Influence of vascular endothelial growth factor on neutrophil activation in asthmatics

Introduction: Asthma is a complex syndrome associated with heterogeneity in the type of inflammation that modulates airway hyperresponsiveness and remodelling. Airway inflammation with neutrophils, cytokines like vascular endothelial growth factor (VEGF) and various gene polymorphisms might be relevant for asthma pathogenesis. Aim: To investigate the expression of CD69 and CD11b markers on peripheral neutrophils after VEGF in vitro stimulation in asthmatics. Furthermore, the possible influence of a genetic factor (del/ins genotype at -2549 -2567 position in the VEGF-promoter gene) was taken into account. Material and methods: 122 subjects (82 asthmatics and 40 controls) participated in our study. CD69 and CD11b presence on peripheral blood neutrophils was detected using the flow cytometric method without exogenous stimulation (negative control), after N-formyl-methionine-leucyl-phenylalanine stimulation (fMLP - positive control) and after VEGF stimulation. Genotyping for the VEGF-promoter region was performed by polymerase chain reaction (PCR). Results: Peripheral neutrophil stimulation with VEGF enhances the activity of these cells and induces CD69 and CD11b expression in a dose-dependent manner compared with unstimulated neutrophils (p > 0.05). CD69 and CD11b markers were slightly presented (p = 0.05 and p = 0.07, respectively) on neutrophils stimulated with fMLP in asthmatics with the ins genotype variant in the VEGF-promoter region. Conclusions: Our results demonstrate that VEGF might insignificantly activate neutrophils in asthmatics. In addition, the modulated expression of CD69 and CD11b on peripheral neutrophils is not related to potential contribution of the VEGF gene polymorphism.