Early Diabetic Retinopathy Research Articles

Effective Fundus Image Decomposition for the Detection of Red Lesions and Hard Exudates to Aid in the Diagnosis of Diabetic Retinopathy.

Diabetic retinopathy (DR) is characterized by the presence of red lesions (RLs), such as microaneurysms and hemorrhages, and bright lesions, such as exudates (EXs). Early DR diagnosis is paramount to prevent serious sight damage. Computer-assisted diagnostic systems are based on the detection of those lesions through the analysis of fundus images. In this paper, a novel method is proposed for the automatic detection of RLs and EXs. As the main contribution, the fundus image was decomposed into various layers, including the lesion candidates, the reflective features of the retina, and the choroidal vasculature visible in tigroid retinas. We used a proprietary database containing 564 images, randomly divided into a training set and a test set, and the public database DiaretDB1 to verify the robustness of the algorithm. Lesion detection results were computed per pixel and per image. Using the proprietary database, 88.34% per-image accuracy (ACCi), 91.07% per-pixel positive predictive value (PPVp), and 85.25% per-pixel sensitivity (SEp) were reached for the detection of RLs. Using the public database, 90.16% ACCi, 96.26% PPV_p, and 84.79% SEp were obtained. As for the detection of EXs, 95.41% ACCi, 96.01% PPV_p, and 89.42% SE_p were reached with the proprietary database. Using the public database, 91.80% ACCi, 98.59% PPVp, and 91.65% SEp were obtained. The proposed method could be useful to aid in the diagnosis of DR, reducing the workload of specialists and improving the attention to diabetic patients.

Observation and quantification of diabetic keratopathy in type 2 diabetes patients using in vivo laser confocal microscopy

Objective: To study the diabetic keratopathy in type 2 diabetes patients with retinopathy by in vivo laser confocal microscopy. Methods: This was a case-control study. Ninety type 2 diabetes patients were involved in this study from May 2015 to December 2019 in Qingdao Eye Hospital. According to the diabetic retinopathy clinical stage, these patients were divided into the non-proliferative diabetic retinopathy (NPDR) group (30 cases), early stage proliferative diabetic retinopathy (PDR) group (30 cases) and intermediate to late stage PDR group (30 cases). Thirty non-diabetic healthy volunteers were included in the control group. The central cornea was observed with an in vivo laser confocal microscope. The corneal nerve fiber density, nerve fiber length, nerve branch density, and nerve fiber tortuosity were compared between groups. The corneal Langerhans cells, epithelial cells, stromal cells and endothelial cells were also compared. Results: There were more nerve fibers and branches in the control group than the other three diabetic groups. The nerve fiber length in the control group, NPDR group, early stage PDR group and intermediate to late stage PDR group was (21.55±2.57), (14.73±1.56), (11.23±1.40) and (8.02±1.33) mm/mm2, respectively, and there were statistically significant differences between the groups (F=316.17, P=0.00). In the nerve fiber density, nerve branch density and curvature, there were statistically significant differences between the groups (F=345.72, 479.46, 167.00, all P=0.00). The basal cell density in the control group, NPDR group, and two PDR groups was (5 761±303), (5 336±367), (4 146±379) and (3 658±365) cells/mm2, respectively, and there were statistically significant differences between the groups (F=234.94, P=0.00). The anterior stromal cell density in the four groups was (836±30), (727±57), (544±59) and (360±47) cells/mm2, respectively, and there were statistically significant differences between the groups (F=535.08, P=0.00). The hexagonal endothelium cell rate in the four groups was 62.0%±5.5%, 51.1%±3.7%, 40.2%±4.0% and 27.8%±3.9%, respectively, and the Langerhans cell density was (1.5±0.6), (4.2±1.3), (6.8±2.1) and (10.9±2.1) cells/mm2, respectively; there were statistically significant differences between the groups (F=342.28, 179.78, all P=0.00). There was no statistically significant difference between the groups in the corneal endothelial cell density (F=1.58, P=0.20). Conclusions: In type 2 diabetes patients with diabetic retinopathy, the corneal nerve fiber and branch density can be significantly reduced, and the density of the hexagonal corneal endothelial cells, epithelial basal cells and anterior stromal cells can also decrease. Langerhans cells may be involved in the development diabetic keratopathy. (Chin J Ophthalmol, 2020, 56: 754-760).

