eye Res 2020; 81:100893. [PMID: 32758681 DOI: 10.1016/j.preteyeres.2020.100893] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 07/20/2020] [Accepted: 07/25/2020] [Indexed: 12/20/2022]
Abstract
Fundus autofluorescence (FAF) imaging is an in vivo imaging method that allows for topographic mapping of naturally or pathologically occurring intrinsic fluorophores of the ocular fundus. The dominant sources are fluorophores accumulating as lipofuscin in lysosomal storage bodies in postmitotic retinal pigment epithelium cells as well as other fluorophores that may occur with disease in the outer retina and subretinal space. Photopigments of the photoreceptor outer segments as well as macular pigment and melanin at the fovea and parafovea may act as filters of the excitation light. FAF imaging has been shown to be useful with regard to understanding of pathophysiological mechanisms, diagnostics, phenotype-genotype correlation, identification of prognostic markers for disease progression, and novel outcome parameters to assess efficacy of interventional strategies in chorio-retinal diseases. More recently, the spectrum of FAF imaging has been expanded with increasing use of green in addition to blue FAF, introduction of spectrally-resolved FAF, near-infrared FAF, quantitative FAF imaging and fluorescence life time imaging (FLIO). This article gives an overview of basic principles, FAF findings in various retinal diseases and an update on recent developments.
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Affiliation(s)
- Steffen Schmitz-Valckenberg
- Department of Ophthalmology, University of Bonn, Bonn, Germany; John A. Moran Eye Center, University of Utah, Salt Lake City, USA
| | - Maximilian Pfau
- Department of Ophthalmology, University of Bonn, Bonn, Germany; Department of Biomedical Data Science, Stanford University, USA
| | | | - Giovanni Staurenghi
- Department of Biomedical and Clinical Science "Luigi Sacco", Luigi Sacco Hospital University of Milan, Italy
| | - Janet R Sparrow
- Departments of Ophthalmology and Pathology and Cell Biology, Columbia University Medical Center, New York, NY, USA
| | - Almut Bindewald-Wittich
- Department of Ophthalmology, University of Bonn, Bonn, Germany; Augenheilkunde Heidenheim MVZ, Heidenheim, Germany
| | - Richard F Spaide
- Vitreous Retina Macula Consultants of New York, New York, NY, USA
| | - Sebastian Wolf
- Department of Ophthalmology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Srinivas R Sadda
- Doheny Eye Institute, David Geffen School of Medicine, University of California, Los Angeles, USA
| | - Frank G Holz
- Department of Ophthalmology, University of Bonn, Bonn, Germany.
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26
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Sauer L, Vitale AS, Milliken CM, Modersitzki NK, Blount JD, Bernstein PS. Autofluorescence Lifetimes Measured with Fluorescence Lifetime Imaging Ophthalmoscopy (FLIO) Are Affected by Age, but Not by Pigmentation or Gender. Transl Vis Sci Technol 2020; 9:2. [PMID: 32879759 PMCID: PMC7442880 DOI: 10.1167/tvst.9.9.2] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 06/07/2020] [Indexed: 12/25/2022] Open
Abstract
Purpose Fluorescence lifetime imaging ophthalmoscopy (FLIO) is a novel modality to investigate the human retina. This study aims to characterize the effects of age, pigmentation, and gender in FLIO. Methods A total of 97 eyes from 97 healthy subjects (mean age 37 ± 18 years, range 9-85 years) were investigated in this study. This study included 47 (49%) females and 50 males. The pigmentation analysis was a substudy including 64 subjects aged 18 to 40 years (mean age 29 ± 6 years). These were categorized in groups A (darkly pigmented, 8), B (medium pigmented, 20), and C (lightly pigmented, 36). Subjects received Heidelberg Engineering FLIO and optical coherence tomography imaging. Retinal autofluorescence lifetimes were detected in two spectral channels (short spectral channel [SSC]: 498-560 nm; long spectral channel [LSC]: 560-720 nm), and amplitude-weighted mean fluorescence lifetimes (τm) were calculated. Additionally, autofluorescence lifetimes of melanin were measured in a cuvette. Results Age significantly affected FLIO lifetimes, and age-related FLIO changes in the SSC start at approximately age 35 years, whereas the LSC shows a consistent prolongation with age from childhood. There were no gender- or pigmentation-specific significant differences of autofluorescence lifetimes. Conclusions This study confirms age-effects in FLIO but shows that the two channels are affected differently. The LSC appears to show the lifelong accumulation of lipofuscin. Furthermore, it is important to know that neither gender nor pigmentation significantly affect FLIO lifetimes. Translational Relevance This study helps to understand the FLIO technology better, which will aid in conducting future clinical studies.
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Affiliation(s)
- Lydia Sauer
- John A. Moran Eye Center, University of Utah, Salt Lake City, UT, USA
| | | | - Cole M Milliken
- John A. Moran Eye Center, University of Utah, Salt Lake City, UT, USA.,Storm Eye Institute, Medical University of South Carolina, Charleston, SC, USA
| | | | - J David Blount
- John A. Moran Eye Center, University of Utah, Salt Lake City, UT, USA
| | - Paul S Bernstein
- John A. Moran Eye Center, University of Utah, Salt Lake City, UT, USA
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27
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Yakovleva MA, Radchenko AS, Feldman TB, Kostyukov AA, Arbukhanova PM, Borzenok SA, Kuzmin VA, Ostrovsky MA. Fluorescence characteristics of lipofuscin fluorophores from human retinal pigment epithelium. Photochem Photobiol Sci 2020; 19:920-930. [PMID: 32441276 DOI: 10.1039/c9pp00406h] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Lipofuscin granules accumulate in the retinal pigment epithelium (RPE) with age, especially in patients with visual diseases, including progressive age-related macular degeneration (AMD). Bisretinoids and their photooxidation and photodegradation products are major sources of lipofuscin granule fluorescence. The present study focused on examining the fluorescence decay characteristics of bisretinoid photooxidation and photodegradation products to evaluate the connection between fluorescence lifetime and spectral characteristics of target fluorophore groups. The primary objective of the study was to apply experimental spectral analysis results of lipofuscin granule fluorescence properties to interpretation of fluorescence lifetime imaging ophthalmoscopy data. Fluorescence analysis of the lipofuscin granule fluorophores in RPE collected from cadaver eyes was performed. The fluorescence lifetimes were measured by picosecond-resolved time correlated single photon counting technique. A global analytical method was applied to analyze data sets. The photooxidation and photodegradation products of bisretinoids exhibited a longer fluorescence lifetime (average value approximately 6 ns) and a shorter wavelength maximum (530-580 nm). Further, these products significantly contributed (more than 30%), to total fluorescence compared to the other fluorophores in lipofuscin granules. Thus, the contribution of oxidized lipofuscin bisretinoids to autofluorescence decay kinetics is an important characteristic for fluorescence lifetime imaging microscopy data analysis. The higher average fluorescence lifetime in AMD eyes was likely due to the higher abundance of oxidized bisretinoids compared with non-oxidized bisretinoids. Because higher level of oxidized bisretinoids is indicative of pathological processes in the retina and RPE, the present findings have the potential to improve fluorescence lifetime imaging approaches for early diagnosis of degenerative processes in the retina and RPE.
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Affiliation(s)
- Marina A Yakovleva
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Kosygin st. 4, 119334, Moscow, Russia
| | - Alexandra Sh Radchenko
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Kosygin st. 4, 119334, Moscow, Russia
| | - Tatiana B Feldman
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Kosygin st. 4, 119334, Moscow, Russia.,Department of Molecular Physiology, Biological Faculty, Lomonosov Moscow State University, Leninskie Gory 1, 119991, Moscow, Russia
| | - Alexey A Kostyukov
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Kosygin st. 4, 119334, Moscow, Russia
| | - Patimat M Arbukhanova
- Sv. Fyodorov Eye Microsurgery Complex, Beskudnikovsky bld. 59a, 127486, Moscow, Russia
| | - Sergey A Borzenok
- Sv. Fyodorov Eye Microsurgery Complex, Beskudnikovsky bld. 59a, 127486, Moscow, Russia
| | - Vladimir A Kuzmin
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Kosygin st. 4, 119334, Moscow, Russia
| | - Mikhail A Ostrovsky
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Kosygin st. 4, 119334, Moscow, Russia.,Department of Molecular Physiology, Biological Faculty, Lomonosov Moscow State University, Leninskie Gory 1, 119991, Moscow, Russia
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28
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Abstract
PURPOSE OF REVIEW This article reviews emerging technologies in retinal imaging, including their scientific background, clinical implications and future directions. RECENT FINDINGS Fluorescence lifetime imaging ophthalmoscopy is a technology that will reveal biochemical and metabolic changes of the retina at the cellular level. Optical coherence tomography is evolving exponentially toward higher resolution, faster speed, increased portability and more cost effective. Adaptive optics scanning laser ophthalmoscopy fluorescein angiography will provide unprecedented detail of the retinal vasculature down to the level of capillaries, enabling earlier and more sensitive detection of retinal vascular diseases. SUMMARY Continued developments in retinal imaging focus on improved resolution, faster speed and noninvasiveness, while providing new information on the structure-function relationship of the retina inclusive of metabolic activity at the cellular level.
