Changes In Retinal Morphology Research Articles

Morphologic Stages of Full-Thickness Macular Hole on Spectral Domain Optical Coherence Tomography

ObjectiveTo describe the sequential morphological changes of the outer retina after full-thickness macular hole formation, utilizing a novel, objective staging system based on optical coherence tomography (OCT), and to determine its association with baseline visual acuity, duration of symptoms, and postoperative visual acuity at 3 months. DesignRetrospective, observational, multicenter study. ParticipantsPatients with idiopathic full-thickness macular hole (FTMH) presenting to St. Michael’s Hospital, Toronto, Canada, and Retina Consultants of Texas, Houston, USA, from 2009-2022. MethodsThe medical charts of 1000 patients with FTMH were reviewed and those with at least two preoperative SD-OCTs were analyzed. A staging system was developed by assessing outer retinal morphology on successive SD-OCT central foveal scans. Main Outcome MeasuresSequential outer retinal morphological changes with SD-OCT over time and their association with baseline visual acuity, duration of symptoms, and postoperative functional outcomes. ResultsFifty-two eyes of 52 patients with a mean age of 65.4 ±8.4 years were included. Sequential outer retinal morphologic changes at the FTMH borders occurred in 4 distinct and reproducible stages as follows: Stage A: separation of the neurosensory retina from the RPE with the well-defined external limiting membrane (ELM), ellipsoid zone (EZ) and interdigitation zone (IDZ) (4/52, 7.6%); Stage B: thickening of EZ (27/52, 51.9%); Stage C: patchy (moth-eaten) photoreceptor loss (16/52, 30.7%) and Stage D: severe or complete loss of ISs and OSs and/or bare ELM (5/52, 9.6%). When assessing the preoperative OCT scans closest to the time of surgery, over a mean follow-up period of 288.9 days (SD 350.4,[5 -1841]), 28.8%(15/52 ) of eyes were in Stage B, 28.8% (15/52) were in Stage C and 42.3 %(22/52 ) were in Stage D.There was a statistically significant association between increasing stage at baseline and longer duration of macular hole symptoms (p=0.032) and worse visual acuity at baseline (p<0.001). Additionally, patients presenting with Stages B and C at the time point closest to surgery had better visual acuity outcomes three months postoperatively compared to those with Stage D(P=0.04). ConclusionsThis SD-OCT staging system describes the sequential in vivo morphologic changes after FTMH formation providing a novel imaging biomarker.

In situ oxidative stress in patients with epiretinal membrane

ContextOxidative stress is an important factor for vitreomacular interface disease development in a theoretical model.PurposeThe aim of the study was to evaluate the correlation between oxidative stress in the human epiretinal membrane (ERM) and retinal morphological changes.Material and methodsThe study included patients scheduled for vitrectomy with epiretinal membrane removal. LogMAR best corrected visual acuity was assessed and optical coherence tomography was performed. Patients were divided into three groups: Type 1 – epiretinal membrane with premacular fibrosis; type 2 – epiretinal membrane with co-existing layer hole; and type 3 – ERM with co-existing full-thickness macular hole. During vitrectomy, epiretinal membranes were collected. Total oxidant status was determined by an automated colorimetric method in homogenates of epiretinal membrane.Statistical analysisThe Mann-Whitney U test, Kruskal-Wallis test and Spearman linear correlation analysis were used. Statistical significance was set with a level of α = 0.05.ResultsTwenty-one Caucasian women (60%) and 14 men (40%) were included in the study. The average age of participants was 74.7 years (95% CI: 71.13–75.45). The mean best corrected visual acuity LogMAR value in the group was 0.8 (95% CI: 0.9–0.7). The mean ratio of total oxidant status to protein level in the collected samples was 0.161 (95% CI: 0.08–0.23) µmol/mg of protein. No correlation was found between total oxidant status and the degree of morphological retinal changes.ConclusionThe study found no significant correlation between the level of oxidative stress in epiretinal membrane and retinal morphological changes.

