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Yuan Y, Dong M, Wen S, Yuan X, Zhou L. Retinal microcirculation: A window into systemic circulation and metabolic disease. Exp Eye Res 2024; 242:109885. [PMID: 38574944 DOI: 10.1016/j.exer.2024.109885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 04/01/2024] [Accepted: 04/02/2024] [Indexed: 04/06/2024]
Abstract
The retinal microcirculation system constitutes a unique terminal vessel bed of the systemic circulation, and its perfusion status is directly associated with the neural function of the retina. This vascular network, essential for nourishing various layers of the retina, comprises two primary microcirculation systems: the retinal microcirculation and the choroidal microcirculation, with each system supplying blood to distinct retinal layers and maintaining the associated neural function. The blood flow of those capillaries is regulated via different mechanisms. However, a range of internal and external factors can disrupt the normal architecture and blood flow within the retinal microcirculation, leading to several retinal pathologies, including diabetic retinopathy, macular edema, and vascular occlusions. Metabolic disturbances such as hyperglycemia, hypertension, and dyslipidemia are known to modify retinal microcirculation through various pathways. These alterations are observable in chronic metabolic conditions like diabetes, coronary artery disease, and cerebral microvascular disease due to advances in non-invasive or minimally invasive retinal imaging techniques. Thus, examination of the retinal microcirculation can provide insights into the progression of numerous chronic metabolic disorders. This review discusses the anatomy, physiology and pathophysiology of the retinal microvascular system, with a particular emphasis on the connections between retinal microcirculation and systemic circulation in both healthy states and in the context of prevalent chronic metabolic diseases.
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Affiliation(s)
- Yue Yuan
- Department of Endocrinology, Shanghai Pudong Hospital, Fudan University, Shanghai, 201399, China.
| | - Meiyuan Dong
- Department of Endocrinology, Shanghai Pudong Hospital, Fudan University, Shanghai, 201399, China; Graduate School of Hebei Medical University, Shijiazhuang, China.
| | - Song Wen
- Department of Endocrinology, Shanghai Pudong Hospital, Fudan University, Shanghai, 201399, China.
| | - Xinlu Yuan
- Department of Endocrinology, Shanghai Pudong Hospital, Fudan University, Shanghai, 201399, China.
| | - Ligang Zhou
- Department of Endocrinology, Shanghai Pudong Hospital, Fudan University, Shanghai, 201399, China; Graduate School of Hebei Medical University, Shijiazhuang, China; Shanghai Key Laboratory of Vascular Lesions Regulation and Remodeling, Shanghai Pudong Hospital, Shanghai, China.
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2
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Aung MH, Aleman TS, Garcia AS, McGeehan B, Ying GS, Avery RA. Stimulus type and duration affect magnitude and evolution of flicker-induced hyperemia measured by laser speckle flowgraphy at the optic disc and peripapillary vessels. Sci Rep 2024; 14:6659. [PMID: 38509194 PMCID: PMC10954713 DOI: 10.1038/s41598-024-57263-z] [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: 08/06/2023] [Accepted: 03/15/2024] [Indexed: 03/22/2024] Open
Abstract
Neurovascular coupling is a vital mechanism employed by the cerebrovascular system, including the eye, to regulate blood flow in periods of neuronal activation. This study aims to investigate if laser speckle flowgraphy (LSFG) can detect coupling response elicited by flickering light stimuli and how variations in stimulus type and duration can affect the magnitude and evolution of blood flow in the optic nerve head (ONH) and peripapillary vessels. Healthy adults were exposed to two types of 10-Hz flicker stimuli: a photopic negative response-like stimulus (PhNR-S) or a visual evoked potential-like stimulus (VEP-S)-each presented in separate 10- and 60-s epochs. Both PhNR-S and VEP-S significantly increased ONH blood flow (p < 0.001) immediately after flicker cessation, with a trend of 60-s stimuli (PhNR-S = 11.6%; VEP-S = 10.4%) producing a larger response than 10-s stimuli (PhNR-S = 7.5%; VEP-S = 6.2%). Moreover, exposure to 60-s stimuli elicited a significantly prolonged ONH hyperemic response, especially with PhNR-S. Lastly, stimulation with either 60-s stimuli elicited a robust increase in blood flow within the peripapillary arterioles (p < 0.01) and venules (p < 0.01) as well. Flicker stimulation with common visual electrophysiology stimuli (PhNR-S and VEP-S) induced a demonstrable increase in ONH and peripapillary vessel blood flow, which varied with flicker duration. Our results validate that LSFG is a robust method to quantify flicker-induced hyperemic responses and to study neurovascular coupling in humans.
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Affiliation(s)
- Moe H Aung
- Departments of Neurology, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA.
