Background Diabetic Retinopathy Research Articles

Assessment of Diabetic Patients' Adherence to Diabetic Retinopathy Screening and the Influencing Factors in Al-Ahsa, Saudi Arabia

BackgroundDiabetic retinopathy (DR) is one of the diabetic complications that leads to the loss of vision. Most diabetic patients will have DR that is varying in its severity under the effect of many factors such as type of diabetes, duration of diabetes, and poor glycemic control. This study aimed to assess the level of adherence of diabetic patients to diabetic retinopathy screening (DRS) and to identify the influencing factors of adherence among diabetic patients in Al Ahsa, Saudi Arabia.MethodsA cross-sectional study was conducted via a self-administered questionnaire among diabetic patients who were attending the primary health-care centers in Al Ahsa, Saudi Arabia, from July to August 2021. This questionnaire included five sections: sociodemographic data, diabetic profile, assessment of the knowledge, attitude toward DRS, and barriers to DRS.ResultsA total of 397 diabetic patients were involved in the study. Diabetic ocular complications were reported among 35.3% of the patients. The most commonly reported diabetic eye complication was cataract (37.1%; 52) followed by retinopathy (36.4%). Among the participants, 32.2% had a good awareness level regarding DR. In addition, 46.9% of diabetic patients have DRS. The most reported barriers were having no visual or eye problems, difficulty getting an appointment, and the cost and lack of information about the screening procedure (50.9%, 50.1%, 42.1%, and 39.8%, respectively). ConclusionImprovement of patients’ knowledge is a significant step to enhancing adherence to DRS. The availability of screening programs and well-established ophthalmology clinics in primary healthcare centers in addition to trained physicians will help to overcome the barriers of DRS.

The relationship between the neutrophil-to-lymphocyte ratio and diabetic retinopathy in adults from the United States: results from the National Health and nutrition examination survey

BackgroundDiabetic retinopathy (DR) is a common complication of diabetes mellitus (DM). Systemic inflammation is intimately associated with DR. The neutrophil-to-lymphocyte ratio (NLR) index is a relatively new indicator of inflammation.MethodsThis cross-sectional study was carried out among adults with DM based on the National Health and Nutrition Examination Survey (NHANES) from 2009 to 2016. NLR was presented as absolute neutrophil counts/ absolute lymphocyte counts. The relationship of NLR levels to DR was analyzed using multivariable logistic regression.ResultsThere were 2772 eligible subjects extracted from the NHANES. In the multivariate analysis, NLR was related to the risk of DR after adjustment for potential confounders. The association between NLR levels and DR was nonlinear, with an inflection point of 4.778. Compared with the baseline values, NLR was not statistically significant on the right side of the inflection point (1.000, 0.914 to 1.094, 0.9974) but was positively associated with DR on the left side (1.236, 1.132 to 1.349, < 0.0001).ConclusionsNLR reflects systemic inflammation that may increase the risk of DR. NLR positively correlates with DR when its value is less than 4.778.

Effect of bone marrow mesenchymal stem cells-derived exosomes on diabetes-induced retinal injury: Implication of Wnt/ b-catenin signaling pathway

BackgroundDiabetic retinopathy (DR) is a serious microvascular complication of diabetes mellitus. Mesenchymal stem cells are currently studied as therapeutic strategy for management of DR. Exosomes, considered as a promising cell-free therapy option, display biological functions similar to those of their parent cells. In retinal development, Wnt/b-catenin signaling provides key cues for functional progression. The present study aimed to evaluate the potential efficacy of bone marrow-derived mesenchymal stem cell-derived exosomes (BM-MSCs-Ex) in diabetes-induced retinal injury via modulation of the Wnt/ b-catenin signaling pathway. MethodsEighty-one rats were allocated into 6 groups (control, DR, DR + DKK1, DR + exosomes, DR + Wnt3a and DR + exosomes+Wnt3a). Evaluation of each group was via histopathological examination, assessment of gene and/or protein expression concerned with oxidative stress (SOD1, SOD2, Nox2, Nox4, iNOS), inflammation (TNF-α, ICAM-1, NF-κB) and angiogenesis (VEGF, VE-cadherin). ResultsResults demonstrated that exosomes blocked the wnt/b-catenin pathway in diabetic retina concomitant with significant reduction of features of DR as shown by downregulation of retinal oxidants, upregulation of antioxidant enzymes, suppression of retinal inflammatory and angiogenic markers. These results were further confirmed by histopathological results, fundus examination and optical coherence tomography. Additionally, exosomes ameliorative effects abrogated wnt3a-triggered retinal injury in DR. ConclusionCollectively, these data demonstrated that exosomes ameliorated diabetes-induced retinal injury via suppressing Wnt/ b-catenin signaling with subsequent reduction of oxidative stress, inflammation and angiogenesis.