Role of caspase-11 non-canonical inflammasomes in retinal ischemia/reperfusion injury

BackgroundRetinal ischemia/reperfusion (IR) injury is a common pathological process in many ophthalmic diseases. Interleukin-1β (IL-1β) is an important inflammatory factor involved in the pathology of retinal IR injury, but the mechanism by which IL-1β is regulated in such injury remains unclear. Caspase-11 non-canonical inflammasomes can regulate the synthesis and secretion of IL-1β, but its role in retinal IR injury has not been elucidated. This study aimed to evaluate the role of caspase-11 non-canonical inflammasomes in retinal IR injury.MethodsRetinal IR injury was induced in C57BL/6J mice by increasing the intraocular pressure to 110 mmHg for 60 min. The post-injury changes in retinal morphology and function and in IL-1β expression were compared between caspase-11 gene knockout (caspase-11−/−) mice and wild-type (WT) mice. Morphological and functional changes were evaluated using hematoxylin–eosin staining and retinal whole mount staining and using electroretinography (ERG), respectively. IL-1β expression in the retina was measured using enzyme-linked immunosorbent assay (ELISA). The levels of caspase-11-related protein were measured using western blot analysis. The location of caspase-11 in the retina was determined via immunofluorescence staining. Mouse type I astrocytes C8-D1A cells were used to validate the effects of caspase-11 simulation via hypoxia in vitro. Small-interfering RNA targeting caspase-11 was constructed. Cell viability was evaluated using the MTT assay. IL-1β expression in supernatant and cell lysate was measured using ELISA. The levels of caspase-11-related protein were measured using western blot analysis.ResultsRetinal ganglion cell death and retinal edema were more ameliorated, and the ERG b-wave amplitude was better after retinal IR injury in caspase-11−/− mice than in WT mice. Further, caspase-11−/− mice showed lower protein expressions of IL-1β, cleaved caspase-1, and gasdermin D (GSDMD) in the retina after retinal IR injury. Caspase-11 protein was expressed in retinal glial cells, and caspase-11 knockdown played a protective role against hypoxia in C8-D1A cells. The expression levels of IL-1β, cleaved caspase-1, and GSDMD were inhibited after hypoxia in the si-caspase-11 constructed cells.ConclusionsRetinal IR injury activates caspase-11 non-canonical inflammasomes in glial cells of the retina. This results in increased protein levels of GSDMD and IL-1β and leads to damage in the inner layer of the retina.

Resveratrol Protects Müller Cells Against Ferroptosis in the Early Stage of Diabetic Retinopathy by Regulating the Nrf2/GPx4/PTGS2 Pathway.

The aim of this study was to investigate the anti-ferroptotic effect of resveratrol (RSV) on retinal Müller cells (RMCs) in the early stages of diabetic retinopathy (DR) via the nuclear factor erythroid 2-related factor 2 (Nrf2)/glutathione peroxidase 4 (GPx4)/prostaglandin-endoperoxide synthase 2 (PTGS2). The retina was obtained from normal and diabetic Sprague-Dawley rats or wild-type and Nrf2 knockout (KO) diabetic mice, with or without RSV (10mg/kg/d) treatment for 12weeks. RMCs transfected with or without SiNrf2 were cultured with high glucose and RSV (20mM). The retinal neurofunctional changes were measured by electroretinogram (ERG). The retinal inner nuclear layer cell mitochondrial morphological changes were detected by transmission electron microscopy. The cell viabilities were measured by cell counting kit-8 (CCK-8) assay. The levels of Fe2+, malonic dialdehyde (MDA), and glutathione (GSH) were measured by colorimetric method. The expression of Nrf2, GPx4, and PTGS2 was detected by quantitative real-time polymerase chain reaction (qRT-PCR), western blotting, and immunocytochemistry. In vivo, RSV inhibited retinal neurofunctional changes and mitochondrial morphological changes; decreased Fe2+, MDA, and PTGS2; and increased GSH, Nrf2, and GPx4 in retina of DM rats. In vitro, RSV decreased MDA and PTGS2 and increased cell viability, GSH, Nrf2, and GPx4. In vivo and vitro, the role of Nrf2-regulated signaling pathway in anti-ferroptosis by RSV was further confirmed using Nrf2 KO mice and pre-transfected SiNrf2 in RMCs. These findings indicated that RSV is a potential therapeutic option for DR and that Nrf2/GPx4/PTGS2 plays a role in the anti-ferroptosis mechanism of RSV on RMCs.

Postoperative Proliferation Detection in Eyes Treated for Rhegmatogenous Retinal Detachment by WideField OCT Angiography.