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29
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Sánchez D, Castilla-Marti M, Marquié M, Valero S, Moreno-Grau S, Rodríguez-Gómez O, Piferrer A, Martínez G, Martínez J, Rojas ID, Hernández I, Abdelnour C, Rosende-Roca M, Vargas L, Mauleón A, Gil S, Alegret M, Ortega G, Espinosa A, Pérez-Cordón A, Sanabria Á, Roberto N, Ciudin A, Simó R, Hernández C, Tárraga L, Boada M, Ruiz A. Evaluation of macular thickness and volume tested by optical coherence tomography as biomarkers for Alzheimer's disease in a memory clinic. Sci Rep 2020; 10:1580. [PMID: 32005868 PMCID: PMC6994670 DOI: 10.1038/s41598-020-58399-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2019] [Accepted: 01/10/2020] [Indexed: 01/22/2023] Open
Abstract
Building on previous studies that report thinning of the macula in Alzheimer’s disease (AD) and mild cognitive impairment (MCI) patients, the use of optical coherence tomography (OCT) has been proposed as a potential biomarker for AD. However, other studies contradict these results. A total of 930 participants (414 cognitively healthy people, 192 with probable amnestic MCI, and 324 probable AD patients) from a memory clinic were consecutively included in this study and underwent a spectral domain OCT scan (Maestro, Topcon) to assess total macular volume and thickness. Macular width measurements were also taken in several subregions (central, inner, and outer rings) and in layers such as the retinal nerve fiber (RNFL) and ganglion cell (CGL). The study employed a design of high ecological validity, with adjustment by age, education, sex, and OCT image quality. AD, MCI, and control groups did not significantly vary with regard to volume and retinal thickness in different layers. When these groups were compared, multivariate-adjusted analysis disclosed no significant differences in total (p = 0.564), CGL (p = 0.267), RNFL (p = 0.574), and macular thickness and volume (p = 0.380). The only macular regions showing significant differences were the superior (p = 0.040) and nasal (p = 0.040) sectors of the inner macular ring. However, adjustment for multiple comparisons nullified this significance. These results are not supporting existing claims for the usefulness of macular thickness as a biomarker of cognitive impairment in a memory unit. OCT biomarkers for AD should be subject to further longitudinal testing.
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Affiliation(s)
- Domingo Sánchez
- Research Center and Memory Clinic, Fundació ACE, Institut Català de Neurociències Aplicades, Universitat Internacional de Catalunya, Barcelona, Spain.
| | - Miguel Castilla-Marti
- Clínica Oftalmológica Dr. Castilla, Barcelona, Spain.,Department of Ophthalmology, Hospital de l'Esperança, Parc de Salut Mar, Barcelona, Spain
| | - Marta Marquié
- Research Center and Memory Clinic, Fundació ACE, Institut Català de Neurociències Aplicades, Universitat Internacional de Catalunya, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
| | - Sergi Valero
- Research Center and Memory Clinic, Fundació ACE, Institut Català de Neurociències Aplicades, Universitat Internacional de Catalunya, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
| | - Sonia Moreno-Grau
- Research Center and Memory Clinic, Fundació ACE, Institut Català de Neurociències Aplicades, Universitat Internacional de Catalunya, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
| | - Octavio Rodríguez-Gómez
- Research Center and Memory Clinic, Fundació ACE, Institut Català de Neurociències Aplicades, Universitat Internacional de Catalunya, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
| | | | - Gabriel Martínez
- Faculty of Medicine and Dentistry, Universidad de Antofagasta, Antofagasta, Chile.,Iberoamerican Cochrane Centre, Barcelona, Spain
| | - Joan Martínez
- Research Center and Memory Clinic, Fundació ACE, Institut Català de Neurociències Aplicades, Universitat Internacional de Catalunya, Barcelona, Spain
| | - Itziar De Rojas
- Research Center and Memory Clinic, Fundació ACE, Institut Català de Neurociències Aplicades, Universitat Internacional de Catalunya, Barcelona, Spain
| | - Isabel Hernández
- Research Center and Memory Clinic, Fundació ACE, Institut Català de Neurociències Aplicades, Universitat Internacional de Catalunya, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
| | - Carla Abdelnour
- Research Center and Memory Clinic, Fundació ACE, Institut Català de Neurociències Aplicades, Universitat Internacional de Catalunya, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
| | - Maitée Rosende-Roca
- Research Center and Memory Clinic, Fundació ACE, Institut Català de Neurociències Aplicades, Universitat Internacional de Catalunya, Barcelona, Spain
| | - Liliana Vargas
- Research Center and Memory Clinic, Fundació ACE, Institut Català de Neurociències Aplicades, Universitat Internacional de Catalunya, Barcelona, Spain
| | - Ana Mauleón
- Research Center and Memory Clinic, Fundació ACE, Institut Català de Neurociències Aplicades, Universitat Internacional de Catalunya, Barcelona, Spain
| | - Silvia Gil
- Research Center and Memory Clinic, Fundació ACE, Institut Català de Neurociències Aplicades, Universitat Internacional de Catalunya, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
| | - Montserrat Alegret
- Research Center and Memory Clinic, Fundació ACE, Institut Català de Neurociències Aplicades, Universitat Internacional de Catalunya, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
| | - Gemma Ortega
- Research Center and Memory Clinic, Fundació ACE, Institut Català de Neurociències Aplicades, Universitat Internacional de Catalunya, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
| | - Ana Espinosa
- Research Center and Memory Clinic, Fundació ACE, Institut Català de Neurociències Aplicades, Universitat Internacional de Catalunya, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
| | - Alba Pérez-Cordón
- Research Center and Memory Clinic, Fundació ACE, Institut Català de Neurociències Aplicades, Universitat Internacional de Catalunya, Barcelona, Spain
| | - Ángela Sanabria
- Research Center and Memory Clinic, Fundació ACE, Institut Català de Neurociències Aplicades, Universitat Internacional de Catalunya, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
| | - Natalia Roberto
- Research Center and Memory Clinic, Fundació ACE, Institut Català de Neurociències Aplicades, Universitat Internacional de Catalunya, Barcelona, Spain
| | - Andreea Ciudin
- Diabetes and Metabolism Research Unit and Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólica Asociada (CIBERDEM), Vall d'Hebron Research Institute, Barcelona, Spain
| | - Rafael Simó
- Diabetes and Metabolism Research Unit and Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólica Asociada (CIBERDEM), Vall d'Hebron Research Institute, Barcelona, Spain
| | - Cristina Hernández
- Diabetes and Metabolism Research Unit and Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólica Asociada (CIBERDEM), Vall d'Hebron Research Institute, Barcelona, Spain
| | - Lluís Tárraga
- Research Center and Memory Clinic, Fundació ACE, Institut Català de Neurociències Aplicades, Universitat Internacional de Catalunya, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
| | - Mercè Boada
- Research Center and Memory Clinic, Fundació ACE, Institut Català de Neurociències Aplicades, Universitat Internacional de Catalunya, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
| | - Agustín Ruiz
- Research Center and Memory Clinic, Fundació ACE, Institut Català de Neurociències Aplicades, Universitat Internacional de Catalunya, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
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Ngolab J, Honma P, Rissman RA. Reflections on the Utility of the Retina as a Biomarker for Alzheimer's Disease: A Literature Review. Neurol Ther 2019; 8:57-72. [PMID: 31833024 PMCID: PMC6908534 DOI: 10.1007/s40120-019-00173-4] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Indexed: 12/12/2022] Open
Abstract
As a part of the central nervous system, the retina may reflect both physiologic processes and abnormalities related to diseases of the brain. Indeed, a concerted effort has been put forth to understand how Alzheimer's disease (AD) pathology may manifest in the retina as a means to assess the state of the AD brain. The development and refinement of ophthalmologic techniques for studying the retina in vivo have produced evidence of retinal degeneration in AD diagnosed patients. In this review, we will discuss retinal imaging techniques implemented to study the changes in AD retina as well as highlight the recent efforts made to correlate such findings to other clinical hallmarks of AD to assess the viability of the retina as a biomarker for AD.
