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Chang S, Yang J, Novoseltseva A, Abdelhakeem A, Hyman M, Fu X, Li C, Chen S, Augustinack JC, Magnain C, Fischl B, Mckee AC, Boas DA, Chen IA, Wang H. Multi-Scale Label-Free Human Brain Imaging with Integrated Serial Sectioning Polarization Sensitive Optical Coherence Tomography and Two-Photon Microscopy. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2303381. [PMID: 37882348 PMCID: PMC10724383 DOI: 10.1002/advs.202303381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 08/29/2023] [Indexed: 10/27/2023]
Abstract
The study of aging and neurodegenerative processes in the human brain requires a comprehensive understanding of cytoarchitectonic, myeloarchitectonic, and vascular structures. Recent computational advances have enabled volumetric reconstruction of the human brain using thousands of stained slices, however, tissue distortions and loss resulting from standard histological processing have hindered deformation-free reconstruction. Here, the authors describe an integrated serial sectioning polarization-sensitive optical coherence tomography (PSOCT) and two photon microscopy (2PM) system to provide label-free multi-contrast imaging of intact brain structures, including scattering, birefringence, and autofluorescence of human brain tissue. The authors demonstrate high-throughput reconstruction of 4 × 4 × 2cm3 sample blocks and simple registration between PSOCT and 2PM images that enable comprehensive analysis of myelin content, vascular structure, and cellular information. The high-resolution 2PM images provide microscopic validation and enrichment of the cellular information provided by the PSOCT optical properties on the same sample, revealing the densely packed fibers, capillaries, and lipofuscin-filled cell bodies in the cortex and white matter. It is shown that the imaging system enables quantitative characterization of various pathological features in aging process, including myelin degradation, lipofuscin accumulation, and microvascular changes, which opens up numerous opportunities in the study of neurodegenerative diseases in the future.
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Affiliation(s)
- Shuaibin Chang
- Department of Electrical and Computer EngineeringBoston University8 St Mary's StBoston02215USA
| | - Jiarui Yang
- Department of Biomedical EngineeringBoston University44 Cummington MallBoston02215USA
| | - Anna Novoseltseva
- Department of Biomedical EngineeringBoston University44 Cummington MallBoston02215USA
| | - Ayman Abdelhakeem
- Department of Electrical and Computer EngineeringBoston University8 St Mary's StBoston02215USA
| | - Mackenzie Hyman
- Department of Biomedical EngineeringBoston University44 Cummington MallBoston02215USA
| | - Xinlei Fu
- Department of Mechanical EngineeringThe Chinese University of Hong KongHong Kong999077China
| | - Chenglin Li
- Department of Mechanical EngineeringThe Chinese University of Hong KongHong Kong999077China
| | - Shih‐Chi Chen
- Department of Mechanical EngineeringThe Chinese University of Hong KongHong Kong999077China
| | - Jean C. Augustinack
- Department of RadiologyMassachusetts General HospitalA.A. Martinos Center for Biomedical Imaging13th StreetBoston02129USA
| | - Caroline Magnain
- Department of RadiologyMassachusetts General HospitalA.A. Martinos Center for Biomedical Imaging13th StreetBoston02129USA
| | - Bruce Fischl
- Department of RadiologyMassachusetts General HospitalA.A. Martinos Center for Biomedical Imaging13th StreetBoston02129USA
| | - Ann C. Mckee
- VA Boston Healthcare SystemU.S. Department of Veteran AffairsBoston02132USA
- Boston University Chobanian and Avedisian School of MedicineBoston University Alzheimer's Disease Research Center and CTE CenterBoston02118USA
- Department of NeurologyBoston University Chobanian and Avedisian School of MedicineBoston02118USA
- Department of Pathology and Laboratory MedicineBoston University Chobanian and Avedisian School of MedicineBoston02118USA
- VA Bedford Healthcare SystemU.S. Department of Veteran AffairsBedfordMA01730‐1114USA
| | - David A. Boas
- Department of Electrical and Computer EngineeringBoston University8 St Mary's StBoston02215USA
