Glucocorticoid therapy increases COX-2 gene expression in nasal polyps<i>in vivo</i>

Abstract

The aim of the present study was to evaluate the in vivo regulation of cyclooxygenase-2 in nasal polyps. In total, 65 patients with nasal polyps were randomly (3:1) treated with (n = 51; 33 with asthma) or without (n = 14) oral prednisone and intranasal budesonide for 2 weeks plus intranasal budesonide for 10 additional weeks. Biopsies were obtained at baseline and after 2 and 12 weeks of treatment. All samples were analysed for cyclooxygenase-1 and cyclooxygenase-2 mRNA. Attempts were made to detect cyclooxygenase-2 protein. At baseline, cyclooxygenase-1 and cyclooxygenase-2 expression did not differ between polyps from nonasthmatic and asthmatic patients. Cyclooxygenase-1 mRNA was unchanged by glucocorticoid treatment, while cyclooxygenase-2 mRNA increased in glucocorticoid-treated patients at week 2 compared with baseline and then decreased at week 12. Within subgroups, increased cyclooxygenase-2 mRNA was found at week 2 in polyps from nonasthmatic and asthmatic patients compared with baseline. At week 12, cyclooxygenase-2 expression remained high in nonasthmatics while it decreased in asthmatics. Cyclooxygenase-2 protein was not detected under any circumstances. Glucocorticoid therapy enhances cyclooxygenase-2 expression in vivo in nasal polyps, a finding that does not follow the generally accepted assumption that cyclooxygenase-2 expression is suppressed by glucocorticoids.