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Affiliation(s)
- Jennifer Ngolab
- Department of Neurosciences, University of California, San Diego, CA, USA
| | - Patrick Honma
- Department of Neurosciences, University of California, San Diego, CA, USA
- Neuroscience Graduate Program, University of California, San Francisco, CA, USA
| | - Robert A Rissman
- Department of Neurosciences, University of California, San Diego, CA, USA.
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31
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Schultz R, Schuster F, Lehmann T, Schmidt J, Augsten R, Hammer M. Simplified approach to least-square fitting of fluorescence lifetime ophthalmoscopy (FLIO) data by fixating lifetimes. BIOMEDICAL OPTICS EXPRESS 2019; 10:5996-6008. [PMID: 31799060 PMCID: PMC6865094 DOI: 10.1364/boe.10.005996] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 09/16/2019] [Accepted: 09/17/2019] [Indexed: 06/10/2023]
Abstract
Fluorescence lifetime imaging ophthalmoscopy (FLIO) is a new imaging modality in ophthalmology. For clinical investigations, the amplitude-weighted mean of two or three lifetime components is usually analyzed. In this study, we investigated the effects of fixation of lifetime components. This resulted in slightly higher fit errors but mean lifetimes were highly correlated to those from fits with variable individual lifetimes. Furthermore, this approach resulted in a similarly good discrimination of diabetic retinopathy patients from controls, a reduction of the computational workload, a de-noising of the mean lifetime images and allows higher local resolution. Thus, fixation of lifetimes in the fit of FLIO data could be superior for clinical routine analysis of FLIO data.
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Affiliation(s)
- Rowena Schultz
- University Hospital Jena, Department of Ophthalmology, 07747 Jena, Germany
| | - Franziska Schuster
- University Hospital Jena, Department of Ophthalmology, 07747 Jena, Germany
| | - Thomas Lehmann
- University Hospital Jena, Institute for Medical Statistics, Computer Science and Data Science, 07747 Jena, Germany
| | - Johanna Schmidt
- University Hospital Jena, Department of Ophthalmology, 07747 Jena, Germany
| | - Regine Augsten
- University Hospital Jena, Department of Ophthalmology, 07747 Jena, Germany
| | - Martin Hammer
- University Hospital Jena, Department of Ophthalmology, 07747 Jena, Germany
- University of Jena, Center for Medical Optics and Photonics, 07743 Jena, Germany
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32
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Sauer L, Calvo CM, Vitale AS, Henrie N, Milliken CM, Bernstein PS. Imaging of Hydroxychloroquine Toxicity with Fluorescence Lifetime Imaging Ophthalmoscopy. ACTA ACUST UNITED AC 2019; 3:814-825. [DOI: 10.1016/j.oret.2019.04.025] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 04/20/2019] [Accepted: 04/23/2019] [Indexed: 12/16/2022]
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Kwon S, Borrelli E, Fan W, Ebraheem A, Marion KM, Sadda SR. Repeatability of Fluorescence Lifetime Imaging Ophthalmoscopy in Normal Subjects With Mydriasis. Transl Vis Sci Technol 2019; 8:15. [PMID: 31114715 PMCID: PMC6506203 DOI: 10.1167/tvst.8.3.15] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 02/10/2019] [Indexed: 11/24/2022] Open
Abstract
Purpose We evaluate the repeatability of fluorescence lifetime imaging ophthalmoscopy (FLIO) in normal subjects with mydriasis and explore factors that influence FLIO imaging. Method Thirty-two healthy participants (63 eyes) were enrolled in this prospective study. The Heidelberg Engineering FLIO system uses a 473 nm blue laser light and the emitted fluorescence is detected in two wavelength channels, short and long spectral channels (SSC, LSC). The mean fluorescence lifetime (τm) values were computed for the entire scan area as well as in five regions of interest (ROI, 1 × 1 mm) at the fovea and superior, nasal, inferior, and temporal portions of the macula. Intraclass correlation coefficients (ICC) and coefficients of variation (CV) were used to assess the repeatability. Age, macular thickness, and vascular density also were correlated with τm. Results The repeatability was good for both channels (ICC, 0.956∼0.995; CV, 9∼16%). The τm for the entire scan was 367.8 ± 58.1 picoseconds (ps) in SSC and 322.5 ± 34.0 ps in LSC. τm was the shortest in the fovea and significantly shorter in the temporal region compared to other regions. τm was positively correlated with age (r = 0.588 for SSC and r = 0.584 for LSC, P = 0.000) and retinal thickness (r = 0.298 for SSC and r = 0.322 for LSC, P = 0.000), and negatively correlated with vascular density (r = −0.112, P = 0.055 for SSC and r = −0.119, P = 0.040 for LSC). Conclusion Repeatable fluorescence lifetime values can be obtained with FLIO, but the lifetimes are affected by age, retinal thickness, vessel density, and macular location. Translational Relevance Establishing repeatability of FLIO can introduce fluorescence lifetime imaging technique, which is used in basic science for analysis of excitation and emission wavelength spectrum of fixed and living cells into clinical practice.
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Affiliation(s)
- Soonil Kwon
- Doheny Eye Institute, Los Angeles, CA, USA.,Department of Ophthalmology, Hallym Sacred Heart Hospital, Hallym University College of Medicine, Anyang, Gyeonggi, South Korea
| | | | | | | | | | - SriniVas R Sadda
- Doheny Eye Institute, Los Angeles, CA, USA.,Department of Ophthalmology, David Geffen School of Medicine at UCLA, Stein Eye Institute, Los Angeles CA, USA
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Sadda SR, Borrelli E, Fan W, Ebraheem A, Marion KM, Harrington M, Kwon S. A pilot study of fluorescence lifetime imaging ophthalmoscopy in preclinical Alzheimer's disease. Eye (Lond) 2019; 33:1271-1279. [PMID: 30923356 DOI: 10.1038/s41433-019-0406-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 02/06/2019] [Accepted: 02/24/2019] [Indexed: 01/03/2023] Open
Abstract
PURPOSE To investigate fluorescence lifetime imaging ophthalmoscopy (FLIO) findings in preclinical Alzheimer's disease (AD). METHODS This prospective, observational study enrolled patients with early AD undergoing Alzheimer's biomarker analysis and matched controls. Alzheimer-associated parameters (β-amyloid [Aβ], total tau in cerebrospinal fluid [CSF], Mini-Mental Status Examination [MMSE], etc.), risk factor-associated data (body mass index [BMI], hypertension, lipid profile, etc.), ganglion cell layer plus inner plexiform layer (GCIPL) thickness in structural optical coherence tomography (OCT), OCT angiography data, and FLIO-derived parameters (τm, τ1, τ2, and τ3) in short and long spectral channels (SSC and LSC) were compared and correlated between the two groups. Additional analyses were performed separately within subgroups of phakic and pseudophakic. RESULTS A total of 28 eyes from 15 subjects (8 control and 7 AD) were included in this analysis. In FLIO parameters, τm in AD group showed longer lifetimes compared to the controls in phakic subjects (593.9 ± 93.3, 454.4 ± 38.6 ps; 475.0 ± 71.6, 394.1 ± 28.2 ps in SSC and LSC of AD and control groups, respectively, p = 0.036 and 0.024). Aβ, tau in CSF, and GCIPL thickness correlated with τm in the LSC for phakic subjects (r = -0.611 to 0.562, p < 0.05 for all), but only the GCIPL thickness showed a correlation with FLIO parameters in pseudophakic subjects (r = -0.893 to -0.795, p < 0.001 for all). CONCLUSION FLIO-derived parameters appear to correlate with Aβ, tau levels in the CSF, and GCIPL thickness on OCT in AD patients. If these findings can be validated in future longitudinal studies, FLIO may prove to be useful as a simple, non-invasive diagnostic tool for AD.
