Genetic association of TIE2 with diabetic retinopathy and diabetic macular edema.

PURPOSE: To evaluate the associations of the TIE2 gene with diabetic retinopathy (DR) and diabetic macular edema (DME). METHODS: This study included a Chinese cohort of 285 non-proliferative DR patients and 433 healthy controls. The DR patients were classified further into those with or without DME. Thirty haplotype-tagging single-nucleotide polymorphisms (SNPs) in TIE2 were genotyped using TaqMan technology. Associations of DR and subtypes were analyzed by logistic regression adjusted for age and sex. Stratification association analysis by sex was performed. RESULTS: TIE2 rs625767 showed a nominal but consistent association with DR [odds ratio (OR) = 0.71, P = 0.005] and subtypes (DR without DME: OR = 0.69, P = 0.016; DME: OR = 0.73, P = 0.045). SNP rs652010 was consistently associated with overall DR (OR = 0.74, P = 0.011) and DR without DME (OR = 0.70, P = 0.016), but not with DME. Moreover, SNPs rs669441, rs10967760, rs549099 and rs639225 showed associations with overall DR, whilst rs17761403, rs664461 and rs1413825 with DR without DME. In stratification analysis, three SNPs, rs625767 (OR = 0.62, P = 0.005), rs669441 (OR = 0.63, P = 0.006) and rs652010 (OR = 0.64, P = 0.007), were associated with DR in females, but not in males. Moreover, one haplotype T-T defined by rs625767 and rs669441 was significantly associated with DR in females only. CONCLUSIONS: This study revealed TIE2 as a susceptibility gene for DR and DME in Chinese, with a sex-specific association in females. Further validation should be warranted.

Association of PON1, APOE and SDF-1 Gene Polymorphisms with Treatment Response to Intravitreal Anti-VEGF Treatment in Patients with Retinal Vein Occlusion.

PURPOSE: The purpose of this study was to determine whether specific genetic polymorphisms affect the response to intravitreal anti-vascular endothelial growth factor (anti-VEGF) treatment in patients with macular oedema secondary to retinal vein occlusion (RVO). METHODS: Participants in this prospective study were 50 patients with macular oedema secondary to RVO, who were treated with intravitreal ranibizumab or aflibercept, and were followed-up for 12 months after initiation of treatment. Five single nucleotide polymorphisms (SNPs) from three different genes (APOE, PON1, SDF-1) were examined as potential predictors for treatment response to intravitreal anti-VEGF agents. RESULTS: Patients with the LL genotype of the PON1 L55M SNP had significantly higher reduction in central subfield thickness (CST) at month 12 after initiation of intravitreal anti-VEGF treatment (101.63 ± 56.80 µm in LL vs. 72.44 ± 39.41 µm in LM vs. 40.25 ± 19.33 µm in MM, p = .026). Patients with the M allele of the PON1 L55M SNP were significantly associated with lower reduction in CST compared to non-carriers (68.29 ± 38.77 µm in LM + MM vs. 101.63 ± 56.80 µm in LL, p = .032). CONCLUSION: PON1 L55M SNP may serve as a promising genetic biomarker for predicting response to intravitreal anti-VEGF treatment in patients with macular oedema due to RVO.

Investigating the associations of macular edema in retinitis pigmentosa.

Macular edema (ME), the accumulation of intraretinal fluid in the macula, is a common sight affecting sequelae of retinitis pigmentosa (RP). However, it is unclear why some patients develop ME, and others do not. This study aims to identify associations between clinical-genetic factors in RP with ME. Patients with clinically confirmed RP cases were identified from the inherited retinal disease database at a large tertiary referral academic center. Demographic and genetic testing findings were noted. Additionally, optical coherence tomography volume scans were graded using a validated grading system. One hundred and six patients (73.1%) were found to have ME in at least one eye (OD = 88, mean = 37.9%, OS = 98, mean = 31.7%). Structurally, the presence of epiretinal membrane (ERM) (p < 0.007) and vitreo-macular traction (VMT) (p < 0.003) were significantly associated with ME. Additionally, X-linked (p < 0.032) and autosomal dominant inheritance (p < 0.039) demonstrated a significant association with ME, with RP1 (p < 0.045) and EYS (p < 0.017) pathogenic variants also significantly associated with ME. This study, in a large cohort of RP patients, confirms previous retinal structural associations for ME in RP and identifies potential new genetic associations.

