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Nouri H, Abtahi SH, Mazloumi M, Samadikhadem S, Arevalo JF, Ahmadieh H. Optical coherence tomography angiography in diabetic retinopathy: A major review. Surv Ophthalmol 2024; 69:558-574. [PMID: 38521424 DOI: 10.1016/j.survophthal.2024.03.004] [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: 09/23/2023] [Revised: 02/29/2024] [Accepted: 03/11/2024] [Indexed: 03/25/2024]
Abstract
Diabetic retinopathy (DR) is characterized by retinal vasculopathy and is a leading cause of visual impairment. Optical coherence tomography angiography (OCTA) is an innovative imaging technology that can detect various pathologies and quantifiable changes in retinal microvasculature. We briefly describe its functional principles and advantages over fluorescein angiography and perform a comprehensive review on its clinical applications in the screening or management of people with prediabetes, diabetes without clinical retinopathy (NDR), nonproliferative DR (NPDR), proliferative DR (PDR), and diabetic macular edema (DME). OCTA reveals early microvascular alterations in prediabetic and NDR eyes, which may coexist with sub-clinical neuroretinal dysfunction. Its applications in NPDR include measuring ischemia, detecting retinal neovascularization, and timing of early treatment through predicting the risk of retinopathy worsening or development of DME. In PDR, OCTA helps characterize the flow within neovascular complexes and evaluate their progression or regression in response to treatment. In eyes with DME, OCTA perfusion parameters may be of predictive value regarding the visual and anatomical gains associated with treatment. We further discussed the limitations of OCTA and the benefits of its incorporation into an updated DR severity scale.
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Affiliation(s)
- Hosein Nouri
- Ophthalmic Research Center, Research Institute for Ophthalmology and Vision Science, Shahid Beheshti University of Medical Sciences, Tehran, Iran; School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Seyed-Hossein Abtahi
- Ophthalmic Research Center, Research Institute for Ophthalmology and Vision Science, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Department of Ophthalmology, Labbafinejad Medical Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
| | - Mehdi Mazloumi
- Eye Research Center, Rasoul Akram Hospital, Iran University of Medical Sciences, Tehran, Iran
| | - Sanam Samadikhadem
- Department of Ophthalmology, Imam Hossein Medical Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - J Fernando Arevalo
- Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| | - Hamid Ahmadieh
- Ophthalmic Research Center, Research Institute for Ophthalmology and Vision Science, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Zhang Z, Deng C, Paulus YM. Advances in Structural and Functional Retinal Imaging and Biomarkers for Early Detection of Diabetic Retinopathy. Biomedicines 2024; 12:1405. [PMID: 39061979 PMCID: PMC11274328 DOI: 10.3390/biomedicines12071405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2024] [Revised: 05/27/2024] [Accepted: 06/10/2024] [Indexed: 07/28/2024] Open
Abstract
Diabetic retinopathy (DR), a vision-threatening microvascular complication of diabetes mellitus (DM), is a leading cause of blindness worldwide that requires early detection and intervention. However, diagnosing DR early remains challenging due to the subtle nature of initial pathological changes. This review explores developments in multimodal imaging and functional tests for early DR detection. Where conventional color fundus photography is limited in the field of view and resolution, advanced quantitative analysis of retinal vessel traits such as retinal microvascular caliber, tortuosity, and fractal dimension (FD) can provide additional prognostic value. Optical coherence tomography (OCT) has also emerged as a reliable structural imaging tool for assessing retinal and choroidal neurodegenerative changes, which show potential as early DR biomarkers. Optical coherence tomography angiography (OCTA) enables the evaluation of vascular perfusion and the contours of the foveal avascular zone (FAZ), providing valuable insights into early retinal and choroidal vascular changes. Functional tests, including multifocal electroretinography (mfERG), visual evoked potential (VEP), multifocal pupillographic objective perimetry (mfPOP), microperimetry, and contrast sensitivity (CS), offer complementary data on early functional deficits in DR. More importantly, combining structural and functional imaging data may facilitate earlier detection of DR and targeted management strategies based on disease progression. Artificial intelligence (AI) techniques show promise for automated lesion detection, risk stratification, and biomarker discovery from various imaging data. Additionally, hematological parameters, such as neutrophil-lymphocyte ratio (NLR) and neutrophil extracellular traps (NETs), may be useful in predicting DR risk and progression. Although current methods can detect early DR, there is still a need for further research and development of reliable, cost-effective methods for large-scale screening and monitoring of individuals with DM.