A comprehensive diagnosis system for early signs and different diabetic retinopathy grades using fundus retinal images based on pathological changes detection

Multi-label classification (MLC) is deemed as an effective and dynamic research topic in the medical image analysis field. For ophthalmologists, MLC benefits can be utilized to detect early diabetic retinopathy (DR) signs, as well as its different grades. This paper proposes a comprehensive computer-aided diagnostic (CAD) system that exploits the MLC of DR grades using colored fundus photography. The proposed system detects and analyzes various retina pathological changes accompanying DR development. We extracted some significant features to differentiate healthy from DR cases as well as differentiate various DR grades. First, we preprocessed the retinal images to eliminate noise and enhance the image quality by using histogram equalization for brightness preservation based on dynamic stretching technique. Second, the images were segmented to extract four pathology variations, which are blood vessels, exudates, microaneurysms, and hemorrhages. Next, six various features were extracted using a gray level co-occurrence matrix, the four extracting areas, and blood-vessel bifurcation points. Finally, the features were supplied to a support vector machine (SVM) classifier to distinguish normal and different DR grades. To train and test the proposed system, we utilized four benchmark datasets (two of them are multi-label datasets) using six performance metrics. The proposed system achieved an average accuracy of 89.2%, sensitivity of 85.1%, specificity of 85.2%, positive predictive value of 92.8%, area under the curve of 85.2%, and Disc similarity coefficient (DSC) of 88.7%. The experiments show promising results as compared with other systems.

Comprehensive analysis of angiogenesis-related genes and pathways in early diabetic retinopathy

BackgroundAngiogenesis is an important parameter in the development of diabetic retinopathy (DR), and it is indicative of an early stage evolving into a late phase. Therefore, examining the role of angiogenic factors in early DR is crucial to understanding the mechanism of neovascularization.MethodsThe present study identified hub genes and pathways associated with angiogenesis in early DR using bioinformatics analysis. Genes from published literature and Gene Expression Omnibus (GEO) were collected and analysed.ResultsWe collected 73 genes from 70 published studies in PubMed, which were referred to as DR-related gene set 1 (DRgset1). The gene expression profile of GSE12610 was downloaded, and 578 differentially expressed genes (DEGs) between diabetic and normal samples were identified. DEGs and DRgset1 were further combined to create DR-related gene set 2 (DRgset2). After an enrichment analysis, we identified 12 GO terms and 2 pathways associated with neovascularization in DRgset1, and 8 GO terms and 2 pathways in DRgset2. We found 39 new genes associated with angiogenesis and verified 8 candidate angiogenesis-related genes in DR cells using real-time PCR: PIK3CB, ALDH3A1, ITGA7, FGF23, THBS1, COL1A1, MAPK13, and AIF1. We identified 10 hub genes associated with neovascularization by constructing a protein-protein interaction (PPI) network: TNF, VEGFA, PIK3CB, TGFB1, EDN1, MMP9, TLR4, PDGFB, MMP2, and THBS1.ConclusionsThe present study analysed angiogenesis-related genes and pathways in early DR in a comprehensive and systematic manner. PIK3CB, ALDH3A1, ITGA7, FGF23, THBS1, COL1A1, MAPK13, and AIF1 may be the candidate genes to further explore the mechanisms of angiogenesis in early DR. TNF, PIK3CB, TGFB1, EDN1, MMP9, TLR4, PDGFB, MMP2, and THBS1 may be new targets for early neovascularization therapy in the future.

Successful induction of diabetes in mice demonstrates no gender difference in development of early diabetic retinopathy.

PurposeFemale mice have been found to be resistant to streptozotocin (STZ)-induced diabetes, and pre-clinical research related to diabetic complications commonly omits females. The purpose of this study was to develop a method to induce diabetes in female mice, and to determine if retinas of diabetic female mice develop molecular changes and histopathological abnormalities comparable to those which develop in male diabetic mice.MethodsTo induce diabetes, animals of both sexes received daily intraperitoneal (i.p.) injection of STZ for 5 consecutive days at 55 mg/kg BW (a dose that is known to induce diabetes in male mice) or for females, 75 mg/kg BW of STZ. Retinal abnormalities that have been implicated in the development of the retinopathy (superoxide generation and expression of inflammatory proteins, iNOS and ICAM-1) were evaluated at 2 months of diabetes, and retinal capillary degeneration was evaluated at 8 months of diabetes.ResultsDaily i.p. injection of STZ for 5 consecutive days at a concentration of 55 mg/kg BW was sufficient to induce diabetes in 100% of male mice, but only 33% of female mice. However, females did become hyperglycemic when the dose of STZ administered was increased to 75 mg/kg BW. The resulting STZ-induced hyperglycemia in female and male mice was sustained for at least 8 months. After induction of the diabetes, both sexes responded similarly with respect to the oxidative stress, expression of iNOS, and degeneration of retinal capillaries, but differed in the limited population evaluated with respect to expression of ICAM-1.ConclusionsThe resistance of female mice to STZ-induced diabetes can be overcome by increasing the dose of STZ used. Female mice can, and should, be included in pre-clinical studies of diabetes and its complications.