- Department of Biomedical EngineeringBoston University44 Cummington MallBoston02215USA
| | - Ichun Anderson Chen
- Department of Biomedical EngineeringBoston University44 Cummington MallBoston02215USA
| | - Hui Wang
- Department of RadiologyMassachusetts General HospitalA.A. Martinos Center for Biomedical Imaging13th StreetBoston02129USA
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Chang S, Yang J, Novoseltseva A, Fu X, Li C, Chen SC, Augustinack JC, Magnain C, Fischl B, Mckee AC, Boas DA, Chen IA, Wang H. Multi-Scale Label-free Human Brain Imaging with Integrated Serial Sectioning Polarization Sensitive Optical Coherence Tomography and Two-Photon Microscopy. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.22.541785. [PMID: 37293092 PMCID: PMC10245911 DOI: 10.1101/2023.05.22.541785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The study of neurodegenerative processes in the human brain requires a comprehensive understanding of cytoarchitectonic, myeloarchitectonic, and vascular structures. Recent computational advances have enabled volumetric reconstruction of the human brain using thousands of stained slices, however, tissue distortions and loss resulting from standard histological processing have hindered deformation-free reconstruction of the human brain. The development of a multi-scale and volumetric human brain imaging technique that can measure intact brain structure would be a major technical advance. Here, we describe the development of integrated serial sectioning Polarization Sensitive Optical Coherence Tomography (PSOCT) and Two Photon Microscopy (2PM) to provide label-free multi-contrast imaging, including scattering, birefringence and autofluorescence of human brain tissue. We demonstrate that high-throughput reconstruction of 4×4×2cm3 sample blocks and simple registration of PSOCT and 2PM images enable comprehensive analysis of myelin content, vascular structure, and cellular information. We show that 2μm in-plane resolution 2PM images provide microscopic validation and enrichment of the cellular information provided by the PSOCT optical property maps on the same sample, revealing the sophisticated capillary networks and lipofuscin filled cell bodies across the cortical layers. Our method is applicable to the study of a variety of pathological processes, including demyelination, cell loss, and microvascular changes in neurodegenerative diseases such as Alzheimer's disease (AD) and Chronic Traumatic Encephalopathy (CTE).
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Affiliation(s)
- Shuaibin Chang
- Department of Electrical and Computer Engineering, Boston University, 8 St Mary’s St, Boston 02215, USA
| | - Jiarui Yang
- Department of Biomedical Engineering, Boston University, 44 Cummington Mall, Boston 02215, USA
| | - Anna Novoseltseva
- Department of Biomedical Engineering, Boston University, 44 Cummington Mall, Boston 02215, USA
| | - Xinlei Fu
- The Chinese University of Hong Kong, Department of Mechanical Engineering, Hong Kong Special Administrative Region, China
| | - Chenglin Li
- The Chinese University of Hong Kong, Department of Mechanical Engineering, Hong Kong Special Administrative Region, China
| | - Shih-Chi Chen
- The Chinese University of Hong Kong, Department of Mechanical Engineering, Hong Kong Special Administrative Region, China
| | - Jean C. Augustinack
- Department of Radiology, Massachusetts General Hospital, A.A. Martinos Center for Biomedical Imaging, 13th Street, Boston 02129, USA
| | - Caroline Magnain
- Department of Radiology, Massachusetts General Hospital, A.A. Martinos Center for Biomedical Imaging, 13th Street, Boston 02129, USA
| | - Bruce Fischl
- Department of Radiology, Massachusetts General Hospital, A.A. Martinos Center for Biomedical Imaging, 13th Street, Boston 02129, USA
| | - Ann C. Mckee
- VA Boston Healthcare System, U.S. Department of Veteran Affairs
- Boston University Chobanian and Avedisian School of Medicine, Boston University Alzheimer’s Disease Research Center and CTE Center
- Department of Neurology, Boston University Chobanian and Avedisian School of Medicine
- Department of Pathology and Laboratory Medicine, Boston University Chobanian and Avedisian School of Medicine