Multi-ancestry GWAS analysis identifies two novel loci associated with diabetic eye disease and highlights APOL1 as a high risk locus in patients with diabetic macular edema.

Diabetic retinopathy (DR) is a common complication of diabetes. Approximately 20% of DR patients have diabetic macular edema (DME) characterized by fluid leakage into the retina. There is a genetic component to DR and DME risk, but few replicable loci. Because not all DR cases have DME, we focused on DME to increase power, and conducted a multi-ancestry GWAS to assess DME risk in a total of 1,502 DME patients and 5,603 non-DME controls in discovery and replication datasets. Two loci reached GWAS significance (p<5x10-8). The strongest association was rs2239785, (K150E) in APOL1. The second finding was rs10402468, which co-localized to PLVAP and ANKLE1 in vascular / endothelium tissues. We conducted multiple sensitivity analyses to establish that the associations were specific to DME status and did not reflect diabetes status or other diabetic complications. Here we report two novel loci for risk of DME which replicated in multiple clinical trial and biobank derived datasets. One of these loci, containing the gene APOL1, is a risk factor in African American DME and DKD patients, indicating that this locus plays a broader role in diabetic complications for multiple ancestries. Trial Registration: NCT00473330, NCT00473382, NCT03622580, NCT03622593, NCT04108156.

Genome-Wide Associations and Confirmatory Meta-Analyses in Diabetic Retinopathy.

The present study aimed to summarize and validate the genomic association signals for diabetic retinopathy (DR), proliferative DR, and diabetic macular edema/diabetic maculopathy. A systematic search of the genome-wide association study (GWAS) catalog and PubMed/MELINE databases was conducted to curate a comprehensive list of significant GWAS discoveries. The top signals were then subjected to meta-analysis using established protocols. The results indicate the need for improved consensus among DR GWASs, highlighting the importance of validation efforts. A subsequent meta-analysis confirmed the association of two SNPs, rs4462262 (ZWINT-MRPS35P3) (odds ratio = 1.38, p = 0.001) and rs7903146 (TCF7L2) (odd ratio = 1.30, p < 0.001), with DR in independent populations, strengthening the evidence of their true association. We also compiled a list of candidate SNPs for further validation. This study highlights the importance of consistent validation and replication efforts in the field of DR genetics. The two identified gene loci warrant further functional investigation to understand their role in DR pathogenesis.

NONSYNDROMIC RETINITIS PIGMENTOSA WITH BILATERAL RETINAL NEOVASCULARIZATION DUE TO HGSNAT MUTATION.

PURPOSE: To describe a case of nonsyndromic retinitis pigmentosa caused by presumed compound heterozygous A615T and T522M mutations in HGSNAT, characterized by bilateral cystoid macular edema and retinal neovascularization. METHODS: Case report. The patient underwent clinical evaluation, multimodal imaging, and next-generation panel sequencing. In silico analysis was performed with PolyPhen-2, SIFT, and MutationTaster. Segregation analysis was not available. RESULTS: A 35-year-old hypertensive man presented with nyctalopia, photopsia, and difficulty reading for six months. He had no family history of visual deficits. The best-corrected visual acuity was 20/25 in the right eye and 20/20 in the left eye. Examination revealed midperipheral bone spicules and macular neovascularization in both eyes. Multimodal imaging demonstrated cystoid macular edema, ellipsoid band loss outside the central macula, and leakage from the neovascularization in both eyes. Sequencing detected four mutations in three genes, including two heterozygous mutations in HGSNAT (c.1843G>A, p.A615T and c.1565C>T, p.T522M). A615T is a pathogenic, hypomorphic mutation. T522M has not been previously phenotypically described. It is predicted damaging by in silico analysis and occurs at a conserved position near the eighth transmembrane domain, adjacent to residues in which missense mutations result in protein misfolding. CONCLUSION: This is, to the best of our knowledge, the first reported case of retinal neovascularization in a case of nonsyndromic retinitis pigmentosa due to HGSNAT mutation. The T522M variant likely functions as a severe mutation alongside the hypomorphic A615T mutation. These findings expand the genotypic and phenotypic spectrum of nonsyndromic retinitis pigmentosa.

