Gene expression of IGF1, IGF1R, and IGFBP3 in epiretinal membranes of patients with proliferative diabetic retinopathy: preliminary study

Evidence for the Hepato-Retinal Axis: A Systematic Review

BACKGROUND AND OBJECTIVE

Liver health has been reported to be associated with retinal pathology in various ways. These include deposition of retino-toxins, neovascular drive, and disruption of the blood-retina barrier. Extrahepatic synthesis of implicated molecules and hemodynamic changes in liver dysfunction are also considered. The objective was to review the current evidence for and against a hepato-retinal axis that may guide further areas of preclinical and clinical investigation.

METHODS

This was a systematic review. PubMed and Cochrane were queried for English language studies examining the connection between hepatic dysfunction and retinal pathology.

RESULTS

Fourteen studies were included and examined out of 604 candidate publications. The studies selected include preclinical studies as well as clinical case series and studies.

CONCLUSIONS

Several liver pathologies may be linked to retinal pathology as mediated by hepatically synthesized molecules. The hepato-retinal axis may be present and further, targeted studies of the axis are warranted. [Ophthalmic Surg Lasers Imaging Retina 2024;55:XX-XX.].

Single-cell RNA sequencing in exploring the pathogenesis of diabetic retinopathy

Diabetic retinopathy (DR) is a leading cause of irreversible blindness in the working-age populations. Despite decades of research on the pathogenesis of DR for clinical care, a comprehensive understanding of the condition is still lacking due to the intricate cellular diversity and molecular heterogeneity involved. Single-cell RNA sequencing (scRNA-seq) has made the high-throughput molecular profiling of cells across modalities possible which has provided valuable insights into complex biological systems. In this review, we summarise the application of scRNA-seq in investigating the pathogenesis of DR, focusing on four aspects. These include the identification of differentially expressed genes, characterisation of key cell subpopulations and reconstruction of developmental 'trajectories' to unveil their state transition, exploration of complex cell‒cell communication in DR and integration of scRNA-seq with genome-wide association studies to identify cell types that are most closely related to DR risk genetic loci. Finally, we discuss the future challenges and expectations associated with studying DR using scRNA-seq. We anticipate that scRNA-seq will facilitate the discovery of mechanisms and new treatment targets in the clinical care landscape for patients with DR. KEY POINTS: Progress in scRNA-seq for diabetic retinopathy (DR) research includes studies on DR patients, non-human primates, and the prevalent mouse models. scRNA-seq facilitates the identification of differentially expressed genes, pivotal cell subpopulations, and complex cell-cell interactions in DR at single-cell level. Future scRNA-seq applications in DR should target specific patient subsets and integrate with single-cell and spatial multi-omics approaches.

Epiretinal membranes in patients with uveitis: an update on the current state of management

PURPOSE

This review aims to summarize the current knowledge concerning the clinical features, diagnostic work-up, and therapeutic approach of uveitic epiretinal membranes (ERM).

METHODS

A thorough investigation of the literature was conducted using the PubMed database. Additionally, a complementary search was carried out on Google Scholar to ensure the inclusion of all relevant items in the collection.

RESULTS

ERM is an abnormal layer at the vitreoretinal interface, resulting from myofibroblastic cell proliferation along the inner surface of the central retina, causing visual impairment. Known by various names, ERM has diverse causes, including idiopathic or secondary factors, with ophthalmic imaging techniques like OCT improving detection. In uveitis, ERM occurrence is common, and surgical intervention involves pars plana vitrectomy with ERM peeling, although debates persist on optimal approaches.

CONCLUSIONS

Histopathological studies and OCT advancements improved ERM understanding, revealing a diverse group of diseases without a unified model. Consensus supports surgery for uveitic ERM in progressive cases, but variability requires careful consideration and effective inflammation management. OCT biomarkers, deep learning, and surgical advances may enhance outcomes, and medical interventions and robotics show promise for early ERM intervention.

Comparison of postoperative morphological changes and retinal displacement in diabetic and idiopathic epiretinal membranes

PURPOSE

To compare the postoperative retinal displacement by optical coherence tomography (OCT) in idiopathic epiretinal membranes (iERM) and diabetic epiretinal membranes (dERM).