- VA Bedford Healthcare System, U.S. Department of Veteran Affairs, Bedford, MA, USA
| | - David A. Boas
- Department of Electrical and Computer Engineering, Boston University, 8 St Mary’s St, Boston 02215, USA
- Department of Biomedical Engineering, Boston University, 44 Cummington Mall, Boston 02215, USA
| | - Ichun Anderson Chen
- Department of Biomedical Engineering, Boston University, 44 Cummington Mall, Boston 02215, USA
| | - Hui Wang
- Department of Radiology, Massachusetts General Hospital, A.A. Martinos Center for Biomedical Imaging, 13th Street, Boston 02129, USA
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Schweitzer D, Haueisen J, Klemm M. Suppression of natural lens fluorescence in fundus autofluorescence measurements: review of hardware solutions. BIOMEDICAL OPTICS EXPRESS 2022; 13:5151-5170. [PMID: 36425615 PMCID: PMC9664869 DOI: 10.1364/boe.462559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 07/25/2022] [Accepted: 07/25/2022] [Indexed: 06/16/2023]
Abstract
Fluorescence lifetime imaging ophthalmoscopy (FLIO), a technique for investigating metabolic changes in the eye ground, can reveal the first signs of diseases related to metabolism. The fluorescence of the natural lens overlies the fundus fluorescence. Although the influence of natural lens fluorescence can be somewhat decreased with mathematical models, excluding this influence during the measurement by using hardware enables more exact estimation of the fundus fluorescence. Here, we analyze four 1-photon excitation hardware solutions to suppress the influence of natural lens fluorescence: aperture stop separation, confocal scanning laser ophthalmoscopy, combined confocal scanning laser ophthalmoscopy and aperture stop separation, and dual point confocal scanning laser ophthalmoscopy. The effect of each principle is demonstrated in examples. The best suppression is provided by the dual point principle, realized with a confocal scanning laser ophthalmoscope. In this case, in addition to the fluorescence of the whole eye, the fluorescence of the anterior part of the eye is detected from a non-excited spot of the fundus. The intensity and time-resolved fluorescence spectral data of the fundus are derived through the subtraction of the simultaneously measured fluorescence of the excited and non-excited spots. Advantages of future 2-photon fluorescence excitation are also discussed. This study provides the first quantitative evaluation of hardware principles to suppress the fluorescence of the natural lens during measurements of fundus autofluorescence.
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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
| | - M. Klemm
- Institute of Biomedical Engineering and Informatics, POB 100565, 98694 Ilmenau, Germany
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Bueno JM, Cruz-Castillo R, Avilés-Trigueros M, Bautista-Elivar N. Arrangement of the photoreceptor mosaic in a diabetic rat model imaged with multiphoton microscopy. BIOMEDICAL OPTICS EXPRESS 2020; 11:4901-4914. [PMID: 33014589 PMCID: PMC7510868 DOI: 10.1364/boe.399835] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 07/23/2020] [Accepted: 07/24/2020] [Indexed: 06/11/2023]
Abstract
Diabetic retinopathy (DR) is defined as a microvascular pathology. However, some data have suggested that the retinal photoreceptors (PRs) might be important in the pathogenesis of this ocular disease. In this study the organization of the PRs in control and diabetic-induced rats was compared using multiphoton microscopy. The PR mosaic was imaged at different locations in non-stained retinas. The density of PRs was directly quantified from cell counting. The spatially resolved density presents a double-slope pattern (from the central retina towards the periphery) in both healthy and pathological samples, although the values for the latter were significantly lower all across the retina. Moreover, Voronoi analysis was performed to explore changes in PR topography. In control specimens a hexagonally packed structure was dominant. However, despite the non-controlled effects of the disease in retinal structures, this PR regularity was fairly maintained in diabetic retinas.
