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Różanowska MB. Lipofuscin, Its Origin, Properties, and Contribution to Retinal Fluorescence as a Potential Biomarker of Oxidative Damage to the Retina. Antioxidants (Basel) 2023; 12:2111. [PMID: 38136230 PMCID: PMC10740933 DOI: 10.3390/antiox12122111] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Revised: 12/05/2023] [Accepted: 12/09/2023] [Indexed: 12/24/2023] Open
Abstract
Lipofuscin accumulates with age as intracellular fluorescent granules originating from incomplete lysosomal digestion of phagocytosed and autophagocytosed material. The purpose of this review is to provide an update on the current understanding of the role of oxidative stress and/or lysosomal dysfunction in lipofuscin accumulation and its consequences, particularly for retinal pigment epithelium (RPE). Next, the fluorescence of lipofuscin, spectral changes induced by oxidation, and its contribution to retinal fluorescence are discussed. This is followed by reviewing recent developments in fluorescence imaging of the retina and the current evidence on the prognostic value of retinal fluorescence for the progression of age-related macular degeneration (AMD), the major blinding disease affecting elderly people in developed countries. The evidence of lipofuscin oxidation in vivo and the evidence of increased oxidative damage in AMD retina ex vivo lead to the conclusion that imaging of spectral characteristics of lipofuscin fluorescence may serve as a useful biomarker of oxidative damage, which can be helpful in assessing the efficacy of potential antioxidant therapies in retinal degenerations associated with accumulation of lipofuscin and increased oxidative stress. Finally, amendments to currently used fluorescence imaging instruments are suggested to be more sensitive and specific for imaging spectral characteristics of lipofuscin fluorescence.
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Affiliation(s)
- Małgorzata B. Różanowska
- School of Optometry and Vision Sciences, College of Biomedical and Life Sciences, Cardiff University, Maindy Road, Cardiff CF24 4HQ, Wales, UK;
- Cardiff Institute for Tissue Engineering and Repair (CITER), Redwood Building, King Edward VII Avenue, Cardiff CF10 3NB, Wales, UK
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2
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Hammer M, Simon R, Meller D, Klemm M. Combining fluorescence lifetime with spectral information in fluorescence lifetime imaging ophthalmoscopy (FLIO). BIOMEDICAL OPTICS EXPRESS 2022; 13:5483-5494. [PMID: 36425633 PMCID: PMC9664887 DOI: 10.1364/boe.457946] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 04/05/2022] [Accepted: 04/07/2022] [Indexed: 06/01/2023]
Abstract
Fluorescence lifetime imaging ophthalmoscopy (FLIO) provides information on fluorescence lifetimes in two spectral channels as well as the peak emission wavelength (PEW) of the fluorescence. Here, we combine these measures in an integral three-dimensional lifetime-PEW metric vector and determine a normal range for this vector from measurements in young healthy subjects. While for these control subjects 97 (±8) % (median (interquartile range)) of all para-macular pixels were covered by this normal vector range, it was 67 (±55) % for the elderly healthy, 38 (±43) % for age-related macular degeneration (AMD)-suspect subjects, and only 6 (±4) % for AMD patients. The vectors were significantly different for retinal pigment epithelium (RPE) lesions in AMD patients from that of non-affected tissue (p < 0.001). Lifetime- PEW plots allowed to identify possibly pathologic fundus areas by fluorescence parameters outside a 95% quantile per subject. In a patient follow-up, changes in fluorescence parameters could be traced in the lifetime-PEW metric, showing their change over disease progression.
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Affiliation(s)
- Martin Hammer
- Department of Ophthalmology, University Hospital Jena, Jena, Germany
- Center for Medical Optics and Photonics, Univ. of Jena, Jena, Germany
| | - Rowena Simon
- Department of Ophthalmology, University Hospital Jena, Jena, Germany
| | - Daniel Meller
- Department of Ophthalmology, University Hospital Jena, Jena, Germany
| | - Matthias Klemm
- Institute of Biomedical Engineering and Informatics, Technical Univ. Ilmenau, Ilmenau, Germany
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Marchese A, Cicinelli MV, Amato A, Bandello F, Gupta V, Miserocchi E, Agarwal A. The Next Steps in Ocular Imaging in Uveitis. Ocul Immunol Inflamm 2022; 31:785-792. [PMID: 35412936 DOI: 10.1080/09273948.2022.2055579] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
PURPOSE To describe the future steps and advances in the field of ocular imaging in uveitis. METHODS Narrative review. RESULTS There have been numerous advances in the field of imaging in uveitis in the past decade. Advanced techniques of imaging of the vitreous, vitreo-retinal interface, retinochoroid, and the sclera can provide significant information that helps in understanding the disease pathogenesis and manifestations. Imaging also helps in establishing a diagnosis in challenging cases, along with the laboratory and other assays. Notable developments in ocular imaging include wide-field and ultra-wide field imaging (including angiographies), automated quantification of the retinochoroidal vasculature using optical coherence tomography (OCT) and OCT angiography, quantification of vitreous cells, and intraoperative use of imaging in uveitis, among others. CONCLUSIONS We have summarized several technological achievements in ocular imaging in the field of uveitis and provided insights into the potential future developments.