- Department of Ophthalmology, Dell Medical School at The University of Texas at Austin, Austin, TX, USA.
| | - Tomas S Aleman
- Department of Ophthalmology, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
- Division of Ophthalmology, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Arielle S Garcia
- Division of Ophthalmology, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Brendan McGeehan
- Department of Ophthalmology, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Gui-Shuang Ying
- Department of Ophthalmology, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Robert A Avery
- Departments of Neurology, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
- Department of Ophthalmology, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
- Division of Ophthalmology, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
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3
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Waheed NK, Rosen RB, Jia Y, Munk MR, Huang D, Fawzi A, Chong V, Nguyen QD, Sepah Y, Pearce E. Optical coherence tomography angiography in diabetic retinopathy. Prog Retin Eye Res 2023; 97:101206. [PMID: 37499857 PMCID: PMC11268430 DOI: 10.1016/j.preteyeres.2023.101206] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2023] [Revised: 07/24/2023] [Accepted: 07/25/2023] [Indexed: 07/29/2023]
Abstract
There remain many unanswered questions on how to assess and treat the pathology and complications that arise from diabetic retinopathy (DR). Optical coherence tomography angiography (OCTA) is a novel and non-invasive three-dimensional imaging method that can visualize capillaries in all retinal layers. Numerous studies have confirmed that OCTA can identify early evidence of microvascular changes and provide quantitative assessment of the extent of diseases such as DR and its complications. A number of informative OCTA metrics could be used to assess DR in clinical trials, including measurements of the foveal avascular zone (FAZ; area, acircularity, 3D para-FAZ vessel density), vessel density, extrafoveal avascular zones, and neovascularization. Assessing patients with DR using a full-retinal slab OCTA image can limit segmentation errors and confounding factors such as those related to center-involved diabetic macular edema. Given emerging data suggesting the importance of the peripheral retinal vasculature in assessing and predicting DR progression, wide-field OCTA imaging should also be used. Finally, the use of automated methods and algorithms for OCTA image analysis, such as those that can distinguish between areas of true and false signals, reconstruct images, and produce quantitative metrics, such as FAZ area, will greatly improve the efficiency and standardization of results between studies. Most importantly, clinical trial protocols should account for the relatively high frequency of poor-quality data related to sub-optimal imaging conditions in DR and should incorporate time for assessing OCTA image quality and re-imaging patients where necessary.
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Affiliation(s)
- Nadia K Waheed
- New England Eye Center, Tufts University School of Medicine, Boston, MA, USA.
| | - Richard B Rosen
- New York Eye and Ear Infirmary of Mount Sinai, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Yali Jia
- School of Medicine, Casey Eye Institute, Oregon Health and Science University, Portland, OR, USA
| | - Marion R Munk
- Augenarzt-Praxisgemeinschaft Gutblick AG, Pfäffikon, Switzerland
| | - David Huang
- School of Medicine, Casey Eye Institute, Oregon Health and Science University, Portland, OR, USA
| | - Amani Fawzi
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Victor Chong
- Institute of Ophthalmology, University College London, London, UK
| | - Quan Dong Nguyen
- Byers Eye Institute, Stanford University School of Medicine, Stanford, CA, USA
| | - Yasir Sepah
- Byers Eye Institute, Stanford University School of Medicine, Stanford, CA, USA
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4
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Ahn J, Baik JW, Kim D, Choi K, Lee S, Park SM, Kim JY, Nam SH, Kim C. In vivo photoacoustic monitoring of vasoconstriction induced by acute hyperglycemia. PHOTOACOUSTICS 2023; 30:100485. [PMID: 37082618 PMCID: PMC10112177 DOI: 10.1016/j.pacs.2023.100485] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 03/19/2023] [Accepted: 03/29/2023] [Indexed: 05/03/2023]
Abstract
Postprandial hyperglycemia, blood glucose spikes, induces endothelial dysfunction, increasing cardiovascular risks. Endothelial dysfunction leads to vasoconstriction, and observation of this phenomenon is important for understanding acute hyperglycemia. However, high-resolution imaging of microvessels during acute hyperglycemia has not been fully developed. Here, we demonstrate that photoacoustic microscopy can noninvasively monitor morphological changes in blood vessels of live animals' extremities when blood glucose rises rapidly. As blood glucose level rose from 100 to 400 mg/dL following intraperitoneal glucose injection, heart/breath rate, and body temperature remained constant, but arterioles constricted by approximately -5.7 ± 1.1% within 20 min, and gradually recovered for another 40 min. In contrast, venular diameters remained within about 0.6 ± 1.5% during arteriolar constriction. Our results experimentally and statistically demonstrate that acute hyperglycemia produces transitory vasoconstriction in arterioles, with an opposite trend of change in blood glucose. These findings could help understanding vascular glucose homeostasis and the relationship between diabetes and cardiovascular diseases.
