Role of Angiopoietins and Tie-2 in Diabetic Retinopathy

Abstract

ObjectiveThe aim of this study was to determine the serum levels of angiopoietin-1 (Ang-1), angiopoietin-2 (Ang-2), soluble vascular endothelial tyrosine kinase receptor (Tie-2) and vascular endothelial growth factor (VEGF), in the serum of type 2 diabetic patients having non-proliferative (NPDR) or proliferative diabetic retinopathy (PDR).MethodsOne hundred patients with type 2 diabetes mellitus were involved in this cross-sectional study. They were classified into 25 diabetic patients without retinopathy, 35 patients with NPDR and 40 PDR patients. The study was carried out in the outpatients clinic of the Research Institute of Ophthalmology, Giza, Egypt from August 2016 through May 2017. Serum VEGF, Ang-1, Ang-2 and Tie-2 receptor levels were assayed using enzyme linked immunosorbent assay (ELISA). Data were analyzed by SPSS version 20 and Microsoft Excel (Version 10) using ANOVA, Harman’s single factor test, and Pearson’s Product Moment Correlation.ResultsThe serum levels of Ang-2 and VEGF were significantly elevated in NPDR groups and PDR group compared to diabetics without retinopathy groups (p<0.001). The serum levels of Ang-1 were significantly higher in the NPDR group compared to the diabetics without retinopathy groups (p<0.01), while no significant difference was observed between the PDR and diabetics without retinopathy groups. Ang-1/Ang-2 ratio was the lowest in the PDR group compared to the NPDR and diabetics without retinopathy groups. The serum levels of Tie-2 were not significantly changed among the three studied groups, serum Ang-2 was positively correlated with VEGF and Tie-2 in the PDR and NPDR groups.ConclusionThe angiopoietin/Tie system and VEGF are essential features in the commencement and development of PDR.

Integrated bioinformatic changes and analysis of retina with time in diabetic rats

“…In previous studies, Kirwin et al (2011) analyzed the microarray data, listed the GO enrichment terms, and discussed the DEGs of the visual cycle in DR. Zhao et al (2017) analyzed the dataset, listed GO enrichment terms, pathway analysis and PPI at three time points in detail. The effects of genes such as CYP2B2 , MASP2 , LRAT , RPE65 , RDH5 , MAPK13 , LRAT and RPE65 on DR were discussed.…”

“…In this study, their expression was down-regulated over time. Kirwin et al (2011) demonstrated that in hyperglycemic state, the expression of visual cycle enzymes is down-regulated.…”

“…The data set provided by Kirwin et al (2011) was downloaded from Gene Expression Omnibus (GEO) ( https://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE28831 ). The preparation of samples is described in their study.…”

“…Due to its high toxicity to beta cells, streptozotocin has been used in scientific studies to induce insulitis and diabetes in experimental animals ( Rossini et al, 1977 ). Kirwin et al (2011) used microarrays to evaluate early changes (up to 3 months) in STZ-induced diabetic rats. They found that the expression of visual cyclin proteins was significantly down-regulated post STZ treatment.…”

“…In previous studies, has been analyzed by two research groups. Kirwin et al (2011) produced the pathological model and performed microarray analysis. Zhao et al (2017) also analyzed the dataset, listed Gene Ontology (GO) enrichment terms and pathway analysis at three time points in detail, and analyzed the protein–protein interaction (PPI) of DEGs.…”