Proliferative retinal changes may occur postsurgery for rhegmatogenous retinal detachment (RRD), possibly preceding recurrent detachment. This study aims to establish the groundwork for an imaging system capable of discerning changes in retinal vessel tortuosity after RRD repair, analyzing widefield optical coherence tomography angiography (WF-OCTA) images. Eighty-eight eyes of 86 patients with RRD who underwent surgical procedures and had repeated imaging with clear widefield optical coherence tomography (WF-OCT) and WF-OCTA on different postoperative days were enrolled in this retrospective study. We compared WF-OCTA images over time to identify alterations in retinal vessel tortuosity and observed regional changes in retinal morphology. After image processing, changes in retinal vessel tortuosity were detected in 66 quadrants. These changes, attributed to retinal traction from proliferative membranes, were observed in 56 quadrants, among which retinal thickness remained unchanged in seven sectors (12.5%) according to the WF-OCT map. In nine quadrants, changes in retinal vessel tortuosity were attributed to changes in subretinal fluid, aligning with observable variations in retinal thickness. Observation of vessel tortuosity changes using WF-OCTA can help detect early postoperative proliferative changes in eyes with RRD. Because WF-OCTA can detect minute vessel tortuosity changes, it can offer a noninvasive alternative for the detection of early postoperative proliferative changes.

Hyperglycemia-independent neonatal streptozotocin-induced retinopathy (NSIR) in rats.

Introduction: Chemicals, such as MNU (N-methyl-N-nitrosourea) and NaIO3 (sodium iodate), are widely used to induce retinal degeneration in rodents. Streptozotocin (STZ) is an analog of N-acetyl glucosamine in which an MNU moiety is linked to a hexose and has a special toxic effect on insulin-producing pancreatic β-cells. It is commonly used to induce hyperglycemia to model diabetes. While intracerebroventricular injection of STZ can produce Alzheimer's disease independent of hyperglycemia, most retinal studies using STZ focus on the effects of hyperglycemia on the retina, but whether STZ has any impact on retinal cells independent of hyperglycemia is unknown. We aimed to investigate the role of cytotoxicity of STZ in rat retina. Methods: Intravitreal or subcutaneous injection of STZ was performed on newborn rats. Electroretinogram (ERG) and H&E staining investigated retinal function and morphological changes. Retinal cell types, cell death, proliferation, inflammation, and angiogenesis were studied by immunostaining. RNA sequencing was performed to examine the transcriptome changes of retinal cells after intravitreal injection of STZ. Results: Intravitreal (5μg or 10μg) or subcutaneous (30mg/kg) injection of STZ at the early stage of newborn rats couldn't induce hyperglycemia but caused NSIR (Neonatal STZ-induced retinopathy), including reduced ERG amplitudes, retinal rosettes and apoptosis, cell cycle arrest, microglial activation, and delayed retinal angiogenesis. STZ did not affect the early-born retinal cell types but significantly reduced the late-born ones. Short-term and long-term hyperglycemia had no significant effects on the NSIR phenotypes. RNA sequencing revealed that STZ induces oxidative stress and activates the p53 pathway of retinal cells. Locally or systemically, STZ injection after P8 couldn't induce SINR when all retinal progenitors exit the cell cycle. Conclusion: NSIR in rats is independent of hyperglycemia but due to STZ's direct cytotoxic effects on retinal progenitor cells. NSIR is a typical reaction to STZ-induced retinal oxidative stress and DNA damage. This significant finding suggests that NSIR may be a valuable model for studying retinal progenitor DNA damage-related diseases, potentially leading to new insights and treatments.

INVESTIGATION OF THE PATHOPHYSIOLOGY OF EPIRETINAL MEMBRANE FOVEOSCHISIS: Analysis of Longitudinal Changes in Visual Functions, Retinal Structures, and Retinal Traction Force.

To analyze the pathophysiology of epiretinal membrane foveoschisis (FS) by evaluating the longitudinal changes in visual function and several optical coherence tomography parameters. The medical records of 33 consecutive patients (35 eyes) with untreated epiretinal membrane foveoschisis were retrospectively reviewed. Best-corrected visual acuity, M-CHARTS score, and optical coherence tomography parameters including epiretinal membrane area, maximum depth of retinal folds, FS area, and FS circularity were evaluated. A wide range of FS area changes was observed at the final follow-up visit (59.68%-240.45% of the baseline FS area). In the FS enlargement group, best-corrected visual acuity and mean M-CHARTS scores significantly worsened and maximum depth of retinal folds significantly increased over time, whereas in the FS non-enlargement group, no significant change was observed in the best-corrected visual acuity, mean M-CHARTS scores, or maximum depth of retinal folds during the follow-up period. Multivariate logistic regression analyses revealed that maximum depth of retinal folds (odds ratio: 1.05, 95% confidence interval: 1.00-1.10, P = 0.048) and FS circularity (odds ratio: 0.91, 95% confidence interval: 0.83-1.00, P = 0.043) were significantly associated with FS enlargement. Epiretinal membrane foveoschisis encompasses diverse pathophysiologies. Since visual functions do not worsen in some cases, monitoring the changes in visual functions and retinal morphology over time is recommended to determine surgical indications.