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Affiliation(s)
- Joongho Ahn
- Departments of Electrical Engineering, Convergence IT Engineering, Mechanical Engineering, and Medical Science and Engineering, and Medical Device Innovation Center, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Jin Woo Baik
- Departments of Electrical Engineering, Convergence IT Engineering, Mechanical Engineering, and Medical Science and Engineering, and Medical Device Innovation Center, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Donggyu Kim
- Departments of Electrical Engineering, Convergence IT Engineering, Mechanical Engineering, and Medical Science and Engineering, and Medical Device Innovation Center, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Karam Choi
- Samsung Advanced Institute of Technology, Samsung Electronics Co. Ltd., Suwon 16678, Republic of Korea
| | - Seunghyun Lee
- Departments of Electrical Engineering, Convergence IT Engineering, Mechanical Engineering, and Medical Science and Engineering, and Medical Device Innovation Center, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Sung-Min Park
- Departments of Electrical Engineering, Convergence IT Engineering, Mechanical Engineering, and Medical Science and Engineering, and Medical Device Innovation Center, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Jin Young Kim
- Departments of Electrical Engineering, Convergence IT Engineering, Mechanical Engineering, and Medical Science and Engineering, and Medical Device Innovation Center, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Sung Hyun Nam
- Samsung Advanced Institute of Technology, Samsung Electronics Co. Ltd., Suwon 16678, Republic of Korea
- Corresponding authors.
| | - Chulhong Kim
- Departments of Electrical Engineering, Convergence IT Engineering, Mechanical Engineering, and Medical Science and Engineering, and Medical Device Innovation Center, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
- Corresponding authors.
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5
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Optical coherence tomography in healthy human subjects in the setting of prolonged dark adaptation. Sci Rep 2023; 13:3725. [PMID: 36879027 PMCID: PMC9988879 DOI: 10.1038/s41598-023-30747-0] [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: 10/27/2022] [Accepted: 02/28/2023] [Indexed: 03/08/2023] Open
Abstract
Human studies have established that short periods of dark adaptation can induce outer retinal thinning and various band intensity changes that can be detected with Optical Coherence Tomography (OCT). Similar findings were observed in mice, including a positive correlation between the degree of outer retinal changes and dark adaptation duration. We decided to assess potential retinal structural changes following prolonged dark adaptation in humans. 40 healthy subjects without any ocular diseases participated in this study. For each subject, one eye was covered for dark adaptation for four hours, and the other eye was left uncovered as a control. Before and after the dark adaptation period, both eyes were assessed with OCT. Using the Heidelberg Spectralis system, basic statistical functions, and qualitative and quantitative analysis, we were able to compare retinal layer thicknesses and band intensities between covered (dark adapted) versus uncovered (control) eyes. Prolonged dark adaptation did not induce any significant thickness, volume, or intensity changes in the outer retina or in the inner or overall retina. These observations thus alter our current understanding of the mechanisms underlying dark adaptation's neuroprotective effects in preventing blindness and require further study.
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6
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Lin Z, Yu H, Shi C, Chen H, Lin G, Shen M, Wang C. Acute hyperglycemia compromises the responses of choroidal vessels using swept-source optical coherence tomography during dark and light adaptations. Front Endocrinol (Lausanne) 2023; 14:1049326. [PMID: 36843596 PMCID: PMC9947340 DOI: 10.3389/fendo.2023.1049326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 01/24/2023] [Indexed: 02/11/2023] Open
Abstract
PURPOSE To clarify the effects of acute hyperglycemia on the responses of choroidal structural components and vascularity index during light modulation in healthy participants using techniques including image binarization and artificial intelligence (AI) segmentation based on swept-source optical coherence tomography (SS-OCT). METHODS Twenty-four eyes of 24 healthy participants were imaged at different stages after ambient light, 40 min of dark adaptation, and 5 min of light adaptation in two imaging sessions: control and after receiving 75 g of oral glucose solution. The choroidal structural parameters, including luminal volume (LV), stromal volume (SV), total choroidal volume (TCV), and choroidal vascularity index (CVI) within a 6 mm area were determined using a custom algorithm based on image binarization and AI segmentation of SS-OCT. These measurements were compared among the conditions after adjusting for axial length, age to identify the differences. RESULTS In the dark, CVI decreased (-0.36 ± 0.09%) significantly in acute hyperglycemia compared to the control condition. During the transition to ambient light, there was an increasing trend in the choroidal parameters compared with the control experiment. However, only TCV (0.38 ± 0.17 mm3) and LV (0.27 ± 0.10 mm3) showed a significant increase at the time point of 5 min after ambient light. CONCLUSION Analysis of choroidal structural parameters and CVI based on SS-OCT images is a potentially powerful method to objectively reflect subtle changes in neurovascular coupling between the choroid and photoreceptor during dark adaptation.