Evaluation of Fetuin-A level in diabetic retinopathy

BackgroundDiabetic retinopathy (DR) is a micro-vascular consequence of diabetes mellitus (DM) that manifests clinically as retinal ischemia, neovascularization, altered retinal permeability, and macular edema. In the adult population, DR is now considered a leading cause of blindness. Fetuin-A is a multifunctional glycoprotein that, because of its dual role in insulin resistance and angiogenesis, could be an early trigger of DR pathogenesis.ObjectiveThis study aimed to evaluate the level of Fetuin-A in diabetic patients with and without retinopathy and demonstrate if it could be used as an early indicator of DR.Patients and methodsA case–control study enrolled 45 participants selected from Al-Zahraa University Hospital, between March 2021 and October 2021, they were divided into three groups: Group 1: healthy control group (n=15); Group 2: type 2 diabetic patients without DR (n=15); and Group 3: type 2 diabetic patients with DR (n=15). All groups were age- and sex-matched and were investigated by enzyme-linked immunosorbent assay (ELISA) to evaluate serum level of Fetuin-A.ResultsThere was a highly significant difference of FBG, 2HPP, and HbA1c between the studied groups (p< 0.001), while there was no significant difference between the three studied groups regarding Fetuin-A. There were no significant correlation between Fetuin-A, glycemic parameters, and diabetic duration in Groups 2 and 3.ConclusionFetuin-A has no significant role in the pathogenesis of diabetic retinopathy.

Macrophages in close proximity to the vitreoretinal interface are potential biomarkers of inflammation during retinal vascular disease

BackgroundDiabetic retinopathy and retinal vein occlusion are vision threatening retinal vascular diseases. Current first-line therapy targets the vascular component, but many patients are treatment-resistant due to unchecked inflammation. Non-invasive inflammatory imaging biomarkers are a significant unmet clinical need for patients. Imaging of macrophage-like cells on the surface of the retina using clinical optical coherence tomography (OCT) is an emerging field. These cells are increased in patients with retinal vascular disease, and could be a potential inflammatory biomarker. However, since OCT is limited by an axial resolution of 5–10 microns, the exact location and identity of these retinal cells is currently unknown.MethodsWe performed OCT followed by confocal immunofluorescence in wild-type mice to identify macrophages within 5–10 microns of the vitreoretinal interface. Next, we used Cx3cr1CreER/+; Rosa26zsGreen/+ mice to fate map retinal surface macrophages. Using confocal immunofluorescence of retinal sections and flatmounts, we quantified IBA1+Tmem119+CD169neg microglia, IBA1+Tmem119negCD169neg perivascular macrophages, and IBA1+Tmem119negCD169+ vitreal hyalocytes. Finally, we modeled neuroinflammation with CCL2 treatment and characterized retinal surface macrophages using flow cytometry, OCT, and confocal immunofluorescence.ResultsWe were able to detect IBA1+ macrophages within 5–10 microns of the vitreoretinal interface in wild-type mice using OCT followed by confirmatory confocal immunofluorescence. Retinal surface macrophages were 83.5% GFP+ at Week 1 and 82.4% GFP+ at Week 4 using fate mapping mice. At steady state, these macrophages included 82% IBA1+Tmem119+CD169neg microglia, 9% IBA1+Tmem119negCD169+ vitreal hyalocytes, and 9% IBA1+Tmem119negCD169neg perivascular macrophages. After CCL2-driven neuroinflammation, many Ly6C+ cells were detectable on the retinal surface using OCT followed by confocal immunofluorescence.ConclusionsMacrophages within close proximity to the vitreoretinal interface are self-renewing cells, and predominantly microglia with minor populations of perivascular macrophages and vitreal hyalocytes at steady state. In the context of neuroinflammation, monocytes and monocyte-derived macrophages are a significant component of retinal surface macrophages. Human OCT-based imaging of retinal surface macrophages is a potential biomarker for inflammation during retinal vascular disease.

Molecular investigation of candidate genes for pyroptosis-induced inflammation in diabetic retinopathy.

