Pathogenesis Of Diabetic Retinopathy Research Articles

Identification of miRNA-mRNA Regulatory Networks Associated with Diabetic Retinopathy using Bioinformatics Analysis.

Diabetic retinopathy (DR) is a major complication of diabetes and a leading cause of visual loss. This study aimed to explore biomarkers for DR that may provide additional reference to DR pathogenesis and development. The differentially expressed genes (DEGs) between the DR and control samples in the GSE53257 dataset were identified. Logistics analyses were performed to identify DR-associated miRNAs and genes, and correlation analysis was performed to determine the correlation between them in GSE160306. A total of 114 DEGs in DR were identified in GSE53257. Three genes, including ATP5A1 (down), DAUFV2 (down), and OXA1L (down), were differentially expressed between DR and control samples in GSE160306. Univariate logistics analysis identified that ATP5A1 (OR=0.007, p = 1.40E-02), NDUFV2 (OR = 0.003, p = 6.40E-03), and OXA1L (OR = 0.093, p = 3.08E-02) were DR-associated genes. ATP5A1 and OXA1L were regulated by multiple miRNAs, of which hsa-let- 7b-5p (OR = 26.071, p = 4.40E-03) and hsa-miR-31-5p (OR = 4.188, p = 5.09E-02) were related to DR. ATP5A1 and OXA1L were closely correlated with each other in DR. The hsa-miR-31-5p-ATP5A1 and hsa-let-7b-5p-OXA1L axes might play novel and important roles in the pathogenesis and development of DR.

Dysregulated CD200-CD200R signaling in early diabetes modulates microglia-mediated retinopathy.

Diabetic retinopathy (DR) is a neurovascular complication of diabetes. Recent investigations have suggested that early degeneration of the neuroretina may occur prior to the appearance of microvascular changes; however, the mechanisms underlying this neurodegeneration have been elusive. Microglia are the predominant resident immune cell in the retina and adopt dynamic roles in disease. Here, we show that ablation of retinal microglia ameliorates visual dysfunction and neurodegeneration in a type I diabetes mouse model. We also provide evidence of enhanced microglial contact and engulfment of amacrine cells, ultrastructural modifications, and transcriptome changes that drive inflammation and phagocytosis. We show that CD200-CD200R signaling between amacrine cells and microglia is dysregulated during early DR and that targeting CD200R can attenuate high glucose-induced inflammation and phagocytosis in cultured microglia. Last, we demonstrate that targeting CD200R in vivo can prevent visual dysfunction, microglia activation, and retinal inflammation in the diabetic mouse. These studies provide a molecular framework for the pivotal role that microglia play in early DR pathogenesis and identify a potential immunotherapeutic target for treating DR in patients.

Association of inflammation-related markers and diabetic retinopathy severity in the aqueous humor, but not serum of type 2 diabetic patients.

Diabetic retinopathy (DR) is a frequent microvascular complication of diabetes mellitus, and inflammatory pathways have been linked to its pathogenesis. In this retrospective, observational pilot study, we aimed to compare the concentrations of four inflammation-related proteins, ZAG, Reg-3a, elafin and RBP-4, in the serum and aqueous humor of healthy controls and diabetic patients with different stages of DR. The concentrations of VEGF-A, IL-8, IL-6 were determined in parallel as internal controls. In the serum, we did not find significant differences in the concentrations of target proteins. In the aqueous humor, higher levels of ZAG, RBP-4, Reg-3a and elafin were observed in advanced nonproliferative DR (NPDR)/ proliferative DR (PDR) compared to controls. The levels of ZAG and RBP-4 were also higher in advanced NPDR/PDR than in nonapparent DR. Normalization of target protein concentrations to the aqueous humor total protein demonstrates that a spill-over from serum due to breakage of the blood-retina barrier only partially accounts for increased inflammation related markers in later stages. In conclusion, we found elevated levels of Reg-3a, RBP-4, elafin and ZAG in advanced stages of diabetic retinopathy. Higher levels of pro-inflammatory proteins, Reg-3a and RBP-4, might contribute to the pathogenesis of diabetic retinopathy, as the parallel increased concentrations of anti-inflammatory molecules elafin and ZAG might indicate a compensatory mechanism.

Highly-Expressed MiR-221-3p Distinctly Increases the Incidence of Diabetic Retinopathy in Patients With Type 2 Diabetes Mellitus.