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Affiliation(s)
- Zhiyang Lin
- Eye Hospital and School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China
| | - Huankai Yu
- Eye Hospital and School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China
- Oujiang Laboratory (Zhejiang Lab for Regenerative Medicine, Vision and Brain Health), Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Ce Shi
- Eye Hospital and School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China
| | - Hongling Chen
- Eye Hospital and School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China
| | - Guangqing Lin
- Eye Hospital and School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China
| | - Meixiao Shen
- Eye Hospital and School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China
- Oujiang Laboratory (Zhejiang Lab for Regenerative Medicine, Vision and Brain Health), Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
- *Correspondence: Meixiao Shen, ; Chenxiao Wang,
| | - Chenxiao Wang
- Eye Hospital and School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China
- *Correspondence: Meixiao Shen, ; Chenxiao Wang,
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7
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Cheung CMG, Fawzi A, Teo KY, Fukuyama H, Sen S, Tsai WS, Sivaprasad S. Diabetic macular ischaemia- a new therapeutic target? Prog Retin Eye Res 2022; 89:101033. [PMID: 34902545 PMCID: PMC11268431 DOI: 10.1016/j.preteyeres.2021.101033] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Revised: 11/25/2021] [Accepted: 12/01/2021] [Indexed: 12/21/2022]
Abstract
Diabetic macular ischaemia (DMI) is traditionally defined and graded based on the angiographic evidence of an enlarged and irregular foveal avascular zone. However, these anatomical changes are not surrogate markers for visual impairment. We postulate that there are vascular phenotypes of DMI based on the relative perfusion deficits of various retinal capillary plexuses and choriocapillaris. This review highlights several mechanistic pathways, including the role of hypoxia and the complex relation between neurons, glia, and microvasculature. The current animal models are reviewed, with shortcomings noted. Therefore, utilising the advancing technology of optical coherence tomography angiography (OCTA) to identify the reversible DMI phenotypes may be the key to successful therapeutic interventions for DMI. However, there is a need to standardise the nomenclature of OCTA perfusion status. Visual acuity is not an ideal endpoint for DMI clinical trials. New trial endpoints that represent disease progression need to be developed before irreversible vision loss in patients with DMI. Natural history studies are required to determine the course of each vascular and neuronal parameter to define the DMI phenotypes. These DMI phenotypes may also partly explain the development and recurrence of diabetic macular oedema. It is also currently unclear where and how DMI fits into the diabetic retinopathy severity scales, further highlighting the need to better define the progression of diabetic retinopathy and DMI based on both multimodal imaging and visual function. Finally, we discuss a complete set of proposed therapeutic pathways for DMI, including cell-based therapies that may provide restorative potential.
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Affiliation(s)
- Chui Ming Gemmy Cheung
- Singapore Eye Research Institution, Singapore National Eye Centre, Singapore; Duke-NUS Medical School, National University of Singapore, Singapore
| | | | - Kelvin Yc Teo
- Singapore Eye Research Institution, Singapore National Eye Centre, Singapore
| | | | | | - Wei-Shan Tsai
- NIHR Moorfields Biomedical Research Centre, Moorfields Eye Hospital, London, United Kingdom
| | - Sobha Sivaprasad
- NIHR Moorfields Biomedical Research Centre, Moorfields Eye Hospital, London, United Kingdom.
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8
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Frohn E, Lebowicz L, Twedt R, Young C. Transforming Confocal Microscopy Imaging Data of Retinal Vasculature into 3D Animation. THE JOURNAL OF BIOCOMMUNICATION 2022; 46:e7. [PMID: 36405854 PMCID: PMC9622356 DOI: 10.5210/jbc.v46i1.12636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
This research study presents a methodology for creation of 3D models from confocal microscopy, specifically the retinal trilaminar capillary network, that can be used in 3D biomedical animation. Biomedical visualization professionals regularly use CT and MRI imaging data to create 3D models and other visuals. Adding confocal microscopy to this toolkit using ImageJ FIJI1 and Materialise Mimics® allows for a wider range of options to create data-driven 3D models of microscopic structures. Understanding the interactions of the neurovascular unit through visualization may be a key to advancing understanding of normal function of the retina and diabetic retinopathy pathology. This Vesalius Trust research poster was presented at the Association of Medical Illustrators' 2021 virtual annual meeting.