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Affiliation(s)
- Zhengwei Zhang
- Department of Ophthalmology, Jiangnan University Medical Center, Wuxi 214002, China;
- Department of Ophthalmology, Wuxi No.2 People’s Hospital, Wuxi Clinical College, Nantong University, Wuxi 214002, China
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI 48105, USA;
| | - Callie Deng
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI 48105, USA;
| | - Yannis M. Paulus
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI 48105, USA;
- Department of Biomedical Engineering, University of Michigan, 1000 Wall Street, Ann Arbor, MI 48105, USA
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Hein M, Qambari H, An D, Balaratnasingam C. Current understanding of subclinical diabetic retinopathy informed by histology and high-resolution in vivo imaging. Clin Exp Ophthalmol 2024; 52:464-484. [PMID: 38363022 DOI: 10.1111/ceo.14363] [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: 10/30/2023] [Revised: 01/21/2024] [Accepted: 01/26/2024] [Indexed: 02/17/2024]
Abstract
The escalating incidence of diabetes mellitus has amplified the global impact of diabetic retinopathy. There are known structural and functional changes in the diabetic retina that precede the fundus photography abnormalities which currently are used to diagnose clinical diabetic retinopathy. Understanding these subclinical alterations is important for effective disease management. Histology and high-resolution clinical imaging reveal that the entire neurovascular unit, comprised of retinal vasculature, neurons and glial cells, is affected in subclinical disease. Early functional manifestations are seen in the form of blood flow and electroretinography disturbances. Structurally, there are alterations in the cellular components of vasculature, glia and the neuronal network. On clinical imaging, changes to vessel density and thickness of neuronal layers are observed. How these subclinical disturbances interact and ultimately manifest as clinical disease remains elusive. However, this knowledge reveals potential early therapeutic targets and the need for imaging modalities that can detect subclinical changes in a clinical setting.
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Affiliation(s)
- Martin Hein
- Physiology and Pharmacology Group, Lions Eye Institute, Perth, Western Australia, Australia
- Centre for Ophthalmology and Visual Science, University of Western Australia, Perth, Western Australia, Australia
| | - Hassanain Qambari
- Physiology and Pharmacology Group, Lions Eye Institute, Perth, Western Australia, Australia
- Centre for Ophthalmology and Visual Science, University of Western Australia, Perth, Western Australia, Australia
| | - Dong An
- Physiology and Pharmacology Group, Lions Eye Institute, Perth, Western Australia, Australia
- Centre for Ophthalmology and Visual Science, University of Western Australia, Perth, Western Australia, Australia
| | - Chandrakumar Balaratnasingam
- Physiology and Pharmacology Group, Lions Eye Institute, Perth, Western Australia, Australia
- Centre for Ophthalmology and Visual Science, University of Western Australia, Perth, Western Australia, Australia
- Department of Ophthalmology, Sir Charles Gairdner Hospital, Perth, Western Australia, Australia
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Echiverri A, Harrison WW. Evaluation of retinal structure and function in prediabetes. DIABETES EPIDEMIOLOGY AND MANAGEMENT 2023; 12:100154. [PMID: 38037572 PMCID: PMC10688557 DOI: 10.1016/j.deman.2023.100154] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/02/2023]
Abstract
Purpose Alterations in retinal structure and function have been well documented in type 2 diabetes (T2DM). However, few studies have evaluated the eye in prediabetes (preDM), a precursor to T2DM. It is unknown which retinal deficits, if any, occur before T2DM diagnosis. This study evaluates retinal structure via optical coherence tomography (OCT) and retinal function via multifocal electroretinogram (mfERG) N1 and P1 in those with PreDM. The goal is to evaluate associations between structure and function across glucose dysfunction. Methods 85 subjects (aged 28-69yrs) were tested with VERIS mfERG and Heidelberg Spectralis OCT. Demographic and health information was collected. Subjects were grouped by HbA1c: 33 controls (HbA1c <5.7%), 31 with preDM (HbA1c 5.7-6.4%), and 21 with T2DM (HbA1c >6.4% at the time of testing or diagnosed by physician) and mild or no retinopathy. mfERG N1 and P1 latency and amplitude were measured for the right eye in the foveal hexagon (central 2.4°). Average macular thickness was also measured over the central 3.3°. Groups were compared with ANOVA and corrected t-tests. Models of these associations with diabetes diagnosis (in groups above) were created with backward multivariate regression. Results The T2DM group was exceptionally well-controlled with an HbA1c of 7.0% ± 0.68 but also had elevated systolic blood pressure compared to other groups (P<0.01). The age of the control group was younger (P<0.01), so other testing was age controlled. There was a borderline but statistically significant difference in P1 between the control group and both the preDM and T2DM groups after Bonferroni corrections (P<0.03). There was also a difference in N1 latency between the control and other groups (P<0.001). A multivariate model demonstrated a significant relationship between T2DM/PreDM diagnosis and delayed N1 latency, reduced foveal thickness, and age. Conclusions Structure and function together can provide an associative model of preDM or T2DM changes for patients. Based on this multivariate model, N1 is strongly associated with preDM and T2DM. N1 findings and decreasing foveal thickness are additive and can together inform ocular health related to preDM. Future longitudinal studies are needed to understand changes in function and structure in preDM and T2DM.