Diabetic retinopathy (DR) is the leading cause of blindness in patients with diabetes mellitus (DM). MiR-221-3p is implicated in microvascular dysfunction in DR, and we explored their relationship. Patients with type 2 diabetes mellitus (T2DM) were allocated to the non-DR (NDR)/nonproliferative DR (NPDR)/proliferative DR (PDR) groups, with their clinical baseline and pathological data collected. The miR-221-3p and VEGF levels were determined by reverse transcription quantitative polymerase chain reaction (RT-qPCR) and ELISA, respectively. Peripheral blood endothelial progenitor cell (EPC) and endothelial cell (EC) ratios were ascertained by flow cytometry. The correlations between miR-221-3p levels and VEGF/EPCs/ECs, the predictive value of serum miR-221-3p levels in DR, and the independent risk factors for DR occurrence in T2DM were analyzed by Pearson's correlation analysis, receiver operating characteristic (ROC) curve, and multifactorial logistic regression analysis. Serum miR-221-3p was highly expressed in DR. Clinical severity of DR was positively correlated with miR-221-3p levels. Endothelial function was impaired in DR. Serum miR-221-3p levels in DR were favorably correlated with VEGF and ECs and negatively associated with EPCs. The area under the curve of serum miR-221-3p in evaluating DR occurrence in patients with T2DM was 0.8178 (1.235 cutoff value, 69.62% sensitivity, and 82.35% specificity). High expression of miR-221-3p increased DR incidence in patients with T2DM. Diabetes course, VEGF, EPCs, ECs, and miR-221-3p levels were independent risk factors for DR development in patients with T2DM. Serum miR-221-3p levels in patients with DR were positively correlated with VEGF and ECs and negatively linked with EPCs. Highly expressed miR-221-3p distinctly increased DR incidence in patients with T2DM and was an independent risk factor for DR development in patients with T2DM. This study assessed serum miR-221-3p level and endothelial function indicators (VEGF, EPCs, and ECs) in patients with DR and analyzed the correlation between each indicator. We found that high serum miR-221-3p expression prominently increased the incidence of DR in patients with T2DM and was an independent risk factor for the development of DR in patients with T2DM. This study provided a scientific basis for further clarification of the pathogenesis of DR, and also provided new ideas for clinical prediction and management of DR.

NEDD4L Promotes IκBα Ubiquitination and Degradation in the Pathogenesis of Diabetic Retinopathy

Purpose The dysregulation of NF-κB signaling activity plays an important role in the pathogenesis of diabetic retinopathy (DR). This study explored the association between NEDD4L and IκBα in DR. Methods The rat model of diabetes was established and altered retinal vascular permeability in these rats was examined through an Evans blue dye assay. A range of glucose concentrations were used to treat retinal vascular endothelial cells (RVECs). The cells viability and apoptosis were assessed through MTT and flow cytometry, while shifts in cell permeability were examined by transendothelial resistance (TEER) and FITC dextran assay. The interaction of NEDD4L and IκBα was tested by Co-IP, while mRNA and protein levels were assessed via qPCR and Western blotting, respectively. Results High glucose suppressed proliferative activity of RVECs, and promoted apoptosis and the protein level of NEDD4L and NF-κB p65, but decreased IκBα. NEDD4L knockdown reversed the changes in inflammation, oxidative stress, and permeability in RVECs exposed to high glucose. Similarly, NEDD4L silencing reverted observed TEER decreases, increased monolayer permeability to FITC dextran, and ZO-1 and Claudin-5 downregulation in response to high glucose. Conversely, the impact of NEDD4L overexpression was reversed by the NF-κB inhibitor PDTC treatment. NEDD4L induced the ubiquitination of IκBα in an IKK-2-dependent manner. Moreover, siNEDD4L treatment alleviated the symptoms of DR through the inactivation of NF-κB signaling in vivo. Conclusions NEDD4L could enhance inflammation, oxidative stress, and permeability in the retinal vascular endothelium by facilitating the ubiquitination of IκBα in an IKK-2-dependent manner. Our results support a role for NEDD4L in the pathogenesis of DR.