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Affiliation(s)
- Emilyn Frohn
- Biomedical Visualization Graduate Program, University of Illinois at Chicago, Chicago, Illinois
| | - Leah Lebowicz
- Biomedical Visualization Graduate Program, University of Illinois at Chicago, Chicago, Illinois
| | - Rex Twedt
- Biomedical Visualization Graduate Program, University of Illinois at Chicago, Chicago, Illinois
| | - Christine Young
- Biomedical Visualization Graduate Program, University of Illinois at Chicago, Chicago, Illinois
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9
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Kim TH, Ding J, Yao X. Intrinsic signal optoretinography of dark adaptation kinetics. Sci Rep 2022; 12:2475. [PMID: 35169239 PMCID: PMC8847457 DOI: 10.1038/s41598-022-06562-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 02/02/2022] [Indexed: 12/13/2022] Open
Abstract
Delayed dark adaptation due to impaired rod photoreceptor homeostasis has been reported as the earliest symptom of eye diseases such as age-related macular degeneration, diabetic retinopathy, and retinitis pigmentosa. Objective measurement of dark adaptation can facilitate early diagnosis to enable prompt intervention to prevent vision loss. However, there is a lack of noninvasive methods capable of spatiotemporal monitoring of photoreceptor changes during dark adaptation. Here we demonstrate functional optical coherence tomography (OCT) for in vivo intrinsic signal optoretinography (ORG) of dark adaptation kinetics in the C57BL/6J mouse retina. Functional OCT revealed a shortening of the outer retina, a rearrangement of the cone and rod photoreceptor interdigitation zone, and a reduction in intrinsic signal amplitude at the photoreceptor inner segment ellipsoid (ISe). A strong positive correlation between the outer retinal shortening and ISe intensity reduction was also confirmed. Functional OCT of dark adaptation kinetics promises an objective method for rapid ORG assessment of physiological integrity of retinal photoreceptors.
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Affiliation(s)
- Tae-Hoon Kim
- Department of Biomedical Engineering, University of Illinois at Chicago, Chicago, IL, 60607, USA
| | - Jie Ding
- Department of Biomedical Engineering, University of Illinois at Chicago, Chicago, IL, 60607, USA
| | - Xincheng Yao
- Department of Biomedical Engineering, University of Illinois at Chicago, Chicago, IL, 60607, USA.
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL, 60612, USA.
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10
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Ong JX, Fawzi AA. Perspectives on diabetic retinopathy from advanced retinal vascular imaging. Eye (Lond) 2022; 36:319-327. [PMID: 34987198 PMCID: PMC8807653 DOI: 10.1038/s41433-021-01825-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 10/05/2021] [Accepted: 10/14/2021] [Indexed: 02/03/2023] Open
Abstract
Diabetic retinopathy (DR) is a microvascular complication of diabetes and the most common cause of acquired vision loss in adults worldwide. DR is associated with long-term chronic hyperglycaemia and its detrimental effects on the neurovascular structure and function of the retina. Direct imaging of the retinal vasculature and staging of DR has been traditionally based on fundoscopy and fluorescein angiography, which provide only 2D views of the retina, and in the case of fluorescein angiography, requires an invasive dye injection. In contrast, advanced retinal imaging modalities like optical coherence tomography angiography (OCTA) and adaptive optics (AO) are non-invasive and provide depth-resolved, 3D visualization of retinal vessel structure as well as blood flow. Recent studies utilizing these imaging techniques have shown promise in evaluating quantitative vascular parameters that correlate tightly to clinical DR staging, elucidating functional changes in early diabetes, and monitoring DR treatment response. In this article, we discuss and synthesize the results of advanced retinal imaging studies in DR and their implications for our clinical and pathophysiologic understanding of the disease. Based on the recent literature, we also propose a model to describe the differential changes in vascular structure and flow that have been described on advanced retinal imaging as DR progresses. Future studies of these imaging modalities in larger and more diverse populations, as well as corroboration with histological and functional studies, will be important to further our understanding of DR.