FIVE-YEAR CHANGES IN METAMORPHOPSIA AND THE ASSOCIATION OF OUTER RETINAL LAYERS AFTER VITRECTOMY FOR RHEGMATOGENOUS RETINAL DETACHMENT INVOLVING THE MACULA.

To evaluate the 5-year changes in metamorphopsia and outer retinal morphology after vitrectomy for macula-off rhegmatogenous retinal detachment. The authors included 21 eyes from 21 patients with macula-off rhegmatogenous retinal detachment who underwent pars plana vitrectomy. Metamorphopsia was quantified using M-CHARTS. Using spectral-domain optical coherence tomography, the authors assessed the risk factors for metamorphopsia severity 5 years after surgery. Metamorphopsia scores substantially improved from 1 month to 5 years postoperatively; however, they remained unchanged from 1 year to 5 years postoperatively. Overall, 11 patients (52.4%) had metamorphopsia 5 years postoperatively. The metamorphopsia scores in eyes with a continuous interdigitation zone and ellipsoid zone at 5 years were considerably lower than those in eyes with a disrupted interdigitation zone. Multiple regression analysis revealed that the metamorphopsia score at 5 years was markedly associated with the score at 1 month and continuous interdigitation zone. No statistically significant change was observed in metamorphopsia scores after 1 year postoperatively, and >50% of the patients had metamorphopsia at 5 years postoperatively. The improvement was associated with lower metamorphopsia scores at 1 month and continuous interdigitation zone at 5 years. Moreover, the study revealed that early metamorphopsia was a poor prognostic marker for long-term functional deficits.

Deep Learning‐Enabled Vasculometry Depicts Phased Lesion Patterns in High Myopia Progression

PurposeTo investigate the potential phases in myopic retinal vascular alterations for further elucidating the mechanisms underlying the progression of high myopia (HM). MethodsFor this retrospective study, participants diagnosed with high myopia at Beijing Tongren Hospital were recruited. Based on bionic mechanisms of human vision, an intelligent image processing model was developed and utilized to extract and quantify the morphological characteristics of retinal vasculatures in different regions measured by papilla-diameter (PD), including vascular caliber, arteriole-to-venule ratio (AVR), tortuosity, the angle of the vascular arch (AVA), the distance of the vascular arch (DVA), density, fractal dimension, and venular length. In addition, the optic disc and the area of peripapillary atrophy (PPA) were also quantified. The characteristics of the overall population, as well as patients aged less than 25 years old, were compared by different genders. Univariate and multiple linear regression analyses were conducted to investigate the correlation of retinal vasculature parameters with PPA width, and detailed trends of the vascular indicators were analyzed to explore the potential existence of staged morphological changes. FindingsThe study included 14,066 fundus photographs of 5775 patients (aged 41.2 ± 18.6 years), of whom 7379 (61.2 %) were female. The study included 12,067 fundus photographs of 5320 patients (aged 41.2 ± 18.6 years). Significant variations in the morphological parameters of retinal vessels were observed between males and females. After adjusting for age and sex, multiple linear regression analysis showed that an increased PPA width ratio was associated with lower AVA (1PD), DVA (1PD), vascular caliber (0.5–1.0 PD), tortuosity (0.5–1.0 PD), density and fractal dimension (all P < 0.001, Spearman’s ρ < 0). Overall, the changes in retinal vascular morphology showed two phases: tortuosity (0.5–1.0PD) and AVA (1PD) decreased rapidly in the first stage but significantly more slowly in the second stage, while vascular density and fractal dimension showed a completely opposite trend with an initial slow decline followed by a rapid decrease. ConclusionsThis study identified two distinct phases of retinal vascular morphological changes during the progression of HM. Traction lesions were predominant in the initial stage, while atrophic lesions were predominant in the later stage. These findings provide further insight into the development mechanism of HM from the perspective of retinal vasculature.