Hyperlipidemia and lipid-lowering therapy in diabetic retinopathy (DR): A bibliometric study and visualization analysis in 1993–2023

BackgroundDiabetic retinopathy (DR) is a common complication in diabetic patients. DR is also a neurodegenerative disease. Patients with hyperglycemia, hyperlipidemia, and hypertension are vulnerable to retinopathy development. While the roles of blood glucose and blood pressure in the development of retinopathy have been extensively studied, the relationship between body fat and DR pathogenesis and the impact of lipid-reducing drugs on DR has just emerged as a research hotspot in DR study. We aim to visualize the contributions and cooperation of reporters, organizations, and nations, in addition to the research hotspots and trends in DR-related lipid research from 1993 to 2023, by bibliometric analysis. MethodsWe extracted all publications about DR-related lipid research from 1993 to 2023 from the Web of Science Core Collection, and bibliometric features were studied using VOSviewer and the CiteSpace program. Results1402 documents were retrieved. The number of studies has risen consistently for three decades, from an average of 16.8/year in the 1990s to 28.8/year in the 2000s, 64.5/year in 2010s, and reached 112/year in 2020–2022, confirming they are hot research topic in the field. These reports were from 93 nations/regions, with the USA, China, Japan, Australia, and England taking the leading positions. Diabetes Research and Clinical Practice was the journal that published the most studies, and Diabetes Care was the most quoted. We identified 6979 authors, with Wong TY having the most papers and being the most commonly co-cited. The most popular keyword, according to our research, is diabetic retinopathy. Oxidative stress, diabetic macular edema (DME), lipid peroxidation, and other topics have often been investigated. ConclusionDR-related lipid research is conducted mainly in North America, Asia, Oceania, and Europe. Much study has centered on the relationship between lipid-lowering therapy and DR pathogenesis. These studies strongly support using lipid-reducing medications (fenofibrate, statins, and omega-3 PUFAs), combined with hyperglycemia and hypertension therapy, to prevent and treat DR. However, the impact of fenofibrate or statin on retinopathy is not correlated with their action on blood lipid profiles. Thus, more randomized clinical trials with primary endpoints related to DR in T1D or T2D are merited. In addition, the lipid biomarker for DR (lipid aldehydes, ALEs, and cholesterol crystals), the action of lipid-reducing medicines on retinopathy, the mechanism of lipid-lowering medications preventing or curing DR, and ocular delivery of lipid-lowering drugs to diabetic patients are predicted as the research focus in the future in the DR-related lipid research field.

Associations of levels of high-molecular-weight adiponectin, secreted frizzled-related protein 5 and vascular endothelial growth factor-165 with diabetic retinopathy

Abstract Background: The pathogenesis of diabetic retinopathy (DR) remains unclear. The aim of the study was to explore the associations of DR with the levels of high-molecular-weight adiponectin (HMW-ADP), secreted frizzled-related protein 5 (SFRP-5) as well as vascular endothelial growth factor-165 (VEGF165). Methods: Based on the diagnostic criteria for DR, non-DR (NDR), proliferative DR (PDR) plus non-proliferative DR (NPDR) groups were set up for type 2 diabetes mellitus (T2DM) patients (n=180) treated from January 2020 to March 2021. The control group consisted of another 60 healthy subjects undergoing physical examinations. Their clinical data were compared. Receiver operating characteristic curves were plotted to assess the predictive values of HMW-ADP, VEGF165 and SFRP-5 for DR. The predictive efficiency of the established nomogram model was assessed. Results: The differences in age, fasting plasma glucose (FPG), T2DM duration, triglyceride (TG), hypertension history, high-density lipoprotein cholesterol (HDL-C), glycosylated haemoglobin (HbA1c), serum creatinine (Scr), homeostasis model assessment of insulin resistance (HOMA-IR), urine acid (UA), SFRP-5 HMW-ADP, and VEGF165 were significant between control and DR groups (P<0.05). HMW-ADP, VEGF165 and SFRP-5 had predictive values for DR (AUC>0.7), and the predictive efficiency of their combination was highest. The duration of T2DM, Scr, UA and VEGF165 were independent risk factors for DR, while HMW-ADP and SFRP-5 were protective factors (P<0.05). Preferable discrimination and accuracy together with clinical applicability were obtained for the nomogram prediction model. Conclusions: The three indicators as a whole have a high predictive value for DR, as potential indicators for the clinical screening of high-risk groups.

Identification of differential immune cells and related diagnostic genes in patients with diabetic retinopathy.