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Affiliation(s)
- Alessandro Marchese
- Department of Ophthalmology, School of Medicine, Vita-Salute San Raffaele University, Milan, Italy.,Department of Ophthalmology, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Maria Vittoria Cicinelli
- Department of Ophthalmology, School of Medicine, Vita-Salute San Raffaele University, Milan, Italy.,Department of Ophthalmology, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Alessia Amato
- Department of Ophthalmology, School of Medicine, Vita-Salute San Raffaele University, Milan, Italy.,Department of Ophthalmology, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Francesco Bandello
- Department of Ophthalmology, School of Medicine, Vita-Salute San Raffaele University, Milan, Italy.,Department of Ophthalmology, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Vishali Gupta
- Department of Ophthalmology, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
| | | | - Aniruddha Agarwal
- Department of Ophthalmology, The Eye Institute, Cleveland Clinic Abu Dhabi, Abu Dhabi, United Arab Emirates (UAE)
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Schultz R, Schwanengel L, Klemm M, Meller D, Hammer M. Spectral fundus autofluorescence peak emission wavelength in ageing and AMD. Acta Ophthalmol 2021; 100:e1223-e1231. [PMID: 34850573 DOI: 10.1111/aos.15070] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 10/26/2021] [Accepted: 11/19/2021] [Indexed: 01/18/2023]
Abstract
PURPOSE To investigate the spectral characteristics of fundus autofluorescence (FAF) in AMD patients and controls. METHODS Fundus autofluorescence spectral characteristics was described by the peak emission wavelength (PEW) of the spectra. Peak emission wavelength (PEW) was derived from the ratio of FAF recordings in two spectral channels at 500-560 nm and 560-720 nm by fluorescence lifetime imaging ophthalmoscopy. The ratio of FAF intensity in both channels was related to PEW by a calibration procedure. Peak emission wavelength (PEW) measurements were done in 44 young (mean age: 24.0 ± 3.8 years) and 18 elderly (mean age: 67.5 ± 10.2 years) healthy subjects as well as 63 patients with AMD (mean age: 74.0 ± 7.3 years) in each pixel of a 30° imaging field. The values were averaged over the central area, the inner and the outer ring of the ETDRS grid. RESULTS There was no significant difference between PEW in young and elderly controls. However, PEW was significantly shorter in AMD patients (ETDRS grid centre: 571 ± 26 nm versus 599 ± 17 nm for elderly controls, inner ring: 596 ± 17 nm versus 611 ± 11 nm, outer ring: 602 ± 16 nm versus 614 ± 11 nm). After a mean follow-up time of 50.8 ± 10.8 months, the PEW in the patients decreased significantly by 9 ± 19 nm in the inner ring of the grid. Patients, showing progression to atrophic AMD in the follow up, had significantly (p ≤ 0.018) shorter PEW at baseline than non-progressing patients. CONCLUSIONS Peak emission wavelength (PEW) is related to AMD pathology and might be a diagnostic marker in AMD. Possibly, a short PEW can predict progression to retinal and/or pigment epithelium atrophy.
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Affiliation(s)
- Rowena Schultz
- Department of Ophthalmology University Hospital Jena Jena Germany
| | | | - Matthias Klemm
- Institute of Biomedical Engineering and Informatics Technical Univ. Ilmenau Ilmenau Germany
| | - Daniel Meller
- Department of Ophthalmology University Hospital Jena Jena Germany
| | - Martin Hammer
- Department of Ophthalmology University Hospital Jena Jena Germany
- Center for Medical Optics and Photonics Univ. of Jena Jena Germany
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Podlipec R, Mur J, Petelin J, Štrancar J, Petkovšek R. Method for controlled tissue theranostics using a single tunable laser source. BIOMEDICAL OPTICS EXPRESS 2021; 12:5881-5893. [PMID: 34692222 PMCID: PMC8515989 DOI: 10.1364/boe.428467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 08/07/2021] [Accepted: 08/13/2021] [Indexed: 06/13/2023]
Abstract
Tissue diseases and related disorders need to be first recognized using diagnostic methods and then later treated by therapeutic methods-a joint procedure called theranostics. One of the main challenges in the field of retinal therapies remains in the success of the treatment, typically improving the local metabolism, by sparing the surrounding tissue and with the immediate information of the laser effect. In our study, we present a concept for real-time controlled tissue theranostics on a proof-of-concept study capable of using a single tunable ps laser source (in terms of irradiance, fluence, and repetition rate), done on ex-vivo human retinal pigment epithelium. We have found autofluorescence intensity and lifetime imaging diagnostics very promising for the recognition and quantification of laser effects ranging from selective non-destructive molecular tissue modification to complete tissue ablation. The main novelty of our work presents the developed algorithm for optimized theranostics based on the model function used to quantify laser-induced tissue changes through the diagnostics descriptors, fluorescence lifetime and fluorescence intensity parameters. This approach, together with the operation of the single adaptable laser source, can serve as a new theranostics method in personalized medicine in the future not only limited to treat retinal diseases.