Vascular Density of Deep, Intermediate and Superficial Vascular Plexuses Are Differentially Affected by Diabetic Retinopathy Severity.

PurposeThe purpose of this study was to evaluate differences in optical coherence tomography angiography (OCTA) metrics in the superficial (SCP), intermediate (ICP), and deep (DCP) vascular plexuses across diabetic retinopathy (DR) severity levels.MethodsThis was a cross sectional observational retrospective chart review study. Eligible patients with diabetes who underwent same day RTVue XR Avanti OCTA, spectral-domain optical coherence tomography (SD-OCT), and 200-degree Optos ultrawide field color imaging. SCP, ICP, and DCP vessel density (VD) and vessel length density (VLD) were assessed using 3-D projection artifact removal software (PAROCTA) software.ResultsOf 396 eyes (237 patients), 16.1% had no DR, 26.9% mild nonproliferative DR (NPDR), 21.1% moderate NPDR, 12.1% severe NPDR, 10.1% proliferative DR (PDR) without panretinal photocoagulation (PRP), and 13.4% PDR with PRP. When comparing mild NPDR to no DR eyes, ICP and DCP VD and VLD were significantly lower, but there was no difference for SCP metrics. In eyes with more severe DR, there were significant differences in SCP VD and VLD between DR severity levels (mild versus moderate NPDR: VD 35.45 ± 3.31 vs. 34.14 ± 3.38, P = 0.008 and VLD 17.59 ± 1.83 vs. 16.80 ± 1.83, P = 0.003; moderate versus severe NPDR: VLD 16.80 ± 1.83 vs. 15.79 ± 1.84, P = 0.019), but no significant differences in ICP or DCP.ConclusionsAlthough VD of each of the three individual layers decreases with increasing DR severity, DR severity has a substantially different effect on OCTA parameters within each layer. Vascular changes in eyes with no to early DR were present primarily in the deeper vascular layers, whereas in eyes with advanced DR the opposite was observed. This study highlights the effects of ICP and the importance of assessing SCP and DCP changes independently across each DR severity level.

Pemafibrate Protects Against Retinal Dysfunction in a Murine Model of Diabetic Retinopathy.

Diabetic retinopathy (DR) is one of the leading causes of blindness globally. Retinal neuronal abnormalities occur in the early stage in DR. Therefore, maintaining retinal neuronal activity in DR may prevent vision loss. Previously, pemafibrate, a novel selective peroxisome proliferator-activated receptor alpha modulator, was suggested as a promising drug in hypertriglyceridemia. However, the role of pemafibrate remains obscure in DR. Therefore, we aimed to unravel systemic and retinal changes by pemafibrate in diabetes. Adult mice were intraperitoneally injected with streptozotocin (STZ) to induce diabetes. After STZ injection, diet supplemented with pemafibrate was given to STZ-induced diabetic mice for 12 weeks. During the experiment period, body weight and blood glucose levels were examined. Electroretinography was performed to check the retinal neural function. After sacrifice, the retina, liver, and blood samples were subjected to molecular analyses. We found pemafibrate mildly improved blood glucose level as well as lipid metabolism, boosted liver function, increased serum fibroblast growth factor21 level, restored retinal functional deficits, and increased retinal synaptophysin protein expression in STZ-induced diabetic mice. Our present data suggest a promising pemafibrate therapy for the prevention of early DR by improving systemic metabolism and protecting retinal function.

Pattern-Reversal Visual Evoked Potentials Tests in Persons with Type 2 Diabetes Mellitus with and without Diabetic Retinopathy.