BackgroundDiabetic retinopathy is a diabetic microvascular complication. Pyroptosis, as a way of inflammatory death, plays an important role in the occurrence and development of diabetic retinopathy, but its underlying mechanism has not been fully elucidated. The purpose of this study is to identify the potential pyroptosis-related genes in diabetic retinopathy by bioinformatics analysis and validation in a diabetic retinopathy model and predict the microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) interacting with them. Subsequently, the competing endogenous RNA (ceRNA) regulatory network is structured to explore their potential molecular mechanism.MethodsWe obtained mRNA expression profile dataset GSE60436 from the Gene Expression Omnibus (GEO) database and collected 51 pyroptosis-related genes from the PubMmed database. The differentially expressed pyroptosis-related genes were obtained by bioinformatics analysis with R software, and then eight key genes of interest were identified by correlation analysis, Gene Ontology (GO) enrichment analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, and protein–protein interaction (PPI) network analysis. Then, the expression levels of these key pyroptosis-related genes were validated with quantitative real-time polymerase chain reaction (qRT-PCR) in human retinal endothelial cells with high glucose incubation, which was used as an in vitro model of diabetic retinopathy. Western blot was performed to measure the protein levels of gasdermin D (GSDMD), dasdermin E (GSDME) and cleaved caspase-3 in the cells. Moreover, the aforementioned genes were further confirmed with the validation set. Finally, the ceRNA regulatory network was structured, and the miRNAs and lncRNAs which interacted with CASP3, TLR4, and GBP2 were predicted.ResultsA total of 13 differentially expressed pyroptosis-related genes were screened from six proliferative diabetic retinopathy patients and three RNA samples from human retinas, including one downregulated gene and 12 upregulated genes. A correlation analysis showed that there was a correlation among these genes. Then, KEGG pathway and GO enrichment analyses were performed to explore the functional roles of these genes. The results showed that the mRNA of these genes was mainly related to inflammasome complex, interleukin-1 beta production, and NOD-like receptor signaling pathway. In addition, eight hub genes—CASP3, TLR4, NLRP3, GBP2, CASP1, CASP4, PYCARD, and GBP1—were identified by PPI network analysis using Cytoscape software. High glucose increased the protein level of GSDMD and GSDME, as critical effectors of pyroptosis, in retinal vascular endothelial cells. Verified by qRT-PCR, the expression of all these eight hub genes in the in vitro model of diabetic retinopathy was consistent with the results of the bioinformatics analysis of mRNA chip. Among them, CASP4, GBP1, CASP3, TLR4, and GBP2 were further validated in the GSE179568 dataset. Finally, 20 miRNAs were predicted to target three key genes—CASP3, GBP2, and TLR4, and 22 lncRNAs were predicted to potentially bind to these 20 miRNAs. Then, we constructed a key ceRNA network that is expected to mediate cellular pyroptosis in diabetic retinopathy.ConclusionThrough the data analysis of the GEO database by R software and verification by qRT-PCR and validation set, we successfully identified potential pyroptosis-related genes involved in the occurrence of diabetic retinopathy. The key ceRNA regulatory network associated with these genes was structured. These findings might improve the understanding of molecular mechanisms underlying pyroptosis in diabetic retinopathy.

A novel and atypical NF-KB pro-inflammatory program regulated by a CamKII-proteasome axis is involved in the early activation of Muller glia by high glucose

BackgroundDiabetic retinopathy (DR) is a microvascular complication of diabetes with a heavy impact on the quality of life of subjects and with a dramatic burden for health and economic systems on a global scale. Although the pathogenesis of DR is largely unknown, several preclinical data have pointed out to a main role of Muller glia (MG), a cell type which spans across the retina layers providing nourishment and support for Retina Ganglion Cells (RGCs), in sensing hyper-glycemia and in acquiring a pro-inflammatory polarization in response to this insult.ResultsBy using a validated experimental model of DR in vitro, rMC1 cells challenged with high glucose, we uncovered the induction of an early (within minutes) and atypical Nuclear Factor-kB (NF-kB) signalling pathway regulated by a calcium-dependent calmodulin kinase II (CamKII)-proteasome axis. Phosphorylation of proteasome subunit Rpt6 (at Serine 120) by CamKII stimulated the accelerated turnover of IkBα (i.e., the natural inhibitor of p65-50 transcription factor), regardless of the phosphorylation at Serine 32 which labels canonical NF-kB signalling. This event allowed the p65-p50 heterodimer to migrate into the nucleus and to induce transcription of IL-8, Il-1β and MCP-1. Pharmacological inhibition of CamKII as well as proteasome inhibition stopped this pro-inflammatory program, whereas introduction of a Rpt6 phospho-dead mutant (Rpt6-S120A) stimulated a paradoxical effect on NF-kB probably through the activation of a compensatory mechanism which may involve phosphorylation of 20S α4 subunit.ConclusionsThis study introduces a novel pathway of MG activation by high glucose and casts some light on the biological relevance of proteasome post-translational modifications in modulating pathways regulated through targeted proteolysis.

Is serum vitamin D associated with diabetic retinopathy and its severity or with diabetes itself ?

ABSTRACT Clinical relevance Vitamin D (VitD) deficiency, which is found in approximately one-third of the population of the world, may play a role in the pathogenesis of diabetic retinopathy. Physicians following diabetes patients should be aware of this relationship and should refer patients to for ophthalmic care for control in a timely manner. Background Diabetic retinopathy is one of the most common complications of diabetic microvascular disease. VitD deficiency has been implicated in the pathogenesis and progression of diabetes and may have a role in development and severity of diabetic retinopathy. The aim of this study was to examine the relationship of serum VitD and some laboratory parameters with the presence of diabetes and retinopathy. Methods In this study, which has a retrospective epidemiological study design, comprehensive ophthalmologic examination data from the eye clinic, laboratory data from fasting blood tests, and internal medicine outpatient clinic examination data were reviewed. All participants were divided into four groups: 109 healthy controls, and 165 patients with type 2 diabetes of whom 54 did not have retinopathy, 64 had proliferative diabetic retinopathy, and 47 had non-proliferative diabetic retinopathy. Participants were also divided into four groups according to their serum VitD levels. Serum 25(OH)D, HbA1C, creatine, calcium, phosphate, triglyceride, low-density lipoprotein, and high-density lipoprotein levels were evaluated. Results In the whole study cohort, 152 (55.5%) were female and 122 (44.5%) were male. A statistically significant difference was observed in VitD between the healthy group and the diabetic and proliferative diabetic retinopathy groups (p ≤ 0.001). However, no significant correlation was observed between the presence of diabetes and retinopathy and serum VitD in logistic regression analyses (p > 0.05). Conclusion Diabetic patients have lower 25(OH)D than non-diabetic patients and there is no direct relationship between 25(OH)D and the development of diabetic retinopathy.