Optical imaging for diabetic retinopathy diagnosis and detection using ensemble models

Diabetes, characterized by heightened blood sugar levels, can lead to a condition called Diabetic Retinopathy (DR), which adversely impacts the eyes due to elevated blood sugar affecting the retinal blood vessels. The most common cause of blindness in diabetics is thought to be Diabetic Retinopathy (DR), particularly in working-age individuals living in poor nations. People with type 1 or type 2 diabetes may develop this illness, and the risk rises with the length of diabetes and inadequate blood sugar management. There are limits to traditional approaches for the early identification of diabetic retinopathy (DR). In order to diagnose diabetic retinopathy, a model based on Convolutional neural network (CNN) is used in a unique way in this research. The suggested model uses a number of deep learning (DL) models, such as VGG19, Resnet50, and InceptionV3, to extract features. After concatenation, these characteristics are sent through the CNN algorithm for classification. By combining the advantages of several models, ensemble approaches can be effective tools for detecting diabetic retinopathy and increase overall performance and resilience. Classification and image recognition are just a few of the tasks that may be accomplished with ensemble approaches like combination of VGG19,Inception V3 and Resnet 50 to achieve high accuracy. The proposed model is evaluated using a publicly accessible collection of fundus images.VGG19, ResNet50, and InceptionV3 differ in their neural network architectures, feature extraction capabilities, object detection methods, and approaches to retinal delineation. VGG19 may excel in capturing fine details, ResNet50 in recognizing complex patterns, and InceptionV3 in efficiently capturing multi-scale features. Their combined use in an ensemble approach can provide a comprehensive analysis of retinal images, aiding in the delineation of retinal regions and identification of abnormalities associated with diabetic retinopathy. For instance, micro aneurysms, the earliest signs of DR, often require precise detection of subtle vascular abnormalities. VGG19′s proficiency in capturing fine details allows for the identification of these minute changes in retinal morphology. On the other hand, ResNet50′s strength lies in recognizing intricate patterns, making it effective in detecting neoneovascularization and complex haemorrhagic lesions. Meanwhile, InceptionV3′s multi-scale feature extraction enables comprehensive analysis, crucial for assessing macular oedema and ischaemic changes across different retinal layers.

O-GlcNAc Modification Is a Promising Therapeutic Target for Diabetic Retinopathy.

Diabetic retinopathy (DR) is a very serious diabetes complication. Changes in the O-linked N-acetylglucosamine (O-GlcNAc) modification are associated with many diseases. However, its role in DR is not fully understood. In this research, we explored the effect of O-GlcNAc modification regulation by activating AMP-activated protein kinase (AMPK) in DR, providing some evidence for clinical DR treatment in the future. Bioinformatics was used to make predictions from the database, which were validated using the serum samples of diabetic patients. As an in vivo model, diabetic mice were induced using streptozotocin (STZ) injection with/without an AMPK agonist (metformin) or an AMPK inhibitor (compound C) treatment. Electroretinogram (ERG) and H&E staining were used to evaluate the retinal functional and morphological changes. In vitro, 661 w cells were exposed to high-glucose conditions, with or without metformin treatment. Apoptosis was evaluated using TUNEL staining. The protein expression was detected using Western blot and immunofluorescence staining. The angiogenesis ability was detected using a tube formation assay. The levels of O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA) in the serum changed in the DR patients in the clinic. In the diabetic mice, the ERG wave amplitude and retinal thickness decreased. In vitro, the apoptotic cell percentage and Bax expression were increased, and Bcl2 expression was decreased in the 661 w cells under high-glucose conditions. The O-GlcNAc modification was increased in DR. In addition, the expression of GFAT/TXNIP O-GlcNAc was also increased in the 661 w cells after the high-glucose treatment. Additionally, the Co-immunoprecipitation(CO-IP) results show that TXNIP interacted with the O-GlcNAc modification. However, AMPK activation ameliorated this effect. We also found that silencing the AMPKα1 subunit reversed this process. In addition, the conditioned medium of the 661 w cells may have affected the tube formation in vitro. Taken together, O-GlcNAc modification was increased in DR with photoreceptor cell degeneration and neovascularization; however, it was reversed after activating AMPK. The underlying mechanism is linked to the GFAT/TXNIP-O-GlcNAc modification signaling axis. Therefore, the AMPKα1 subunit plays a vital role in the process.