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Affiliation(s)
- SriniVas R Sadda
- Doheny Eye Institute, University of California, Los Angeles, CA, USA.,Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Enrico Borrelli
- Doheny Eye Institute, University of California, Los Angeles, CA, USA
| | - Wenying Fan
- Doheny Eye Institute, University of California, Los Angeles, CA, USA
| | - Adel Ebraheem
- Doheny Eye Institute, University of California, Los Angeles, CA, USA
| | - Kenneth M Marion
- Doheny Eye Institute, University of California, Los Angeles, CA, USA
| | - Michael Harrington
- Molecular Neurology Program, Huntington Medical Research Institutes, Pasadena, CA, USA
| | - Soonil Kwon
- Doheny Eye Institute, University of California, Los Angeles, CA, USA. .,Department of Ophthalmology, Hallym Sacred Heart Hospital, Hallym University College of Medicine, Anyang, Gyeonggi, South Korea.
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35
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Chiquita S, Rodrigues-Neves AC, Baptista FI, Carecho R, Moreira PI, Castelo-Branco M, Ambrósio AF. The Retina as a Window or Mirror of the Brain Changes Detected in Alzheimer's Disease: Critical Aspects to Unravel. Mol Neurobiol 2019; 56:5416-5435. [PMID: 30612332 DOI: 10.1007/s12035-018-1461-6] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 12/17/2018] [Indexed: 11/24/2022]
Abstract
Alzheimer's disease is the most frequent cause of dementia worldwide, representing a global health challenge, with a massive impact on the quality of life of Alzheimer's disease patients and their relatives. The diagnosis of Alzheimer's disease constitutes a real challenge, because the symptoms manifest years after the first degenerative changes occurring in the brain and the diagnosis is based on invasive and/or expensive techniques. Therefore, there is an urgent need to identify new reliable biomarkers to detect Alzheimer's disease at an early stage. Taking into account the evidence for visual deficits in Alzheimer's disease patients, sometimes even before the appearance of the first disease symptoms, and that the retina is an extension of the brain, the concept of the retina as a window to look into the brain or a mirror of the brain has received increasing interest in recent years. However, only a few studies have assessed the changes occurring in the retina and the brain at the same time points. Unlike previous reviews on this subject, which are mainly focused on brain changes, we organized this review by comprehensively summarizing findings related with structural, functional, cellular, and molecular parameters in the retina reported in both Alzheimer's disease patients and animal models. Moreover, we separated the studies that assessed only the retina, and those that assessed both the retina and brain, which are few but allow establishing correlations between the retina and brain. This review also highlights some inconsistent results in the literature as well as relevant missing gaps in this field.
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Affiliation(s)
- Samuel Chiquita
- iCBR, Coimbra Institute for Clinical and Biomedical Research, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
- CNC.IBILI Consortium, University of Coimbra, Coimbra, Portugal
| | - Ana C Rodrigues-Neves
- iCBR, Coimbra Institute for Clinical and Biomedical Research, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
- CNC.IBILI Consortium, University of Coimbra, Coimbra, Portugal
| | - Filipa I Baptista
- iCBR, Coimbra Institute for Clinical and Biomedical Research, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
- CNC.IBILI Consortium, University of Coimbra, Coimbra, Portugal
| | - Rafael Carecho
- iCBR, Coimbra Institute for Clinical and Biomedical Research, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
- CNC.IBILI Consortium, University of Coimbra, Coimbra, Portugal
| | - Paula I Moreira
- CNC.IBILI Consortium, University of Coimbra, Coimbra, Portugal
- CNC, Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- Institute of Physiology, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Miguel Castelo-Branco
- CNC.IBILI Consortium, University of Coimbra, Coimbra, Portugal
- CIBIT, Coimbra Institute for Biomedical Imaging and Translational Research, ICNAS, Institute of Nuclear Sciences Applied to Health, University of Coimbra, Coimbra, Portugal
| | - António F Ambrósio
- iCBR, Coimbra Institute for Clinical and Biomedical Research, Faculty of Medicine, University of Coimbra, Coimbra, Portugal.
- CNC.IBILI Consortium, University of Coimbra, Coimbra, Portugal.
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Sadda SR, Borrelli E, Fan W, Ebraheem A, Marion KM, Kwon S. Impact of mydriasis in fluorescence lifetime imaging ophthalmoscopy. PLoS One 2018; 13:e0209194. [PMID: 30592718 PMCID: PMC6310355 DOI: 10.1371/journal.pone.0209194] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2018] [Accepted: 11/30/2018] [Indexed: 11/19/2022] Open
Abstract
Fluorescence lifetime imaging ophthalmoscopy (FLIO) is a novel technique that measures in vivo autofluorescence intensity decay over time of endogenous fluorophores in the retina. The Heidelberg Engineering FLIO system was used to obtain two 30 degree scans centered on the fovea of both eyes. The FLIO system uses a 473nm blue scanning laser light source and the emitted fluorescence is detected in two wavelengths channels, short and long spectral channels (SSC, LSC). Since the mydriatic status influence the FLIO result, the impact of mydriasis on FLIO need to be clarified. In this prospective, observational study, the impact of mydriasis on measurements from fluorescence lifetime imaging ophthalmoscope (FLIO) images in normal subjects were evaluated. 12 healthy participants (24 eyes) were volunteered and all subjects were scanned twice and the mean fluorescence lifetime (τm) values were computed with dilation and without dilation on different days. Intraclass correlation coefficients (ICC) and coefficients of variation (CV) were calculated from the measured τm in dilated, nondilated and between the dilated and non-dilated setting. Test duration was also compared and correlated with lifetimes in both settings. Repeatability was excellent for both the dilation and non-dilation settings (ICC; 0.967–0.996; 0.926–0.986, respectively). The agreement between the dilation and non-dilation settings, however, were lower (ICC; 0.688–0.970). The τm in the non-dilation setting was significantly longer than in the dilation setting for the SSC (P<0.05). The FLIO test duration in the non-dilation setting was significantly longer than with dilation for the SSC (P <0.05). Although good repeatability in τm measurements between imaging sessions were observed both with and without dilation, the agreement was not as good when comparing dilated with non-dilated measurements. Since FLIO without mydriasis results in longer τm in the SSC and takes a longer time for image acquisition, maximal dilation is recommended for FLIO testing.
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Affiliation(s)
- SriniVas R Sadda
- Department of Ophthalmology, David Geffen School of Medicine at UCLA, Doheny Eye Center, Los Angeles, CA
- Department of Ophthalmology, David Geffen School of Medicine at UCLA, Stein Eye Institute, Los Angeles, CA
| | - Enrico Borrelli
- Department of Ophthalmology, David Geffen School of Medicine at UCLA, Doheny Eye Center, Los Angeles, CA
| | - Wenying Fan
- Department of Ophthalmology, David Geffen School of Medicine at UCLA, Doheny Eye Center, Los Angeles, CA
| | - Adel Ebraheem
- Department of Ophthalmology, David Geffen School of Medicine at UCLA, Doheny Eye Center, Los Angeles, CA
| | - Kenneth M Marion
- Department of Ophthalmology, David Geffen School of Medicine at UCLA, Doheny Eye Center, Los Angeles, CA
| | - Soonil Kwon
- Department of Ophthalmology, David Geffen School of Medicine at UCLA, Doheny Eye Center, Los Angeles, CA
- Department of Ophthalmology, Hallym Sacred Heart Hospital, Hallym University College of Medicine, Anyang, Gyeonggi, South Korea
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Lopez Sanchez MIG, van Wijngaarden P, Trounce IA. Amyloid precursor protein-mediated mitochondrial regulation and Alzheimer's disease. Br J Pharmacol 2018; 176:3464-3474. [PMID: 30471088 DOI: 10.1111/bph.14554] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2018] [Revised: 10/29/2018] [Accepted: 11/10/2018] [Indexed: 12/16/2022] Open
Abstract
Despite clear evidence of a neuroprotective physiological role of amyloid precursor protein (APP) and its non-amyloidogenic processing products, APP has been investigated mainly in animal and cellular models of amyloid pathology in the context of Alzheimer's disease. The rare familial mutations in APP and presenilin-1/2, which sometimes drive increased amyloid β (Aβ) production, may have unduly influenced Alzheimer's disease research. APP and its cleavage products play important roles in cellular and mitochondrial metabolism, but many studies focus solely on Aβ. Mitochondrial bioenergetic metabolism is essential for neuronal function, maintenance and survival, and multiple reports indicate mitochondrial abnormalities in patients with Alzheimer's disease. In this review, we focus on mitochondrial abnormalities reported in sporadic Alzheimer's disease patients and the role of full-length APP and its non-amyloidogenic fragments, particularly soluble APPα, on mitochondrial bioenergetic metabolism. We do not review the plethora of animal and in vitro studies using mutant APP/presenilin constructs or experiments using exogenous Aβ. In doing so, we aim to invigorate research and discussion around non-amyloidogenic APP processing products and the mechanisms linking mitochondria and complex neurodegenerative disorders such as sporadic Alzheimer's disease. LINKED ARTICLES: This article is part of a themed section on Therapeutics for Dementia and Alzheimer's Disease: New Directions for Precision Medicine. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.18/issuetoc.