Background Currently, diabetic retinopathy (DR) has a wide recognition as a neurovascular rather than a microvascular diabetic complication with an increasing need for enhanced detection approaches. Pattern-reversal visual evoked potentials (PRVEPs) test, as an objective electrophysiological measure of the optic nerve and retinal function, can be of great value in the detection of diabetic retinal changes. Objectives The use of two sizes of checkerboard PRVEPs testing to detect any neurological changes in persons with type 2 diabetes mellitus (T2DM) with and without a clinically detected DR. Also, to compare the results according to the candidate age, duration, and glycemic status of T2DM. Methods This study included 50 candidates as group A with T2DM and did not have a clinically detected DR and 50 candidates as group B with T2DM and had a clinically detected early DR and 50 candidates as controls who were neither diabetic nor had any other medical or ophthalmic condition that might affect PRVEPs test results. The PRVEPs were recorded in the consultant unit of ophthalmology in Almawani Teaching Hospital. Monocular PRVEPs testing of both eyes was done by using large (60 min) and small (15 min) checks to measure N75 latency and P100 latency and amplitude. Results There was a statistically significant P100 latency delay and P100 amplitude reduction in both groups A and B in comparison with the controls. The difference between groups A and B was also significant. In both test results of groups A and B, the proportions of abnormal P100 latency were higher than those of P100 amplitude with a higher abnormal proportions in 15 min test. Conclusions The PRVEP test detected neurological changes, mainly as conductive alterations affecting mostly the foveal region prior to any overt DR clinical changes, and these alterations were heightened by the presence of DR clinical changes.

Effect of panretinal photocoagulation on macular vasculature using optical coherence tomography angiography.

To evaluate the changes of macular vascular density in the superficial capillary (SCP) and the deep capillary plexus (DCP), foveal avascular area (FAZ), choroidal flow, and macular thickness after pan-retinal photocoagulation (PRP). In this prospective interventional non-comparative case series, patients with very severe nonproliferative (NPDR) and early proliferative diabetic retinopathy (PDR) and no significant macular edema who were candidates for pan-retinal photocoagulation underwent measurement of corrected distance visual acuity (CDVA), optical coherence tomography (OCT), Optical coherence tomography angiography (OCTA) at the baseline, 1, and 6 months following completion of PRP treatment. Thirty-nine eyes from 21 patients with diabetes were enrolled. Superficial and deep capillary plexus densities in the foveal and parafoveal area didn't change significantly 1 and 6 months post-PRP (p > 0.1 in all of them). The FAZ area constricted 6 months following PRP (p = 0.075). Based on the calculated circularity index, the FAZ became significantly more circular after 6 months of follow-up (p = 0.047). Although the choroidal flow area increased after PRP this increase wasn't statically significant neither at 1 month nor at 6 months post-PRP (p = 0.31 and 0.23, respectively). Although OCTA parameters were not significantly affected by PRP at both short-term (1 month) and long-term (6 months) follow-ups, the FAZ area became significantly circular after PRP may be due to redistribution of blood flow in hypoperfused foveal capillary plexus.

Short note on Diabetic Retinopathy

Diabetic retinopathy is an eye disease or condition that can cause vision and blindness in people who have diabetes. It also effects the blood vessels in the retina the sensitivities layer of tissue in the eyes. Diabetic patient needs to get eye check up at least once in year. At early stages diabetic retinopathy may not have any symptoms but finding it in the early stages can protect from the loss of vision. Diabetics ca n be controlled by staying physically active, eating healthy, taking medication regularly.

Leveraging Multimodal Deep Learning Architecture with Retina Lesion Information to Detect Diabetic Retinopathy.

PurposeTo improve disease severity classification from fundus images using a hybrid architecture with symptom awareness for diabetic retinopathy (DR).MethodsWe used 26,699 fundus images of 17,834 diabetic patients from three Taiwanese hospitals collected in 2007 to 2018 for DR severity classification. Thirty-seven ophthalmologists verified the images using lesion annotation and severity classification as the ground truth. Two deep learning fusion architectures were proposed: late fusion, which combines lesion and severity classification models in parallel using a postprocessing procedure, and two-stage early fusion, which combines lesion detection and classification models sequentially and mimics the decision-making process of ophthalmologists. Messidor-2 was used with 1748 images to evaluate and benchmark the performance of the architecture. The primary evaluation metrics were classification accuracy, weighted κ statistic, and area under the receiver operating characteristic curve (AUC).ResultsFor hospital data, a hybrid architecture achieved a good detection rate, with accuracy and weighted κ of 84.29% and 84.01%, respectively, for five-class DR grading. It also classified the images of early stage DR more accurately than conventional algorithms. The Messidor-2 model achieved an AUC of 97.09% in referral DR detection compared to AUC of 85% to 99% for state-of-the-art algorithms that learned from a larger database.ConclusionsOur hybrid architectures strengthened and extracted characteristics from DR images, while improving the performance of DR grading, thereby increasing the robustness and confidence of the architectures for general use.Translational RelevanceThe proposed fusion architectures can enable faster and more accurate diagnosis of various DR pathologies than that obtained in current manual clinical practice.