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Affiliation(s)
- Juan M. Bueno
- Laboratorio de Óptica, Instituto Universitario de Investigación en Óptica y Nanofísica, Universidad de Murcia, Murcia, Spain
| | - Ricardo Cruz-Castillo
- Área Académica de Matemáticas y Física, Instituto de Ciencias Básicas e Ingeniería, Universidad Autónoma del Estado de Hidalgo, Hidalgo, Mexico
| | - Marcelino Avilés-Trigueros
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia e Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca, “Campus Mare Nostrum” de Excelencia International, Murcia, Spain
| | - Nazario Bautista-Elivar
- Departamento de Ingeniería Eléctrica, Tecnológico Nacional de México, Instituto Tecnológico de Pachuca, Hidalgo, Mexico
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Miura Y. Two-Photon Microscopy (TPM) and Fluorescence Lifetime Imaging Microscopy (FLIM) of Retinal Pigment Epithelium (RPE) of Mice In Vivo. Methods Mol Biol 2019; 1753:73-88. [PMID: 29564782 DOI: 10.1007/978-1-4939-7720-8_5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Retinal pigment epithelium (RPE), a monolayer of epithelial cells located between the neural retina and the choroid, plays a significant role in the maintenance of retinal function. Its in vivo imaging is still technically challenging in human eye. With the mouse eye, there is a possibility to look into the RPE through the sclera using two-photon microscopy (TPM). TPM is a two photon-excited nonlinear fluorescence microscopy that enables the observation of deep tissues up to several hundred micrometers. Since the simultaneous absorption of two photons occurs only at the focal plane, spatial resolution of the TPM is quite high, such that pinhole as used in a confocal microscope is not necessary. TPM enables observation of autofluorescence at the cellular level, and thus may provide new insights into the fluorescent molecules in/around RPE cells.The combination of TPM with fluorescence lifetime imaging microscopy (FLIM) may expand the breadth of information about cells and tissues. Fluorescence lifetime is a fluorophore-specific property, which is independent of fluorescence intensity and changes with the alteration of molecular environment. FLIM may have therefore the potentials to distinguish different fluorophores and to indicate the change in the environment of a fluorophore. Some energy metabolisms-related intracellular fluorophores, such as NADH (nicotinamide adenine dinucleotide) and FAD (flavin adenine dinucleotide), show characteristic fluorescence lifetimes that shift under different molecular environments, and thus their fluorescence lifetime have been used to indicate cell energy metabolic states. These nonlabeling imaging methods offer us the opportunity to engage in the study of the RPE in vivo as well as in vitro both in morphological as well as metabolic aspects.
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Affiliation(s)
- Yoko Miura
- Institute of Biomedical Optics, University of Lübeck, Lübeck, Germany. .,Department of Ophthalmology, University of Lübeck, Lübeck, Germany.
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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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7
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In vivo two-photon imaging of retina in rabbits and rats. Exp Eye Res 2018; 166:40-48. [DOI: 10.1016/j.exer.2017.04.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 04/25/2017] [Accepted: 04/25/2017] [Indexed: 11/21/2022]
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Stremplewski P, Komar K, Palczewski K, Wojtkowski M, Palczewska G. Periscope for noninvasive two-photon imaging of murine retina in vivo. BIOMEDICAL OPTICS EXPRESS 2015; 6:3352-61. [PMID: 26417507 PMCID: PMC4574663 DOI: 10.1364/boe.6.003352] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Revised: 08/01/2015] [Accepted: 08/02/2015] [Indexed: 05/18/2023]
Abstract
Two-photon microscopy allows visualization of subcellular structures in the living animal retina. In previously reported experiments it was necessary to apply a contact lens to each subject. Extending this technology to larger animals would require fitting a custom contact lens to each animal and cumbersome placement of the living animal head on microscope stage. Here we demonstrate a new device, periscope, for coupling light energy into mouse eye and capturing emitted fluorescence. Using this periscope we obtained images of the RPE and their subcellular organelles, retinosomes, with larger field of view than previously reported. This periscope provides an interface with a commercial microscope, does not require contact lens and its design could be modified to image retina in larger animals.