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Affiliation(s)
- Rok Podlipec
- Laboratory of Biophysics, Condensed Matter Physics Department, Jožef Stefan Institute, Jamova cesta 39, Ljubljana, Slovenia
- Helmholtz-Zentrum Dresden-Rossendorf e.V., Ion Beam Center, Bautzner Landstraße 400, Dresden 01328, Germany
| | - Jaka Mur
- Faculty of Mechanical Engineering, University of Ljubljana, Aškerčeva 6, Ljubljana, Slovenia
| | - Jaka Petelin
- Faculty of Mechanical Engineering, University of Ljubljana, Aškerčeva 6, Ljubljana, Slovenia
| | - Janez Štrancar
- Laboratory of Biophysics, Condensed Matter Physics Department, Jožef Stefan Institute, Jamova cesta 39, Ljubljana, Slovenia
| | - Rok Petkovšek
- Faculty of Mechanical Engineering, University of Ljubljana, Aškerčeva 6, Ljubljana, Slovenia
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Pole C, Ameri H. Fundus Autofluorescence and Clinical Applications. J Ophthalmic Vis Res 2021; 16:432-461. [PMID: 34394872 PMCID: PMC8358768 DOI: 10.18502/jovr.v16i3.9439] [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] [Received: 04/01/2021] [Accepted: 05/01/2021] [Indexed: 12/20/2022] Open
Abstract
Fundus autofluorescence (FAF) has allowed in vivo mapping of retinal metabolic derangements and structural changes not possible with conventional color imaging. Incident light is absorbed by molecules in the fundus, which are excited and in turn emit photons of specific wavelengths that are captured and processed by a sensor to create a metabolic map of the fundus. Studies on the growing number of FAF platforms has shown each may be suited to certain clinical scenarios. Scanning laser ophthalmoscopes, fundus cameras, and modifications of these each have benefits and drawbacks that must be considered before and after imaging to properly interpret the images. Emerging clinical evidence has demonstrated the usefulness of FAF in diagnosis and management of an increasing number of chorioretinal conditions, such as age-related macular degeneration, central serous chorioretinopathy, retinal drug toxicities, and inherited retinal degenerations such as retinitis pigmentosa and Stargardt disease. This article reviews commercial imaging platforms, imaging techniques, and clinical applications of FAF.
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Affiliation(s)
- Cameron Pole
- Retina Division, USC Roski Eye Institute, Keck School of Medicine, University of South California, Los Angeles, CA, USA
| | - Hossein Ameri
- Retina Division, USC Roski Eye Institute, Keck School of Medicine, University of South California, Los Angeles, CA, USA
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Vujosevic S, Toma C, Sarao V, Veritti D, Brambilla M, Muraca A, De Cillà S, Villani E, Nucci P, Lanzetta P. Color Fundus Autofluorescence to Determine Activity of Macular Neovascularization in Age-Related Macular Degeneration. Transl Vis Sci Technol 2021; 10:33. [PMID: 34003918 PMCID: PMC7910646 DOI: 10.1167/tvst.10.2.33] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose To evaluate with color fundus autofluorescence (FAF) different lesion components of macular neovascularization (MNV) secondary to age-related macular degeneration (AMD) and to assess its activity. Methods In total, 137 eyes (102 patients) with MNV underwent a complete eye examination, including color fundus photography, optical coherence tomography (OCT), OCT angiography, and confocal color FAF, with an excitation wavelength at 450 nm. Each image was imported into a custom-image analysis software for quantitative estimation of emission wavelength and green and red emission fluorescence (GEFC/REFC) intensity, considering both single components of neovascular AMD and different MNV types (type 1 and type 2 MNV, active and inactive MNV). Results Subretinal fluid (SRF) had significantly higher values of GEFC (P = 0.008 and P = 0.0004) and REFC intensity (P = 0.005 and P = 0.0003) versus fibrosis and atrophy. The emission wavelength from SRF was lower compared to atrophy (P = 0.024) but not to fibrosis (P = 0.46). No significant differences were detected between type 1 and 2 MNV. Considering active versus inactive MNVs, a difference was detected for all evaluated parameters (P < 0.001). Mean FAF wavelength of both MNV with SRF and intraretinal fluid (IRF) was lower versus inactive MNV (P < 0.001 and P = 0.005). MNV with SRF (P < 0.001) had higher values of GEFC and REFC versus inactive MNV (P < 0.001). MNV with IRF had higher values of GEFC versus inactive MNV (P = 0.05). Conclusions Quantitative color FAF can differentiate active versus inactive MNV, whereas no differences were found between type 1 and type 2 MNV. If these data can be further confirmed, color FAF may be useful for automatic detection of active MNV in AMD and as a guide for treatment. Translational Relevance Automatic quantitative evaluation of green and red emission components of FAF in AMD can help determine the activity of MNV and guide the treatment.