Assessment of Macular Perfusion in Early Diabetic Retinopathy Patient Using Optical Coherence Tomography Angiography..

Abstract Background: The chronic hyperglycemia of diabetes leads to long-term damage, and deterioration of different organs, especially the eyes, kidneys, nerves, and blood vessels. The riskiest complication includes diabetic retinopathy and maculopathy. Aim of the study: Assessment of macular perfusion in early subclinical diabetic retinopathy patients by using noninvasive technology Optical Coherence Tomography Angiography (OCTA), to prevent vision loss. Patients and methods: a prospective case series observational study includes 44 eyes for 33 candidates, 30 eyes for diabetic Patients and 14 eyes for normal non-diabetic, Patients' Age group is 30 – 60 years old. Results: regarding both groups diabetic and non-diabetic, patients with normal fundus picture, 46.2% had very mild to mild affection of macular perfusion (SVP-VD 50 ± 3.5%, DVP-VD 56 ± 3.0%) with FAZ perimeter range (1.3-1.5) mm, 53.8% did not have macular perfusion affection and none of the patients had moderate affection of macular perfusion. While patients whom fundus picture showing mild-NPDR, 11.1% had very mild to mild affection of macular perfusion and 88.9% had moderate affection of macular perfusion (SVP –VD 45 ± 4.5%, DVP-VD 50 ± 4.0%) with FAZ perimeter range (1.7-2.8) mm, a significant difference between groups (P-value <.0001). Conclusion: Macular perfusion is markedly affected by diabetes duration despite of good clinical fundus picture. OCTA is very beneficial in investigating diabetic maculopathy and ischemia in early stages. Keywords: Macular Perfusion, Diabetic Retinopathy, Optical Coherence Tomography Angiography.

Long-term lutein administration attenuates retinal inflammation and functional deficits in early diabetic retinopathy using the Ins2Akita/+ mice

IntroductionLutein is a carotenoid whose protective effects in the retina have been reported in various studies. The effect of lutein has not been reported in the retina of the Ins2Akita/+...

ASSESSMENT OF THE EFFECT OF PANRETINAL PHOTOCOAGULATION (PRP) ON MACULAR THICKNESS IN EYES WITH PROLIFERATIVE DIABETIC RETINOPATHY (PDR) WITHOUT CLINICALLY SIGNIFICANT MACULAR EDEMA

Background: Proliferative diabetic retinopathy (PDR) is the most advanced stage of DR. It significantly increases the risk for progressive vision loss, and without intervention, approximately one half of eyes ultimately experience severe vision loss. Although PRP is the gold standard treatment of PDR by reducing moderate visual loss by 50% in treatment groups, it also caused significant macular edema, which is recognized as the most common cause of decreased visual acuity in diabetic eyes. Optical Coherent Tomography (OCT) helps us studying these macular edema and its characteristics. Objective: To investigate the changes in macular thickness and morphology after panretinal photocoagulation (PRP) in eyes with proliferative diabetic retinopathy (PDR) and without clinically significant macular edema. Patients and Methods: This study enrolled 20 eyes of 15 patients with early proliferative diabetic retinopathy (PDR) without any clinically significant macular edema. Panretinal photocoagulation was applied 3 sessions, one week apart. Fundus fluorescein angiography and OCT were carried out for all patients before PRP. Baseline and post PRP visual acuity and central foveal thickness were evaluated after 3 months. Results: The mean patient age was 59.00±9.93 years (range, 33-72 years). Fifteen of the 20 eyes (75%) had stable or improved vision, while 5 eyes (25%) had worsened by 3 months following PRP. Mean preoperative vision was 0.50±0.1 decimal fraction, and although worsened at 3 months 0.48±0.15 decimal fraction, this was statistically insignificant (P = 0.453). Mean pre- PRP central foveal thickness was 253.05 ± 18.53 μm (ranging from 227 – 281μ), increased significantly to 281.45 ± 28.71 μm (ranging from 240 – 344μ) at 3 months’ follow-up (P˂ 0.001). Three months after PRP, 15 eyes developed complications. The most common abnormality was cystoid edema seen in 6 eyes (30%), followed by diffuse macular edema in 4 eyes (20%), posterior vitreous detachment (PVD) in 2 eyes (10%), neuro sensory detachment in two eyes (10%), and epiretinal membrane (ERM) in one eye (5%). Conclusion: Panretinal photocoagulation is safe, effective in treating and preserving vision in proliferative diabetic retinopathy (PDR), although causing temporary drop in vision and changes in macular morphology/thickness.