Diabetic retinopathy (DR) is a frequent microvascular abnormality associated with diabetes mellitus. The loss of retinal immunity is an important underlying mechanism of the DR pathogenesis, including the change in retinal immunosuppressive characteristics and the blood-retinal barrier disturbances. Therefore, this investigation screens immune-associated biomarkers in the retina of DR patients. In this investigation, the differential expression genes (DEGs) were acquired from Gene Expression Omnibus data GSE102485. The relative expression of 22 immune cell types in each sample was calculated by CIBERSORT analysis based on gene expression profile. The core module closely associated with immune infiltration was also screened by weighted gene co-expression network analysis (WGCNA). The overlapping DEGs and module genes were the differentially expressed immune-related genes (DEIRGs). With the help of the genes/proteins (STRING) database and MCODE plug-in, the protein-protein interaction (PPI) network hub genes were screened. Furthermore, the miRNA-hub genes and transcription factor (TF)-hub gene regulatory network were used to explain the possible signal pathways in DR. The hub genes verification was carried out by Polymerase Chain Reaction. Lastly, select CSF1R and its related pathway factor p-ERK1/2 to verify their expression in RF/6A under normal and high glucose environments. A total of 3583 principle DEGs, that enriched immune-related GO terms and infection-related pathways were identified. CIBERSORT analysis showed that naive B cells, M2 macrophages, eosinophils, and neutrophil infiltration were significantly different. After intersecting 3583 DEGs, 168 DEIRGs and 181 module genes were identified. Furthermore, 15 hub genes, TYROBP, FCGR3A, CD163, FCGR2A, PTPRC, TLR2, CD14, VSIG4, HCK, CSF1R, LILRB2, ITGAM, CTSS, CD86, and LY86, were identified via PPI network. The identified hub genes were up-regulated in DR and showed a high DR diagnostic value. Regulatory networks of the miRNA- and TF-hub genes can help understand the etiology of disease at the genetic level and optimize treatment strategy. CD14, VSIG4, HCK, and CSF1R were verified to be highly expressed in the vitreous of patients with DR. n RF/6A, CSF1R, and p-ERK1/2 were significantly overexpressed under high glucose conditions, with a statistically significant difference. This investigation identified 15 genes (TYROBP, FCGR3A, CD163, FCGR2A, PTPRC, TLR2, CD14, VSIG4, HCK, CSF1R, LILRB2, ITGAM, CTSS, CD86, and LY86) as hub DR genes, which may serve as a new potential point for the diagnosis and treatment of DR. CSF1R/p-ERK1/2 signaling may promotes the development of retinal neovascularization.

Assessment of Serum Levels of Advanced Oxidation Protein Products in Type 2 Diabetic Patients with and without Retinopathy Taking Different Antidiabetic Treatments

The goal of this study was to investigate the protein peroxidation role by measuring serum levels of advanced oxidation protein products (AOPP) in type 2 diabetic patients with or without retinopathy and comparing them to controls to see if circulating AOPP levels can be used as a detection biomarker for DR. And see which of the two widely used antidiabetic treatment groups had the most impact on this oxidative stress marker. The groups were divided into two subgroups: 1) 70 type 2 diabetic patients (36 male, 34 female), 35 with diabetic retinopathy (DR) and 35 with no evidence of DR, and 2) non-diabetic controls (11 male, 9 female) were chosen from Ibn AL-Haitham Hospital for Ophthalmology and a Specialized Center for Endocrinology and Diabetes. AOPP levels were significantly higher in diabetic patients with (12.5±5.6 ng/ml) or without DR (5.1±4 ng/ml) when compared to those of controls (1.45 0.8 ng/ml) (p<0.05). AOPP levels were higher in the late stage of DR compared to the early stage(14 3.15 ng/ml ) and ( 10 2.13 ng/ml) respectively so. Furthermore, Dipeptidyl peptidase-4 inhibitors (DPP-4 inhibitors) cause a better reduction in AOPP levels compared to Sulfonylureas (SUs) in the NDR group. Increased protein oxidation may involve in the pathogenesis and severity of DR and the serum AOPP levels have the prospect to become a marker for the diagnosis of DR. DPP-4 inhibitors were better in slowing the progression of the disease compared to SUs.

Nifuroxazide repurposing for protection from diabetes-induced retinal injury in rats: Implication of oxidative stress and JAK/STAT3 axis.