Effect of retinol and α-tocopherol supplementation on photoreceptor and retinal ganglion cell apoptosis in diabetic rats model

BackgroundDiabetic retinopathy (DR) is the most common microvascular complication of diabetes. Retinol and α-tocopherol of diabetic models prevent the damage of photoreceptor and retinal ganglion cells (RGC) caused by hyperglycemia.ObjectiveThis study aims to examine the effect of retinol and α-tocopherol on photoreceptor and RGC densities and the expression of caspase-3 and -7 on the retinal layers of the diabetic rat model.MethodsAlloxan 150 mg/kg body weight single dose was used to develop animal models, which were separated into eight groups. These consist of one group without intervention (group 1), one positive control with only induced alloxan (group 2), and others receiving retinol (group 3 and 6), α-tocopherol (group 4 and 7), or their combination (group 5 and 8). Furthermore, histopathological examination was performed using Hematoxylin–Eosin staining to evaluate the photoreceptor and RGC densities, while immunohistochemistry staining evaluated the caspase-3 and -7 expressions.ResultsIn the treatment group, the highest and lowest densities were identified in diabetic rats given α-tocopherol (group 7) and retinol (group 3) respectively. The caspase-3 and -7 expression showed that the group given α-tocopherol (group 7) had the lowest value.ConclusionIn diabetic rats, retinol and α-tocopherol compounds maintained densities and prevented photoreceptor and RGC death. However, α-tocopherol was more promising than retinol or combinations in the prevention of retinal cells apoptosis.

Association of polymorphisms in the erythropoietin gene with diabetic retinopathy: a case–control study and systematic review with meta-analysis

BackgroundDiabetic retinopathy (DR) is characterized by ischemia, hypoxia, and angiogenesis. Erythropoietin (EPO), an angiogenic hormone, is upregulated in DR, and the association of EPO genetic variants with DR is still uncertain, as conflicting results have been reported. Therefore, we performed a case–control study followed by a meta-analysis to investigate whether the rs1617640, rs507392, and rs551238 polymorphisms in EPO gene are associated with DR.MethodsThe case–control study included 1042 Southern Brazilians with type 2 diabetes (488 without DR and 554 with DR). Eligible studies for the meta-analysis were searched from electronic databases up to June 1, 2021. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were estimated for five genetic inheritance models.ResultsThe minor alleles of the EPO polymorphisms had nearly the same frequency in all groups of patients (35%), and no association was detected with DR in the case–control study. The meta-analysis included 14 independent sets of cases and controls with 9117 subjects for the rs1617640 polymorphism and nine independent sets with more than 5000 subjects for the rs507392 and rs551238 polymorphisms. The G allele of the rs1617640 polymorphism was suggestively associated with DR under the dominant (OR = 0.82, 95% CI: 0.68–0.98), heterozygous additive (OR = 0.82, 95% CI: 0.69–0.97), and overdominant (OR = 0.88, 95% CI: 0.79–0.97) models. In the subgroup analyses, the G allele was also suggestively associated with proliferative DR (PDR), non-proliferative DR (NPDR), and DR (PDR + NPDR) among patients with type 1 diabetes (T1DM) or non-Asian ancestry. After considering the Bonferroni correction for multiple comparisons, the G allele remained associated with NPDR and DR in T1DM. Regarding the rs507392 and rs551238 polymorphisms, no association was found between these variants and DR.ConclusionOur findings provide additional support to EPO as a susceptibility gene for DR, with the rs1617640 polymorphism deserving further investigation.