The retinal tyrosine kinome of diabetic Akimba mice highlights potential for specific Src family kinase inhibition in retinal vascular disease

Although anti-VEGF therapies have radically changed clinical practice, there is still an urgent demand for novel, integrative approaches for sight-threatening retinal vascular diseases. As we hypothesize that protein tyrosine kinases are key signaling mediators in retinal vascular disease, we performed a comprehensive activity-based tyrosine kinome profiling on retinal tissue of 12-week-old Akimba mice, a translational model displaying hallmarks of early and advanced diabetic retinopathy. Western blotting was used to confirm retinal tyrosine kinase activity in Akimba mice. HUVEC tube formation and murine organotypic choroidal sprouting assays were applied to compare tyrosine kinase inhibitors with different specificity profiles. HUVEC toxicity and proliferation were evaluated using the CellTox™ Green Cytotoxicity and PrestoBlue™ Assays. Our results indicate a shift of the Akimba retinal tyrosine kinome towards a hyperactive state. Functional network analysis of significantly hyperphosphorylated peptides and upstream kinase prediction revealed a central role for Src-FAK family kinases. Western blotting confirmed hyperactivity of this signaling node in the retina of Akimba mice. We demonstrated that not only Src but also FAK family kinase inhibitors with different selectivity profiles were able to suppress angiogenesis in vitro and ex vivo. In the latter model, the novel selective Src family kinase inhibitor eCF506 was able to achieve potent reduction of angiogenesis, comparable to the less specific inhibitor Dasatinib. None of the tested compounds demonstrated acute endothelial cell toxicity. Overall, the collected findings provide the first comprehensive overview of retinal tyrosine kinome changes in the Akimba model of diabetic retinopathy and for the first time highlight Src family kinase inhibition using highly specific inhibitors as an attractive therapeutic intervention for retinal vascular pathology.

Retinal blood oxygen saturation and vascular endothelial growth factor-A in early diabetic retinopathy: A protocol for systematic review and meta-analysis.

Background:Diabetic retinopathy (DR) remains the most common microvascular complication of diabetes; both its high prevalence and associated high risk of vision loss lead it to the major global health burden. Despite significant research efforts, there still remains much of the underlying pathology not fully understand. In the past studies, inner retinal blood flow disturbances are widely assessed as a potential biomarker of DR. However, the results have been variable and even contradictory. Improved methods to figure out the metabolic disturbances associated with DR are essential. Some research showed that both vascular endothelial growth factor-A and blood oxygen saturation are higher in DR patients and correlated with disease severity. Therefore, we decided to conduct a systematic review and meta-analysis to find out the connection of them and provide robust evidence on the mechanism underlying this connection to help us better understand the pathophysiology behind the hypoxic retina and find better ways to treat DR.Methods:This study will be conducted according to Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols. We will do electronic searches from PubMed, EMBASE, Web of Science, Cochrane Library, Wanfang database, CNKI, and VIP database. Two reviewers will screen all the references independently and any disagreement will be solved by the third involvement. All data will be extracted by 2 independent reviewers according to a standardized data extraction sheet. Based on the type of studies, 2 reviewers will independently use different scales to assess the risk of bias. Any disagreements and conflicts will be resolved by discussing it with a third reviewer. We will conduct a random-effects meta-analysis. Individual and pooled odds ratios/relative risks and associated 95% confidence intervals will be calculated as well as between-study heterogeneity. The potential for publication bias will also be evaluated. If possible, we will explore reasons for potential between-study heterogeneity.Results:This study is a protocol for systematic review and meta-analysis without results. Associated data analysis will be carried out after the protocol.Conclusion:The protocol aims to guide a meta-analysis whose purpose is investigating the association between retinal blood oxygen saturation and vascular endothelial growth factors in patients with early DR and trying to find out the mechanism that the changing of retinal oxygen saturation in patients with DR.INPLASY registration number:INPLASY202040161

