Influence of exhaled breath condensates from children with asthma on endothelial cells cultured in vitro. Do we really know everything about our breath condensate?

INTRODUCTION: Asthma-associated remodelling involves subepithelial fibrosis and increased vascularization of the bronchial wall. The latter may be associated with excessive production of several angiogenesis regulators which may be found in exhaled breath condensates (EBCs) collected from children with asthma. AIM: To assess the influence of EBC samples of asthmatic children and healthy controls on in vitro cultures of normal human lung microvascular endothelial cells (HLMVEC) and murine endothelial cell line (C-166). Moreover, the proteomic profile of cytokines in EBC samples was analysed. MATERIAL AND METHODS: Breath condensates collected from children with mild asthma (n = 10) and from healthy controls (n = 10) were used for experiments. Colorimetric tetrazolium salt reduction assay was used to evaluate the effect of EBCs on HLMVEC and C-166 cell lines. Furthermore, influence of EBCs on C-166 cell line was assessed using Annexin V-binding assay. The cytokine screening of EBC samples was performed using a proteome microarray system. RESULTS: The EBCs from patients with asthma revealed a weak inhibitory influence on human and murine endothelial cells. Surprisingly, EBCs from healthy children led to cell death, mainly by the induction of apoptosis. There were no statistically significant differences in the cytokine profile between EBC samples from children with asthma and healthy controls. CONCLUSIONS: Our preliminary report shows for the first time that the incubation of EBCs from healthy controls induced apoptosis in endothelial cells. The detailed mechanism responsible for this action remains unknown and requires further research.