AIM: To identify different metabolites, proteins and related pathways to elucidate the causes of proliferative diabetic retinopathy (PDR) and resistance to anti-vascular endothelial growth factor (VEGF) drugs, and to provide biomarkers for the diagnosis and treatment of PDR. METHODS: Vitreous specimens from patients with diabetic retinopathy were collected and analyzed by Liquid Chromatography-Mass Spectrometry (LC-MS/MS) analyses based on 4D label-free technology. Statistically differentially expressed proteins (DEPs), Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway representation and protein interactions were analyzed. RESULTS: A total of 12 samples were analyzed. The proteomics results showed that a total of 58 proteins were identified as DEPs, of which 47 proteins were up-regulated and 11 proteins were down-regulated. We found that C1q and tumor necrosis factor related protein 5 (C1QTNF5), Clusterin (CLU), tissue inhibitor of metal protease 1 (TIMP1) and signal regulatory protein alpha (SIRPα) can all be specifically regulated after aflibercept treatment. GO functional analysis showed that some DEPs are related to changes in inflammatory regulatory pathways caused by PDR. In addition, protein-protein interaction (PPI) network evaluation revealed that TIMP1 plays a central role in neural regulation. In addition, CD47/SIRPα may become a key target to resolve anti-VEGF drug resistance in PDR. CONCLUSION: Proteomic analysis is an approach of choice to explore the molecular mechanisms of PDR. Our data show that multiple proteins are differentially changed in PDR patients after intravitreal injection of aflibercept, among which C1QTNF5, CLU, TIMP1 and SIRPα may become targets for future treatment of PDR and resolution of anti-VEGF resistance.

BACKGROUND:The dysregulation of the innate immune system plays a crucial role in the development of Diabetic Retinopathy (DR). To gain an insight into the underlying mechanism of DR, it is essential to identify specific biomarkers associated with immune cell infiltration. METHODS:In this study, we retrieved the GSE94019 and GSE60436 datasets from the Gene Expression Omnibus (GEO) database. By utilizing CIBERSORT, MCPcounter, and xCell algorithms, we conducted a comprehensive analysis of the immune cell infiltration landscape in DR. The limma package was employed to identify Differentially Expressed Necroptosis-related Genes (DENRGs). Subsequently, enrichment analysis was performed to investigate the potential functions of the DENRGs. To identify the core DENRGs, the CytoHubba plug-in in Cytoscape software was utilized. The expression levels of these core DENRGs were verified in an independent dataset. RESULTS:Our analysis identified 213 DENRGs, and among them, Platelet-derived Growth Factor subunit A (PDGFA) was identified as a core DENRG. Notably, the expression of PDGFA was found to be upregulated in DR, and this finding was further validated in the GSE102485 dataset. Additionally, the results of GSVA and GSEA revealed that in the high PDGFA group, there was activation of pathways related to inflammation and the immune system. Moreover, analysis of immune infiltration demonstrated a significant association between PDGFA gene expression and the infiltration levels of specific immune cells, including basophils, macrophages M1, macrophages, neutrophils, monocytes, NK cells, and B cells. CONCLUSION:The involvement of neutrophils in the development and progression of DR is suggested. PDGFA has emerged as a potential marker and is linked to the infiltration of immune cells in DR. These findings shed new light on the underlying mechanisms of DR.

AIM:To investigate the cobalt chloride(CoCl2)simulated hypoxic environment's effect on the gene expression and protein secretion of vascular endothelial growth factor(VEGF)of rats' retinal progenitor cells(RPCs). METHODS: RPCs were separated, cultured and identified by the use of neurospheres-adhesive culture. RT-PCR and ELISA were used to detect the change of RPCs VEGF's expression after 24-hour intervention of CoCl2 with different concentration(0, 50, 100, 150μmol/L and 200μmol/L), and detect the change of RPCs VEGF's expression in 150μmol/L CoCl2 for different period(0, 12, 24, 36, 48, 72 hours). RESULTS: The RPCs cultured by neurospheres-adhesive culture system could highly express the specificity of stem cells(Nestin), and express mature retinal neuron after natural differentiation. After culturing them in the hypoxic environment for the same period, the gene express of VEGF gradually increased and then decreased with the increasing concentration of CoCl2, and peaked(P≤0.05)when the concentration of CoCl2 was 150μmol/L. When the concentration of CoCl2 was 150μmol/L, the gene expression of VEGF also gradually increased and then decreased with the increasing hypoxia intervention period, and peaked(P≤0.05)when the hypoxia intervention period was 36 hours, the change of protein and gene expression were consistent. CONCLUSION: The RPCs cultured by neurospheres-adhesive culture system can better express the specificity of stem cells. Under CoCl2 simulated hypoxic environment, hypoxia strengthens RPCs VEGF's secretion and dependent on the time and dose.

AIM:To demonstrate the effect of Ahmed glaucoma valve implantation and intravitreal avastin in the treatment of neovascular glaucoma(NVG).METHODS:A retrospective random case series study was performed.Twenty eyes of twenty cases who presented with NVG were first treated with intravitreal bevacizumab 2.5 mg in 0.1 mL,then with Ahmed glaucoma valve implantation after regression of iris neovessels.Cases were followed up for 6-36(mean 24) months with observation on visual acuity,IOP control,regression of iris neovessels,and complications during or after surgery.RESULTS:All cases regressed iris neovessels at different degree within 1 week after injection.At final follow-up,the IOP of 16 eyes were all less than 21mmHg without any drugs and of 3 eyes with 1-3 kinds of anti-glaucoma drugs after combined Ahmed glaucoma valve implantation.The IOP of one eye was controlled after cryotherapy.The mean IOP dropped from 44.17±16.17mmHg preoperatively to 13.62±3.81mmHg postoperatively.IOP reduction was statistically different between preoperative and postoperative(t=11.028,P=0.000) at final follow-up.Visual acuity was improved in 8 cases(40%) and was no changed in 12 cases.No serious complications were observed during or after intravitreous injection and Ahmed glaucoma valve implantation.CONCLUSION:Ahmed glaucoma valve implantation and intravitreal avastin in the treatment of NVG is useful and safe.On one hand,it improves the success rate of surgery and preserves visual function,furthermore its complications are less.However,its chronic effect needs to further follow-up.At the same time,we should take some treatment to the protopathy of this disease.