Glucocorticoid-Induced Differential Expression of the Sialylated and Nonsialylated Lewis a Epitopes and Respective Binding Sites in Human Nasal Polyps Maintained under ex vivo Tissue Culture Conditions

We characterized the anti-inflammatory effects of budesonide on the expression of adhesion molecules involving Lewis^a (Le^a) epitope, its sialylated derivative (sLe^a), and their respective binding sites in human nasal polyposis. By computer-assisted microscopy, we quantitatively characterized the level of histochemical expression of L- and P-selectins, sialylated and nonsialylated Le^a epitopes, and their respective binding sites in both surface epithelium and glandular epithelium of human nasal polyps obtained from surgical resection, maintained under ex vivo tissue culture conditions for 24 hours, and treated or not with budesonide. Intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1) were chosen as methodological controls, because data already published in the literature clearly indicated budesonide-mediated effects on ICAM-1 and VCAM-1 levels of expression. The present data show that budesonide significantly modified the levels of expression of ICAM-1 and VCAM-1, and to a lesser extent that of P-selectin, in the surface and glandular epithelia. Budesonide markedly decreased the levels of expression of the binding sites for both Le^a and sLe^a, while those of Le^a and sLe^a remained globally unchanged. In conclusion, the present study documents that glucocorticoid-induced effects can encompass receptors for Le^a epitopes different from E- and P-selectins on epithelial cells of human nasal polyps.