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Affiliation(s)
- M Isabel G Lopez Sanchez
- Ophthalmology, Department of Surgery, University of Melbourne, Melbourne, VIC, Australia.,Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, VIC, Australia
| | - Peter van Wijngaarden
- Ophthalmology, Department of Surgery, University of Melbourne, Melbourne, VIC, Australia.,Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, VIC, Australia
| | - Ian A Trounce
- Ophthalmology, Department of Surgery, University of Melbourne, Melbourne, VIC, Australia.,Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, VIC, Australia
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Sánchez D, Castilla-Marti M, Rodríguez-Gómez O, Valero S, Piferrer A, Martínez G, Martínez J, Serra J, Moreno-Grau S, Hernández-Olasagarre B, De Rojas I, Hernández I, Abdelnour C, Rosende-Roca M, Vargas L, Mauleón A, Santos-Santos MA, Alegret M, Ortega G, Espinosa A, Pérez-Cordón A, Sanabria Á, Ciudin A, Simó R, Hernández C, Villoslada P, Ruiz A, Tàrraga L, Boada M. Usefulness of peripapillary nerve fiber layer thickness assessed by optical coherence tomography as a biomarker for Alzheimer's disease. Sci Rep 2018; 8:16345. [PMID: 30397251 PMCID: PMC6218495 DOI: 10.1038/s41598-018-34577-3] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 10/17/2018] [Indexed: 12/14/2022] Open
Abstract
The use of optical coherence tomography (OCT) has been suggested as a potential biomarker for Alzheimer’s Disease based on previously reported thinning of the retinal nerve fiber layer (RNFL) in Alzheimer’s disease’s (AD) and Mild Cognitive Impairment (MCI). However, other studies have not shown such results. 930 individuals (414 cognitively healthy individuals, 192 probable amnestic MCI and 324 probable AD) attending a memory clinic were consecutively included and underwent spectral domain OCT (Maestro, Topcon) examinations to assess differences in peripapillary RNFL thickness, using a design of high ecological validity. Adjustment by age, education, sex and OCT image quality was performed. We found a non-significant decrease in mean RNFL thickness as follows: control group: 100,20 ± 14,60 µm, MCI group: 98,54 ± 14,43 µm and AD group: 96,61 ± 15,27 µm. The multivariate adjusted analysis revealed no significant differences in mean overall (p = 0.352), temporal (p = 0,119), nasal (p = 0,151), superior (p = 0,435) or inferior (p = 0,825) quadrants between AD, MCI and control groups. These results do not support the usefulness of peripapillary RNFL analysis as a marker of cognitive impairment or in discriminating between cognitive groups. The analysis of other OCT measurements in other retinal areas and layers as biomarkers for AD should be tested further.
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Affiliation(s)
- Domingo Sánchez
- Alzheimer Research Center and Memory Clinic of Fundació ACE, Institut Català de Neurociències Aplicades, Barcelona, Spain.
| | - Miguel Castilla-Marti
- Clínica Oftalmológica Dr. Castilla, Barcelona, Spain.,Valles Ophthalmology Research, Hospital General de Catalunya, Sant Cugat del Vallès, Spain
| | - Octavio Rodríguez-Gómez
- Alzheimer Research Center and Memory Clinic of Fundació ACE, Institut Català de Neurociències Aplicades, Barcelona, Spain
| | - Sergi Valero
- Alzheimer Research Center and Memory Clinic of Fundació ACE, Institut Català de Neurociències Aplicades, Barcelona, Spain.,Psychiatry Department, Hospital Universitari Vall d'Hebron, CIBERSAM, Universitat Autònoma de Barcelona, Barcelona, Spain
| | | | - Gabriel Martínez
- Faculty of Medicine and Dentistry. Faculty of Medicine and Dentistry, Universidad de Antofagasta, Antofagasta, Chile.,Iberoamerican Cochrane Centre, Barcelona, Spain
| | - Joan Martínez
- Alzheimer Research Center and Memory Clinic of Fundació ACE, Institut Català de Neurociències Aplicades, Barcelona, Spain
| | - Judit Serra
- Alzheimer Research Center and Memory Clinic of Fundació ACE, Institut Català de Neurociències Aplicades, Barcelona, Spain
| | - Sonia Moreno-Grau
- Alzheimer Research Center and Memory Clinic of Fundació ACE, Institut Català de Neurociències Aplicades, Barcelona, Spain
| | - Begoña Hernández-Olasagarre
- Alzheimer Research Center and Memory Clinic of Fundació ACE, Institut Català de Neurociències Aplicades, Barcelona, Spain
| | - Itziar De Rojas
- Alzheimer Research Center and Memory Clinic of Fundació ACE, Institut Català de Neurociències Aplicades, Barcelona, Spain
| | - Isabel Hernández
- Alzheimer Research Center and Memory Clinic of Fundació ACE, Institut Català de Neurociències Aplicades, Barcelona, Spain
| | - Carla Abdelnour
- Alzheimer Research Center and Memory Clinic of Fundació ACE, Institut Català de Neurociències Aplicades, Barcelona, Spain
| | - Maitée Rosende-Roca
- Alzheimer Research Center and Memory Clinic of Fundació ACE, Institut Català de Neurociències Aplicades, Barcelona, Spain
| | - Liliana Vargas
- Alzheimer Research Center and Memory Clinic of Fundació ACE, Institut Català de Neurociències Aplicades, Barcelona, Spain
| | - Ana Mauleón
- Alzheimer Research Center and Memory Clinic of Fundació ACE, Institut Català de Neurociències Aplicades, Barcelona, Spain
| | - Miguel A Santos-Santos
- Alzheimer Research Center and Memory Clinic of Fundació ACE, Institut Català de Neurociències Aplicades, Barcelona, Spain
| | - Montserrat Alegret
- Alzheimer Research Center and Memory Clinic of Fundació ACE, Institut Català de Neurociències Aplicades, Barcelona, Spain
| | - Gemma Ortega
- Alzheimer Research Center and Memory Clinic of Fundació ACE, Institut Català de Neurociències Aplicades, Barcelona, Spain
| | - Ana Espinosa
- Alzheimer Research Center and Memory Clinic of Fundació ACE, Institut Català de Neurociències Aplicades, Barcelona, Spain
| | - Alba Pérez-Cordón
- Alzheimer Research Center and Memory Clinic of Fundació ACE, Institut Català de Neurociències Aplicades, Barcelona, Spain
| | - Ángela Sanabria
- Alzheimer Research Center and Memory Clinic of Fundació ACE, Institut Català de Neurociències Aplicades, Barcelona, Spain
| | - Andrea Ciudin
- Diabetes and Metabolism Research Unit and Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólica Asociada (CIBERDEM), Vall d'Hebron Research Institute, Barcelona, Spain
| | - Rafael Simó
- Diabetes and Metabolism Research Unit and Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólica Asociada (CIBERDEM), Vall d'Hebron Research Institute, Barcelona, Spain
| | - Cristina Hernández
- Diabetes and Metabolism Research Unit and Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólica Asociada (CIBERDEM), Vall d'Hebron Research Institute, Barcelona, Spain
| | - Pablo Villoslada
- Institut d'Investigacions Biomèdiques August Pi Sunyer (IDIBAPS), Barcelona, Spain
| | - Agustín Ruiz
- Alzheimer Research Center and Memory Clinic of Fundació ACE, Institut Català de Neurociències Aplicades, Barcelona, Spain
| | - Lluís Tàrraga
- Alzheimer Research Center and Memory Clinic of Fundació ACE, Institut Català de Neurociències Aplicades, Barcelona, Spain
| | - Mercè Boada
- Alzheimer Research Center and Memory Clinic of Fundació ACE, Institut Català de Neurociències Aplicades, Barcelona, Spain