The prevalence of diabetic retinopathy in the occupied Palestinian territories: a national cross-sectional study

BackgroundDiabetic retinopathy is a complication of diabetes that affects the eyes and can lead to blindness if not adequately managed. No national or population-based estimates of diabetic retinopathy in Palestine exist. High-quality ophthalmic services are not available at the primary health care level for patients with diabetes in all sectors. Specialised eye centres are lacking. St John of Jerusalem Eye Hospital Group, which consists of five facilities in the West Bank and Gaza Strip, is the only provider of expert eye care in Palestine. The aim of this study was to determine the population prevalence of diabetic retinopathy among people with diabetes aged 50 years and older in Palestine. MethodsThis survey was part of a larger population-based survey using the rapid assessment of avoidable blindness (RAAB) methodology to estimate prevalence of vision impairment, blindness, and disability in individuals aged 50 years and older in Palestine. It was a nationally representative, cross-sectional, population-based survey in Gaza Strip and West Bank. Based on an expected prevalence of blindness of 3·4% in individuals aged 50 years and older, 20% precision level, 95% confidence level, 10% non-response rate, and a design effect of 1·4 to account for clustering, a sample size of 4224 participants aged 50 years and older was determined. 69 clusters in the West Bank and 52 clusters in the Gaza Strip were selected with probability proportionate to size from a list of areas from the Palestinian Central Bureau of Statistics population and housing census of 2017. Within each cluster, 35 people aged 50 years or older were randomly selected for examination in their homes. Three teams collected data; each consisted of a nurse and an ophthalmologist. Dilated fundus examination and Scottish diabetic retinopathy grading were done by the ophthalmologist in each team. Participants were classified as having diabetes if they had been diagnosed by a health professional, or if their random blood glucose (RBG) was 200 mg/dL or above on the day of data collection, as measured by a portable glucometer. Ethical approval was obtained from the St John of Jerusalem Eye Hospital Group and the London School of Hygiene & Tropical Medicine ethics committees. Informed oral witnessed consent was obtained from all participants. FindingsThe survey was conducted between July, 2018, and April, 2019. 4224 individuals were asked to participate, of whom 376 did not, leaving 3848 participants. The number of previously diagnosed and newly diagnosed patients with diabetes was 1176 (486 male, 690 female) and 103 (55 male, 48 female), respectively. The overall prevalence of diabetes across West Bank and Gaza was 33·2% (95% CI 31·5–34·9; 1279 of 3848 participants). The prevalence was higher in women (738 of 2047 [36·1%, 95% CI 33·6–38·5]) than in men (541 of 1801 [30·0%, 27·9–32·2), and in Gaza Strip (639 [35·8%] of 1783) than in West Bank (640 [31·0%] of 2065; p=0·002). Only 539 (46·3%) of 1164 patients with diagnosed diabetes who consented to blood blucose measurement had controlled blood glucose (RBG <200 mg/dL). 483 (41·1%) of 1176 patients with previously diagnosed diabetes had never had an eye check-up or had not been checked in the 2 years before the survey. 327 (25·6%) of 1279 patients with diabetes refused dilated fundus examination; 952 patients did undergo this examination, and 457 (48·0%, 95% CI 43·5–52·6) had diabetic retinopathy or maculopathy. Vision impairment was more common in those with diabetes (428 [33·5%] of 1279) than in those without (652 [25·4%] of 2569). 43 (3·4%) of 1279 participants with diabetes had blindness, compared with 65 (2·5%) of 2569 patients without diabetes. The principal cause of blindness in Gaza Strip was diabetic retinopathy (23 [32·4%] of 71) and in West Bank was untreated cataract (19 [51·4%] of 37). Diabetic retinopathy was the main cause of blindness, severe visual impairment, and moderate visual impairment among patients with diabetes. InterpretationDiabetes and diabetic retinopathy are substantial health problems in Palestine. Earlier detection and proper management at primary health care clinics and by outreach clinics for marginalised populations could be key. Referral networks between health-care sectors and specialised eye centres might provide the necessary infrastructure. FundingFred Hollows Foundation, Australia, German Federal Ministry for Economic Cooperation and Development.

Correlation between ultrawide-field fluorescence contrast results and white blood cell indexes in diabetic retinopathy

BackgroundDiabetic retinopathy (DR) is one of the most common microvascular complications of diabetes. DR involves a state of systemic inflammation, and chronic inflammation can promote microvascular and macrovascular diseases in diabetic patients and accelerate disease progression. Ultrawide-field FFA (UWFA) systems are increasingly being used to examine a wider retina. The aim of this study was to explore the correlation between the different manifestations of retinopathy under UWFA and the systemic indicators of white blood cells in patients with diabetic retinopathy.MethodsThis retrospective study included the hospitalized DR patients in the Department of Ophthalmology and Endocrinology of the Affiliated Hospital 2 of Nantong University between January 2016 and March 2019. This study examined the correlations between the UWFA examination results and glycated hemoglobin (HbA1c), routine blood tests,and the neutrophil-to-lymphocyte ratio of patients with clinically diagnosed DR during hospitalization.ResultsA total of 115 patients with DR (53 females and 62 males) were included (199 eyes: 102 right eyes and 97 left eyes). UWFA revealed that most eyes (77.4%) had grade 4 microvascular leakage, 52.8% had grade 0 capillary non-perfusion area, 59.3% had grade 0 neovascularization, and 92.0% had grade 0 fibrous proliferative membranes. Microvascular leakage was correlated with the NLR (r = 0.186, P = 0.027). Capillary non-perfusion area was correlated with the monocyte ratio (r = 0.144, P = 0.042) and the eosinophil ratio (r = 0.123, P = 0.044). Neovascularization was correlated to the monocyte ratio (r = 0.324, P = 0.018). Finally, the fibrous proliferative membrane was correlated to the monocyte ratio (r = 0.418, P = 0.002). Only the eosinophil ratio was independently associated with proliferative DR (odds ratio = 1.25, 95% confidence interval: 1.04–1.51, P = 0.018).ConclusionThe results of UWFA imaging in patients with DR are correlated with white blood cell population indexes. The eosinophil ratio was independently associated with proliferative DR.