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Affiliation(s)
- Janice X Ong
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Amani A Fawzi
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
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11
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Vujosevic S, Cunha-Vaz J, Figueira J, Löwenstein A, Midena E, Parravano M, Scanlon PH, Simó R, Hernández C, Madeira MH, Marques IP, C-V Martinho A, Santos AR, Simó-Servat O, Salongcay RP, Zur D, Peto T. Standardisation of Optical Coherence Tomography Angiography Imaging Biomarkers in Diabetic Retinal Disease. Ophthalmic Res 2021; 64:871-887. [PMID: 34348330 DOI: 10.1159/000518620] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 07/12/2021] [Indexed: 11/19/2022]
Affiliation(s)
| | - José Cunha-Vaz
- AIBILI-Association for Innovation and Biomedical Research on Light and Image, Coimbra, Portugal
- Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - João Figueira
- AIBILI-Association for Innovation and Biomedical Research on Light and Image, Coimbra, Portugal
- Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Anat Löwenstein
- Ophthalmology Division, Tel Aviv Medical Center, affiliated to Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Edoardo Midena
- Department of Neuroscience, University of Padua, Padua, Italy
| | | | - Peter Henry Scanlon
- Department of Ophthalmology, Gloucestershire Hospitals NHS Foundation Trust, Cheltenham, United Kingdom
| | - Rafael Simó
- Diabetes and Metabolism Research Unit, Vall d'Hebron Research Institute, Barcelona, Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain
| | - Cristina Hernández
- Diabetes and Metabolism Research Unit, Vall d'Hebron Research Institute, Barcelona, Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain
| | - Maria H Madeira
- AIBILI-Association for Innovation and Biomedical Research on Light and Image, Coimbra, Portugal
- Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Inês P Marques
- AIBILI-Association for Innovation and Biomedical Research on Light and Image, Coimbra, Portugal
- Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, University of Coimbra, Coimbra, Portugal
- Department of Orthoptics, School of Health, Polytechnic of Porto, Porto, Portugal
| | - António C-V Martinho
- AIBILI-Association for Innovation and Biomedical Research on Light and Image, Coimbra, Portugal
| | - Ana R Santos
- AIBILI-Association for Innovation and Biomedical Research on Light and Image, Coimbra, Portugal
- Department of Orthoptics, School of Health, Polytechnic of Porto, Porto, Portugal
| | - Olga Simó-Servat
- Diabetes and Metabolism Research Unit, Vall d'Hebron Research Institute, Barcelona, Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain
| | - Recivall P Salongcay
- Centre for Public Health, Queen's University Belfast, Belfast, United Kingdom
- Eye and Vision Institute, The Medical City, Pasig, Philippines
| | - Dinah Zur
- Ophthalmology Division, Tel Aviv Medical Center, affiliated to Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Tunde Peto
- Centre for Public Health, Queen's University Belfast, Belfast, United Kingdom
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12
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Clarkson-Townsend DA, Bales KL, Marsit CJ, Pardue MT. Light Environment Influences Developmental Programming of the Metabolic and Visual Systems in Mice. Invest Ophthalmol Vis Sci 2021; 62:22. [PMID: 33861321 PMCID: PMC8083116 DOI: 10.1167/iovs.62.4.22] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 03/27/2021] [Indexed: 02/06/2023] Open
Abstract
Purpose Light is a salient cue that can influence neurodevelopment and the immune system. Light exposure out of sync with the endogenous clock causes circadian disruption and chronic disease. Environmental light exposure may contribute to developmental programming of metabolic and neurological systems but has been largely overlooked in Developmental Origins of Health and Disease (DOHaD) research. Here, we investigated whether developmental light exposure altered programming of visual and metabolic systems. Methods Pregnant mice and pups were exposed to control light (12:12 light:dark) or weekly light cycle inversions (circadian disruption [CD]) until weaning, after which male and female offspring were housed in control light and longitudinally measured to evaluate differences in growth (weight), glucose tolerance, visual function (optomotor response), and retinal function (electroretinogram), with and without high fat diet (HFD) challenge. Retinal microglia and macrophages were quantified by positive Iba1 and CD11b immunofluorescence. Results CD exposure caused impaired visual function and increased retinal immune cell expression in adult offspring. When challenged with HFD, CD offspring also exhibited altered retinal function and sex-specific impairments in glucose tolerance. Conclusions Overall, these findings suggest that the light environment contributes to developmental programming of the metabolic and visual systems, potentially promoting a pro-inflammatory milieu in the retina and increasing the risk of visual disease later in life.
