Expression Of Endocan,VEGF-A And HGF/SF In Patients With High Altitude Polycythemia Based On GEO Database

Objective:We screen key upregulated genes that are related to angiogenesis expression in tip cell by bioinformatics analysis.We test plasma product proteins levels of key upregulated genes in HAPC patients to provide a scientific basis for pathogenesis research,diagnosis,and treatment of HAPC.Method:We downloaded GSE19284 from the Gene Expression Omnibus database(GEO)and differentially expressed genes(DEGs)between tip cell and stalk cell were screened using the Limma package in Bioconductor.Differential expression was qualified as a parameter,fold change(FC).We set a screening standard as |log2FC|?1 and P<0.05.Biological functions of significant upregulated genes were studied using GO analysis.We took those DEGs that were related to angiogenesis expression as candidate molecule and 22 patients with HAPC from the Affiliated Hospital of Qinghai University(HAPC group)joined this study.Then we had 22 healthy adult volunteers as healthy control group(HC group),who had been selected in the medical examination center of Affiliated Hospital of Qinghai University.Plasma protein levels of candidate molecules were tested through enzyme-linked immunosorbent assay(ELISA)and further compared between each one.The clinical data were collected and results was analyzed using SPSS software,and P < 0.05 meant considered statistically significant.Result:A total of 181 DEGs including 26 up-regulated and 155 downregulated genes were identified.Endocan is the most highly up-regulated gene.Biological functions of these upregulated DEGs were studied using GO analysis.Meaningful GO category was selected(P<0.05;FDR<0.05).Biological processes involved in angiogenesis was labeled as GO:0001525 and GO:0001568.Upregulated DEGs were VEGF-A,ESM-1(Endocan)and Angpt-2 in two biological processes.HAPC study of VEGF-A and Angpt-2 has been going already.Endocan was the most highly up-regulated gene in tip cell,but its role in HAPC was still unknown so far.We thus studied in Endocan,its upstream VEGF-A and its downstream HGF/SF.The expression of Endocan in HAPC group(0.67±0.09 ng/ml)was higher than it in HC group(0.35±0.08 ng/ml).The level of VEGF-A in HAPC group(0.56±0.10 ng/ml)was also higher than it in HC group(0.43±0.09 ng/ml.There were no statistically significant differences in the HGF/HF between two groups.Conclusion:1?Endocan is the most highly up-regulated gene and expressed specifically in tip cells which plays a critical role in angiogenesis.2?The levels of Endocan and VEGF-A in HAPC group were higher than those in HC group.No difference was observed in HGF/SF level between these two groups.3?Endocan is a downstream factor of VEGF-A.Endocan cooperates with VEGF-A to enhance angiogenesis.They may involve in the physiologic and pathologic angiogenesis in HAPC and promote HAPC development.