Epithelial cell proliferation in nasal polyps could be up-regulated by platelet-derived growth factor.

The modifications of epithelial differentiation and proliferation observed in nasal polyps (NP) could be related to local secretion of growth factors, among which platelet-derived growth factor (PDGF) could play a key role. We therefore prospectively studied, by immunohistochemistry, proliferating cell nuclear antigen (PCNA, an S-phase cell marker), PDGF, and CD-68 (activated macrophages marker) expression in NP and inferior turbinate mucosa (NM) in 11 patients. Our data show that PCNA and PDGF expression are increased in NP epithelium, while CD-68 expression is increased in NP epithelium and lamina propria when compared to NM. Increased local PDGF secretion by numerous activated macrophages could therefore be involved in epithelial cell proliferation up-regulation in NP. PDGF could also be involved in the pathogenesis of NP via its connective tissue remodeling actions.