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Affiliation(s)
- Danielle A. Clarkson-Townsend
- Gangarosa Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, Georgia, United States
- Center for Visual and Neurocognitive Rehabilitation, Atlanta VA Healthcare System, Decatur, Georgia, United States
| | - Katie L. Bales
- Center for Visual and Neurocognitive Rehabilitation, Atlanta VA Healthcare System, Decatur, Georgia, United States
- Department of Ophthalmology, Emory University, Atlanta, Georgia, United States
| | - Carmen J. Marsit
- Gangarosa Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, Georgia, United States
| | - Machelle T. Pardue
- Center for Visual and Neurocognitive Rehabilitation, Atlanta VA Healthcare System, Decatur, Georgia, United States
- Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia, United States
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Tripathy S, Le HG, Cicinelli MV, Gill MK. Longitudinal Changes on Optical Coherence Tomography Angiography in Retinal Vein Occlusion. J Clin Med 2021; 10:jcm10071423. [PMID: 33916005 PMCID: PMC8037411 DOI: 10.3390/jcm10071423] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 03/20/2021] [Accepted: 03/25/2021] [Indexed: 01/26/2023] Open
Abstract
Background: To evaluate the longitudinal changes on optical coherence tomography angiography (OCTA) in retinal vein occlusion (RVO). Methods: Retrospective study of patients with RVO treated with intravitreal anti-vascular endothelial growth factors (VEGF) for macular edema. Foveal avascular zone (FAZ) area, vessel density (VD), vessel length density (VLD), and adjusted flow index (AFI) were calculated. The unaffected eye of each participant was used as a control. Results: Twelve RVO eyes were included, receiving 6 ± 3 anti-VEGF injections over a follow-up of 10.4 ± 3.1 months. Compared to fellow eyes, RVO eyes had lower VD and VLD at inclusion (p = 0.07 and p = 0.04) and last visit (p = 0.002 and p < 0.001). VD, AFI, and VLD did not change over time, while FAZ area increased in RVO eyes (+0.016 ± 0.024 mm2, p = 0.04). AFI correlated with duration of disease (r = 0.63, p = 0.02). Visual acuity was inversely related to VD and VLD over the follow-up. Conclusions: OCTA parameters remained stable with sustained anti-VEGF treatment in RVO, while changes in the FAZ area may suggest capillary remodeling after RVO.
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Affiliation(s)
- Swetapadma Tripathy
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, 645 N Michigan Avenue, Ste 440, Chicago, IL 60611, USA; (S.T.); (H.-G.L.); (M.V.C.)
| | - Hong-Gam Le
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, 645 N Michigan Avenue, Ste 440, Chicago, IL 60611, USA; (S.T.); (H.-G.L.); (M.V.C.)
| | - Maria Vittoria Cicinelli
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, 645 N Michigan Avenue, Ste 440, Chicago, IL 60611, USA; (S.T.); (H.-G.L.); (M.V.C.)
- School of Medicine, Vita-Salute San Raffaele University, 20132 Milan, Italy
- Department of Ophthalmology, IRCCS San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Manjot K. Gill
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, 645 N Michigan Avenue, Ste 440, Chicago, IL 60611, USA; (S.T.); (H.-G.L.); (M.V.C.)
- Correspondence:
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14
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Zhang YS, Mucollari I, Kwan CC, Dingillo G, Amar J, Schwartz GW, Fawzi AA. Reversed Neurovascular Coupling on Optical Coherence Tomography Angiography Is the Earliest Detectable Abnormality before Clinical Diabetic Retinopathy. J Clin Med 2020; 9:jcm9113523. [PMID: 33142724 PMCID: PMC7692675 DOI: 10.3390/jcm9113523] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2020] [Revised: 10/21/2020] [Accepted: 10/27/2020] [Indexed: 12/20/2022] Open
Abstract
Diabetic retinopathy (DR) has traditionally been viewed as either a microvasculopathy or a neuropathy, though neurovascular coupling deficits have also been reported and could potentially be the earliest derangement in DR. To better understand neurovascular coupling in the diabetic retina, we investigated retinal hemodynamics by optical coherence tomography angiography (OCTA) in individuals with diabetes mellitus (DM) but without DR (DM no DR) and mild non-proliferative DR (mild NPDR) compared to healthy eyes. Using an experimental design to monitor the capillary responses during transition from dark adaptation to light, we examined 19 healthy, 14 DM no DR and 11 mild NPDR individuals. We found that the only structural vascular abnormality in the DM no DR group was increased superficial capillary plexus (SCP) vessel density (VD) compared to healthy eyes, while mild NPDR eyes showed significant vessel loss in the SCP at baseline. There was no significant difference in inner retinal thickness between the groups. During dark adaptation, the deep capillary plexus (DCP) VD was lower in mild NPDR individuals compared to the other two groups, which may leave the photoreceptors more susceptible to ischemia in the dark. When transitioning from dark to ambient light, both diabetic groups showed a qualitative reversal of VD trends in the SCP and middle capillary plexus (MCP), with significantly decreased SCP at 5 min and increased MCP VD at 50 s compared to healthy eyes, which may impede metabolic supply to the inner retina during light adaptation. Mild NPDR eyes also demonstrated DCP dilation at 50 s and 5 min and decreased adjusted flow index at 5 min in light. Our results show altered neurovascular responses in all three macular vascular plexuses in diabetic subjects in the absence of structural neuronal changes on high resolution imaging, suggesting that neurovascular uncoupling may be a key mechanism in the early pathogenesis of DR, well before the clinical appearance of vascular or neuronal loss.