METHODS

This retrospective study included 36 iERM and 22 dERM cases. In cross-sectional OCT images (B-scan) the presence of foveal pit, subfoveal fluid, cotton ball sign (CBS), intraretinal cystic changes (ICC), disorganization of retinal inner layers (DRILs) and ectopic inner foveal layer (EIFL) were recorded. Central macular thickness (CMT) and EIFL thicknesses were calculated. Retinal displacement was quantified using infrared image of OCT approach consisting of the fovea to disc margin, interarcade distance and perimacular distances.

RESULTS

The presence of subfoveal fluid (p = 0.014) and DRIL (p = 0.02) was significantly higher in the dERM group. CMT decreased significantly in both groups (p˂0.001). The EIFL was significantly thicker in the iERM group compared to the dERM group (p = 0.049), and it decreased significantly in the iERM group postoperatively. In the iERM group, while the fovea-disc margin distance decreased, the interarcade and perimacular distance increased significantly (p˂0.001). In the dERM group, the disc-fovea distance change was not significant (p = 0.082). Significant visual improvement was achieved with vitrectomy in both groups (p˂0.001). In the dERM group, the presence of DRIL was associated with lower pre and post-op visual acuity (VA) (r = 0.596 and p = 0.004 for pre-operative and r = 0.567 and p = 0.007 for post-operative).

CONCLUSION

Significant retinal displacement occurs after vitrectomy in both iERM and dERM. The low VA in the dERM group may be related to the presence of DRILs.

Choroidal Vascularity Index Fluctuations in Epiretinal Membranes in Vitreoretinal Surgery: Comparison Between Idiopathic and Diabetic Ones

Purpose

The aim of the study was to analyze choroidal vascularity index (CVI) fluctuations in patients with epiretinal membrane after vitreoretinal surgery, comparing idiopathic and secondary diabetic ones.

Methods

Thirty eyes suffering from idiopathic ERMs (I-ERMS; n = 15) and diabetic ERMs (D-ERMS; n = 15) were analyzed in this observational prospective study. Anatomical (central macular thickness) and functional (best-corrected visual acuity) parameters were analyzed preoperatively and at 1 and 3 months after vitrectomy. Perfusion findings regarding CVI and luminal area were also calculated.

Results

At 1 month after surgery, the luminal area and CVI significantly decreased in the I-ERMS group, whereas they were increased in the D-ERMS group. At the 3-month follow-up, the CVI tended to return to baseline values in I-ERMS and to reduce in D-ERMS, but without any statistical differences.

Conclusions

The significant change in the CVI after surgery seems to imply that the choroidal layer is affected by vitreomacular disease and can become a novel potential biomarker of predictiveness in vitreoretinal surgery.

Translational Relevance

The aim of the study was to focus on the early choroidal changes to better understand initial predictive elements of long-term functional postoperative outcomes.

Untangling the Extracellular Matrix of Idiopathic Epiretinal Membrane: A Path Winding among Structure, Interactomics and Translational Medicine

Idiopathic epiretinal membranes (iERMs) are fibrocellular sheets of tissue that develop at the vitreoretinal interface. The iERMs consist of cells and an extracellular matrix (ECM) formed by a complex array of structural proteins and a large number of proteins that regulate cell–matrix interaction, matrix deposition and remodelling. Many components of the ECM tend to produce a layered pattern that can influence the tractional properties of the membranes. We applied a bioinformatics approach on a list of proteins previously identified with an MS-based proteomic analysis on samples of iERM to report the interactome of some key proteins. The performed pathway analysis highlights interactions occurring among ECM molecules, their cell receptors and intra- or extracellular proteins that may play a role in matrix biology in this special context. In particular, integrin β1, cathepsin B, epidermal growth factor receptor, protein-glutamine gamma-glutamyltransferase 2 and prolow-density lipoprotein receptor-related protein 1 are key hubs in the outlined protein–protein cross-talks. A section on the biomarkers that can be found in the vitreous humor of patients affected by iERM and that can modulate matrix deposition is also presented. Finally, translational medicine in iERM treatment has been summed up taking stock of the techniques that have been proposed for pharmacologic vitreolysis.

Dissecting the Pathogenesis of Diabetic Retinopathy Based on the Biological ceRNA Network and Genome Variation Disturbance

Background

Diabetic retinopathy (DR) is the most important manifestation of diabetic microangiopathy. It is essential to explore the gene regulatory relationship and genomic variation disturbance of biological networks in DR progression.

Methods

In this study, we constructed a comprehensive lncRNA-mRNA ceRNA network of DR procession (CLMN) and explored its topological characteristics.