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Affiliation(s)
- Angelica Echiverri
- University of Houston College of Optometry, 4401 Martin Luther King Blvd, Houston, TX 77204, USA
| | - Wendy W. Harrison
- University of Houston College of Optometry, 4401 Martin Luther King Blvd, Houston, TX 77204, USA
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Ebrahimi M, Sivaprasad S, Thompson P, Perry G. Retinal Neurodegeneration in Euglycemic Hyperinsulinemia, Prediabetes, and Diabetes. Ophthalmic Res 2022; 66:385-397. [PMID: 36463857 DOI: 10.1159/000528503] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Accepted: 11/23/2022] [Indexed: 12/23/2023]
Abstract
Diabetic retinopathy (DR) is a challenging public health problem mainly because of its growing prevalence and risk of blindness. In general, our current knowledge and practice have failed to prevent the onset or progression of DR to sight-threatening complications. While there are treatment options for sight-threatening complications of DR, it is crucial to pay more attention to the early stages of DR to decrease its prevalence. Growing evidence suggests many pathologic changes occur before clinical presentations of DR in euglycemic hyperinsulinemia, prediabetes, and diabetes. These pathological changes occur in retinal neurons, glia, and microvasculature. A new focus on these preclinical pathologies - especially on hyperinsulinemia - may provide further insight into disease mechanisms, endpoints for clinical trials, and druggable targets in early disease. Here, we review the current evidence on the pathophysiological changes reported in preclinical DR and appraise preventive and treatment options for DR.
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Affiliation(s)
- Moein Ebrahimi
- Network of Immunity in Infection, Malignancy, and Autoimmunity, Universal Scientific Education and Research Network (USERN), Tehran, Iran
| | - Sobha Sivaprasad
- NIHR Moorfields Biomedical Research Centre, Moorfields Eye Hospital, London, UK
| | - Paul Thompson
- Imaging Genetics Center, Mark and Mary Stevens Institute for Neuroimaging and Informatics, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - George Perry
- Department of Biology, University of Texas and San Antonio, San Antonio, Texas, USA
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Toyama T, Kawai H, Hashimoto Y, Azuma K, Shiraya T, Numaga J, Obuchi S, Ueta T. Macular and peripapillary retinal nerve fiber layer thinning in eyes with prediabetes in the elderly population: OTASSHA study. Graefes Arch Clin Exp Ophthalmol 2022; 261:1275-1281. [PMID: 36454323 DOI: 10.1007/s00417-022-05925-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 10/26/2022] [Accepted: 11/22/2022] [Indexed: 12/03/2022] Open
Abstract
PURPOSE To investigate retinal thickness parameters in the elderly with prediabetes mellitus (preDM) and type 2 DM without retinopathy (non-diabetic retinopathy [NDR]). METHODS This cross-sectional study included a total of 1273 eyes without retinal pathologies of 699 volunteers aged ≥ 65 years were included. The eyes were categorized into non-DM (606 eyes), preDM (480 eyes), and NDR (187 eyes) groups according to their HbA1c levels. Fundus photography, swept-source optical coherence tomography, and comprehensive systemic examination were conducted. The thicknesses of the retinal nerve fiber layer in the macula (mRNFL) and peripapillary (pRNFL), ganglion cell complex (GCC), and ganglion cell inner plexiform layer (GCIPL), as well as central subfield thickness (CST) and central foveal thickness (CFT) were investigated for their association with DM stage using linear mixed model. RESULTS A statistically significant thinning of mRNFL was observed in preDM vs. non-DM and in NDR vs. preDM in 3/6 sectors. A significant thinning of pRNFL was observed in preDM vs. non-DM and in NDR vs. preDM in 2/12 sectors. Such DM stage-dependent thinning of RNFL was observed mainly in the temporal and superior sectors. GCIPL and GCC were less sensitive to reflect DM-dependent inner retinal thinning. CST and CFT were not significantly associated with different DM stages. CONCLUSION The thinning of mRNFL in the temporal and superior sectors might be a sensitive parameter associated with early neurodegeneration in preDM and NDR.