Genome-wide association study of the response of patients with diabetic macular edema to intravitreal Anti-VEGF injection.

Diabetic macular edema (DME), a complication of diabetes mellitus, is a leading cause of adult-onset blindness worldwide. Recently, intravitreal anti-VEGF injection has been used as a first-line treatment. This study analyzed the association between the genetic profile of patients with DME and their response to treatment. Intravitreal anti-VEGF injections were administered monthly for three months to Korean patients diagnosed with DME, who were classified into two groups depending on whether they responded to anti-VEGF therapy or showed recurrence within six months. Peripheral blood samples were used for genetic analyses. Genome-wide association analysis results sowed that the genes DIRC3 on chromosome 2 (rs16857280, p = 1.2 × 10-6), SLCO3A1 on chromosome 15 (rs12899055, p = 2.5 × 10-6), and RAB2A on chromosome 8 (rs2272620, p = 4.6 × 10-6) were associated with treatment response to intravitreal anti-VEGF injection. SLC35F1, TMEM132D, KIAA0368, HPCAL1, IGF2BP3, SPN2S, COL23A1, and CREB5 were also related to treatment response (p < 5.0 × 10-5). Using the KEGG pathway analysis, RAB2A and CREB5 were found to be associated with AMPK signaling related to VEGF (p = 0.018). The identified genetic biomarkers can elucidate the factors affecting patient response to intravitreal anti-VEGF injection and help select appropriate therapeutic strategy.

CD8+T Cell-Related Gene Biomarkers in Macular Edema of Diabetic Retinopathy.

Background: CD8+T lymphocytes have a strong pro-inflammatory effect in all parts of the tissue, and some studies have demonstrated that its concentration in the vitreous increased significantly, suggesting that CD8+T cells play a pivotal role in the inflammatory response of diabetic retinopathy (DR). However, the infiltration of CD8+T cells in the DR retina, especially in diabetic macular edema (DME), and its related genes are still unclear. Methods: Download the GSE16036 dataset from the Gene Expression Omnibus (GEO) database. The ImmuCellAI program was performed to evaluate the abundance of 24 immune cells including CD8+T cells. The CD8+T cell-related genes (DECD8+TRGs) between non-proliferative diabetic retinopathy (NPDR) and DME were detected via difference analysis and correlation analysis. Enrichment analysis and protein-protein interaction (PPI) network mapping were implemented to explore the potential function of DECD8+TRGs. Lasso regression, support vector machine recursive feature elimination (SVM-RFE), CytoHubba plug-in and MCODE plug-in in Cytoscape software, and Weighted Gene Co-Expression Network Analysis (WGCNA) were performed to comprehensively analyze and obtain Hub DECD8+TRGs. Hub DECD8+TRGs expression patterns were further validated in other two DR-related independent datasets. The CD8+TRG score was defined as the genetic characterization of Hub DECD8+TRGs using the GSVA sample scoring method, which can be administered to distinguish early and advanced diabetic nephropathy (DN) as well as normal and DN. Finally, the transcription level of DECD8+TRGs in DR model mouse were verified by quantitative real-time PCR (qPCR). Results: A total of 371 DECD8+TRGs were identified, of which 294 genes were positively correlated and only 77 genes were negatively correlated. Eight genes (IKZF1, PTPRC, ITGB2, ITGAX, TLR7, LYN, CD74, SPI1) were recognized as Hub DECD8+TRGs. DR and DN, which have strong clinical correlation, have been proved to be associated with CD8+T cell-related hub genes by multiple independent data sets. Hub DECD8+TRGs can not only distinguish PDR from normal and DN from normal, but also play a role in the early and progressive stages of the two diseases (NPDR vs DME, Early DN vs Advanced DN). The qPCR transcription level and trend of Hub DECD8+TRGs in DR mouse model was basically the same as that in human transcriptome. Conclusion: This study not only increases our understanding of the molecular mechanism of CD8+T cells in the progression of DME, but also expands people's cognitive vision of the molecular mechanism of crosstalk of CD8+T cells in the eyes and kidneys of patients with diabetes.

