Angiogenic Factors Play a Significant Role in Nasal Airway Remodeling in Allergic Rhinitis

© Copyright The Korean Academy of Asthma, Allergy and Clinical Immunology • The Korean Academy of Pediatric Allergy and Respiratory Disease http://e-aair.org The definition of remodeling is “model again or differently, reconstruct.” In the airway, reaction to chronic inflammatory conditions can lead to changes in the structural components of the airway wall, known as airway remodeling. Airway remodeling in response to allergens is a well-known key feature of pathogenesis in asthma, a representative allergic disease of the lower airway. The structural changes in airway remodeling comprise epithelial disruption, smooth muscle hypertrophy, goblet cell hyperplasia, subepithelial fibrosis, inflammatory cell infiltration, and vascular remodeling such as neovascularization. The nasal and bronchial mucosa present similarities, and epidemiologic studies have revealed that allergic rhinitis and asthma are closely related with each other. Therefore, once regarded as two separate disease entities, they are now considered to be a common disease with different clinical manifestations. Thus, airway remodeling is presumed to occur in allergic rhinitis. Many previous studies have shown that airway remodeling exists in allergic rhinitis, although it seems to be less extensive than that in asthma. Several studies have been performed to elucidate the epithelial changes in the nasal mucosa of patients with allergic rhinitis. An electron microscopic study has revealed that damaged epithelium and tight junctions of the epithelial cells were found in the nasal mucosa of patients with allergic rhinitis. Allergic patients also present a marked goblet cell hyperplasia, and have a thicker epithelium than normal persons. However, there was a contradictory result that patients with perennial rhinitis have an epithelium thickness comparable with that of normal persons. In addition, the epithelial damage is less extensive in the nose than in the bronchi of the same asthmatic patients. Also, there is pseudo-thickening of the reticular basement membrane caused by collagen deposition in allergic rhinitis, although the extent was less severe than in asthma. Furthermore, matrix metalloproteinases (MMPs), major proteolytic enzymes that Angiogenic Factors Play a Significant Role in Nasal Airway Remodeling in Allergic Rhinitis