The potential effects and mechanisms of hispidulin in the treatment of diabetic retinopathy based on network pharmacology

BackgroundDiabetic retinopathy (DR), one of the most common and severe microvascular complication of diabetes mellitus (DM), is mainly caused by diabetic metabolic disorder. So far, there is no effective treatment for DR. Eriocauli Flos, a traditional Chinese herb, has been used in treating the ophthalmic diseases including DR. However, the active ingredients and molecular mechanisms of Eriocauli Flos to treat diabetic retinopathy remain elusive.MethodsHere, the systems pharmacology model was developed via constructing network approach. 8 active components which were screened by oral bioavailability (OB ≥ 30%) and drug-likeness (DL ≥ 0.18) and 154 targets were selected from Eriocauli Flos through TCMSP database. Another 3593 targets related to DR were obtained from Genecards, OMIM, TTD, and Drugbank databases. The 103 intersecting targets of DR and Eriocauli Flos were obtained by Draw Venn Diagram. In addition, protein-protein interaction network was established from STRING database and the compound-target network was constructed by Cytoscape which screened top 12 core targets with cytoNCA module. Then the overlapping targets were analyzed by GO and KEGG enrichment. Moreover, two core targets were selected to perform molecular docking simulation. Subsequently, CCK8 assay, RT-PCR and Western blotting were applied to further reveal the mechanism of new candidate active component from Eriocauli Flos in high glucose-induced HRECs.ResultsThe results showed that the overlapping targets by GO analysis were enriched in cellular response to chemical stress, response to oxidative stress, response to reactive oxygen species, reactive oxygen species metabolic process and so on. Besides, the overlapping targets principally regulated pathways such as AGE-RAGE signaling pathway in diabetic complications, lipid atherosclerosis, fluid shear stress and atherosclerosis, and PI3K-Akt signaling pathway. Molecular docking exhibited that VEGFA and TNF-α, had good bindings to the great majority of compounds, especially the compound hispidulin. In vitro, hispidulin ameliorated high-glucose induced proliferation by down-regulating the expression of p-ERK, p-Akt, and VEGFA; meanwhile inhibited the mRNA levels of TNF-α.ConclusionsIn this study, through network pharmacology analysis and experimental validation, we found that hispidulin maybe has a potential targeted therapy effect for DR by decreasing the expression of p-Akt, p-ERK, and VEGFA, which resulted in ameliorating the proliferation in HRECs.

Protective effect of pentraxin 3 on pathological retinal angiogenesis in an in vitro model of diabetic retinopathy

BackgroundDiabetic retinopathy (DR) is the most common retinal microvascular disease caused by diabetes. Previous studies indicated that Pentraxin 3 (PTX3), an acute phase reactant, was closely related to the development of DR. But the exact effect of PTX3 in diabetic retinopathy needs more investigations. MethodsReal-time fluorescence quantitative polymerase chain reaction (qRT-PCR) analysis and western blot (WB) were used to detect the expression of PTX3 in vitro. The Ki67 immunofluorescent staining, scratch-wound migration assay, and tube formation experiments were performed to detect the effect of PTX3 knockdown and overexpression on the fibroblast growth factor (FGF)-induced proliferation, migration and tube-forming ability of human retinal microvascular endothelial cells (HRMECs). The phosphorylation levels of extracellular regulated protein kinases (ERK) and fibroblast growth factor receptor (FGFR) in HRMECs were detected by WB. ResultsIn vitro, the mRNA and protein expressions of PTX3 in the high-concentration glucose condition group were upregulated compared with the normal group (p < 0.05). The proliferation, migration and tube-forming abilities of HRMECs exposed to high-concentration glucose were enhanced (p < 0.01, p < 0.01, p < 0.05 respectively), and the phosphorylation of FGFR and ERK1/2 were increased (p < 0.01, p < 0.05 respectively) compared with the normal condition group. Compared with the high glucose condition group, the proliferation, migration and tube-forming abilities of HRMECs in the high glucose + PTX3 siRNA condition group were further strengthened (p < 0.001, p < 0.0001, p < 0.05 respectively), and the phosphorylation of FGFR and ERK1/2 were increased (p < 0.001, p < 0.01 respectively). Compared with the high glucose condition group, the proliferation, migration and tube-forming abilities of HRMECs in the high glucose + PTX3 overexpression condition group were compromised (p < 0.001, p < 0.05, p < 0.01 respectively), and the phosphorylation of FGFR and ERK1/2 were inhibited (p < 0.001, p < 0.0001 respectively). Neither the scramble siRNA condition group nor the blank plasmid condition group showed significant difference on the proliferation, migration and tube-forming abilities of HRMECs compared with the high glucose condition group (p > 0.05). ConclusionsThe upregulated expression of PTX3 may play a protective role on pathological angiogenesis in DR. PTX3 may serve as a new target for the treatment of DR.