The prevalence of diabetes mellitus (DM) is alarmingly increasing worldwide. Diabetic retinopathy (DR) is a prevailing DM microvascular complication, representing the major cause of blindness in working-age population. Inflammation is a crucial player in DR pathogenesis. JAK/STAT3 axis is a pleotropic cascade that modulates diverse inflammatory events. Nifuroxazide (Nifu) is a commonly used oral antibiotic with reported JAK/STAT3 inhibition activity. The present study investigated the potential protective effect of Nifu against diabetes-induced retinal injury. Effect of Nifu on oxidative stress, JAK/STAT3 axis and downstream inflammatory mediators has been also studied. Diabetes was induced in Sprague Dawley rats by single intraperitoneal injection of streptozotocin (50 mg/kg). Animals were assigned into four groups: normal, Nifu control, DM, and DM + Nifu. Nifu was orally administrated at 25 mg/kg/day for 8 weeks. The effects of Nifu on oxidative stress, JAK/STAT3 axis proteins, inflammatory factors, tight junction proteins, histological, and ultrastructural alterations were evaluated using spectrophotometry, gene and protein analyses, and histological studies. Nifu administration to diabetic rats attenuated histopathological and signs of retinal injury. Additionally, Nifu attenuated retinal oxidative stress, inhibited JAK and STAT3 phosphorylation, augmented the expression of STAT3 signaling inhibitor SOCS3, dampened the expression of transcription factor of inflammation NF-κB, and inflammatory cytokine TNF-α. Collectively, the current study indicated that Nifu alleviated DR progression in diabetic rats, suggesting beneficial retino-protective effect. This can be attributed to blocking JAK/STAT3 axis in retinal tissues with subsequent amelioration of oxidative stress and inflammation.

Lychee seed polyphenol ameliorates DR via inhibiting inflammasome/apoptosis and angiogenesis in hRECs and db/db mice

Blood retinal barrier (BRB) damage is an important pathogenesis of diabetic retinopathy, and alleviating BRB damage has become a key target for DR treatment. We previously found that Lycopene seed polyphenols (LSP) maintained BRB integrity by inhibiting NLRP3 inflammasome-mediated inflammation. However, it is still unknown whether LSP inhibits retinal neovascularization with abnormal capillaries and its mechanism of action. Here, we employed db/db mice and hRECs to find that LSP increases the level of glycolipid metabolism, maintains the morphology of retinal endothelial cells and inhibits acellular capillary neogenesis. Mechanistic studies revealed that LSP inhibits the NLRP3 inflammasome, reduces cell apoptosis in retinal tissue, increases tight junction protein (TJ) expression, and reduces vascular endothelial growth factor (VEGF) and Ve-Cadherin in vivo and in vitro. Collectively, this study finds that LSP inhibits inflammation and angiogenesis to improve BRB function to ameliorate DR.

Comparative analysis of co-culture and monoculture models in simulating diabetic neurovascular dysfunction: insights into diabetic retinopathy.

Interaction between retinal vascular endothelial cells and neurons plays a critical role in the pathogenesis of diabetic retinopathy (DR). This study aims to compare an in vitro model over a monoculture model to simulate the neurovascular coupling under the hyperglycemic microenvironment of diabetes. Rat retinal vascular endothelial cells (RRMECs) and ganglion cells (RGCs) were seeded mono- or co-cultured in a normal (NG, 5.5 mM) and high (HG, 75 mM) glucose concentrations culture medium. Cell viability was detected by the cell counting kit-8 (CCK-8) assay. The ability of migration and lumen formation of RRMECs were determined by scratch wound, transwell migration, and lumen formation assays. The apoptosis index of cells was calculated and detected by propidium iodide (PI)/Hoechst staining. Quantitative and morphological analysis of RGCs was performed through the labeling of RGCs by brain-specific homeobox/POU domain protein 3A (BRN3A) and anti-beta-III tubulin (TUJ1). The gene and protein expression levels of occludin (OCLN) and zonula occludens-1 (ZO-1) were evaluated by quantitative real-time polymerase chain reaction and enzyme-linked immunosorbent assay. The viability, migration, and lumen formation abilities of RRMECs in the HG group significantly increased (P<0.05) in both mono- and co-culture models. Migration and lumen formation abilities of RRMECs in the co-culture with HG were lower than that in the monoculture group (P<0.05). The viability of RGCs cells with HG significantly decreased in both mono- and co-culture models (Pmono<0.001, Pco<0.001), the apoptosis index of RGCs in the co-culture with HG was higher than that in the monoculture (P=0.010). The protein and gene expression of OCLN, and ZO-1 in RRMECs significantly decreased with HG culture medium in both culture models (P<0.05). In the HG group, the protein and gene expression level of the ZO-1 and OCLN of RRMECs significantly decreased in the co-culture model than that in the monoculture model (P<0.05). Compared with mono cell culture, the established co-culture in vitro system for diabetic neurovascular dysfunction can better stimulate the micro-environment of the retinal neurovascular unit.