Aspects of Histopathological and Ultrastructural Retinal Changes in Chronic Exposure to Hydroxychloroquine.

Background and Objective: Hydroxychloroquine sulfate (HCQ) is a lysosomotropic agent administered in systemic lupus erythematosus and rheumatoid arthritis that has fewer toxic effects than chloroquine. However, HCQ may still be responsible for retinal toxicity. In this study, we observed structural changes in the retinas of experimental rats after prolonged exposure to HCQ. Matherials and Methods: We investigated several aspects regarding retinal changes, at both the histopathological and ultrastructural levels. We used 96 male albino Wistar rats distributed into four equal groups (n = 24 per group): the first three groups were treated with different doses of HCQ (50, 100, and 200 mg/kg HCQ, injected intraperitoneally in a single dose daily), and the last group (the control group, n = 24) was treated with saline solution administered in the same way (0.4 mL of saline solution). The treated groups received HCQ daily for 4 months, and every month, six animals from each group were sacrificed to assess retinal changes. The eyes were examined via optical (OM) and electronic microscopy (EM). Statistical analysis was deployed, and results regarding retinal morpho-photometry were acquired. Results: We observed structural retinal changes in both high and low doses of HCQ; while high doses determined a significant thinning of the retina, lower doses caused retinal thickening. Morphological retinal changes upon exposure to HCQ are believed to be caused by accumulated HCQ in lysosomes found in retinal ganglion cells and in the inner nuclear and photoreceptor cell layers. Such changes were most evident in the group receiving HCQ intraperitoneally in doses of 100 mg/kg for a longer period (4 months). Conclusions: The present study highlights histopathological and ultrastructural retinal changes induced by chronic HCQ administration, which were strongly connected to the dosage and period of exposure.

Quantitative evaluation of metamorphopsia with M-CHARTS™ and evaluation of retinal morphologic changes by optical coherence tomography before and after pars plana vitrectomy in patients with idiopathic epiretinal membrane

Purpose: We aimed to quantitatively evaluate metamorphopsia pre- and postoperatively in patients with idiopathic epiretinal membrane(iERM) using M-CHARTS™ and to evaluate the relationship between morphological changes in retinal layers on optical coherence tomography (OCT) and metamorphopsia scores.Materials and Methods: This prospective study included 42 patients followed in Akdeniz University Hospital Ophthalmology Clinic diagnosed with iERM by fundus examination and OCT between 2020-2022. Detailed ophthalmologic findings, visual acuities, metamorphopsia scores, and OCT parameters of all patients were recorded. The relationship between pre- and postoperative visual acuity, metamorphopsia scores and OCT parameters was investigated. Changes in OCT parameters were compared by evaluating patients with stable or increasing metamorphopsia scores as one group (Group1) and patients with decreasing metamorphopsia scores as the other group (Group 2).Results: In “Group 2,” preoperative Ganglion Cell Layer+Inner Plexiform Layer (Central) (GCL+IPL (C)) was significantly (p:0.028) higher than in “Group 1.”Conclusion: A statistically significant preoperative thickness difference in the OCT parameters of the GCL+IPL (C) layer was associated with the quantitative metamorphopsia complaints of the patients. The thickness of the preoperative GCL+IPL (C) layer can be considered an important indicator of symptoms of metamorphopsia determining functional success after surgery.

CD38 Deficiency Protects Mouse Retinal Ganglion Cells Through Activating the NAD+/Sirt1 Pathway in Ischemia-Reperfusion and Optic Nerve Crush Models.