International collaboration for the development of clinical guidelines in low and middle-income countries: case study on the development of a national framework and clinical guidelines for diabetic retinopathy in Ghana

BackgroundDiabetic retinopathy is a leading cause of blindness in many countries across the world. Ghana has seen a rise in diabetic retinopathy and is working on various strategies to prevent blindness. Clinical guidelines are seen as a promising strategy for improving quality and reducing cost of care. Little is known about the processes of collaborative guideline development in the African context.MethodsThis case study discusses the process of developing clinical guidelines for diabetic retinopathy in Ghana via a collaboration with the Kenya team that had previously developed guidelines for Kenya.ResultsThe main lesson learnt was the ability to overcome challenges. The main output achieved was the draft national framework, guidelines and training slides on the guidelines.ConclusionHorizontal international collaboration can aid development of clinical guidelines.

Identification and Validation of Autophagy-Related Genes in Diabetic Retinopathy.

BackgroundDiabetic retinopathy (DR) is one of the most common microvascular complications of diabetes, which is associated with damage of blood-retinal barrier and ischemia of retinal vasculature. It devastates visual acuity due to leakage of retinal vessels and aberrant pathological angiogenesis in diabetic patients. The etiology of DR is complex, accumulated studies have shown that autophagy plays an important role in the pathogenesis of DR, but its specific mechanism needs to be further studied.MethodsThis study chose the online Gene Expression Omnibus (GEO) microarray expression profiling dataset GSE146615 to carry on the research. Autophagy-related genes that were potentially differentially expressed in DR were screened by R software. Then, the differentially expressed autophagy-related genes were analyzed by correlation analysis, tissue-specific gene expression, gene-ontology (GO) enrichment analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis and protein-protein interaction (PPI) network analysis. Finally, retinal pigment epithelial cell line (ARPE-19) incubated with high glucose (HG) was used to mimic the DR model, and the mRNA level of key genes was verified by quantitative real-time polymerase chain reaction (qRT-PCR) in vitro.ResultsA total of 23 differentially expressed autophagy-related genes (9 up-regulated genes and 14 down-regulated genes) were identified by differential expression analysis. The analysis of tissue-specific gene expression showed that these differentially expressed autophagy-related genes were enriched in the retina. GO and KEGG enrichment analysis showed that differentially expressed autophagy-related genes were significantly enriched in autophagy-related pathways such as regulation of autophagy and macroautophagy. Then 10 hub genes were identified by PPI network analysis and construction of key modules. Finally, qRT-PCR confirmed that the expression of MAPK3 in the DR model was consistent with the results of bioinformatics analysis of mRNA chip.ConclusionThrough bioinformatics analysis, we identified 23 potential DR autophagy-related genes, among which the down-regulated expression of MAPK3 may affect the occurrence and development of DR by regulating autophagy. It provides a novel insight into the pathogenesis of DR.

A Multi-Branch Convolutional Neural Network for Screening and Staging of Diabetic Retinopathy Based on Wide-Field Optical Coherence Tomography Angiography

BackgroundDiabetic retinopathy (DR) is one of the major causes of blindness in adults suffering from diabetes. With the development of wide-field optical coherence tomography angiography (WF-OCTA), it is to become a gold standard for diagnosing DR. The demand for automated DR diagnosis system based on OCTA images have been fostered due to large diabetic population and pervasiveness of retinopathy cases. Materials and methodsIn this study, 288 diabetic patients and 97 healthy people were imaged by the swept-source optical coherence tomography (SS-OCT) with 12 mm × 12 mm single scan centered on the fovea. A multi-branch convolutional neural network (CNN) was proposed to classify WF-OCTA images into four grades: no DR, mild non-proliferative diabetic retinopathy (NPDR), moderate to severe NPDR, and proliferative diabetic retinopathy (PDR). ResultsThe proposed model achieved a classification accuracy of 96.11%, sensitivity of 98.08% and specificity of 89.43% in detecting DR. The accuracy of the model for DR staging is 90.56%, which is higher than that of other mainstream convolution neural network models. ConclusionThis technology enables early diagnosis and objective tracking of disease progression, which may be useful for optimal treatment to reduce vision loss.