Proteomic analysis of diabetic retinas.

As a metabolic disease, diabetes often leads to health complications such as heart failure, nephropathy, neurological disorders, and vision loss. Diabetic retinopathy (DR) affects as many as 100 million people worldwide. The mechanism of DR is complex and known to impact both neural and vascular components in the retina. While recent advances in the field have identified major cellular signaling contributing to DR pathogenesis, little has been reported on the protein post-translational modifications (PTM) - known to define protein localization, function, and activity - in the diabetic retina overall. Protein glycosylation is the enzymatic addition of carbohydrates to proteins, which can influence many protein attributes including folding, stability, function, and subcellular localization. O-linked glycosylation is the addition of sugars to an oxygen atom in amino acids with a free oxygen atom in their side chain (i.e., threonine, serine). To date, more than 100 congenital disorders of glycosylation have been described. However, no studies have identified the retinal O-linked glycoproteome in health or disease. With a critical need to expedite the discovery of PTMomics in diabetic retinas, we identified both global changes in protein levels and the retinal O-glycoproteome of control and diabetic mice. We used liquid chromatography/mass spectrometry-based proteomics and high throughput screening to identify proteins differentially expressed and proteins differentially O-glycosylated in the retinas of wildtype and diabetic mice. Changes in both global expression levels of proteins and proteins differentially glycosylated in the retinas of wild-type and diabetic mice have been identified. We provide evidence that diabetes shifts both global expression levels and O-glycosylation of metabolic and synaptic proteins in the retina. Here we report changes in the retinal proteome of diabetic mice. We highlight alterations in global proteins involved in metabolic processes, maintaining cellular structure, trafficking, and neuronal processes. We then showed changes in O-linked glycosylation of individual proteins in the diabetic retina.

Down-regulation of histone deacetylase 7 reduces biological activities of retinal microvascular endothelial cells under high glucose condition and related mechanism.

To investigate the expression and effect of histone deacetylase 7 (HDAC7) in human retinal microvascular endothelial cells (HRMECs) under high glucose condition and related mechanism, and the expression of HDAC7 in the retinal tissue in diabetic rats. The expression of HDAC7 in HRMECs under high glucose and the retinal tissue from normal or diabetic rats were detected with immunohistochemistry and Western blot. LV-shHDAC7 HRMECs were used to study the effect of HDAC7 on cell activities. Cell count kit-8 (CCK-8), 5-ethynyl-2'-deoxyuridine (EdU), flow cytometry, scratch test, Transwell test and tube formation assay were used to examine the ability of cell proliferation, migration, and angiogenesis. Finally, a preliminary exploration of its mechanism was performed by Western blot. The expression of HDAC7 was both up-regulated in retinal tissues of diabetic rats and high glucose-treated HRMECs. Down-regulation of HDAC7 expression significantly reduced the ability of proliferation, migration, and tube formation, and reversed the high glucose-induced high expression of CDK1/Cyclin B1 and vascular endothelial growth factor in high glucose-treated HRMECs. High glucose can up-regulate the expression of HDAC7 in HRMECs. Down-regulation of HDAC7 can inhibit HRMECs activities. HDAC7 is proposed to be involved in pathogenesis of diabetic retinopathy and a therapeutic target.