The purpose of this study was to investigate the protective effect of CD38 deletion on retinal ganglion cells (RGCs) in a mouse retinal ischemia/reperfusion (I/R) model and an optic nerve crush (ONC) model, and to elucidate the underlying molecular mechanisms. Retinal I/R and ONC models were constructed in mice. PCR was used to identify the deletion of CD38 gene in mice, hematoxylin and eosin (H&E) staining was used to evaluate the changes in retinal morphology, and electroretinogram (ERG) was used to evaluate the changes in retinal function. The survival of RGCs and activation of retinal macroglia were evaluated by immunofluorescence staining. The expression of Sirt1, CD38, Ac-p65, Ac-p53, TNF-α, IL-1β, and Caspase3 proteins in the retina was further evaluated by protein imprinting. In retinal I/R and ONC models, CD38 deficiency reduced the loss of RGCs and activation of macroglia and protected the retinal function. CD38 deficiency increased the concentration of NAD+, reduced the degree of acetylation of NF-κB p65 and p53, and reduced expression of the downstream inflammatory cytokines TNFα, IL-1β, and apoptotic protein Caspase3 in the retina in the ONC model. Intraperitoneal injection of the Sirt1 inhibitor EX-527 partially counteracted the effects of CD38 deficiency, suggesting that CD38 deficiency acts at least in part through the NAD+/Sirt1 pathway. CD38 plays an important role in the pathogenesis of retinal I/R and ONC injury. CD38 deletion protects RGCs by attenuating inflammatory responses and apoptosis through the NAD+/Sirt1 pathway.

Erratum in: Pentosan Polysulfate Sodium Causes Diminished Function and Subtle Morphological Changes in Retina and RPE of Mice.

Erratum in: Pentosan Polysulfate Sodium Causes Diminished Function and Subtle Morphological Changes in Retina and RPE of Mice.

Three-Year Follow-Up Study Investigating Changes in Retinal Vascular Morphology and the Relationship with Diabetic Retinopathy in Children with Type 1 Diabetes Mellitus.

This study aimed to investigate changes in retinal microvascular morphology and associated factors, and their relationship with diabetic retinopathy (DR) in children with type 1 diabetes mellitus (T1DM). Thirty-eight children enrolled in this 3-year follow-up study underwent complete ophthalmic examinations including fundus photography. Retinal vascular parameters were measured automatically and compared between baseline and follow-up. Multiple linear regression was used to investigate factors affecting changes in vascular parameters. Binary logistic regression was used to analyze the relationship between retinal microvascular morphology and DR. The caliber of all retinal vessels (within 1-1.5 papillary diameter [PD] from the center of the optic disc, p = 0.030; 1.5-2 PD, p = 0.003), arterioles, and venules (1.5-2 PD, p = 0.001) was narrower in nearly all regions in the follow-up group compared with the baseline group. Vascular tortuosity increased in the central part of the retina and decreased in the periphery. The density (1-1.5 PD, p = 0.030) and fractal dimension (p = 0.037) of retinal vessels were increased at the end of the follow-up compared with baseline. Retinal vascular caliber was independently correlated with DR (odds ratio 0.793 [95% confidence interval 0.633-0.993]; p = 0.044). Retinal microvascular morphology in children with T1DM varied with the disease course. Narrower retinal vessels may be an independent risk factor for DR. Results of this study emphasized the importance of regular follow-up of fundus vascular morphology for the detection of early DR in children with T1DM.

One year monitoring of retinal morphologic and functional changes in traumatic optic neuropathy patients

BackgroundTo analyze the morphologic and functional change in traumatic optic neuropathy (TON) divided by the mechanism of optic nerve injury.MethodsA retrospective analysis of 58 patients who were diagnosed as monocular TON from February 2015 to August 2021 was conducted at in CHA Bundang Medical Center in Seongnam, South Korea. The patients visited the clinic of the department of ophthalmology for more than 6 months and at least 4 times during this period.Results44 patients were classified as blunt TON patients, and 14 patients were surgical TON patients. The visual acuity showed significant decrease in traumatic eyes at the first visit after injury compared to fellow eyes and maintained the injured status during the 1-year follow-up period in blunt TON. In surgical TON, the visual acuity slightly improved during 1 month follow-up period. RNFL thickness tended to be decreased at 1 month after first visit blunt TON patients, which was earlier than surgical TON patients. GCIPL thickness showed earlier decreased than RNFL thickness in both blunt and surgical TON patients.ConclusionsIn both blunt and surgical TON eyes, there was a notable thinning in both RNFL and GCIPL, with particularly remarkable reduction in GCIPL in early phase. Therefore, analyzing each retinal layer thickness using OCT in conjunction with assessing visual function would be necessary. This combined approach is not only crucial for understanding clinical courses of each TON, but also predicting the morphological and functional deteriorations in TON.