Results

Modular and functional analysis indicated that the organization of CLMN performed fundamental and specific functions in diabetes and DR pathology. The differential expression of hub ceRNA nodes and positive correlation reveals the highly connected ceRNA regulation and important roles in the regulating of DR pathology. A large proportion of SNPs in the TFBS, DHS, and enhancer regions of lncRNAs will affect lncRNA transcription and further cause expression variation. Some SNPs were found to disrupt the lncRNA functional elements such as miRNA target binding sites. These results indicate the complex nature of genotypic effects in the disturbing of CLMN and further contribute to gene expression variation and different disease phenotypes.

Conclusion

The identification of individual genomic variations and analysis of biological network disturbance by these genomic variations will help provide more personalized treatment plans and promote the development of precision medicine for DR.

Genetic associated complications of type 2 Diabetes Mellitus: a review

According to the International Diabetes Federation, the number of adults (age of 20-79) being diagnosed with Diabetes Mellitus (DM) have increased from 285 million in year 2009 to 463 million in year 2019 which comprises of 95% Type 2 DM patient (T2DM). Research have claimed that genetic predisposition could be one of the factors causing T2DM complications. In addition, T2DMcomplications cause an incremental risk to mortality. Therefore, this article aims to discuss some complications of T2DM in and their genetic association. The complications that are discussed in this article are diabetic nephropathy, diabetes induced cardiovascular disease, diabetic neuropathy, Diabetic Foot Ulcer (DFU) and Alzheimer's disease. According to the information obtained, genes associated with diabetic nephropathy (DN) are gene GABRR1 and ELMO1 that cause injury to glomerular. Replication of genes FRMD3, CARS and MYO16/IRS2 shown to have link with DN. The increase of gene THBS2, NGAL, PIP, TRAF6 polymorphism, ICAM-1 encoded for rs5498 polymorphism and C667T increase susceptibility towards DN in T2DM patient. Genes associated with cardiovascular diseases are Adiponectin gene (ACRP30) and Apolipoprotein E (APOE) polymorphism gene with ξ2 allele. Haptoglobin (Hp) 1-1 genotype and Mitochondria Superoxide Dismutase 2 (SOD2) plays a role in cardiovascular events. As for genes related to diabetic neuropathy, Janus Kinase (JAK), mutation of SCN9A and TRPA1 gene and destruction of miRNA contribute to pathogenesis of diabetic neuropathy among T2DM patients. Expression of cytokine IL-6, IL-10, miR-146a are found to cause diabetic neuropathy. Besides, A1a16Va1 gene polymorphism, an oxidative stress influence was found as one of the gene factors. Diabetic retinopathy (DR) is believed to have association with Monocyte Chemoattractant Protein-1 (MCP-1) and Insulin-like Growth Factor 1 (IGF1). Over-expression of gene ENPP1, IL-6 pro-inflammatory cytokine, ARHGAP22's protein rs3844492 polymorphism and TLR4 heterozygous genotype are contributing to significant pathophysiological process causing DR, while research found increases level of UCP1 gene protects retina cells from oxidative stress. Diabetic Foot Ulcer (DFU) is manifested by slowing in reepithelialisation of keratinocyte, persistence wound inflammation and healing impairment. Reepithelialisation disturbance was caused by E2F3 gene, reduction of Tacl gene encoded substance P causing persistence inflammation while expression of MMp-9 polymorphism contributes to healing impairment. A decrease in HIF-1a gene expression leads to increased risk of pathogenesis, while downregulation of TLR2 increases severity of wound in DFU patients. SNPs alleles has been shown to have significant association between the genetic dispositions of T2DM and Alzheimer's disease (AD). The progression of AD can be due to the change in DNA methylation of CLOCK gene, followed with worsening of AD by APOE4 gene due to dyslipidaemia condition in T2DM patients. Insulin resistance is also a factor that contributes to pathogenesis of AD.