Transcriptomic clock predicts vascular changes of prodromal diabetic retinopathy

Diabetic retinopathy is a common complication of long-term diabetes and that could lead to vision loss. Unfortunately, early diabetic retinopathy remains poorly understood. There is no effective way to prevent or treat early diabetic retinopathy until patients develop later stages of diabetic retinopathy. Elevated acellular capillary density is considered a reliable quantitative trait present in the early development of retinopathy. Hence, in this study, we interrogated whole retinal vascular transcriptomic changes via a Nile rat model to better understand the early pathogenesis of diabetic retinopathy. We uncovered the complexity of associations between acellular capillary density and the joint factors of blood glucose, diet, and sex, which was modeled through a Bayesian network. Using segmented regressions, we have identified different gene expression patterns and enriched Gene Ontology (GO) terms associated with acellular capillary density increasing. We developed a random forest regression model based on expression patterns of 14 genes to predict the acellular capillary density. Since acellular capillary density is a reliable quantitative trait in early diabetic retinopathy, and thus our model can be used as a transcriptomic clock to measure the severity of the progression of early retinopathy. We also identified NVP-TAE684, geldanamycin, and NVP-AUY922 as the top three potential drugs which can potentially attenuate the early DR. Although we need more in vivo studies in the future to support our re-purposed drugs, we have provided a data-driven approach to drug discovery.

Comparative proteomics of proliferative diabetic retinopathy in people with Type 2 diabetes highlights the role of inflammation, visual transduction, and extracellular matrix pathways.

To explore the vitreous humor proteome from type 2 diabetes subjects with proliferative diabetic retinopathy (PDR) in the Indian population. We performed mass spectrometry-based label-free quantitative analysis of vitreous proteome of PDR (n = 13) and idiopathic macular hole (IMH; control) subjects (n = 14). Nine samples of PDR and 10 samples of IMH were pooled as case and control, respectively, and compared. Four samples each of PDR and IMH were analyzed individually without pooling to validate the results of the pooled analysis. Comparative quantification was performed using Scaffold software which calculated the fold changes of differential expression. Bioinformatics analysis was performed using DAVID and STRING software. We identified 469 proteins in PDR and 517 proteins in IMH vitreous, with an overlap of 172 proteins. Also, 297 unique proteins were identified in PDR and 345 in IMH. In PDR vitreous, 37 proteins were upregulated (P < 0.05) and 19 proteins were downregulated compared to IMH. Protein distribution analysis clearly demonstrated a separation of protein expression in PDR and IMH. Significantly upregulated proteins included fibrinogen gamma chain, fibrinogen beta chain, and carbonic anhydrase 1 and downregulated proteins included alpha-1-antitrypsin, retinol-binding protein 3, neuroserpin, cystatin C, carboxypeptidase E and cathepsin-D. Diabetic retinopathy pathogenesis involves proteins which belong to inflammation, visual transduction, and extracellular matrix pathways. Validation-based experiments using enzyme-linked immunosorbent assay (ELISA) or western blotting are needed to establish cause and effect relationships of these proteins to the disease state, to develop them as biomarkers or drug molecules.

The Value of White Cell Inflammatory Biomarkers as Potential Predictors for Diabetic Retinopathy in Type 2 Diabetes Mellitus (T2DM).

The pathogenesis of diabetic retinopathy is still challenging, with recent evidence proving the key role of inflammation in the damage of the retinal neurovascular unit. This study aims to investigate the predictive value of the neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte (PLR), lymphocyte-to-monocyte ratio (LMR), and systemic inflammation index (SII) for diabetic retinopathy (DR) and its severity. We performed a retrospective study on 129 T2DM patients, divided into three groups: without retinopathy (NDR), non-proliferative DR (NPDR), and proliferative DR (PDR). NLR, MLR, and SII were significantly higher in the PDR group when compared to NDR and NPDR (3.2 ± 1.6 vs. 2.4 ± 0.9 and 2.4 ± 1.1; p = 0.005; 0.376 ± 0.216 vs. 0.269 ± 0.083 and 0.275 ± 0.111, p = 0.001; 754.4 ± 514.4 vs. 551.5 ± 215.1 and 560.3 ± 248.6, p = 0.013, respectively). PDR was correlated with serum creatinine (OR: 2.551), NLR (OR: 1.645), MPV (OR: 1.41), and duration of diabetes (OR: 1.301). Logistic regression analysis identified three predictive models with very good discrimination power for PDR (AUC ROC of 0.803, 0.809, and 0.830, respectively): combining duration of diabetes with NLR, MLR, and, respectively, PLR, MPV, and serum creatinine. NLR, MPV, SII, and LMR were associated with PDR and could be useful when integrated into comprehensive risk prediction models.