The Correlation Between MicroRNAs and Diabetic Retinopathy.

Micro ribonucleic acids (miRNAs), as a category of post-transcriptional gene inhibitors, have a wide range of biological functions, are involved in many pathological processes, and are attractive therapeutic targets. Considerable evidence in ophthalmology indicates that miRNAs play an important role in diabetic retinopathy (DR), especially in inflammation, oxidative stress, and neurodegeneration. Targeting specific miRNAs for the treatment of DR has attracted much attention. This is a review focusing on the pathophysiological roles of miRNAs in DR, diabetic macular edema, and proliferative DR complex multifactorial retinal diseases, with particular emphasis on how miRNAs regulate complex molecular pathways and underlying pathomechanisms. Moreover, the future development potential and application limitations of therapy that targets specific miRNAs for DR are discussed.

Younger Age and Albuminuria are Associated with Proliferative Diabetic Retinopathy and Diabetic Macular Edema in the South Indian GeNetics of DiAbeTic Retinopathy (SIGNATR) Study.

Purpose: The purpose of the South Indian GeNetics of DiAbeTic Retinopathy (SIGNATR) Study is to identify non-genetic and genetic risk factors associated with diabetic retinopathy (DR). This report examines the non-genetic risk factors for DR in South Indian patients.Methods: Participants with South Indian ancestry and type 2 diabetes (T2D) were included from two sources: the Sankara Nethralaya Diabetic Retinopathy and Molecular Genetics Study (SN-DREAMS) and prospective recruitment at Sankara Nethralaya affiliates. Fundus photography and optical coherence tomography (OCT) were obtained on participants. Fundus images were graded for DR severity and OCTs were graded for center-involved diabetic macular edema (ciDME). Multivariate analyses were performed using stepwise logistic regression to assess effects of the demographic and clinical factors on proliferative DR (PDR) and DME.Results: Among the 2941 participants with DR grading, participants with PDR were more likely to be younger [odds ratio (OR)=0.95], men (OR = 1.83), have a longer duration of diabetes (OR = 1.10), have a higher hemoglobin A1c (OR = 1.12), have albuminuria (OR = 5.83), have hypertension (OR = 1.69), have a higher HDL (OR = 1.02) and a lower total cholesterol (OR = 0.99) (all p < 0.05). Among the 483 participants with gradable OCT scans, participants who had ciDME were more likely to be younger (OR = 0.97), men (OR = 2.80), have a longer duration of diabetes (OR = 1.06), have lower triglycerides (OR = 0.99), and have albuminuria (OR = 3.12) (all p < 0.05).Conclusions: Younger age, male sex, longer duration of diabetes, higher HbA1c, and presence of albuminuria were identified as risk factors for PDR and DME in a South Indian population with T2D.

Gene Biomarkers Related to Th17 Cells in Macular Edema of Diabetic Retinopathy: Cutting-Edge Comprehensive Bioinformatics Analysis and In Vivo Validation.

