Vascular endothelial growth factor gene variations as a risk predictor in disc degeneration / Variação do gene fator de crescimento endotelial vascular como preditor de risco para a degeneração discal

ABSTRACT Objective: To evaluate the frequency of polymorphisms in the vascular endothelial growth factor (VEGF) gene, as well as to identify a potential risk haplotype among the polymorphic regions in this gene in patients with disc degeneration and in the Control Group. Methods: This study analyzed a total of 217 individuals distributed into the Disc Degeneration and Control Groups. Peripheral blood was collected from all patients to detect VEGF gene polymorphisms identified by qPCR (rs699947, rs1570360, rs2010963, rs833061 and rs3025039). All patients presenting disc degeneration had the confirmation by nuclear magnetic resonance test and were rated according to disc degeneration level. Results: All polymorphisms were in Hardy- Weinberg equilibrium (p>0.05) in the studied population. The genotypic frequency for Disc Degeneration and Control Group were rs699947 p = 0.475, rs1570360 p = 0.862, rs2010963 p = 0.823, rs833061 p=0.596 and rs3025039 p=0.230. In haplotype analysis, the compositions CAGGC (p=0.094) and CCGGC (p=0.054) stood out. Conclusion: The correlation between VEGF gene polymorphism as a risk predictor for disc degeneration was negative in the studied population. However, the VEGF gene has a large polymorphic region, and it is activated by various catabolic and metabolic factors in the disc degeneration process, which has not been fully elucidated.

RESUMO Objetivo: Avaliar a frequência dos polimorfismos no gene fator de crescimento endotelial vascular (VEGF), bem como identificar potencial haplótipo de risco entre as regiões polimórficas deste gene em pacientes com degeneração discal e em Grupo Controle. Métodos: Este estudo analisou 217 pacientes distribuídos nos Grupos Degeneração Discal e Grupo Controle. Foi coletado sangue periférico de todos os pacientes para a detecção dos polimorfismos do gene VEGF identificados por qPCR (rs699947, rs1570360, rs2010963, rs833061 e rs3025039). Todos os pacientes que apresentaram degeneração discal tiveram a confirmação por meio de ressonância magnética nuclear e avaliação do nível de degeneração do disco. Resultados: Todos os polimorfismos foram encontrados no equilíbrio de Hardy-Weinberg (p>0,05) na população estudada. A frequência genotípica para o Grupo Degeneração de Disco e do Grupo Controle foi rs699947 p=0,475, rs1570360 p=0,862, rs2010963 p=0,823, rs833061 p=0,596 e rs3025039 p=0,230. Para a análise do haplótipo, destacaram-se as composições CAGGC (p=0,094) e CCGGC (p=0,054). Conclusão: A correlação entre os polimorfismos do gene VEGF como preditor de risco para degeneração discal foi negativa na população estudada. No entanto, o VEGF possui grande região polimórfica, ativada por vários fatores catabólicos e metabólicos no processo de degeneração discal, que não está completamente elucidado.

Expression of anti-angiogenic vascular endothelial growth factor isoforms VEGFxxxb in human retinal pigment epithelium cells / 中华实验眼科杂志

Background Hypoxia can increase the secretion of vascular endothelial growth factor-A (VEGF A) by retinal pigment epithelium (RPE) cells and initiate choroidal neovascularization (CNV) consequently.Two VEGF-A isoforms,the angiogenic VEGF-A family (VEGFxxx) and the anti-angiogenic VEGF-A family (VEGFxxxb),are found and formed by alternative splicing.However,the expressing changes and its effect in human RPE cells under the normoxia and hypoxia are unclear.Objective This study was to investigate the expression of VEGFxxx b in human RPE cells under hypoxia.Methods ARPE-19,a human RPE cell line,were cultured.CoCl2 150 μmol/L was added into the medium to mimic the hypoxia environment for 0 hour (normoxia group),3,12 and 24 hours to induce the hypoxia cells.The cells or suspension was harvested at various time points.The expressions of VEGFxxx mRNA and VEGFxxxb mRNA in the cells were detected,and the expressions of the total VEGF-A protein and VEGFxxxb protein in the cells were assayed by Western blot.ELISA was used to determine the contents of total VEGF-A and VEGFxxxb proteins in suspension.Results VEGFxxx mRNA and VEGFxxxb mRNA were expressed in the ARPE-19 cells in both normoxia and hypoxia,and multiple VEGFxxx mRNA isoforms appeared,including VEGF121 mRNA,VEGF165 mRNA and extremely faint VEGF189 mRNA,but only VEGF165b band was seen in VEGFxxxb mRNA.With the prolong of hypoxia culture,the expression of VEGFxxx mRNA showed gradual increase,while VEGFxxx b mRNA appeared gradual decrease.Western blot exhibited that VEGFxxxb was expressed in the cells cultured by normoxia and hypoxia with the strongest expression in VEGF165b.The VEGFxxxb content in suspension of medium was (166.82± 2.55) pg/ml under the normoxia environment and (125.35 ±2.10) pg/ml in 24 hours under the hypoxia,and the total VEGF-A protein elevated from (294.27 ± 11.97) pg/ml under the normoxia environment to (582.26 ± 12.98) pg/ml in 24 hours under the hypoxia.In addition,the proportion of VEGFxxxb to total VEGF-A in the cells lowed from (56.71 ± 1.02) ％ under the normoxia environment to (21.53 ±0.08) ％ in 24 hours under the hypoxia.Conclusions VEGFxxxb isoforms are expressed in both normoxia and hypoxia ARPE-19 cells.VEGFxxxb isoform is a predominant isoform in normoxia ARPE-19 cells.In hypoxia ARPE-19 cells,however,the expression of VEGF A is significantly stronger than that of VEGFxxxb.