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Affiliation(s)
- Patrycjusz Stremplewski
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Torun, Grudziadzka 5, 87-100 Torun, Poland
| | - Katarzyna Komar
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Torun, Grudziadzka 5, 87-100 Torun, Poland
| | - Krzysztof Palczewski
- Department of Pharmacology, Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Maciej Wojtkowski
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Torun, Grudziadzka 5, 87-100 Torun, Poland
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Palczewska G, Golczak M, Williams DR, Hunter JJ, Palczewski K. Endogenous fluorophores enable two-photon imaging of the primate eye. Invest Ophthalmol Vis Sci 2014; 55:4438-47. [PMID: 24970255 DOI: 10.1167/iovs.14-14395] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
PURPOSE Noninvasive two-photon imaging of a living mammalian eye can reveal details of molecular processes in the retina and RPE. Retinyl esters and all-trans-retinal condensation products are two types of retinoid fluorophores present in these tissues. We measured the content of these two types of retinoids in monkey and human eyes to validate the potential of two-photon imaging for monitoring retinoid changes in human eyes. METHODS Two-photon microscopy (TPM) was used to visualize excised retina from monkey eyes. Retinoid composition and content in human and monkey eyes were quantified by HPLC and mass spectrometry (MS). RESULTS Clear images of inner and outer segments of rods and cones were obtained in primate eyes at different eccentricities. Fluorescence spectra from outer segments revealed a maximum emission at 480 nm indicative of retinols and their esters. In cynomolgus monkey and human retinal extracts, retinyl esters existed predominantly in the 11-cis configuration along with notable levels of 11-cis-retinol, a characteristic of cone-enriched retinas. Average amounts of di-retinoid-pyridinium-ethanolamine (A2E) in primate and human eyes were 160 and 225 pmol/eye, respectively. CONCLUSIONS These data show that human retina contains sufficient amounts of retinoids for two-photon excitation imaging. Greater amounts of 11-cis-retinyl esters relative to rodent retinas contribute to the fluorescence signal from both monkey and human eyes. These observations indicate that TPM imaging found effective in mice could detect early age- and disease-related changes in human retina.
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Affiliation(s)
| | - Marcin Golczak
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio, United States
| | - David R Williams
- Center for Visual Science, University of Rochester, Rochester, New York, United States The Institute of Optics, University of Rochester, Rochester, New York, United States
| | - Jennifer J Hunter
- Center for Visual Science, University of Rochester, Rochester, New York, United States Flaum Eye Institute, University of Rochester, Rochester, New York, United States Department of Biomedical Engineering, University of Rochester, Rochester, New York, United States
| | - Krzysztof Palczewski
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio, United States
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Masihzadeh O, Ammar DA, Kahook MY, Lei TC. Coherent anti-stokes Raman scattering (CARS) microscopy: a novel technique for imaging the retina. Invest Ophthalmol Vis Sci 2013; 54:3094-101. [PMID: 23580484 DOI: 10.1167/iovs.13-11642] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To image the cellular and noncellular structures of the retina in an intact mouse eye without the application of exogenous fluorescent labels using noninvasive, nondestructive techniques. METHODS Freshly enucleated mouse eyes were imaged using two nonlinear optical techniques: coherent anti-Stokes Raman scattering (CARS) and two-photon autofluorescence (TPAF). Cross sectional transverse sections and sequential flat (en face) sagittal sections were collected from a region of sclera approximately midway between the limbus and optic nerve. Imaging proceeded from the surface of the sclera to a depth of ∼60 μm. RESULTS The fluorescent signal from collagen fibers within the sclera was evident in the TPAF channel; the scleral collagen fibers showed no organization and appeared randomly packed. The sclera contained regions lacking TPAF and CARS fluorescence of ∼3 to 15 μm in diameter that could represent small vessels or scleral fibroblasts. Intense punctate CARS signals from the retinal pigment epithelial layer were of a size and shape of retinyl storage esters. Rod outer segments could be identified by the CARS signal from their lipid-rich plasma membranes. CONCLUSIONS CARS microscopy can be used to image the outer regions of the mammalian retina without the use of a fluorescent dye or exogenously expressed recombinant protein. With technical advancements, CARS/TPAF may represent a new avenue for noninvasively imaging the retina and might complement modalities currently used in clinical practice.
