Abstract
Nasal polyps are usually observed in patients with chronic sinusitis and/or allergic rhinitis. Histological findings of nasal polyps are characterized by edematous stroma containing hyperplastic mucous glands, infiltrating inflammatory cells, and proliferating blood vessels. The etiology of nasal polyps remains, however, to be clarified. Since vascular endothelial growth factor (VEGF) induces vascular hyperpermeability and angiogenesis, it may play an important role in nasal polyp formation. For this reason, we studied the VEGF expression in nasal polyps.
Thirteen subjects with nasal polyps were enrolled in this study and underwent endoscopic sinus surgery or polypotomy. Frozen sections of resected nasal polyps were cut to a 5μm thickness and stained with antihuman VEGF, tryptase, and EG2 antibody.
VEGF expression was shown in infiltrating inflammatory cells and in fibroblasts and vascular endothelial cells in all nasal polyps. VEGF-positive cells in allergic subjects outnumbered those in nonallergic subjects, and correlated with the number of tryptase-positive and EG2-positive cells. The immunohistochemical study of serial sections also showed VEGF expression in mast cells and eosinophils.
These findings suggest that VEGF is an important factor in nasal polyp formation, and that mast cells and eosinophils contribute to this formation by producing VEGF in allergic subjects.