326-OR: Faricimab for Diabetic Macular Edema: A Novel Anti–Angiopoietin-2/Anti–Vascular Endothelial Growth Factor Bispecific Antibody in Clinical Trials

In the United States, diabetic retinopathy (DR) and diabetic macular edema (DME) are a leading cause of blindness among working-age adults. The introduction of vascular endothelial growth factor-A (VEGF) inhibitors has improved the management of DME and allowed regression of DR severity. However, DR/DME is a multifactorial disease, and targeting additional pathways holds promise for better outcomes. Angiopoietin-2 (Ang-2) is upregulated in the eyes of patients with diabetes and promotes vascular destabilization and inflammation. Faricimab, a novel bispecific antibody targeting both Ang-2 and VEGF, was evaluated in the BOULEVARD (NCT02699450) phase 2 trial for DME. Patients (N = 168 treatment-naïve [TN]; N = 61 previously anti-VEGF treated) were randomized 1:1:1 to intravitreal ranibizumab 0.3 mg, faricimab 1.5 mg (TN only), or faricimab 6.0 mg, every 4 weeks for 20 weeks followed by 16 weeks of observation. BOULEVARD met its primary outcome: faricimab 6.0 mg achieved greater mean gains (letters) from baseline in best-corrected visual acuity than ranibizumab at week 24 in TN patients (faricimab 6.0 mg, +13.9; faricimab 1.5 mg, +11.7; ranibizumab, +10.3; faricimab 6.0 mg vs. ranibizumab, +3.6; P = 0.03; 80% CI, 1.5, 5.6). The Early Treatment Diabetic Retinopathy Study DR Severity Scale (DRSS) was used to score vascular abnormalities and disease severity on color fundus images. A change of ≥ 2 steps is considered clinically significant. The proportion of TN patients with ≥ 2-step improvement from baseline at week 24 on the DRSS was 38.6%, 27.7%, and 12.2%, respectively. There were no new or unexpected safety outcomes with faricimab. In conclusion, faricimab achieved better vision outcomes versus anti-VEGF monotherapy in TN patients, suggesting Ang-2 is a viable target for DR/DME. Phase 3 trials YOSEMITE (NCT03622580) and RHINE (NCT03622593) for faricimab in DME are ongoing. Disclosure V. Sheth: Consultant; Self; Genentech, Inc. J. Sahni: Employee; Self; Roche Pharma. Stock/Shareholder; Self; Roche Pharma. I. Stoilov: Employee; Self; Genentech, Inc. J.R. Willis: Employee; Self; Genentech, Inc. R. Weikert: Employee; Self; Roche Pharma. Funding F. Hoffmann-La Roche, Ltd.; Genentech, Inc.

Predictors of Early Diabetic Retinopathy Regression with Ranibizumab in the RIDE and RISE Clinical Trials.

PurposeTo investigate the predictors of early diabetic retinopathy (DR) improvement in the RIDE/RISE (NCT00473382/NCT00473330) clinical trials.Patients and MethodsIn RIDE/RISE, adult patients with vision loss due to diabetic macular edema (DME) were randomized to monthly intravitreal ranibizumab 0.3 or 0.5 mg (n=502 total) or sham (n=257). DR severity was graded (using the Early Treatment Diabetic Retinopathy Study Diabetic Retinopathy Severity Scale). In this post hoc analysis of RIDE/RISE, eyes with baseline DR score ≥35 were evaluated for ≥2-step improvements, and eyes with baseline DR score ≥43 were evaluated for ≥3-step improvements. The characteristics associated with ≥2- or ≥3-step DR improvement at months 3 or 6 were assessed using univariate and/or multivariable analyses.ResultsThe percentage of eyes with a ≥2- or ≥3-step DR improvement was 20.1% and 3.7% at month 3 and 31.2% and 5.8% at month 6. Odds of ≥2-step DR improvement at months 3 or 6 were significantly greater in eyes with moderately severe to severe nonproliferative DR (NPDR) at baseline versus less severe or more severe DR (both P<0.0001). At month 6, odds of ≥2-step DR improvement were significantly greater in eyes with no DME at month 3 (P=0.008). Most patients with ≥3-step DR improvement at months 3 or 6 had proliferative DR (PDR) at baseline (83.3% and 66.7%).ConclusionThe strongest predictors of DR response to ranibizumab at month 6 were baseline DR severity and DME quiescence at month 3. Eyes with the most robust early improvements had moderately severe or severe NPDR or PDR at baseline.