TNFAIP8 overexpression aggravates retinal pathophysiological features of diabetic retinopathy

Our previous research shown that tumor necrosis factor-alpha-induced protein 8 (TNFAIP8) is elevated in the plasma extracellular vesicles and vitreous humor in diabetic retinopathy (DR). TNFAIP8 also significantly increases the viability of human retinal microvascular endothelial cells (HRMECs) and promotes cell migration and tube formation in vitro. To comprehensively explore its role in DR, we investigated the effect of TNFAIP8 on DR development using an animal model in this study. A TNFAIP8-overexpressing adeno-associated virus (AAV) vector and streptozotocin-induced mouse model was used. The AAV-TNFAIP8 vector was injected into the mice intravitreally, and the effect was evaluated. The evaluation included analysis of retinal structure and function using electroretinography, optical coherence tomography, and histological assessment. The influence of TNFAIP8 on the avascular area, retinal leukostasis, and the expression levels of inflammatory factors was also determined. TNFAIP8 significantly decreased a/b-wave amplitude and retinal thickness in diabetic mice. Histological assessment showed that TNFAIP8 aggravated pathological abnormalities with distorted organization of the retina. TNFAIP8 also significantly increased the avascular area, leukostasis, and the expression of inflammatory factors, such as TNFα, IL1β, ICAM1, and GFAP, in the retina. The results of this study support the role of TNFAIP8 in DR pathogenesis. A mechanistic understanding of TNFAIP8 may offer novel therapeutic strategies.

Liraglutide intervention improves high-glucose-induced reactive gliosis of Müller cells and ECM dysregulation

Reactive gliosis of Müller cells plays an important role in the pathogenesis of diabetic retinopathy (DR). Liraglutide, a glucagon-like peptide-1 receptor (GLP-1R) agonist, has been shown to improve DR by inhibiting reactive gliosis. However, the mechanism of inhibition has yet to be elucidated. This study investigated the effects of liraglutide on Müller glia reactivity in the early stages of DR and the underlying mechanisms. Proteomics combined with bioinformatics analysis, HE staining, and immunofluorescence staining revealed ganglion cell loss, reactive gliosis of Müller cells, and extracellular matrix (ECM) imbalance in rats with early stages of DR. High glucose (HG) exposure up-regulated GFAP and TNF-α expression and down-regulated ITGB1 expression and FN1 content in extracellular fluid in rMC1 cells, thereby promoting reactive gliosis. GLP-1R knockdown and HG+DAPT inhibition experiments show that liraglutide balances ECM levels by inhibiting activation of the Notch1/Hes1 pathway and ameliorates high-glucose-induced Müller glia reactivity. Thus, the study provides new targets and ideas for improvement of DR in early stages.

Plasma and aqueous levels of subfatin, preptin and betatrophin in patients with diabetic retinopathy

AimTo examine subfatin, preptin and betatrophin levels in plasma and aqueous in patients with diabetes mellitus (DM) (with and without retinopathy).Material and methodSixty patients, who were similar in terms of age and gender, and were scheduled for operation due to cataract, were included in the study. The patients were divided into three groups as Group C (20 weeks without diabetes and comorbidity), Group DM (20 patients with DM but no retinopathy) and Group DR (20 patients with diabetic retinopathy). The preoperative body mass index (BMI), fasting plasma glucose, HbA1c, lipid profile levels of all patients in the groups were examined. Blood samples were also taken for plasma subfatin, preptin and betatrophin levels. At the beginning of the cataract surgery, 0.1 ml of aqueous fluid was taken from the anterior chamber. Plasma and aqueous subfatin, preptin and betatrophin levels were analyzed by ELISA (enzyme-linked immunosorbent assays) method.ResultsIn our study results, there was a significant difference in BMI, fasting plasma glucose and hemoglobin A1c levels (p < 0.05 for all parameters). Plasma and aqueous subfatin levels were higher in Group DR compared to Group C (p < 0.001, p = 0.036, respectively). Plasma and aqueous preptin levels were higher in group DR and group DM than in group C (p = 0.001, p = 0.002, p < 0.001, p = 0.001, respectively). Plasma and aqueous betatrophin levels were higher in Group DR compared to group C (p = 0.001, p = 0.010, respectively).ConclusionSubfatin, preptin and betatrophin molecules may have an important role in the pathogenesis of diabetic retinopathy.