Vitreous from idiopathic epiretinal membrane patients induces glial-to-mesenchymal transition in Müller cells

Idiopathic epiretinal membranes (ERMs) are fibrocellular membranes containing extracellular matrix proteins and epiretinal cells of retinal and extraretinal origin. iERMs lead to decreased visual acuity and their pathogenesis has not been completely defined. Macroglial Müller cells appear to play a pivotal role in the pathogenesis of iERM where they may undergo glial-to-mesenchymal transition (GMT), a transdifferentiation process characterized by the downregulation of Müller cell markers, paralleled by the upregulation of pro-fibrotic myofibroblast markers. Previous observations from our laboratory allowed the molecular identification of two major clusters of iERM patients (named iERM-A and iERM-B), iERM-A patients being characterized by less severe clinical features and a more "quiescent" iERM gene expression profile when compared to iERM-B patients. In the present work, Müller MIO-M1 cells were exposed to vitreous samples obtained before membrane peeling from the same cohort of iERM-A and iERM-B patients. The results demonstrate that iERM vitreous induces proliferation, migration, and GMT in MIO-M1 cells, a phenotype consistent with Müller cell behavior during iERM progression. However, even though the vitreous samples obtained from iERM-A patients were able to induce a complete GMT in MIO-M1 cells, iERM-B samples caused only a partial GMT, characterized by the downregulation of Müller cell markers in the absence of upregulation of pro-fibrotic myofibroblast markers. Together, the results indicate that a relationship may exist among the ability of iERM vitreous to modulate GMT in Müller cells, the molecular profile of the corresponding iERMs, and the clinical features of iERM patients.

Assessment of a New Nanostructured Microemulsion System for Ocular Delivery of Sorafenib to Posterior Segment of the Eye

Eye drop formulations allowing topical treatment of retinal pathologies have long been sought as alternatives to intravitreal administration. This study aimed to assess whether a novel nanostructured microemulsions system (NaMESys) could be usefully employed to deliver sorafenib to the retina following topical instillation. NaMESys carrying 0.3% sorafenib (NaMESys-SOR) proved to be cytocompatible in vitro on rabbit corneal cells, and well-tolerated following b.i.d. ocular administration to rabbits during a 3-month study. In rats subject to retinal ischemia-reperfusion, NaMESys-SOR significantly inhibited retinal expression of tumor necrosis factor-alpha (TNFα, 20.7%) and inducible nitric oxide synthase (iNos, 87.3%) mRNAs in comparison to controls. Similarly, in streptozotocin-induced diabetic rats, NaMESys-SOR inhibited retinal expression of nuclear factor kappa B (NFκB), TNFα, insulin like growth factor 1 (IGF1), IGF1 receptor (IGF1R), vascular endothelial growth factor receptor 1 (VEGFR1) and 2 (VEGFR2) mRNAs by three-fold on average compared to controls. Furthermore, a reduction in TNFα, VEGFR1 and VEGFR2 protein expression was observed by western blot. Moreover, in mice subject to laser-induced choroidal neovascularization, NaMESys-SOR significantly inhibited neovascular lesions by 54%. In conclusion, NaMESys-SOR was shown to be a well-tolerated ophthalmic formulation able to deliver effective amounts of sorafenib to the retina, reducing proinflammatory and pro-angiogenic mediators in reliable models of proliferative retinopathies. These findings warrant further investigations on the full therapeutic potential of NaMESys-SOR eye drops, aiming to address unmet needs in the pharmacotherapy of retinal neovascular diseases.

VEGF-Independent Activation of Müller Cells by the Vitreous from Proliferative Diabetic Retinopathy Patients

Proliferative diabetic retinopathy (PDR), a major complication of diabetes mellitus, results from an inflammation-sustained interplay among endothelial cells, neurons, and glia. Even though anti-vascular endothelial growth factor (VEGF) interventions represent the therapeutic option for PDR, they are only partially efficacious. In PDR, Müller cells undergo reactive gliosis, produce inflammatory cytokines/chemokines, and contribute to scar formation and retinal neovascularization. However, the impact of anti-VEGF interventions on Müller cell activation has not been fully elucidated. Here, we show that treatment of MIO-M1 Müller cells with vitreous obtained from PDR patients stimulates cell proliferation and motility, and activates various intracellular signaling pathways. This leads to cytokine/chemokine upregulation, a response that was not mimicked by treatment with recombinant VEGF nor inhibited by the anti-VEGF drug ranibizumab. In contrast, fibroblast growth factor-2 (FGF2) induced a significant overexpression of various cytokines/chemokines in MIO-M1 cells. In addition, the FGF receptor tyrosine kinase inhibitor BGJ398, the pan-FGF trap NSC12, the heparin-binding protein antagonist N-tert-butyloxycarbonyl-Phe-Leu-Phe-Leu-Phe Boc2, and the anti-inflammatory hydrocortisone all inhibited Müller cell activation mediated by PDR vitreous. These findings point to a role for various modulators beside VEGF in Müller cell activation and pave the way to the search for novel therapeutic strategies in PDR.