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Affiliation(s)
- Omid Masihzadeh
- Department of Ophthalmology, University of Colorado Denver, Aurora, Colorado, USA
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Structured illumination microscopy of autofluorescent aggregations in human tissue. Micron 2011; 42:330-5. [DOI: 10.1016/j.micron.2010.06.016] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2010] [Revised: 06/16/2010] [Accepted: 06/17/2010] [Indexed: 11/19/2022]
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12
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Lu RW, Li YC, Ye T, Strang C, Keyser K, Curcio CA, Yao XC. Two-photon excited autofluorescence imaging of freshly isolated frog retinas. BIOMEDICAL OPTICS EXPRESS 2011; 2:1494-503. [PMID: 21698013 PMCID: PMC3114218 DOI: 10.1364/boe.2.001494] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2011] [Revised: 05/07/2011] [Accepted: 05/07/2011] [Indexed: 05/07/2023]
Abstract
The purpose of this study was to investigate cellular sources of autofluorescence signals in freshly isolated frog (Rana pipiens) retinas. Equipped with an ultrafast laser, a laser scanning two-photon excitation fluorescence microscope was employed for sub-cellular resolution examination of both sliced and flat-mounted retinas. Two-photon imaging of retinal slices revealed autofluorescence signals over multiple functional layers, including the photoreceptor layer (PRL), outer nuclear layer (ONL), outer plexiform layer (OPL), inner nuclear layer (INL), inner plexiform layer (IPL), and ganglion cell layer (GCL). Using flat-mounted retinas, depth-resolved imaging of individual retinal layers further confirmed multiple sources of autofluorescence signals. Cellular structures were clearly observed at the PRL, ONL, INL, and GCL. At the PRL, the autofluorescence was dominantly recorded from the intracellular compartment of the photoreceptors; while mixed intracellular and extracellular autofluorescence signals were observed at the ONL, INL, and GCL. High resolution autofluorescence imaging clearly revealed mosaic organization of rod and cone photoreceptors; and sub-cellular bright autofluorescence spots, which might relate to connecting cilium, was observed in the cone photoreceptors only. Moreover, single-cone and double-cone outer segments could be directly differentiated.
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Affiliation(s)
- Rong-Wen Lu
- Department of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Yi-Chao Li
- Department of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Tong Ye
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Christianne Strang
- Department of Vision Sciences, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Kent Keyser
- Department of Vision Sciences, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Christine A. Curcio
- Department of Ophthalmology, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Xin-Cheng Yao
- Department of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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Hunter JJ, Masella B, Dubra A, Sharma R, Yin L, Merigan WH, Palczewska G, Palczewski K, Williams DR. Images of photoreceptors in living primate eyes using adaptive optics two-photon ophthalmoscopy. BIOMEDICAL OPTICS EXPRESS 2010; 2:139-48. [PMID: 21326644 PMCID: PMC3028489 DOI: 10.1364/boe.2.000139] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2010] [Revised: 12/14/2010] [Accepted: 12/14/2010] [Indexed: 05/18/2023]
Abstract
In vivo two-photon imaging through the pupil of the primate eye has the potential to become a useful tool for functional imaging of the retina. Two-photon excited fluorescence images of the macaque cone mosaic were obtained using a fluorescence adaptive optics scanning laser ophthalmoscope, overcoming the challenges of a low numerical aperture, imperfect optics of the eye, high required light levels, and eye motion. Although the specific fluorophores are as yet unknown, strong in vivo intrinsic fluorescence allowed images of the cone mosaic. Imaging intact ex vivo retina revealed that the strongest two-photon excited fluorescence signal comes from the cone inner segments. The fluorescence response increased following light stimulation, which could provide a functional measure of the effects of light on photoreceptors.
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Affiliation(s)
- Jennifer J. Hunter
- Flaum Eye Institute, University of Rochester, 601 Elmwood Avenue, Rochester, NY, 14642, USA
- Center for Visual Science, University of Rochester, 601 Elmwood Avenue, Rochester, NY, 14642, USA
| | - Benjamin Masella
- Institute of Optics, University of Rochester, 601 Elmwood Avenue, Rochester, NY, 14642, USA
- Center for Visual Science, University of Rochester, 601 Elmwood Avenue, Rochester, NY, 14642, USA
| | - Alfredo Dubra
- Flaum Eye Institute, University of Rochester, 601 Elmwood Avenue, Rochester, NY, 14642, USA
- Center for Visual Science, University of Rochester, 601 Elmwood Avenue, Rochester, NY, 14642, USA
| | - Robin Sharma
- Institute of Optics, University of Rochester, 601 Elmwood Avenue, Rochester, NY, 14642, USA
- Center for Visual Science, University of Rochester, 601 Elmwood Avenue, Rochester, NY, 14642, USA