Background: Previous studies have shown that T-helper 17 (Th17) cell-related cytokines are significantly increased in the vitreous of proliferative diabetic retinopathy (PDR), suggesting that Th17 cells play an important role in the inflammatory response of diabetic retinopathy (DR), but its cell infiltration and gene correlation in the retina of DR, especially in diabetic macular edema (DME), have not been studied. Methods: The dataset GSE160306 was downloaded from the Gene Expression Omnibus (GEO) database, which contains 9 NPDR samples and 10 DME samples. ImmuCellAI algorithm was used to estimate the abundance of Th17 cells in 24 kinds of infiltrating immune cells. The differentially expressed Th17 related genes (DETh17RGs) between NPDR and DME were documented by difference analysis and correlation analysis. Through aggregate analyses such as gene ontology (GO) and Kyoto Encyclopedia of Gene and Genome (KEGG) pathway enrichment analysis, a protein-protein interaction (PPI) network was constructed to analyze the potential function of DETh17RGs. CytoHubba plug-in algorithm, Lasso regression analysis and support vector machine recursive feature elimination (SVM-RFE) were implemented to comprehensively identify Hub DETh17RGs. The expression archetypes of Hub DETh17RGs were further verified in several other independent datasets related to DR. The Th17RG score was defined as the genetic characterization of six Hub DETh17RGs using the GSVA sample score method, which was used to distinguish early and advanced diabetic nephropathy (DN) as well as normal and diabetic nephropathy. Finally, real-time quantitative PCR (qPCR) was implemented to verify the transcription levels of Hub DETh17RGs in the STZ-induced DR model mice (C57BL/6J). Results: 238 DETh17RGs were identified, of which 212 genes were positively correlated while only 26 genes were negatively correlated. Six genes (CD44, CDC42, TIMP1, BMP7, RHOC, FLT1) were identified as Hub DETh17RGs. Because DR and DN have a strong correlation in clinical practice, the verification of multiple independent datasets related to DR and DN proved that Hub DETh17RGs can not only distinguish PDR patients from normal people, but also distinguish DN patients from normal people. It can also identify the initial and advanced stages of the two diseases (NPDR vs DME, Early DN vs Advanced DN). Except for CDC42 and TIMP1, the qPCR transcription levels and trends of other Hub DETh17RGs in STZ-induced DR model mice were consistent with the human transcriptome level in this study. Conclusion: This study will improve our understanding of Th17 cell-related molecular mechanisms in the progression of DME. At the same time, it also provides an updated basis for the molecular mechanism of Th17 cell crosstalk in the eye and kidney in diabetes.

Identifying Genetic Biomarkers Predicting Response to Anti-Vascular Endothelial Growth Factor Injections in Diabetic Macular Edema.

Intraocular anti-vascular endothelial growth factor (VEGF) therapies are the front-line treatment for diabetic macular edema (DME); however, treatment response varies widely. This study aimed to identify genetic determinants associated with anti-VEGF treatment response in DME. We performed a genome-wide association study on 220 Australian patients with DME treated with anti-VEGF therapy, genotyped on the Illumina Global Screening Array, and imputed to the Haplotype Reference Consortium panel. The primary outcome measures were changes in central macular thickness (CMT in microns) and best-corrected visual acuity (BCVA in ETDRS letters) after 12 months. Association between single nucleotide polymorphism (SNP) genotypes and DME outcomes were evaluated by linear regression, adjusting for the first three principal components, age, baseline CMT/BCVA, duration of diabetic retinopathy, and HbA1c. Two loci reached genome-wide significance (p < 5 × 10−8) for association with increased CMT: a single SNP on chromosome 6 near CASC15 (rs78466540, p = 1.16 × 10−9) and a locus on chromosome 12 near RP11-116D17.1 (top SNP rs11614480, p = 2.69 × 10−8). Four loci were significantly associated with reduction in BCVA: two loci on chromosome 11, downstream of NTM (top SNP rs148980760, p = 5.30 × 10−9) and intronic in RP11-744N12.3 (top SNP rs57801753, p = 1.71 × 10−8); one near PGAM1P1 on chromosome 5 (rs187876551, p = 1.52 × 10−8); and one near TBC1D32 on chromosome 6 (rs118074968, p = 4.94 × 10−8). In silico investigations of each locus identified multiple expression quantitative trait loci and potentially relevant candidate genes warranting further analysis. Thus, we identified multiple genetic loci predicting treatment outcomes for anti-VEGF therapies in DME. This work may potentially lead to managing DME using personalized treatment approaches.

Bulk Gene Expression Deconvolution Reveals Infiltration of M2 Macrophages in Retinal Neovascularization.