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Jia Y, Lin Q, Xiao Y, Zhou X, Zou H, Yang C. Are we overlooking the neurodegeneration in the early stage of Type 1 Diabetes Mellitus without Visual Impairment or Diabetic Retinopathy: is it probably occurred before retinal vasculature dysfunction? Curr Eye Res 2022; 48:433-440. [PMID: 36420789 DOI: 10.1080/02713683.2022.2152056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE Using electrophysiology (ERG) to investigate the early alterations of retinal function in diabetic children and adolescents without diabetic retinopathy (DR) or visual impairment (VI). METHODS We recorded and compared the data of full-field flicker ERGs between 59 normal subjects and 60 children and adolescents with type 1 diabetes mellitus (T1DM) from the Children's Hospital of Fudan University in Shanghai. RESULTS In both groups, patients with diabetes and healthy controls were matched for age, gender, weight, height, BMI, intraocular pressure (IOP), and best-corrected visual acuity (BCVA). Among the parameters of the outcomes of ERG, the implicit time in eyes in DM patients was significantly prolonged compared to normal eyes (p = .008, 16 Td-s; p = .000, 32 Td-s). In the case group, we found significantly positive correlation between implicit time and BMI (p < .05), as well as implicit time and axial length (AL). CONCLUSIONS The study reveals that the dysfunction of retina in DM children can be detected with ERGs. It also shows that hyperglycemia has an impact on the occurrence of neurodegeneration in the early stage of DM.
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Affiliation(s)
- Yan Jia
- Department of Ophthalmology, Children’s Hospital of Fudan University, Shanghai, China
| | - Qiurong Lin
- Shanghai Eye Diseases Prevention & Treatment Center, Shanghai Eye Hospital, Shanghai, China
| | - Ying Xiao
- Department of Ophthalmology, Children’s Hospital of Fudan University, Shanghai, China
| | - Xiaohong Zhou
- Department of Ophthalmology, Children’s Hospital of Fudan University, Shanghai, China
| | - Haidong Zou
- Shanghai Eye Diseases Prevention & Treatment Center, Shanghai Eye Hospital, Shanghai, China
| | - Chenhao Yang
- Department of Ophthalmology, Children’s Hospital of Fudan University, Shanghai, China
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Xu Y, Zhu X, Wang Y, Chu Z, Wang RK, Lu L, Zou H. Early Retinal Microvasculopathy in Prediabetic Patients and Correlated Factors. Ophthalmic Res 2022; 66:367-376. [PMID: 36382640 DOI: 10.1159/000527957] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2022] [Accepted: 10/27/2022] [Indexed: 12/23/2023]
Abstract
INTRODUCTION We aimed to detect early retinal microcirculation changes in prediabetic patients and investigate their correlation with clinical examinations. METHODS Forty-seven prediabetic individuals, 29 controls, and 81 type 2 diabetic mellitus (T2DM) patients were enrolled in this study. A review of clinical data and spectral-domain optical coherence tomography angiography (SD-OCTA) parameters of macular vessel diameter (VD), foveal avascular zone (FAZ), and macular vessel area density (VAD) was performed. RESULTS Levels of low-density lipoprotein cholesterol and triglycerides in prediabetes and T2DM groups were significantly higher than those in the control group. The urine microalbumin-to-creatinine ratio (ACR) was mildly and moderately increased in the prediabetes and T2DM groups, respectively. The estimated glomerular filtration rate of the three groups was within the normal range. SD-OCTA showed that VAD in the superficial macular area was decreased in the prediabetes group compared to the control group (p = 0.01). The FAZ size, particularly in the deep layer, was expanded in the prediabetes group. In the deep retinal layer of the macular area, VD and FAZ size in the prediabetes group were larger than those in the control group. In the prediabetes group, the axial length was significantly correlated with macular VD and FAZ size (p < 0.05), and ACR was correlated with FAZ size (p < 0.05). Age had a negative correlation with VAD (p < 0.01). ACR had a positive correlation with FAZ size (p < 0.05). CONCLUSIONS Enlargement and irregularity of the FAZ area, deep capillary dilation, and a decrease in VAD occur in the retina of prediabetic patients with mild kidney function impairment.
