The pathogenesis of nasal polyps is associated with the interaction between mucosal epithelial cells, extracellular matrix and inflammatory cell, and their chemical mediators. Fibroblasts are major structural components of nasal mucosa and play an important role as a source of chemical mediators and tissue remodeling. The aim of this study was to evaluate the effect of airborne fungi in the production of extracellular matrix from nasal fibroblasts with the interaction of activated eosinophils.
Nasal fibroblasts were isolated from nasal polyp and normal inferior turbinates. Nasal fibroblasts were stimulated with Alternaria alternate at 100 ug/ml and Aspergillus fumigatus at 50 ug/ml. Eosinophils from peripheral blood were extracted then stimulated with both fungi. Nasal fibroblasts were co-cultured with activated eosinophils with or without physical contact for 24 hours. Then α-smooth muscle actin (α-SMA), collagen type I, TIMP-1, MMP-9, fibronectin mRNA expression were determined with real time RT-PCR and protein production was determined with western blot method
Alternaria and Aspergillus enhanced extracellular matrix mRNA expression from nasal polyp fibroblasts about 2.4 to 7.1 times than normal control. However, only Alternaria induced the production of eosinophil peroxide and superoxide from eosinophils. Co-culture of activated eosinophils with fungi and nasal fibroblasts enhanced extracellular matrix mRNA expression 1.8 to 2.6 times than co-cultured with non-activated eosinophil group.
Airborne fungi enhance the extracellular matrix mRNA expression and protein production not only by direct stimulation of fibroblasts, but also by the interaction of activated eosinophils with fibroblasts. In the pathogenesis of nasal polyps, fungi play an important role through the production of extracellular matrix from fibroblasts and inducing tissue remodeling.