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Guo L, Normando EM, Shah PA, De Groef L, Cordeiro MF. Oculo-visual abnormalities in Parkinson's disease: Possible value as biomarkers. Mov Disord 2018; 33:1390-1406. [DOI: 10.1002/mds.27454] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Revised: 05/16/2018] [Accepted: 05/18/2018] [Indexed: 12/16/2022] Open
Affiliation(s)
- Li Guo
- Glaucoma and Retinal Degenerative Disease Research Group, Institute of Ophthalmology; University College London; London UK
| | - Eduardo M. Normando
- Glaucoma and Retinal Degenerative Disease Research Group, Institute of Ophthalmology; University College London; London UK
- Western Eye Hospital, Imperial College Healthcare National Health Service Trust; London UK
- Imperial College Ophthalmology Research Group, Department of Surgery and Cancer, Imperial College London; London UK
| | - Parth Arvind Shah
- Glaucoma and Retinal Degenerative Disease Research Group, Institute of Ophthalmology; University College London; London UK
| | - Lies De Groef
- Glaucoma and Retinal Degenerative Disease Research Group, Institute of Ophthalmology; University College London; London UK
- Neural Circuit Development and Regeneration Research Group, Department of Biology; University of Leuven; Leuven Belgium
| | - M. Francesca Cordeiro
- Glaucoma and Retinal Degenerative Disease Research Group, Institute of Ophthalmology; University College London; London UK
- Western Eye Hospital, Imperial College Healthcare National Health Service Trust; London UK
- Imperial College Ophthalmology Research Group, Department of Surgery and Cancer, Imperial College London; London UK
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Lagarto JL, Dyer BT, Talbot CB, Peters NS, French PMW, Lyon AR, Dunsby C. Characterization of NAD(P)H and FAD autofluorescence signatures in a Langendorff isolated-perfused rat heart model. BIOMEDICAL OPTICS EXPRESS 2018; 9:4961-4978. [PMID: 30319914 PMCID: PMC6179415 DOI: 10.1364/boe.9.004961] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 08/10/2018] [Accepted: 08/11/2018] [Indexed: 05/22/2023]
Abstract
Autofluorescence spectroscopy is a promising label-free approach to characterize biological samples with demonstrated potential to report structural and biochemical alterations in tissues in a number of clinical applications. We report a characterization of the ex vivo autofluorescence fingerprint of cardiac tissue, exploiting a Langendorff-perfused isolated rat heart model to induce physiological insults to the heart, with a view to understanding how metabolic alterations affect the autofluorescence signals. Changes in the autofluorescence intensity and lifetime signatures associated with reduced nicotinamide adenine dinucleotide (phosphate) (NAD(P)H) and flavin adenine dinucleotide (FAD) were characterized during oxygen- or glucose-depletion protocols. Results suggest that both NAD(P)H and FAD autofluorescence intensity and lifetime parameters are sensitive to changes in the metabolic state of the heart owing to oxygen deprivation. We also observed changes in NAD(P)H fluorescence intensity and FAD lifetime parameter on reperfusion of oxygen, which might provide information on reperfusion injury, and permanent tissue damage or changes to the tissue during recovery from oxygen deprivation. We found that changes in the autofluorescence signature following glucose-depletion are, in general, less pronounced, and most clearly visible in NAD(P)H related parameters. Overall, the results reported in this investigation can serve as baseline for future investigations of cardiac tissue involving autofluorescence measurements.
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Affiliation(s)
- João L Lagarto
- Photonics Group, Department of Physics, Imperial College London, Prince Consort Road, London SW7 2AZ, UK
- Authors contributed equally to this work
| | - Benjamin T Dyer
- National Heart and Lung Institute, Imperial College London, Du Cane Road, London W12 0NN, UK
- Authors contributed equally to this work
| | - Clifford B Talbot
- Photonics Group, Department of Physics, Imperial College London, Prince Consort Road, London SW7 2AZ, UK
| | - Nicholas S Peters
- National Heart and Lung Institute, Imperial College London, Du Cane Road, London W12 0NN, UK
| | - Paul M W French
- Photonics Group, Department of Physics, Imperial College London, Prince Consort Road, London SW7 2AZ, UK
| | - Alexander R Lyon
- National Heart and Lung Institute, Imperial College London, Du Cane Road, London W12 0NN, UK
- Authors contributed equally to this work
| | - Chris Dunsby
- Photonics Group, Department of Physics, Imperial College London, Prince Consort Road, London SW7 2AZ, UK
- Centre for Pathology, Imperial College London, Du Cane Road, London, W12 0NN, UK
- Authors contributed equally to this work
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Sauer L, Andersen KM, Dysli C, Zinkernagel MS, Bernstein PS, Hammer M. Review of clinical approaches in fluorescence lifetime imaging ophthalmoscopy. JOURNAL OF BIOMEDICAL OPTICS 2018; 23:1-20. [PMID: 30182580 PMCID: PMC8357196 DOI: 10.1117/1.jbo.23.9.091415] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2018] [Accepted: 07/24/2018] [Indexed: 05/04/2023]
Abstract
Autofluorescence-based imaging techniques have become very important in the ophthalmological field. Being noninvasive and very sensitive, they are broadly used in clinical routines. Conventional autofluorescence intensity imaging is largely influenced by the strong fluorescence of lipofuscin, a fluorophore that can be found at the level of the retinal pigment epithelium. However, different endogenous retinal fluorophores can be altered in various diseases. Fluorescence lifetime imaging ophthalmoscopy (FLIO) is an imaging modality to investigate the autofluorescence of the human fundus in vivo. It expands the level of information, as an addition to investigating the fluorescence intensity, and autofluorescence lifetimes are captured. The Heidelberg Engineering Spectralis-based fluorescence lifetime imaging ophthalmoscope is used to investigate a 30-deg retinal field centered at the fovea. It detects FAF decays in short [498 to 560 nm, short spectral channel (SSC) and long (560 to 720 nm, long spectral channel (LSC)] spectral channels, the mean fluorescence lifetimes (τm) are calculated using bi- or triexponential approaches. These are meant to be relatively independent of the fluorophore's intensity; therefore, fluorophores with less intense fluorescence can be detected. As an example, FLIO detects the fluorescence of macular pigment, retinal carotenoids that help protect the human fundus from light damages. Furthermore, FLIO is able to detect changes related to various retinal diseases, such as age-related macular degeneration, albinism, Alzheimer's disease, diabetic retinopathy, macular telangiectasia type 2, retinitis pigmentosa, and Stargardt disease. Some of these changes can already be found in healthy eyes and may indicate a risk to developing such diseases. Other changes in already affected eyes seem to indicate disease progression. This review article focuses on providing detailed information on the clinical findings of FLIO. This technique detects not only structural changes at very early stages but also metabolic and disease-related alterations. Therefore, it is a very promising tool that might soon be used for early diagnostics.