Gene expression analysis identifies two distinct molecular clusters of idiopatic epiretinal membranes

Idiopathic epiretinal membranes (ERMs) are fibrocellular membranes containing extracellular matrix proteins and epiretinal cells of retinal and extraretinal origin. iERMs lead to decreased visual acuity and their pathogenesis has not been completely defined. Aim of this study was to provide a molecular characterization of iERMs by gene expression analysis. To this purpose, 56 iERMs obtained by pars plana vitrectomy were analyzed for the expression levels of genes encoding biomarkers of the cellular and molecular events occurring in iERMs. RT-qPCR analysis showed significant differences in the levels of cell population, extracellular matrix and cytokine/growth factor biomarkers among the iERMs investigated. Hierarchical clustering of RT-qPCR data identified two distinct iERM clusters, Cluster B samples representing transcriptionally "activated" iERMs when compared to transcriptionally "quiescent" Cluster A specimens. Further, Cluster B could be subdivided in two subgroups, Cluster B1 iERMs, characterized by a marked glial cell activation, and Cluster B2 samples characterized by a more pro-fibrotic phenotype. Preoperative decimal best-corrected visual acuity and post-surgery inner segment/outer grading values were higher in Cluster A patients, that showed a prevalence of fovea-attached type iERMs with near-normal inner retina, than in Cluster B patients, that presented more severe clinical and spectral domain optical coherence tomography (SD-OCT) features. In conclusion, this molecular characterization has identified two major clusters of iERM specimens with distinct transcriptional activities that reflect different clinical and SD-OCT features of iERM patients. This retrospective work paves the way to prospective whole-genome transcriptomic studies to allow a molecular classification of iERMs and for the identification of molecular signature(s) of prognostic and therapeutic significance.

A Review of Last Decade Developments on Epiretinal Membrane Pathogenesis

Epiretinal membrane (ERM) is a pathologic tissue that develops at the vitreoretinal interface. ERM is responsible for pathological changes of vision with varying degrees of clinical significance. It is either idiopathic or secondary to a wide variety of diseases such as proliferative diabetic retinopathy (PDR) and proliferative vitreoretinopathy (PVR). A great variation in the prevalence of idiopathic ERM among different ethnic groups proposed that genetic and lifestyle factors may play a role in ERM occurrence. Histopathological studies demonstrate that various cell types including retinal pigment epithelium (RPE) cells, fibrocytes, fibrous astrocytes, myofibroblast-like cells, glial cells, endothelial cells (ECs) and macrophages, as well as trophic and transcription factors, including transforming growth factor (TGF), vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF) etc., are directly or indirectly involved in the pathogenesis of idiopathic or secondary ERMs. These processes are driven (on the last count) by more than 50 genes, such as Tumor Necrosis Factor (TNF), CCL2 (chemokine (C-C motif) ligand )), Metastasis Associated Lung Adenocarcinoma Transcript 1 )MALAT1(, transforming growth factor (TGF)-β1, TGF-β2, Interleukin-6 (IL-6), IL-10, VEGF and glial fibrillary acidic protein (GFAP), some of which have been studied more intensely than others. The present paper tried to summarize, highlight and cross-correlate the major findings made in the last decade on the function of these genes and their association with different types of cells, genes and gene expression products in the ERM formation.

3-Acetyl-oleanolic acid ameliorates non-alcoholic fatty liver disease in high fat diet-treated rats by activating AMPK-related pathways