Purpose: This study interrogated the transcriptional features and immune cellular landscape of the retinae of rats subjected to oxygen-induced retinopathy (OIR). Methods: Bulk RNA sequencing was performed with retinal RNA isolated from control and OIR rats. Gene set enrichment analysis (GSEA) was undertaken to identify gene sets associated with immune responses in retinal neovascularization. Bulk gene expression deconvolution analysis by CIBERSORTx was performed to identify immune cell types involved in retinal neovascularization, followed by functional enrichment analysis of differentially expressed genes (DEGs). Protein-protein interaction analysis was performed to predict the hub genes relevant to identified immune cell types. CIBERSORTx was applied to profile immune cell types in the macula of patients with both proliferative diabetic retinopathy (PDR) and diabetic macular edema using a public RNA-seq dataset. Results: Transcriptome analysis by GSEA revealed that the retina of OIR rats and patients with PDR is characterized by increased immunoregulatory interactions and complement cascade. Deconvolution analysis demonstrated that M2 macrophages infiltrate the retinae of OIR rats and patients with PDR. Functional enrichment analysis of DEGs in OIR rats showed that the dysregulated genes are related to leukocyte-mediated immunity and myeloid leukocyte activation. Downstream protein-protein interaction analysis revealed that several potential hub genes, including Ccl2, Itgam, and Tlr2, contribute to M2 macrophage infiltration in the ischemic retina. Conclusions: This study highlights application of the gene expression deconvolution tool to identify immune cell types in inflammatory ocular diseases with transcriptomes, providing a new approach to assess changes in immune cell types in diseased ocular tissues.

Two siblings with Heimler syndrome caused by PEX1 variants: follow-up of ophthalmologic findings.

BACKGROUND: Heimler syndrome (OMIM number #234580 and #616617) is a rare condition comprising sensorineural hearing loss (SNHL), nail abnormalities and amelogenesis imperfecta. In addition, patients with this syndrome can have retinal dystrophies. Heimler syndrome is caused by bi-allelic pathogenic variants in the PEX1 or PEX6 gene. Only few patients with this syndrome have been reported. We hereby describe two siblings with genetically confirmed Heimler syndrome and provide imaging of the ocular phenotype. MATERIALS AND METHODS: The medical records of the siblings were reviewed retrospectively. RESULTS: Both brother and sister were diagnosed with SNHL and amelogenesis imperfecta of the permanent teeth; one of the affected siblings also had nail abnormalities. Both patients presented to the ophthalmology department with suboptimal visual acuity, fundus abnormalities and intraretinal cystoid spaces. Full-field electroretinogram revealed a cone-rod dysfunction. A genetic analysis revealed a homozygous likely pathogenic variant c.3077 T > C (p.Leu1026Pro) in the PEX1 gene in both siblings. The parents are heterozygous carriers of the variant. CONCLUSION: We recommend performing regular ophthalmic examination in patients with Heimler syndrome since the ophthalmic manifestations can manifest later in life. Our patients presented with cone-rod dystrophy and intraretinal cystoid spaces. Review of the literature shows that the ocular phenotype can be very variable in patients with Heimler syndrome.

Serum exosomal miR-377-3p inhibits retinal pigment epithelium proliferation and offers a biomarker for diabetic macular edema.

OBJECTIVES: Diabetic macular edema (DME) is a complication of diabetes mellitus that leads to diabetic retinopathy. Thus far, the role of serum exosomal microRNAs (miRNAs) in DME progression remains elusive. This study investigated serum exosomal miRNAs from patients with type 2 diabetes (T2D) and DME to identify miRNAs associated with expression of vascular endothelial growth factor (VEGF), a pivotal component in DME progression; it also evaluated the diagnostic values of these miRNAs for DME. METHODS: Serum was collected from patients with T2D who did (n = 20) and did not have DME (n = 24). Exosomes were isolated from serum and subjected to real-time polymerase chain reaction, western blotting, luciferase reporter, and miRNA profiling analyses. RESULTS: VEGF was significantly upregulated in ARPE-19 cells treated with exosomes from patients with T2D and DME, compared with exosomes from patients with T2D alone. Among the top 10 downregulated miRNAs identified during exosomal miRNA profiling, miR-377-3p inhibited the expression of VEGF. Luciferase reporter assays confirmed that miR-377-3p could directly regulate VEGF expression. Receiver operating characteristic analysis identified serum exosomal miR-377-3p as a potential biomarker for DME. CONCLUSION: Serum exosomal miR-377-3p inhibits VEGF expression to suppress retinal pigment epithelium proliferation and offers a diagnostic biomarker for DME.