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Affiliation(s)
- Lydia Sauer
- University Hospital Jena, Jena, Thuringia, Germany
- University of Utah, John A. Moran Eye Center, Salt Lake City, Utah, United States
| | - Karl M. Andersen
- University of Utah, John A. Moran Eye Center, Salt Lake City, Utah, United States
- Geisinger Commonwealth School of Medicine, Scranton, Pennsylvania, United States
| | - Chantal Dysli
- Bern University Hospital, Inselspital, Department of Ophthalmology, Bern, Switzerland
| | - Martin S. Zinkernagel
- Bern University Hospital, Inselspital, Department of Ophthalmology, Bern, Switzerland
| | - Paul S. Bernstein
- University of Utah, John A. Moran Eye Center, Salt Lake City, Utah, United States
| | - Martin Hammer
- University Hospital Jena, Jena, Thuringia, Germany
- University of Jena, Center for Biomedical Optics and Photonics, Jena, Germany
- Address all correspondence to: Martin Hammer, E-mail:
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Batista A, Breunig HG, König A, Morgado AM, König K. Assessment of the metabolism and morphology of the porcine cornea, lens and retina by 2-photon imaging. JOURNAL OF BIOPHOTONICS 2018; 11:e201700324. [PMID: 29575612 DOI: 10.1002/jbio.201700324] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 03/21/2018] [Indexed: 06/08/2023]
Abstract
Two-photon imaging is a noninvasive imaging technique with increasing importance in the biological and medical fields since it allows intratissue cell imaging with high resolution. We demonstrate the feasibility of using a single 2-photon instrument to evaluate the cornea, the crystalline lens and the retina based on their autofluorescence (AF). Image acquisition was performed using a custom-built 2-photon microscope for 5-dimensional microscopy with a near infrared broadband sub-15 femtosecond laser centered at 800 nanometers. Signals were detected using a spectral photomultiplier tube. The spectral ranges for the analysis of each tissue/layer AF were determined based on the spectra of each tissue as well as of pure endogenous fluorophores. The cornea, lens and retina are characterized at multiple depths with subcellular resolution based on their morphology and AF lifetime. Additionally, the AF lifetime of NAD(P)H was used to assess the metabolic activity of the cornea epithelium, endothelium and keratocytes. The feasibility to evaluate the metabolic activity of lens epithelial cells was also demonstrated, which may be used to further investigate the pathogenesis of cataracts. The results illustrate the potential of multimodal multiphoton imaging as a novel ophthalmologic technique as well as its potential as a diagnostic tool.
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Affiliation(s)
- Ana Batista
- Biophotonics and Laser Technology, Saarland University, Saarbrücken, Germany
- JenLab GmbH, Saarbrücken, Germany
| | - Hans G Breunig
- Biophotonics and Laser Technology, Saarland University, Saarbrücken, Germany
- JenLab GmbH, Saarbrücken, Germany
| | - Aisada König
- Biophotonics and Laser Technology, Saarland University, Saarbrücken, Germany
- JenLab GmbH, Saarbrücken, Germany
| | - António M Morgado
- Department of Physics, University of Coimbra, Coimbra, Portugal
- Coimbra Institute for Biomedical Imaging and Translational Research/Institute of Nuclear Sciences Applied to Heath (CIBIT/ICNAS), University of Coimbra, Coimbra, Portugal
| | - Karsten König
- Biophotonics and Laser Technology, Saarland University, Saarbrücken, Germany
- JenLab GmbH, Saarbrücken, Germany
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Sauer L, Gensure RH, Hammer M, Bernstein PS. Fluorescence Lifetime Imaging Ophthalmoscopy: A Novel Way to Assess Macular Telangiectasia Type 2. Ophthalmol Retina 2018; 2:587-598. [PMID: 30116796 PMCID: PMC6089530 DOI: 10.1016/j.oret.2017.10.008] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
PURPOSE Macular Telangiectasia Type 2 (MacTel) is an uncommon, late-onset complex retinal disease that leads to central vision loss. No causative gene(s) have been identified so far, resulting in a challenging clinical diagnostic dilemma because retinal changes of early stages are often subtle. The objective of this study was to investigate the benefit of fluorescence lifetime imaging ophthalmoscopy (FLIO) for retinal imaging in patients with MacTel. DESIGN Cross-sectional study from a tertiary-care retinal referral practice. SUBJECTS AND CONTROLS 42 eyes of 21 patients (mean age 60.5±13.3 years) with MacTel as well as an age-matched healthy control group (42 eyes of 25 subjects, mean age 60.8±13.4 years). METHODS A 30° retinal field centered at the fovea was investigated using FLIO. This camera is based on a Heidelberg Engineering Spectralis system. Fundus autofluorescence (FAF) decays were detected in short (498-560 nm, SSC) and long (560-720 nm, LSC) spectral channels. The mean fluorescence lifetime, τm, was calculated from a 3-exponential approximation of the FAF decays. For MacTel patients, macular pigment (MP), OCT, blue light reflectance, fluorescein angiography, as well as fundus photography, were also recorded. MAIN OUTCOME MEASURES Mean FAF lifetime (τm) images. RESULTS FLIO of MacTel patients shows a unique pattern of prolonged τm at the temporal side of the fovea in patients with MacTel in the "MacTel area" within 5-6° of the foveal center. In early stages, this region appears crescent-shaped, while advanced stages show a ring-like pattern. This pattern corresponds well with other imaging modalities and gives an especially high contrast of the affected region even in minimally affected individuals. Additionally, FLIO provides a novel means to monitor the abnormal MP distribution. In one case, FLIO showed changes suggestive of MacTel within a clinically normal parent of two MacTel patients. CONCLUSIONS FLIO detects retinal changes in patients with MacTel with high contrast, presenting a distinctive signature that is a characteristic finding of the disease. The non-invasive properties of this novel imaging modality provide a valuable addition to clinical assessment of early changes in the disease that could lead to more accurate diagnosis of MacTel.
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Affiliation(s)
- Lydia Sauer
- John A. Moran Eye Center, University of Utah, Salt Lake City, UT, USA
- University Hospital Jena, Bachstraße 18, 07743, Jena, Germany
| | | | - Martin Hammer
- University Hospital Jena, Bachstraße 18, 07743, Jena, Germany
| | - Paul S. Bernstein
- John A. Moran Eye Center, University of Utah, Salt Lake City, UT, USA
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Spectral analysis of fundus autofluorescence pattern as a tool to detect early stages of degeneration in the retina and retinal pigment epithelium. Eye (Lond) 2018; 32:1440-1448. [PMID: 29786089 DOI: 10.1038/s41433-018-0109-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2017] [Revised: 02/27/2018] [Accepted: 03/30/2018] [Indexed: 01/14/2023] Open
Abstract
PURPOSE The aim of this work is the determination of quantitative diagnostic criteria based on the spectral characteristics of fundus autofluorescence to detect early stages of degeneration in the retina and retinal pigment epithelium (RPE). METHODS RPE cell suspension samples were obtained from the cadaver eyes with and without signs of age-related macular degeneration (AMD). Fluorescence analysis at an excitation wavelength of 488 nm was performed. The fluorescence lifetimes of lipofuscin-granule fluorophores were measured by counting time-correlated photon method. RESULTS Comparative analysis of fluorescence spectra of RPE cell suspensions from the cadaver eyes with and without signs of AMD showed a significant difference in fluorescence intensity at 530-580 nm in response to fluorescence excitation at 488 nm. It was notably higher in eyes with visual pathology than in normal eyes regardless of the age of the eye donor. Measurements of fluorescence lifetimes of lipofuscin fluorophores showed that the contribution of photooxidation and photodegradation products of bisretinoids to the total fluorescence at 530-580 nm of RPE cell suspensions was greater in eyes with visual pathology than in normal eyes. CONCLUSION Because photooxidation and photodegradation products of bisretinoids are markers of photodestructive processes, which can cause RPE cell death and initiate degenerative processes in the retina, quantitative determination of increases in these bisretinoid products in lipofuscin granules may be used to establish quantitative diagnostic criteria for degenerative processes in the retina and RPE.
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Sauer L, Klemm M, Peters S, Schweitzer D, Schmidt J, Kreilkamp L, Ramm L, Meller D, Hammer M. Monitoring foveal sparing in geographic atrophy with fluorescence lifetime imaging ophthalmoscopy - a novel approach. Acta Ophthalmol 2018; 96:257-266. [PMID: 29105362 DOI: 10.1111/aos.13587] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 08/09/2017] [Indexed: 01/12/2023]
Abstract
PURPOSE To investigate fundus autofluorescence (FAF) lifetimes in geographic atrophy (GA) with a focus on macular pigment (MP) and foveal sparing. METHODS The study included 35 eyes from 28 patients (mean age 79.2 ± 8.0 years) with GA. A 30° retinal field, centred at the macula, was investigated using fluorescence lifetime imaging ophthalmoscopy (FLIO). The FLIO technology is based on a Heidelberg Engineering Spectralis system. Decays of FAF were detected in a short (498-560 nm, SSC) and long (560-720 nm, LSC) spectral channel. The mean fluorescence lifetime, τm , was calculated from a three-exponential approximation of the FAF decays. Macular optical coherence tomography (OCT) scans as well as fundus photography were recorded. RESULTS Review of FLIO data reveals specific patterns of significantly prolonged τm in regions of GA (SSC 616 ± 343 ps, LSC 615 ± 154 ps) as compared to non-atrophic regions. Large τm differences between the fovea and atrophic areas correlate with better visual acuity (VA). Shorter τm at the fovea than within other non-atrophic regions indicates sparing, which was identified in 16 eyes. Seventy per cent of patients treated with lutein supplementation showed foveal sparing, whereas the rate among non-supplemented patients was 22%. CONCLUSION Using FLIO, we present a novel way to detect foveal sparing, investigate MP, and analyse variability of τm in different foveal regions (including the prognostic valuable border region) in GA. These findings support the potential utility of FLIO in monitoring disease progression. The findings also highlight the possibly protective effect of lutein supplementation, with implication in recording the presence and distributional pattern of MP.