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Affiliation(s)
- Stela Vujosevic
- Eye Clinic IRCCS MultiMedica, Milan, Italy.,University Hospital Maggiore della Carità, Eye Clinic, Novara, Italy
| | - Caterina Toma
- University Hospital Maggiore della Carità, Eye Clinic, Novara, Italy
| | - Valentina Sarao
- Department of Medicine-Ophthalmology, University of Udine, Udine, Italy.,Istituto Europeo di Microchirurgia Oculare-IEMO, Udine, Italy
| | - Daniele Veritti
- Department of Medicine-Ophthalmology, University of Udine, Udine, Italy
| | - Marco Brambilla
- Department of Medical Physics, University Hospital Maggiore Della Carità, Novara, Italy
| | - Andrea Muraca
- University Hospital Maggiore della Carità, Eye Clinic, Novara, Italy
| | - Stefano De Cillà
- University Hospital Maggiore della Carità, Eye Clinic, Novara, Italy.,Department of Health Sciences, University East Piedmont "A. Avogadro," Novara, Italy
| | - Edoardo Villani
- Eye Clinic IRCCS MultiMedica, Milan, Italy.,Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - Paolo Nucci
- Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - Paolo Lanzetta
- Department of Medicine-Ophthalmology, University of Udine, Udine, Italy.,Istituto Europeo di Microchirurgia Oculare-IEMO, Udine, Italy
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Vujosevic S, Toma C, Nucci P, Brambilla M, De Cillà S. Quantitative Color Fundus Autofluorescence in Patients with Diabetes Mellitus. J Clin Med 2020; 10:E48. [PMID: 33375699 PMCID: PMC7796312 DOI: 10.3390/jcm10010048] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 12/07/2020] [Accepted: 12/19/2020] [Indexed: 01/09/2023] Open
Abstract
A new short wavelength confocal blue-light 450 nm-fundus autofluorescence (color-FAF) allows for visualization of minor fluorophores (e.g., advanced glycation end products, AGEs), besides lipofuscin. The aim of the present pilot study was to quantitatively evaluate color-FAF in patients with diabetes mellitus (DM) and to correlate these data with different stages of retinal disease severity. Optical coherence tomography and color-FAF images of 193 patients/eyes and 18 controls were analyzed using a custom software for quantification of the long (red) and short (green) wavelength components of the emission spectrum (REFC/GEFC). Measurements were performed in nine quadrants of the 6-mm ETDRS macular grid. Foveal GEFC and REFC intensities were higher in patients with DM compared to controls (p = 0.015 and p = 0.006 respectively) and in eyes with center involving diabetic macular edema (DME) compared to eyes without DME (p < 0.001). A positive correlation was found between GEFC and REFC intensities and central retinal thickness, r = 0.37 (p < 0.001) and r = 0.42 (p < 0.001), respectively. No differences were found in color-FAF among different DR severity groups. Quantitative color-FAF could become helpful for the metabolic evaluation of retina in patients with DM and in DME; however, further histologic and immunohistochemical studies on distribution of different retinal fluorophores in DM are needed to better understand its role.
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Affiliation(s)
- Stela Vujosevic
- Eye Clinic, IRCCS MultiMedica, 20123 Milan, Italy
- University Hospital Maggiore della Carità, Eye Clinic, 28100 Novara, Italy; (C.T.); (S.D.C.)
| | - Caterina Toma
- University Hospital Maggiore della Carità, Eye Clinic, 28100 Novara, Italy; (C.T.); (S.D.C.)
| | - Paolo Nucci
- Department of Clinical Sciences and Community Health, University of Milan, 20123 Milan, Italy;
| | - Marco Brambilla
- Department of Medical Physics, University Hospital Maggiore della Carità, 28100 Novara, Italy;
| | - Stefano De Cillà
- University Hospital Maggiore della Carità, Eye Clinic, 28100 Novara, Italy; (C.T.); (S.D.C.)
- Department of Health Sciences, University East Piedmont “A. Avogadro”, 28100 Novara, Italy
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