Interleukin-6 trans-signaling inhibition prevents oxidative stress in a mouse model of early diabetic retinopathy

PurposeDiabetic retinopathy (DR), a microvascular complication of diabetes, is the leading cause of visual disability and blindness in diabetic patients. Chronic hyperglycemia leads to increased oxidative stress and inflammation in the retina, resulting in microvascular damage. Our recent in vitro studies have demonstrated that inhibition of interleukin-6 (IL-6) trans-signaling significantly reduces oxidative stress in retinal endothelial cells. The purpose of this study was to further explore the relationship between IL-6 trans-signaling and oxidative stress using a streptozotocin (STZ) induced mouse model of early diabetic retinopathy. MethodsDiabetes was induced in eight week-old male C57BL/6J mice using STZ injections. sgp130Fc (mouse sgp130Fc protein) treatment was used for inhibition of IL-6 trans-signaling. Studies were conducted to evaluate the effects of IL-6 trans-signaling on oxidative balance at the systemic and retinal level. ResultsDecreased antioxidant capacity and increased oxidative stress was observed in diabetic mice, which returned to near-normal levels with sgp130Fc treatment. Similarly, superoxide levels, lipid peroxidation, and markers of oxidative DNA damage were increased in the diabetic retina, and these effects were abrogated by sgp130Fc treatment. Inhibition of IL-6 trans-signaling also restored normal expression of catalase and endothelial nitric oxide synthase in mouse retinas. ConclusionsInhibition of IL-6 trans-signaling significantly reduces diabetes-induced oxidative damage at the systemic level and in the retina. These findings provide further evidence for the role of IL-6 trans-signaling in diabetes-mediated oxidative stress.

Transcriptomics analysis of pericytes from retinas of diabetic animals reveals novel genes and molecular pathways relevant to blood-retinal barrier alterations in diabetic retinopathy

Selective pericyte loss, the histological hallmark of early diabetic retinopathy (DR), enhances the breakdown of the blood-retinal barrier (BRB) in diabetes. However, the role of pericytes on BRB alteration in diabetes and the signaling pathways involved in their effects are currently unknown. To understand the role of diabetes-induced molecular alteration of pericytes, we performed transcriptomic analysis of sorted retinal pericytes from mice model of diabetes. Retinal tissue from non-diabetic and diabetic (duration 3 months) mouse eyes (n = 10 in each group) were used to isolate pericytes through fluorescent activated cell sorting (FACS) using pericyte specific fluorescent antibodies, PDGFRb-APC. For RNA sequencing and qPCR analysis, a cDNA library was generated using template switching oligo and the resulting libraries were sequenced using paired-end Illumina sequencing. Molecular functional pathways were analyzed using differentially expressed genes (DEGs). Differential expression analysis revealed 217 genes significantly upregulated and 495 genes downregulated, in pericytes isolated from diabetic animals. These analyses revealed a core set of differentially expressed genes that could potentially contribute to the pericyte dysfunction in diabetes and highlighted the pattern of functional connectivity between key candidate genes and blood retinal barrier alteration mechanisms. The top up-regulated gene list included: Ext2, B3gat3, Gpc6, Pip5k1c and Pten and down-regulated genes included: Notch3, Xbp1, Gpc4, Atp1a2 and AKT3. Out of these genes, we further validated one of the down regulated genes, Notch 3 and its role in BRB alteration in diabetic retinopathy. We confirmed the downregulation of Notch3 expression in human retinal pericytes exposed to Advanced Glycation End-products (AGEs) treatment mimicking the chronic hyperglycemia effect. Exploration of pericyte-conditioned media demonstrated that loss of NOTCH3 in pericyte led to increased permeability of endothelial cell monolayers. Collectively, we identify a role for NOTCH3 in pericyte dysfunction in diabetes. Further validation of other DEGs to identify cell specific molecular change through whole transcriptomic approach in diabetic retina will provide novel insight into the pathogenesis of DR and novel therapeutic targets.