| | - Lu Yin
- Center for Visual Science, University of Rochester, 601 Elmwood Avenue, Rochester, NY, 14642, USA
| | - William H. Merigan
- Flaum Eye Institute, University of Rochester, 601 Elmwood Avenue, Rochester, NY, 14642, USA
- Center for Visual Science, University of Rochester, 601 Elmwood Avenue, Rochester, NY, 14642, USA
| | - Grazyna Palczewska
- Polgenix, Inc., 11000 Cedar Avenue, Suite 260, Cleveland, OH, 44106, USA
| | - Krzysztof Palczewski
- Polgenix, Inc., 11000 Cedar Avenue, Suite 260, Cleveland, OH, 44106, USA
- Department of Pharmacology, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, 44106, USA
| | - David R. Williams
- Flaum Eye Institute, University of Rochester, 601 Elmwood Avenue, Rochester, NY, 14642, USA
- Institute of Optics, University of Rochester, 601 Elmwood Avenue, Rochester, NY, 14642, USA
- Center for Visual Science, University of Rochester, 601 Elmwood Avenue, Rochester, NY, 14642, USA
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Bueno JM, Gualda EJ, Artal P. Adaptive optics multiphoton microscopy to study ex vivo ocular tissues. JOURNAL OF BIOMEDICAL OPTICS 2010; 15:066004. [PMID: 21198178 DOI: 10.1117/1.3505018] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
We develop an adaptive optics (AO) multiphoton microscope by incorporating a deformable mirror and a Hartmann-Shack wavefront sensor. The AO module operating in closed-loop is used to correct for the aberrations of the illumination laser beam. This increases the efficiency of the nonlinear processes in reducing tissue photodamage, improves contrast, and enhances lateral resolution in images of nonstained ocular tissues. In particular, the use of AO in the multiphoton microscope provides a better visualization of ocular structures, which are relevant in ophthalmology. This instrument might be useful to explore the possible connections between changes in ocular structures and the associated pathologies.
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Affiliation(s)
- Juan M Bueno
- Universidad de Murcia, Laboratorio de Óptica, Campus de Espinardo, Murcia, 30100 Spain.
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15
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Gualda EJ, Bueno JM, Artal P. Wavefront optimized nonlinear microscopy of ex vivo human retinas. JOURNAL OF BIOMEDICAL OPTICS 2010; 15:026007. [PMID: 20459252 DOI: 10.1117/1.3369001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
A multiphoton microscope incorporating a Hartmann-Shack (HS) wavefront sensor to control the ultrafast laser beam's wavefront aberrations has been developed. This instrument allowed us to investigate the impact of the laser beam aberrations on two-photon autofluorescence imaging of human retinal tissues. We demonstrated that nonlinear microscopy images are improved when laser beam aberrations are minimized by realigning the laser system cavity while wavefront controlling. Nonlinear signals from several human retinal anatomical features have been detected for the first time, without the need of fixation or staining procedures. Beyond the improved image quality, this approach reduces the required excitation power levels, minimizing the side effects of phototoxicity within the imaged sample. In particular, this may be important to study the physiology and function of the healthy and diseased retina.
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Affiliation(s)
- Emilio J Gualda
- Universidad de Murcia, Laboratorio de Optica, Campus de Espinardo (CiOyN), Murcia, 30100 Spain
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17
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Agopov M, Lomb L, La Schiazza O, Bille JF. Second harmonic generation imaging of the pig lamina cribrosa using a scanning laser ophthalmoscope-based microscope. Lasers Med Sci 2009; 24:787-92. [PMID: 19224333 DOI: 10.1007/s10103-008-0641-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2008] [Accepted: 12/23/2008] [Indexed: 10/21/2022]
Abstract
We describe a novel scanning laser ophthalmoscope (SLO)-based on a video-rate second harmonic generation imaging microscope. A titanium:sapphire femtosecond laser was coupled to a modified SLO. The laser beam was scanned over the sample, and the light produced by second harmonic generation (SHG) was collected for imaging at video-speed. The device was used for imaging the lamina cribrosa (LC) of enucleated pig eyes. A resolution comparable to that of commercial multiphoton microscopes was reached. The SHG images were used for determining the average pore size of the LC determined from the images; the pressure dependence of the pore size was studied by the artificial increasing of the hydrostatic pressure in the eye. A pressure increase of 44.3 mmHg enlarged the average pore size of 62 analyzed pores by a statistically significant amount. The relative pore growth was measured at four different pressure levels in 25 pores. The pressure was increased in 15 mmHg steps. A general tendency for monothonic growth was observed, although single pores grew by no means linearly.
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Affiliation(s)
- M Agopov
- Kirchhoff-Institut für Physik, INF 227, Heidelberg, Germany.
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