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Affiliation(s)
| | - Matthias Klemm
- Institute of Biomedical Engineering and Informatics; Technical University Ilmenau; Ilmenau Germany
| | | | - Dietrich Schweitzer
- University Hospital Jena; Jena Germany
- Center for Medical Optics and Photonics; University of Jena; Jena Germany
| | | | | | - Lisa Ramm
- Department of Ophthalmology; University Hospital Carl-Gustav Carus; TU Dresden; Dresden Germany
| | | | - Martin Hammer
- University Hospital Jena; Jena Germany
- Center for Medical Optics and Photonics; University of Jena; Jena Germany
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Le Marois A, Suhling K. Quantitative Live Cell FLIM Imaging in Three Dimensions. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1035:31-48. [PMID: 29080129 DOI: 10.1007/978-3-319-67358-5_3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
In this chapter, the concept of fluorescence lifetime and its utility in quantitative live cell imaging will be introduced, along with methods to record and analyze FLIM data. Relevant applications in 3D tissue and live cell imaging, including multiplexed FLIM detection, will also be detailed.
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Affiliation(s)
- Alix Le Marois
- Department of Physics, King's College London, Strand, London, WC2R 2LS, UK
| | - Klaus Suhling
- Department of Physics, King's College London, Strand, London, WC2R 2LS, UK.
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Mahajan D, Votruba M. Can the retina be used to diagnose and plot the progression of Alzheimer's disease? Acta Ophthalmol 2017; 95:768-777. [PMID: 29220126 DOI: 10.1111/aos.13472] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2016] [Accepted: 04/03/2017] [Indexed: 12/25/2022]
Abstract
Alzheimer's disease (AD) is a neurodegenerative disease and the most common cause of senile dementia. It impairs the quality of life of a person and their family, posing a serious economic and social threat in developed countries. The fact that the diagnosis can only be definitively made post-mortem, or when the disease is fairly advanced, presents a serious problem if novel therapeutic interventions are to be devised and used early in the course of the disease. There is therefore a pressing need for more sensitive and specific diagnostic tests with which we can detect AD in the preclinical stage. The tau proteins and beta-amyloid proteins start to accumulate 20 years before the symptoms begin to manifest. Detecting them in the preclinical stage would be a potential breakthrough in the management of AD. A high degree of clinical suspicion is needed to correlate problems in cognition with the changes in the eye, particularly the retina, pupil and ocular movements, so that the disease can be detected early and managed in the prodromal phase. In this systematic review, we ask the question whether the retina can be used to make a specific and early diagnosis of AD.
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Affiliation(s)
- Deepti Mahajan
- School of Optometry and Vision Sciences; Cardiff University; Cardiff UK
| | - Marcela Votruba
- School of Optometry and Vision Sciences; Cardiff University; Cardiff UK
- University Hospital of Wales; Cardiff UK
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Kusne Y, Wolf AB, Townley K, Conway M, Peyman GA. Visual system manifestations of Alzheimer's disease. Acta Ophthalmol 2017; 95:e668-e676. [PMID: 27864881 DOI: 10.1111/aos.13319] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 10/07/2016] [Indexed: 12/13/2022]
Abstract
Alzheimer's disease (AD) is an increasingly common disease with massive personal and economic costs. While it has long been known that AD impacts the visual system, there has recently been an increased focus on understanding both pathophysiological mechanisms that may be shared between the eye and brain and how related biomarkers could be useful for AD diagnosis. Here, were review pertinent cellular and molecular mechanisms of AD pathophysiology, the presence of AD pathology in the visual system, associated functional changes, and potential development of diagnostic tools based on the visual system. Additionally, we discuss links between AD and visual disorders, including possible pathophysiological mechanisms and their relevance for improving our understanding of AD.
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Affiliation(s)
- Yael Kusne
- University of Arizona College of Medicine; Phoenix Arizona USA
| | - Andrew B. Wolf
- University of Colorado School of Medicine; Aurora Colorado USA
| | - Kate Townley
- University of Arizona College of Medicine; Phoenix Arizona USA
| | - Mandi Conway
- University of Arizona College of Medicine; Phoenix Arizona USA
- Arizona Retinal Specialists; Sun City Arizona USA
| | - Gholam A. Peyman
- University of Arizona College of Medicine; Phoenix Arizona USA
- Arizona Retinal Specialists; Sun City Arizona USA
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Abstract
Fluorescence lifetime (FLT) is a robust intrinsic property and material constant of fluorescent matter. Measuring this important physical indicator has evolved from a laboratory curiosity to a powerful and established technique for a variety of applications in drug discovery, medical diagnostics and basic biological research. This distinct trend was mainly driven by improved and meanwhile affordable laser and detection instrumentation on the one hand, and the development of suitable FLT probes and biological assays on the other. In this process two essential working approaches emerged. The first one is primarily focused on high throughput applications employing biochemical in vitro assays with no requirement for high spatial resolution. The second even more dynamic trend is the significant expansion of assay methods combining highly time and spatially resolved fluorescence data by fluorescence lifetime imaging. The latter approach is currently pursued to enable not only the investigation of immortal tumor cell lines, but also specific tissues or even organs in living animals. This review tries to give an actual overview about the current status of FLT based bioassays and the wide range of application opportunities in biomedical and life science areas. In addition, future trends of FLT technologies will be discussed.
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Affiliation(s)
- Franz-Josef Meyer-Almes
- Department of Chemical Engineering and Biotechnology, University of Applied Sciences Darmstadt, Haardtring 100, D-64295 Darmstadt, Germany
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Le Marois A, Labouesse S, Suhling K, Heintzmann R. Noise-Corrected Principal Component Analysis of fluorescence lifetime imaging data. JOURNAL OF BIOPHOTONICS 2017; 10:1124-1133. [PMID: 27943625 DOI: 10.1002/jbio.201600160] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 09/23/2016] [Accepted: 11/14/2016] [Indexed: 05/08/2023]
Abstract
Fluorescence Lifetime Imaging (FLIM) is an attractive microscopy method in the life sciences, yielding information on the sample otherwise unavailable through intensity-based techniques. A novel Noise-Corrected Principal Component Analysis (NC-PCA) method for time-domain FLIM data is presented here. The presence and distribution of distinct microenvironments are identified at lower photon counts than previously reported, without requiring prior knowledge of their number or of the dye's decay kinetics. A noise correction based on the Poisson statistics inherent to Time-Correlated Single Photon Counting is incorporated. The approach is validated using simulated data, and further applied to experimental FLIM data of HeLa cells stained with membrane dye di-4-ANEPPDHQ. Two distinct lipid phases were resolved in the cell membranes, and the modification of the order parameters of the plasma membrane during cholesterol depletion was also detected. Noise-corrected Principal Component Analysis of FLIM data resolves distinct microenvironments in cell membranes of live HeLa cells.
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Affiliation(s)
- Alix Le Marois
- Department of Physics, King's College London, Strand, WC2R 2LS, London, United Kingdom
| | - Simon Labouesse
- Institute Fresnel, Avenue Escadrille Normandie Niemen, 13013, Marseille, France
- Leibniz Institute of Photonic Technology, Albert-Einstein-Straße 9, 07745, Jena, Germany
| | - Klaus Suhling
- Department of Physics, King's College London, Strand, WC2R 2LS, London, United Kingdom
| | - Rainer Heintzmann
- Leibniz Institute of Photonic Technology, Albert-Einstein-Straße 9, 07745, Jena, Germany
- Institute of Physical Chemistry, Abbe Centre of Photonics, Friedrich Schiller University Jena, Helmholtzweg 4, 07743, Jena, Germany
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