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Affiliation(s)
- Yi Xu
- Department of Preventative Ophthalmology, Shanghai Eye Disease Prevention and Treatment Center/Shanghai Eye Hospital, Shanghai, China
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Engineering Research Center of Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China
- National Clinical Research Center for Eye Diseases, Shanghai, China
- Shanghai Key Laboratory of Fundus Diseases, Shanghai, China
| | - Xiaofeng Zhu
- Department of Preventative Ophthalmology, Shanghai Eye Disease Prevention and Treatment Center/Shanghai Eye Hospital, Shanghai, China,
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China,
- Shanghai Engineering Research Center of Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China,
- National Clinical Research Center for Eye Diseases, Shanghai, China,
- Shanghai Key Laboratory of Fundus Diseases, Shanghai, China,
| | - Yongyi Wang
- Department of Medical Administration, Huizhou First Hospital, Huizhou, China
| | - Zhongdi Chu
- Departments of Bioengineering and Ophthalmology, University of Washington, Seattle, Washington, USA
| | - Ruikang K Wang
- Departments of Bioengineering and Ophthalmology, University of Washington, Seattle, Washington, USA
| | - Lina Lu
- Department of Preventative Ophthalmology, Shanghai Eye Disease Prevention and Treatment Center/Shanghai Eye Hospital, Shanghai, China
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Engineering Research Center of Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China
- National Clinical Research Center for Eye Diseases, Shanghai, China
- Shanghai Key Laboratory of Fundus Diseases, Shanghai, China
| | - Haidong Zou
- Department of Preventative Ophthalmology, Shanghai Eye Disease Prevention and Treatment Center/Shanghai Eye Hospital, Shanghai, China
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Engineering Research Center of Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China
- National Clinical Research Center for Eye Diseases, Shanghai, China
- Shanghai Key Laboratory of Fundus Diseases, Shanghai, China
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Lechner J, Medina RJ, Lois N, Stitt AW. Advances in cell therapies using stem cells/progenitors as a novel approach for neurovascular repair of the diabetic retina. Stem Cell Res Ther 2022; 13:388. [PMID: 35907890 PMCID: PMC9338609 DOI: 10.1186/s13287-022-03073-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 07/20/2022] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND Diabetic retinopathy, a major complication of diabetes mellitus, is a leading cause of sigh-loss in working age adults. Progressive loss of integrity of the retinal neurovascular unit is a central element in the disease pathogenesis. Retinal ischemia and inflammatory processes drive interrelated pathologies such as blood retinal barrier disruption, fluid accumulation, gliosis, neuronal loss and/or aberrant neovascularisation. Current treatment options are somewhat limited to late-stages of the disease where there is already significant damage to the retinal architecture arising from degenerative, edematous and proliferative pathology. New preventive and interventional treatments to target early vasodegenerative and neurodegenerative stages of the disease are needed to ensure avoidance of sight-loss. MAIN BODY Historically, diabetic retinopathy has been considered a primarily microvascular disease of the retina and clinically it is classified based on the presence and severity of vascular lesions. It is now known that neurodegeneration plays a significant role during the pathogenesis. Loss of neurons has been documented at early stages in pre-clinical models as well as in individuals with diabetes and, in some, even prior to the onset of clinically overt diabetic retinopathy. Recent studies suggest that some patients have a primarily neurodegenerative phenotype. Retinal pigment epithelial cells and the choroid are also affected during the disease pathogenesis and these tissues may also need to be addressed by new regenerative treatments. Most stem cell research for diabetic retinopathy to date has focused on addressing vasculopathy. Pre-clinical and clinical studies aiming to restore damaged vasculature using vasoactive progenitors including mesenchymal stromal/stem cells, adipose stem cells, CD34+ cells, endothelial colony forming cells and induced pluripotent stem cell derived endothelial cells are discussed in this review. Stem cells that could replace dying neurons such as retinal progenitor cells, pluripotent stem cell derived photoreceptors and ganglion cells as well as Müller stem cells are also discussed. Finally, challenges of stem cell therapies relevant to diabetic retinopathy are considered. CONCLUSION Stem cell therapies hold great potential to replace dying cells during early and even late stages of diabetic retinopathy. However, due to the presence of different phenotypes, selecting the most suitable stem cell product for individual patients will be crucial for successful treatment.
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Affiliation(s)
- Judith Lechner
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry, and Biomedical Science, Queen's University Belfast, Belfast, UK.
| | - Reinhold J Medina
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry, and Biomedical Science, Queen's University Belfast, Belfast, UK
| | - Noemi Lois
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry, and Biomedical Science, Queen's University Belfast, Belfast, UK
| | - Alan W Stitt
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry, and Biomedical Science, Queen's University Belfast, Belfast, UK.