3-Acetyl-oleanolic acid (3Ac-OA) is a derivative of oleanolic acid (OA), which has shown therapeutic beneficial effects on diabetes and metabolic syndrome. In this study we investigated whether 3Ac-OA exerted beneficial effect on non-alcoholic fatty liver disease (NAFLD) in rats and its potential underlying mechanisms. Treatment with 3Ac-OA (1-100 μmol/L) dose-dependently decreased the intracellular levels of total cholesterol (TC) and triglyceride (TG) in FFA-treated primary rat hepatocytes and human HepG2 cell lines in vitro. Furthermore, oil red staining studies showed that 3Ac-OA caused dose-dependent decrease in the number of lipid droplets in FFA-treated primary rat hepatocytes. SD rats were fed a high fat diet (HFD) for 6 weeks and subsequently treated with 3Ac-OA (60, 30, 15 mg·kg^-1·d^-1) for 4 weeks. 3Ac-OA administration significantly decreased the body weight, liver weight and serum TC, TG, LDL-C levels in HFD rats. Furthermore, 3AcOA administration ameliorated lipid accumulation and cell apoptosis in the liver of HFD rats. Using adipokine array analyses, we found that the levels of 11 adipokines (HGF, ICAM, IGF-1, IGFBP-3, IGFBP-5, IGFBP-6, lipocalin-2, MCP-1, M-CSF, Pref-1 and RAGE) were increased by more than twofold in the serum of 3Ac-OA-treated rats, whereas ICAM, IGF-1 and lipocalin-2 had levels increased by more than 20-fold. Moreover, 3Ac-OA administration significantly increased the expression of glucose transporter type 2 (GLUT-2) and low-density lipoprotein receptor (LDLR), as well as the phosphorylation of AMP-activated protein kinase (AMPK), protein kinase B (AKT) and glycogen synthase kinase 3β (GSK-3β) in the liver tissues of HFD rats. In conclusion, this study demonstrates that 3Ac-OA exerts a protective effect against hyperlipidemia in NAFLD rats through AMPK-related pathways.

Personalized Proteomics in Proliferative Vitreoretinopathy Implicate Hematopoietic Cell Recruitment and mTOR as a Therapeutic Target

PURPOSE

To profile vitreous cytokine expression of proliferative vitreoretinopathy (PVR) patients.

DESIGN

Case-control study.

METHODS

Liquid biopsies were collected from 2 groups: control subjects (n = 3) undergoing pars plana vitrectomy to remove an epiretinal membrane (ERM), and test subjects (n = 7) with varying degrees of PVR. A high-throughput cytokine screen measured expression of 200 cytokines. Cytokine expression patterns were prospectively validated in separate cohorts of control patients and those with PVR-A, PVR-B, and PVR-C (n = 10 for each group). Expression changes were evaluated by analysis of variance (significant P value < .05), hierarchical cluster algorithm, and pathway analysis, to identify candidate pathways for prospective studies.

RESULTS

In PVR vitreous, 29 cytokines were upregulated compared to controls. Early PVR vitreous showed upregulation of T-cell markers, profibrotic cytokines, and cytokines downstream of mTOR activation (IL-2, IL-6, and IL-13), whereas in late PVR vitreous, cytokines driving monocyte responses and stem-cell recruitment (SDF-1) prevailed. Prospective validation confirmed the differential expression of specific cytokines from PVR-A to C.

CONCLUSIONS

Early PVR is characterized by activation of T cells and mTOR signaling, whereas advanced PVR is characterized by a chronic monocyte response. PVR might be treated by rational repositioning of existing drugs that target mTOR and IL-6. Our analysis demonstrates that successful therapeutic intervention will be highly dependent on the specific therapeutic target and the stage of PVR. This study provides insights into cytokines that will serve as biomarkers and therapeutic targets. These biomarkers will help design clinical trials that intervene at appropriate times.

Genome-wide DNA methylation variation in maternal and cord blood of gestational diabetes population

AIMS

Gestational diabetes mellitus (GDM) has always been a concerning issue for pregnant women. In recent studies, GDM was found to be related to epigenetic modifications, which would alter gene expressions, thus affecting the patients' and their offspring's health, leading to a higher probability of developing metabolic syndromes and diabetes later in life.

METHODS

In this study, we collected both maternal and cord blood samples from 16 pregnant women and their newborns, including eight exposed to GDM. GDM was diagnosed via a 75g oral glucose tolerance test (OGTT) at 24-28weeks of pregnancy. DNA methylation was measured at 841,573 CpG sites via the Infinium HumanMethylationEPIC BeadChip. An Ingenuity Pathway Analysis was conducted afterwards to identify genes and pathways epigenetically affected by GDM.

RESULTS

We identified the top 200 loci and their corresponding genes in the maternal blood group (n=151) and cord blood group (n=167), both of which were methylated differently in the GDM and unexposed group. Metabolic disease-related pathways and molecules, such as interleukin-6 and interleukin-10 were identified in both groups. These results suggested that GDM has epigenetic effects on both mother and their offspring, which might result in future metabolic syndromes or diabetes.

CONCLUSIONS

The high-throughput platform enabled us to analyze methylation sites throughout the genome and identify the most promising genes and pathways associated with GDM.