Association of VEGF Gene Family Variants with Central Macular Thickness and Visual Acuity after Aflibercept Short-Term Treatment in Diabetic Patients: A Pilot Study.

INTRODUCTION: Diabetic retinopathy (DR) is one of the major vision-threatening causes worldwide. Searching for an individualized therapeutic strategy to prevent its progress is challenging. OBJECTIVE: This work aimed to investigate the association of angiogenesis-inducer vascular endothelial growth factor (VEGF) gene family and related receptor variants (rs833069, rs12366035, rs7664413, rs7993418, and rs2305948) with susceptibility of DR and the response to 1 dose of aflibercept treatment in type 2 diabetes mellitus (T2DM). METHODS: Consecutive eligible patients with T2DM (n = 125) and 110 unrelated controls were enrolled in this preliminary prospective case-controlled study. Genotyping was identified using TaqMan real-time PCR. Adjusted odds ratio (OR) with 95% confidence interval (CI) was applied to assess the strength of the association with the clinical/ophthalmological characteristics and early response to intravitreal aflibercept treatment in terms of improved visual acuity (BCVA) and central macular thickness (CMT). RESULTS: We found that both VEGFB rs12366035 and VEGFC rs7664413 conferred higher risk for DR progression under allelic (OR [95% CI]: 1.71 [1.07-2.74]), homozygote comparison (3.55 [1.32-9.57]), and recessive (3.77 [1.43-9.93]) models for the former and under allelic (2.09 [1.25-3.490, homozygote comparison (2.76 [1.02-7.45]), and recessive (2.62 [0.98-6.98] models for the latter. In contrast, VEGFR1 rs7993418 conferred protection against DR under heterozygote comparison and dominant models. The rs12366035*T/T genotype showed the worst pretreatment BCVA score (0.35 ± 0.24) compared to other corresponding genotypes (0.66 ± 0.26 in C/T and 0.54 ± 0.25 in C/C carriers) (p = 0.008). Meanwhile, patients with rs7993418*G/G of VEGFR1 exhibited a significant reduction in CMT after aflibercept injection (12.26 ± 35.43 µ in G/G vs. 3.57 ± 8.74 µ in A/A) (p = 0.037). CONCLUSIONS: Polymorphisms of the studied VEGF/receptors could be considered as genetic risk factors of DM/DR development and could play an important role in aflibercept early response for DR patients in the study population.

Identifying Genetic Risk Factors for Diabetic Macular Edema and the Response to Treatment.

Diabetic retinopathy (DR) is the most common microvascular complication of diabetes mellitus (DM). DR is complex and the term encompasses several clinical subtypes of diabetic eye disease, including diabetic macular edema (DME), the most frequent cause of central vision loss in DR patients. Both genetic and environmental factors contribute to the pathophysiology of DR and its subtypes. While numerous studies have identified several susceptibility genes for DR, few have investigated the impact of genetics on DME susceptibility. This review will focus on the current literature surrounding genetic risk factors associated with DME. We will also highlight the small number of studies investigating the genetics of response to antivascular endothelial growth factor (anti-VEGF) injection, which is used to treat DME.

MicroRNA Expression in the Aqueous Humor of Patients with Diabetic Macular Edema.

We identified and compared secreted microRNA (miRNA) expression in aqueous humor (AH) and plasma samples among patients with: type 2 diabetes mellitus (T2D) complicated by non-proliferative diabetic retinopathy (DR) associated with diabetic macular edema (DME) (DME group: 12 patients); T2D patients without DR (D group: 8 patients); and non-diabetic patients (CTR group: 10 patients). Individual patient AH samples from five subjects in each group were profiled on TaqMan Low Density MicroRNA Array Cards. Differentially expressed miRNAs identified from profiling were then validated in single assay for all subjects. The miRNAs validated in AH were then evaluated in single assay in plasma. Gene Ontology (GO) analysis was conducted. From AH profiling, 119 mature miRNAs were detected: 86 in the DME group, 113 in the D group and 107 in the CTR group. miRNA underexpression in the DME group was confirmed in single assay for let-7c-5p, miR-200b-3p, miR-199a-3p and miR-365-3p. Of these four, miR-199a-3p and miR-365-3p were downregulated also in the plasma of the DME group. GO highlighted 54 validated target genes of miR-199a-3p, miR-200b-3p and miR-365-3p potentially implied in DME pathogenesis. Although more studies are needed, miR-200b-3p, let-7c-5p, miR-365-3p and miR-199a-3p represent interesting molecules in the study of DME pathogenesis.

