Expression of vascular endothelial growth factor in exuberant tracheal granulation tissue in children.

Prolonged tracheotomy and endotracheal intubation often induce symptoms of airway obstruction and delay decannulation and extubation. Bronchoscopic examination of patients undergoing these treatments usually shows the presence of exuberant (pseudopapillary or nodular) granulation tissue occupying the airway lumen. An immunohistochemical analysis was undertaken of vascular endothelial growth factor (VEGF) expression in exuberant tracheal granulation tissue (n=17) obtained from children treated with prolonged tracheotomy or endotracheal intubation. Increased levels of VEGF protein and mRNA were expressed mainly by tracheal epithelial cells that migrated to cover the granulation tissue and partly by pericapillary macrophages in this tissue, whereas normal tracheal epithelium did not express VEGF. The VEGF expression level correlated significantly with the severity of the exuberant granulation tissue response (p=0.0018). As VEGF induces angiogenesis and vascular permeability, characteristics of granulation tissue, and plays a pivotal role in granulation tissue development, enhanced VEGF expression may be involved in the development of exuberant tracheal granulation tissue.