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Srinivasan S, Sivaprasad S, Rajalakshmi R, Anjana RM, Malik RA, Kulothungan V, Natarajan V, Raman R, Bhende M. Early retinal functional alteration in relation to diabetes duration in patients with type 2 diabetes without diabetic retinopathy. Sci Rep 2022; 12:11422. [PMID: 35794201 PMCID: PMC9259684 DOI: 10.1038/s41598-022-15425-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 06/23/2022] [Indexed: 12/24/2022] Open
Abstract
To examine the retinal structure and function in relation to diabetes duration and glycemia in patients without diabetic retinopathy (DR). 85 adults with type 2 diabetes without DR or macular edema underwent dilated indirect ophthalmoscopy, optical coherence tomography (OCT), ultra-wide field fundus photography, multifocal electroretinography (mfERG) and HbA1C assessment. Patients were stratified as those with diabetes duration < 10 years and ≥ 10 years. Right eyes of all participants were analyzed. mfERG was analysed as ring 12, 34, 56. No significant differences were noted in OCT-derived retinal thickness measures between groups. mfERG P1 latencies were delayed, and amplitudes (nV/deg2) were reduced in all three rings in those with diabetes duration ≥ 10 years vs. < 10 years, with significant correlations to diabetes duration in all rings. Logistic regression showed that duration of diabetes ≥ 10 years was associated with greater age (odds ratio (OR) 1.081, 95% CI 1.022, 1.143) and lower P1 amplitudes in the middle ring (OR 0.924, 95% CI 0.854, 0.999). No significant correlations were observed between HbA1c and retinal measures. In the absence of DR, early retinal functional alterations are detectable on mfERG in patients with longer diabetes duration, but with no difference in OCT-derived retinal thickness.
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Affiliation(s)
| | - Sobha Sivaprasad
- grid.512112.4NIHR Moorfields Biomedical Research Centre, London, UK
| | - Ramachandran Rajalakshmi
- grid.429336.90000 0004 1794 3718Dr. Mohan’s Diabetes Specialties Centre and Madras Diabetes Research Foundation, Chennai, India
| | - Ranjit Mohan Anjana
- grid.429336.90000 0004 1794 3718Dr. Mohan’s Diabetes Specialties Centre and Madras Diabetes Research Foundation, Chennai, India
| | - Rayaz A. Malik
- grid.416973.e0000 0004 0582 4340Weill Cornell Medicine-Qatar, Education City, Doha, Qatar ,grid.498924.a0000 0004 0430 9101Central Manchester University Hospitals Foundation Trust, Manchester, UK
| | - Vaitheeswaran Kulothungan
- grid.508060.bNational Centre for Disease Informatics and Research (NCDIR) & Indian Council of Medical Research (ICMR), Bangalore, India
| | - Viswanathan Natarajan
- grid.414795.a0000 0004 1767 4984Department of Preventive Ophthalmology, Sankara Nethralaya, Chennai, India
| | - Rajiv Raman
- grid.414795.a0000 0004 1767 4984Shri Bhagwan Mahavir Vitreoretinal Services, Sankara Nethralaya, Chennai, India
| | - Muna Bhende
- grid.414795.a0000 0004 1767 4984Shri Bhagwan Mahavir Vitreoretinal Services, Sankara Nethralaya, Chennai, India
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Association of prediabetes with retinal microvasculature on swept-source optical coherence tomography angiography in the elderly. Retina 2022; 42:1130-1136. [DOI: 10.1097/iae.0000000000003416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Ratra D, Dalan D, Prakash N, Kaviarasan K, Thanikachalam S, Das UN, Angayarkanni N. Quantitative analysis of retinal microvascular changes in prediabetic and diabetic patients. Indian J Ophthalmol 2021; 69:3226-3234. [PMID: 34708778 PMCID: PMC8725133 DOI: 10.4103/ijo.ijo_1254_21] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Purpose: To evaluate and correlate retinal microvascular changes in prediabetic and diabetic patients with functional and systemic parameters. Methods: Optical coherence tomography angiography (OCTA) was performed on all subjects after medical evaluation and laboratory investigations for blood sugar, glycosylated hemoglobin, and others. Automated quantification of vascular indices of the superficial plexus were analyzed. Results: Hundred and eleven persons (222 eyes) were grouped into prediabetic (PDM) (60 eyes), diabetic without retinopathy (NDR) (56 eyes), diabetic with retinopathy (DR) (66 eyes), and healthy controls (CTR) (40 eyes). The superficial retinal capillary plexus showed no significant changes in the prediabetic and NDR groups; however, central foveal thickness (CFT) was significantly reduced in PDM (P = 0.04). The circularity of the foveal avascular zone (FAZ) (P = 0.03) and the vessel density (VD) (P = 0.01) showed significant reduction from PDM to NDR. All vascular parameters were significantly reduced in DR and correlated with disease severity. The CFT correlated significantly with FAZ area. The VD and perfusion density were seen to correlate significantly with HbA1c and contrast sensitivity. The visual acuity was significantly correlated with the FAZ. Logistic regression revealed VD [OR 20.42 (7.9–53)] and FAZ perimeter [OR 9.8 (4.2–23.2)] as the strongest predictors of DR. Conclusion: The changes in OCTA can help predict onset of DR. FAZ changes are seen in early stages and are correlated well with systemic parameters, making it an easy target to monitor and screen for severity of DR. Significant reduction in the CFT in PDM suggests that neuronal damage precedes vascular changes.