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Affiliation(s)
- Yi Stephanie Zhang
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA; (Y.S.Z.); (I.M.); (C.C.K.); (G.D.); (J.A.); (G.W.S.)
| | - Ilda Mucollari
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA; (Y.S.Z.); (I.M.); (C.C.K.); (G.D.); (J.A.); (G.W.S.)
| | - Changyow C. Kwan
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA; (Y.S.Z.); (I.M.); (C.C.K.); (G.D.); (J.A.); (G.W.S.)
| | - Gianna Dingillo
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA; (Y.S.Z.); (I.M.); (C.C.K.); (G.D.); (J.A.); (G.W.S.)
| | - Jaspreet Amar
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA; (Y.S.Z.); (I.M.); (C.C.K.); (G.D.); (J.A.); (G.W.S.)
| | - Gregory W. Schwartz
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA; (Y.S.Z.); (I.M.); (C.C.K.); (G.D.); (J.A.); (G.W.S.)
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Amani A. Fawzi
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA; (Y.S.Z.); (I.M.); (C.C.K.); (G.D.); (J.A.); (G.W.S.)
- Correspondence:
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15
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Gerhard G, Chua J, Tan B, Wong D, Schmidl D, Schmetterer L. Retinal Neurovascular Coupling in Diabetes. J Clin Med 2020; 9:jcm9092829. [PMID: 32882896 PMCID: PMC7565465 DOI: 10.3390/jcm9092829] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 08/23/2020] [Accepted: 08/27/2020] [Indexed: 12/15/2022] Open
Abstract
Neurovascular coupling, also termed functional hyperemia, is one of the physiological key mechanisms to adjust blood flow in a neural tissue in response to functional activity. In the retina, increased neural activity, such as that induced by visual stimulation, leads to the dilatation of retinal arterioles, which is accompanied by an immediate increase in retinal and optic nerve head blood flow. According to the current scientific view, functional hyperemia ensures the adequate supply of nutrients and metabolites in response to the increased metabolic demand of the neural tissue. Although the molecular mechanisms behind neurovascular coupling are not yet fully elucidated, there is compelling evidence that this regulation is impaired in a wide variety of neurodegenerative and vascular diseases. In particular, it has been shown that the breakdown of the functional hyperemic response is an early event in patients with diabetes. There is compelling evidence that alterations in neurovascular coupling precede visible signs of diabetic retinopathy. Based on these observations, it has been hypothesized that a breakdown of functional hyperemia may contribute to the retinal complications of diabetes such as diabetic retinopathy or macular edema. The present review summarizes the current evidence of impaired neurovascular coupling in patients with diabetes. In this context, the molecular mechanisms of functional hyperemia in health and disease will be covered. Finally, we will also discuss how neurovascular coupling may in future be used to monitor disease progression or risk stratification.
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Affiliation(s)
- Garhöfer Gerhard
- Department of Clinical Pharmacology, Medical University Vienna, 1090 Vienna, Austria; (G.G.); (D.S.)
| | - Jacqueline Chua
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore 169856, Singapore; (J.C.); (B.T.); (D.W.)
- Academic Clinical Program, Duke-NUS Medical School, Singapore 169857, Singapore
- SERI-NTU Advanced Ocular Engineering (STANCE), Singapore 639798, Singapore
| | - Bingyao Tan
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore 169856, Singapore; (J.C.); (B.T.); (D.W.)
- SERI-NTU Advanced Ocular Engineering (STANCE), Singapore 639798, Singapore
| | - Damon Wong
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore 169856, Singapore; (J.C.); (B.T.); (D.W.)
- SERI-NTU Advanced Ocular Engineering (STANCE), Singapore 639798, Singapore
| | - Doreen Schmidl
- Department of Clinical Pharmacology, Medical University Vienna, 1090 Vienna, Austria; (G.G.); (D.S.)
| | - Leopold Schmetterer
- Department of Clinical Pharmacology, Medical University Vienna, 1090 Vienna, Austria; (G.G.); (D.S.)
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore 169856, Singapore; (J.C.); (B.T.); (D.W.)
- Academic Clinical Program, Duke-NUS Medical School, Singapore 169857, Singapore
- SERI-NTU Advanced Ocular Engineering (STANCE), Singapore 639798, Singapore
- Institute for Health Technologies, Nanyang Technological University, Singapore 308232, Singapore
- Center for Medical Physics and Biomedical Engineering, Medical University Vienna, 1090 Vienna, Austria
- Institute of Molecular and Clinical Ophthalmology, CH-4031 Basel, Switzerland
- Correspondence: ; Tel.: +43-1-40400-29810
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