Circ_NNT suppresses the apoptosis and inflammation in glucose-induced human retinal pigment epithelium by regulating miR-320b/TIMP3 axis in diabetic retinopathy

BackgroundDiabetic retinopathy (DR) is a frequent complication of diabetes. Recent reports have showed that circular RNAs (circRNAs) play important roles in DR progression. Herein, the aim of this study was to explore the role and molecular mechanism of circ_NNT in DR process. MethodsHuman retinal pigment epithelial cells ARPE-19 were treated with high glucose (HG) in experimental group. The expression of circ_NNT, miR-320b, and TIMP3 (TIMP Metallopeptidase Inhibitor 3) were determined using quantitative real-time polymerase chain reaction and Western blot. In vitro experiments were conducted by 5-ethynyl-2′-deoxyuridine (EdU) assay, MTT assay, flow cytometry, Western blot, and ELISA. The binding interaction was confirmed using dual-luciferase reporter and pull-down assays. ResultsHG stimulation led to a decrease of circ_NNT and TIMP3 expression, and an increase of miR-320b expression in ARPE-19 cells. Functionally, circ_NNT up-regulation reversed HG-evoked apoptosis and inflammation in ARPE-19 cells. Mechanistically, circ_NNT acted as a sponge for miR-320b to elevate TIMP3 expression. Further rescue experiments showed that miR-320b elevation attenuated the protective effects of circ_NNT on HG-induced ARPE-19 cells. Moreover, inhibition of miR-320b protected ARPE-19 cells against HG-evoked apoptosis and inflammation, which were abolished by TIMP3 knockdown. ConclusionCirc_NNT protected ARPE-19 cells against HG-evoked apoptosis and inflammation via elevating TIMP3 through sequestering miR-320b, indicating that up-regulation of circ_NNT might contribute to the inhibition of DR process.

Evaluation of Hemodynamic Changes in Retrobulbar Blood Vessels Using Color Doppler Imaging in Diabetic Patients.

Background—Diabetic retinopathy is a common complication of long-standing hyperglycemia. Microangiopathy-induced retinal changes are well-visualized on ophthalmoscopic examination. However, certain hemodynamic alterations have also been documented in the diabetic population, which have not been completely understood. Aim—To study the hemodynamic changes in retrobulbar circulation in diabetic patients with and without retinopathy, and to compare these changes with non-diabetic controls. Materials and Methods—This hospital-based prospective study included 50 diabetic and 50 non-diabetic patients. The diabetic groups consisted of 25 patients without retinopathy and 25 patients with retinopathy, and were labeled as Groups I and II, respectively. All subjects underwent orbital color Doppler ultrasonography using a linear high-frequency probe. The color Doppler parameters (peak systolic velocity (PSV), end-diastolic velocity (EDV), and resistive index (RI)) were measured and recorded using the spectral waveform of the ophthalmic artery (OA), central retinal artery (CRA), and short posterior ciliary arteries (SPCA). Comparison of obtained values was carried out using appropriate tests of significance. Results—The resistive indices of the ophthalmic, central retinal, and short posterior ciliary arteries were significantly higher in diabetic patients compared to controls (p < 0.001). The difference was also significant between Group I and Group II. Comparison of PSV and EDV of CRA and SPCAs among three groups using one-way ANOVA revealed a significant difference, with the highest blood flow velocities in the control group and the lowest in diabetics with retinopathy. The ophthalmic artery showed no significant change in blood flow velocity. Analysis using the Pearson correlation coefficient provided a positive correlation between the RI values of OA, CRA, and SPCA and the presence of diabetic retinopathy (OA = r 0.417, p < 0.001; CRA = r 0.466, p < 0.001; SPCA = r 0.438; p < 0.001). Conclusions—The resistive index of OA, CRA, and SPCA is a reliable indicator to assess diabetic-associated hemodynamic changes. The use of orbital color Doppler ultrasonography in diabetic patients can help in the identification of patients who are at risk of developing retinopathy.

MG53 represses high glucose-induced inflammation and angiogenesis in human retinal endothelial cells by repressing the EGR1/STAT3 axis

Background Diabetic retinopathy (DR) is a vascular complication of diabetes mellitus that leads to visual injury and blindness. Both angiogenesis and inflammation play an important role in the pathogenesis of DR. Here we aimed to explore the mechanisms of mitsugumin 53 (MG53) in ameliorating the dysfunction induced by high glucose (HG) in humans retinal microvascular endothelial cells (HRECs). Methods HRECs were subjected to HG in the presence or absence of MG53 overexpression. The effect of MG53 on cell viability and inflammatory response in HG-treated HRECs was measured using the Cell Counting Kit-8 and ELISAs, respectively. Expression of MG53, EGR1, p-STAT3, FGF2, TGFB1, and Angiopoietin-1 in HG-treated HRECs was quantified by western blot or quantitative real-time polymerase chain reaction. Results HG significantly downregulated MG53 in HRECs, which reduced cell viability while inducing angiogenesis and inflammatory response. Upregulation of MG53 reversed these effects of HG. MG53 directly interacted with EGR1 and repressed its expression, which decreased phosphorylation of STAT3 and downregulated FGF2, TGFB1, and Angiopoietin-1. EGR1 up-regulation or STAT3 activation antagonized the protective effects of MG53. Conclusion MG53 alleviates HG-induced dysfunction in HRECs by repressing EGR1/STAT3 signaling. Thereby MG53 may have therapeutic potential in DR.