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Affiliation(s)
- Dhanashree Ratra
- Department of Vitreoretinal Diseases, Medical Research Foundation, Sankara Nethralaya, Chennai, Tamil Nadu, India
| | - Daleena Dalan
- Department of Vitreoretinal Diseases, Medical Research Foundation, Sankara Nethralaya, Chennai, Tamil Nadu, India
| | - Nandini Prakash
- RS Mehta Jain Department of Biochemistry, Vision Research Foundation, Chennai, Tamil Nadu, India
| | - Kuppan Kaviarasan
- Department of Biomedical Sciences, Sri Ramachandra Institute of Higher Education and Research, Chennai, Tamil Nadu, India
| | - Sadagopan Thanikachalam
- Cardiology Care Center, Sri Ramachandra Institute of Higher Education and Research, Chennai, Tamil Nadu, India
| | - Undurti N Das
- BioScience Research Centre, GVP Hospital and Medical College, Visakhapatnam, Andhra Pradesh, India
| | - Narayansamy Angayarkanni
- RS Mehta Jain Department of Biochemistry, Vision Research Foundation, Chennai, Tamil Nadu, India
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13
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Huang H, Kuang X, Zhu X, Cheng H, Zou Y, Du H, Tang H, Zhou L, Zeng J, Liu H, Yan J, Long C, Shen H. Maintaining blood retinal barrier homeostasis to attenuate retinal ischemia-reperfusion injury by targeting the KEAP1/NRF2/ARE pathway with lycopene. Cell Signal 2021; 88:110153. [PMID: 34571190 DOI: 10.1016/j.cellsig.2021.110153] [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: 03/22/2021] [Revised: 09/13/2021] [Accepted: 09/16/2021] [Indexed: 12/15/2022]
Abstract
Retinal ischemia-reperfusion (I/R) often results in intractable visual impairments, where blood retinal barrier (BRB) homeostasis mediated by retinal pigment epithelium (RPE) and retinal microvascular endothelium (RME) is crucial. However, strategies targeting the BRB are limited. Thus, we investigated the inconclusive effect of lycopene (LYC) in retinal protection under I/R. LYC elevated cellular viability and reversed oxidative stress in aRPE-19 cells/hRME cells under I/R conditions based on oxygen-glucose deprivation (OGD) in vitro. Molecular analysis showed that LYC promoted NRF2 expression and enhanced the downstream factors of the KEAP1/NRF2/ARE pathway: LYC increased the activities of antioxidants, including SOD and CAT, whereas it enhanced the mRNA expression of HO-1 (ho-1) and NQO-1 (nqo-1). The activation resulted in restrained ROS and MDA. On the other hand, LYC ameliorated the damage to retinal function and morphology in a mouse I/R model, which was established by unilateral ligation of the left pterygopalatine artery/external carotid artery and reperfusion. LYC promoted the expression of NRF2 in both the neural retina and the RPE choroid in vivo. This evidence revealed the potential of LYC in retinal protection under I/R, uncovering the pharmacological effect of the KEAP1/NRF2/ARE pathway in BRB targeting. The study generates new insights into scientific practices in retinal research.
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Affiliation(s)
- Hao Huang
- State Key laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China; Department of Ophthalmology, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou 510120, China
| | - Xielan Kuang
- State Key laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China; Biobank of Eye, State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China
| | - Xiaobo Zhu
- State Key laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China
| | - Hao Cheng
- Department of Ophthalmology, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou 510120, China
| | - Yuxiu Zou
- State Key laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China
| | - Han Du
- State Key laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China
| | - Han Tang
- State Key laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China
| | - Linbin Zhou
- State Key laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China
| | - Jingshu Zeng
- State Key laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China
| | - Huijun Liu
- State Key laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China
| | - Jianhua Yan
- State Key laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China
| | - Chongde Long
- State Key laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China.
| | - Huangxuan Shen
- State Key laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China; Biobank of Eye, State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China.