The role of IL-6-174 G/C polymorphism and intraocular IL-6 levels in the pathogenesis of ocular diseases: a systematic review and meta-analysis.

Interleukin-6 (IL-6) is one of the key regulators behind the inflammatory and pathological process associated with ophthalmic diseases. The role of IL-6-174 G/C polymorphism as well as intraocular IL-6 levels among various eye disease patients differ across studies and has not been systematically reviewed. Thus, this study aims to provide a summary to understand the relationship between IL-6 and ophthalmic disease. In total, 8,252 and 11,014 subjects for IL-6-174 G/C and intraocular levels of IL-6, respectively, were retrieved from PubMed, Scopus and Web of Science. No association was found between IL-6-174 G/C polymorphisms with ocular diseases. Subgroup analyses revealed a suggestive association between the GC genotype of IL-6-174 G/C with proliferative diabetic retinopathy (PDR). Further, the level of intraocular IL-6 among ocular disease patients in general was found to be higher than the control group [standardized mean difference (SMD) = 1.41, 95% confidence interval (CI) 1.24-1.58, P < 0.00001]. Closer examination through subgroup analyses yielded similar results in several ocular diseases. This study thus indicates that the IL-6-174 G/C polymorphism does not predispose patients to ocular disease, although the GC genotype is likely to be a genetic biomarker for PDR. Moreover, intraocular IL-6 concentrations are related to the specific manifestations of the ophthalmic diseases. Further studies with larger sample sizes are warranted to confirm this conclusion.

Micro-RNAs in the aqueous humour of patients with diabetic macular oedema.

IMPORTANCE: Micro-RNAs (miRNAs) have been studied as new biomarkers or mediators in various diseases, but the value of aqueous humour (AH) miRNAs in diabetic macular oedema (DMO) is still not known. BACKGROUND: To compare AH miRNAs and related cytokine expression in DMO patients and healthy controls. DESIGN: Prospective cross-sectional study. PARTICIPANTS: Twenty naïve DMO patients and 13 control subjects, who were scheduled for intravitreal injection and cataract surgery, respectively. METHODS: AH samples were collected at the beginning of each procedure and analysed using a miRNA polymerase chain reaction (PCR) array composed of 84 miRNAs, reverse transcripase-quantitative PCR (qPCR) for verifying selected differentially expressed miRNAs, and a cytokine assay, the results of which were compared with bioinformatics conducted to find out genes associated with DMO-related miRNAs. MAIN OUTCOMES MEASURES: AH expression of miRNAs and cytokines and the bioinformatics results. RESULTS: Five miRNAs (hsa-miR-185-5p, hsa-miR-17-5p, hsa-miR-20a-5p, hsa-miR-15b-5p and hsa-miR-15a-5p) showing a fold change greater than -50 in log2 values in the miRNA PCR array were selected, all significantly down-regulated in the DMO group compared to the control group (P < .05), and showed a direct relationship with tumour necrosis factor, nuclear factor kappa B subunit 1 and interleukin-6 (IL-6) in bioinformatics analysis, all of which were related to vascular endothelial growth factor (VEGF). In the cytokine assay, the aqueous concentrations of VEGF, placental growth factor, IL-6 and IL-8 were significantly higher in the DMO group compared to the control group. CONCLUSIONS AND RELEVANCE: This study is the first to perform miRNA profiling of the AH of DMO patients. We identified differentially expressed miRNAs in DMO AH, which may be used as potential biomarkers or novel therapeutic targets for DMO.