Role of Angiogenic Factors in Airway Remodeling in an Allergic Rhinitis Murine Model

PURPOSE There is growing evidence that nasal airway remodeling occurs in allergic rhinitis (AR). Although angiogenesis is an important component of airway remodeling in asthma, its involvement in AR has been little studied. Furthermore, information regarding the role of potent angiogenic factors, such as vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF), in the nasal airway remodeling process is limited. This study was conducted to investigate the role of VEGF and PDGF in nasal airway remodeling, and to assess the preventive effects of anti-angiogenic drugs on this process in a murine AR model. METHODS Mice were systemically sensitized and subjected to inhalation of ovalbumin (OVA) twice a week for 3 months. Control mice were challenged with phosphate buffered saline, while the treatment group received SU1498, a VEGF receptor inhibitor, and/or AG1296, a PDGF receptor inhibitor, via intraperitoneal injection 4 hours prior to each OVA inhalation. Staining using hematoxylin and eosin, Masson's trichrome, and periodic acid-Schiff were separately performed to assess eosinophil infiltration, subepithelial fibrosis, and goblet cell hyperplasia, respectively, in the nasal airway. Immunohistochemical staining for matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinase-1 (TIMP-1) was also conducted. RESULTS Repetitive intranasal inhalation of OVA resulted in significant increases in eosinophil infiltration, subepithelial fibrosis, goblet cell count, and MMP-9/TIMP-1 expression. Administration of SU1498 or AG1296 prevented these abnormal responses. CONCLUSIONS The results of this study suggest that a causal relationship may exist between angiogenic factors and nasal airway remodeling in AR. Inhibition of VEGF or PDGF receptors may, in turn, suppress the remodeling process through the regulation of MMP-9/TIMP-1 expression.