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14
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Reduction of Glut1 in the Neural Retina But Not the RPE Alleviates Polyol Accumulation and Normalizes Early Characteristics of Diabetic Retinopathy. J Neurosci 2021; 41:3275-3299. [PMID: 33622781 DOI: 10.1523/jneurosci.2010-20.2021] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 12/16/2020] [Accepted: 02/11/2021] [Indexed: 01/04/2023] Open
Abstract
Hyperglycemia is a key determinant for development of diabetic retinopathy (DR). Inadequate glycemic control exacerbates retinopathy, while normalization of glucose levels delays its progression. In hyperglycemia, hexokinase is saturated and excess glucose is metabolized to sorbitol by aldose reductase via the polyol pathway. Therapies to reduce retinal polyol accumulation for the prevention of DR have been elusive because of low sorbitol dehydrogenase levels in the retina and inadequate inhibition of aldose reductase. Using systemic and conditional genetic inactivation, we targeted the primary facilitative glucose transporter in the retina, Glut1, as a preventative therapeutic in diabetic male and female mice. Unlike WT diabetics, diabetic Glut1 +/- mice did not display elevated Glut1 levels in the retina. Furthermore, diabetic Glut1 +/- mice exhibited ameliorated ERG defects, inflammation, and oxidative stress, which was correlated with a significant reduction in retinal sorbitol accumulation. Retinal pigment epithelium-specific reduction of Glut1 did not prevent an increase in retinal sorbitol content or early hallmarks of DR. However, like diabetic Glut1 +/- mice, reduction of Glut1 specifically in the retina mitigated polyol accumulation and diminished retinal dysfunction and the elevation of markers for oxidative stress and inflammation associated with diabetes. These results suggest that modulation of retinal polyol accumulation via Glut1 in photoreceptors can circumvent the difficulties in regulating systemic glucose metabolism and be exploited to prevent DR.SIGNIFICANCE STATEMENT Diabetic retinopathy affects one-third of diabetic patients and is the primary cause of vision loss in adults 20-74 years of age. While anti-VEGF and photocoagulation treatments for the late-stage vision threatening complications can prevent vision loss, a significant proportion of patients do not respond to anti-VEGF therapies, and mechanisms to stop progression of early-stage symptoms remain elusive. Glut1 is the primary facilitative glucose transporter for the retina. We determined that a moderate reduction in Glut1 levels, specifically in the retina, but not the retinal pigment epithelium, was sufficient to prevent retinal polyol accumulation and the earliest functional defects to be identified in the diabetic retina. Our study defines modulation of Glut1 in retinal neurons as a targetable molecule for prevention of diabetic retinopathy.
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15
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Frizziero L, Midena G, Longhin E, Berton M, Torresin T, Parrozzani R, Pilotto E. Early Retinal Changes by OCT Angiography and Multifocal Electroretinography in Diabetes. J Clin Med 2020; 9:jcm9113514. [PMID: 33143008 PMCID: PMC7692230 DOI: 10.3390/jcm9113514] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 10/26/2020] [Accepted: 10/29/2020] [Indexed: 12/21/2022] Open
Abstract
Background: To evaluate the earliest retinal morphological and functional changes in diabetic eyes without or with early signs of diabetic retinopathy (DR). Methods: Twenty-two eyes with no DR (noDR group), 22 eyes with mild DR (DR group), and 18 healthy nondiabetic eyes (controls) were enrolled. All eyes were studied by means of spectral domain optical coherence tomography (OCT), OCT angiography (OCTA), and multifocal electroretinogram (mfERG). Results: A significantly higher number of OCT hyperreflective intraretinal foci (HRF) was found in both noDR and DR groups versus controls, but not between DR groups. The OCTA parameters of the superficial vascular plexus (SVP) were significantly reduced in the noDR group both versus controls and DR group (p < 0.05). The OCTA parameters of the intermediate capillary plexus (ICP) were significantly reduced in the DR group versus controls. An increased number of altered hexagons on mfERG was found in the noDR versus the DR group (p = 0.0192). Conclusions: Retinal vascular and functional parameters are differently involved in diabetic eyes; major vascular changes in the SVP and functional alterations of the mfERG are present in diabetic eyes with no clinical microvascular signs of DR, while ICP is mainly involved when early ophthalmoscopic signs of DR are present. The integrated use of mfERG and OCTA provides new significant insights into the pathogenesis of diabetic related retinal disease.
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Affiliation(s)
- Luisa Frizziero
- IRCCS—Fondazione Bietti, 00198 Rome, Italy
- Correspondence: ; Tel.: +39-049-821-2110
| | - Giulia Midena
- Institute of Ophthalmology, Policlinico Gemelli, IRCCS, 00168 Rome, Italy;
| | - Evelyn Longhin
- Department of Ophthalmology, University of Padova, 35128 Padova, Italy; (E.L.); (T.T.); (R.P.); (E.P.)
| | | | - Tommaso Torresin
- Department of Ophthalmology, University of Padova, 35128 Padova, Italy; (E.L.); (T.T.); (R.P.); (E.P.)
| | - Raffaele Parrozzani
- Department of Ophthalmology, University of Padova, 35128 Padova, Italy; (E.L.); (T.T.); (R.P.); (E.P.)
| | - Elisabetta Pilotto
- Department of Ophthalmology, University of Padova, 35128 Padova, Italy; (E.L.); (T.T.); (R.P.); (E.P.)
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