IGF1 gene polymorphisms associated with diabetic retinopathy risk in Chinese Han population

Objective

This study aimed to explore the association of insulin-like growth factor 1 gene (IGF1) polymorphisms with diabetic retinopathy (DR) in a Chinese Han population.

Methods

Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used for genotyping. Genotype frequencies were compared by chi-square test. Odds ratio (OR) with 95% confidence interval (95%CI) was calculated to express the risk intensity of DR. Linkage disequilibrium between IGF1 polymorphisms was analyzed by Haploview. Serum IGF1 concentration was measured by enzyme-linked immunosorbent assays (ELISA) and assessed by student's t test.

Results

AG genotype of rs6218 and TT genotype of rs35767 were significantly associated with the elevated risk of DR (rs6218: OR=1.77, P=0.04; rs35767: OR=2.32, P=0.03) and type II diabetes mellitus (T2DM) (rs6218: OR=1.92, P=0.00. rs35767: OR=2.29, P=0.02). Only T allele of rs35767 significantly increased the risk of DR (OR=1.45, P=0.04), however, rs6218 (OR=1.92, P=0.00), rs35767 (OR=0.02, P=0.02) and rs5742612 (OR=2.21, P=0.04) showed obvious association with T2DM. Haplotypes were only associated with T2DM, but not DR. Minor allele homozygote of rs35767 was obviously correlated with serum IGF1 level.

Conclusion

IGF1 rs6218 and rs35767 polymorphisms contribute to the risk of DR. IGF1 rs35767 polymorphism may participate in the regulation of serum IGF1 concentration in DR.

Gene expression levels of the insulin-like growth factor family in patients with AMD before and after ranibizumab intravitreal injections

Purpose

The present study focused on the assessment of the mRNA levels of the insulin-like growth factor (IGF) family in patients with the exudative form of age-related macular degeneration (AMD) before and after ranibizumab intravitreal injections.

Patients and methods

An analysis of the expression profile of the IGF family of genes in patients with AMD was carried out using the oligonucleotide microarray and quantitative reverse transcriptase polymerase chain reaction (RT-qPCR) methods.

Results

In the peripheral blood mononuclear cells (PBMCs) obtained from AMD group receiving ranibizumab compared to the peripheral blood mononuclear cells from AMD group before ranibizumab treatment using oligonucleotide microarray technique, six statistically significant differentially expressed transcripts related to the IGF family were detected (unpaired t-test, p<0.05, fold change >1.5). Moreover, analysis using the real-time RT-qPCR technique revealed statistically significant differences in the IGF2 and IGF2R mRNA levels (Mann–Whitney U test, p<0.05) between the two groups that were studied. Statistical analyses of both oligonucleotide microarray and real-time RT-qPCR results demonstrated a significant decreased expression only for IGF2 mRNA.

Conclusion

Our results revealed a changed expression of IGF2 mRNA after ranibizumab treatment.

Growth Factors in the Pathogenesis of Retinal Neurodegeneration in Diabetes Mellitus

Neurodegeneration is an initial process in the development of diabetic retinopathy (DR).

High quantities of glutamate, oxidative stress, induction of the renin-angiotensin system (RAS) and elevated levels of RAGE are crucial elements in the retinal neurodegeneration caused by diabetes mellitus. At least, there is emerging proof to indicate that the equilibrium between the neurotoxic and neuroprotective components will affect the state of the retinal neurons.

Somatostatin (SST), pigment epithelium-derived factor (PEDF), and erythropoietin (Epo) are endogenous neuroprotective peptides that are decreased in the eye of diabetic persons and play an essential role in retinal homeostasis. On the other hand, insulin-like growth factor 1 (IGF-1), and vascular endothelial growth factor (VEGF) are pivotal proteins which participate in the development of new capillaries and finally cause damage to the retinal neurons. During recent years, our knowledge about the function of growth factors in the pathogenesis of retinal neurodegeneration has increased. However, intensive investigations are needed to clarify the basic processes that contribute to retinal neurodegeneration and its association with damage to the capillary blood vessels. The objective of this review article is to show new insights on the role of neurotransmitters and growth factors in the pathogenesis of diabetic retinopathy. The information contained in this manuscript may provide the basis for novel strategies based on the factors of neurodegeneration to diagnose, prevent and treat DR in its earliest phases.