A retinal vessel segmentation network with multiple-dimension attention and adaptive feature fusion

The incidence of blinding eye diseases is highly correlated with changes in retinal morphology, and is clinically detected by segmenting retinal structures in fundus images. However, some existing methods have limitations in accurately segmenting thin vessels. In recent years, deep learning has made a splash in the medical image segmentation, but the lack of edge information representation due to repetitive convolution and pooling, limits the final segmentation accuracy. To this end, this paper proposes a pixel-level retinal vessel segmentation network with multiple-dimension attention and adaptive feature fusion. Here, a multiple dimension attention enhancement (MDAE) block is proposed to acquire more local edge information. Meanwhile, a deep guidance fusion (DGF) block and a cross-pooling semantic enhancement (CPSE) block are proposed simultaneously to acquire more global contexts. Further, the predictions of different decoding stages are learned and aggregated by an adaptive weight learner (AWL) unit to obtain the best weights for effective feature fusion. The experimental results on three public fundus image datasets show that proposed network could effectively enhance the segmentation performance on retinal blood vessels. In particular, the proposed method achieves AUC of 98.30%, 98.75%, and 98.71% on the DRIVE, CHASE_DB1, and STARE datasets, respectively, while the F1 score on all three datasets exceeded 83%. The source code of the proposed model is available at https://github.com/gegao310/VesselSeg-Pytorch-master.

Effects of hemoglobin concentration on retinochoroidal vascular plexuses: an optical coherence tomography angiography study.

To evaluate retinal and choroidal microvascular structures using optical coherence tomography angiography (OCTA) in patients with anemia and polycythemia vera (PV). In this prospective study, 142 patients (142 eyes) were enrolled and divided into 3 groups: the anemia (n = 56), PV (n = 46), and healthy groups (n = 40, controls). For each patient, 6- × 6-mm macular angiography images were taken using an OCTA system (optovue, Inc., Fremont). For each eye analyzed, the software automatically measured vessel density (VD) in the superficial capillary plexus (SCP), deep capillary plexus (DCP; superior, nasal, temporal, and inferior quadrants), choriocapillaris (CC), and foveal avascular zone (FAZ). The OCTA analysis revealed that the VD of the DCP was significantly decreased in the superior and inferior hemispheres of the whole area, multiple quadrants of the perifovea, and CC with a 1-mm2 flow area in the anemia group compared with the PV group (p < 0.017), but the VD of the SCP did not show any significant difference in any quadrant between the two groups (p > 0.017). When compared with the healthy group, the anemia and PV groups showed a significant difference in multiple quadrants of the parafovea and temporal quadrant of the perifovea in the VD of the SCP and CC with a 2-mm2 flow area (p < 0.017). The FAZ and non-flow area did not manifest any significant difference between the groups (p > 0.017). The hemoglobin concentrations in the anemia, PV, and healthy groups were 8.11 ± 1.33, 17.5 ± 1.2, and 15.6 ± 0.73g/dL, respectively, indicating statistically significant differences between the groups (p < 0.001). In this study, quantitative OCTA analysis revealed a higher tendency for retinal and choroidal microvascular morphological changes in patients with anemia and PV. The outcomes of the current investigation can provide new insights into the retinal and choroidal pathophysiologies found in patients with hemoglobin abnormalities.

Study on the mechanism of 20-hydroxyeicosatetraenoic acid in retinal ischemia-reperfusion injury.

To explore the effect of 20-hydroxyeicosatetraenoic acid (20-HETE) on retinal ischemia-reperfusion injury (RIRI) and the protective effect of N-hydroxy-N'-(4-n-butyl-2-methylphenyl)formamidine (HET0016) on RIRI. Male Sprague-Dawley rats were randomly divided into the normal control group, experimental model group (RIRI group), experimental solvent group (RIRI + solvent group), and experimental treatment group (RIRI + HET0016 group). The levels of 20-HETE, tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β) in the retina of rats at 24 h after reperfusion were measured by enzyme-linked immunosorbent assay. Hematoxylin-eosin staining was used to observe the retinal morphological and thickness changes at 24 h, 48 h, and 7 days after reperfusion. The number and localized expression of matrix metalloproteinase-9-positive cells in the retina of the rats at 24 h after reperfusion and the activation and localized expression of retinal microglia at 48 h after reperfusion were measured using an immunohistochemical method. The nuclear metastasis of nuclear factor kappa-B (NF-κB, p65) cells at 24 h after reperfusion was observed using an immunofluorescence method. Overall, 20-HETE might activate microglia to aggravate RIRI by the NF-κB pathway, but HET0016 has significant protective effects for the retina.