Type 2 diabetes alters mesenchymal stem cell secretome composition and angiogenic properties

This study aimed at characterizing the impact of type 2 diabetes mellitus (T2DM) on the bone marrow mesenchymal stem cell (BMMSC) secretome and angiogenic properties. BMMSCs from Zucker diabetic fatty rats (ZDF) (a T2DM model) and Zucker LEAN littermates (control) were cultured. The supernatant conditioned media (CM) from BMMSCs of diabetic and control rats were collected and analysed. Compared to results obtained using CM from LEAN‐BMMSCs, the bioactive content of ZDF‐BMMSC CM (i) differently affects endothelial cell (HUVEC) functions in vitro by inducing increased (3.5‐fold; P < 0.01) formation of tubule‐like structures and migration of these cells (3‐fold; P < 0.001), as well as promotes improved vascular formation in vivo, and (ii) contains different levels of angiogenic factors (e.g. IGF1) and mediators, such as OSTP, CATD, FMOD LTBP1 and LTBP2, which are involved in angiogenesis and/or extracellular matrix composition. Addition of neutralizing antibodies against IGF‐1, LTBP1 or LTBP2 in the CM of BMMSCs from diabetic rats decreased its stimulatory effect on HUVEC migration by approximately 60%, 40% or 40%, respectively. These results demonstrate that BMMSCs from T2DM rats have a unique secretome with distinct angiogenic properties and provide new insights into the role of BMMSCs in aberrant angiogenesis in the diabetic milieu.

Precision Medicine: Personalized Proteomics for the Diagnosis and Treatment of Idiopathic Inflammatory Disease

IMPORTANCE

To better characterize posterior uveitis, vitreous samples from 15 patients were subjected to antibody arrays, and the expression levels of 200 human cytokines were evaluated. Expression was analyzed by 1-way analysis of variance (significance at P < .01), unsupervised cluster algorithm, and pathway analysis.

OBSERVATIONS

Unbiased clustering of patients, based on their cytokine expression profile, suggested that particular protein networks and molecular pathways are altered in various forms of uveitis. Expression of interleukin 23 (IL-23), IL-1 receptor I (IL-1RI), IL-17R, tissue inhibitors of metalloproteinase 1 and 2 (TIMP-1 and TIMP-2), insulinlike growth factor-binding protein 2 (IGFBP-2), nerve growth factor (b-NGF), platelet-derived growth factor receptor β polypeptide (PDGFRb), bone morphogenic protein 4 (BMP-4), and stem cell factor (SCF) constituted a common cytokine signature in the vitreous of patients with uveitis. In 1 patient with progressive, idiopathic visual loss, this last-line analysis implicated retinal autoimmunity, a diagnosis that was validated when her serum sample was found to contain antibodies to S-arrestin, a retinal protein and potent cause of autoimmune retinal degeneration.

CONCLUSIONS AND RELEVANCE

The analysis identifies a common cytokine signature for posterior uveitis and guides the diagnosis of a patient with idiopathic uveitis. Personalized treatment reversed the visual loss, illustrating how proteomic tools may individualize therapy.

MiR-18b suppresses high-glucose-induced proliferation in HRECs by targeting IGF-1/IGF1R signaling pathways

MicroRNAs (miRNAs) are important for the proliferation of endothelial cells and have been shown to be involved in diabetic retinopathy (DR). In previous study, we found that miRNAs might play a critical role in hyperglycemia-induced endothelial cell proliferation based on miRNA expression profiling. Here, the roles of microRNA-18b (miR-18b) in the proliferation of human retinal endothelial cells (HRECs) were investigated in an in vitro model of HRECs grown in high glucose. We identified that levels of miR-18b were decreased in high-glucose-induced HRECs, compared with those in cells incubated in normal glucose. However, the reduction of miR-18b up-regulated vascular endothelial growth factor (VEGF) secretion and promoted effects on in vitro proliferation of HRECs. Mechanistically, insulin growth factor-1 (IGF-1) was identified as a target of miR-18b. IGF-1 simulation could antagonize the effect induced by miR-18b up-regulation, promoting cell proliferation and increasing VEGF production. In contrast, the opposite results were observed with silencing IGF-1, which was consistent with the effects of miR-18b overexpression. MiR-18b exerted its function on VEGF synthesis and cell proliferation by suppressing the IGF-1/insulin growth factor-1 receptor (IGF1R) pathway, consequently inhibiting the downstream phosphorylation of Akt, MEK, and ERK. Hence, this may provide a new insight into understanding the mechanism of DR pathogenesis, as well as a potential therapeutic target for proliferative DR.