Background: Cell resistance to glucocorticoids is a major problem in the treatment of nasal polyposis (NP).
Objectives: The objectives of this study were to observe the effect of budesonide on the expression of IL-1beta, TNF-alpha, granulocyte macrophage-colony stimulating factor, intercellular adhesion molecule (ICAM)-1, basic fibroblast growth factor, eotaxin-2, glucocorticoid receptor (GR)-alpha, GR-beta, c-Fos and p65 in nasal polyps and to correlate their expression to clinical response.
Methods: Biopsies from nasal polyps were obtained from 20 patients before and after treatment with topical budesonide. Clinical response to treatment was monitored by a questionnaire and nasal endoscopy. The mRNA levels of the studied genes were measured by real-time quantitative (RQ)-PCR.
Results: There was a significant decrease in the expression of TNF-alpha (P<0.05), eotaxin-2 (P<0.05) and p65 (P<0.05) in NP after treatment. Poor responders to glucocorticoids showed higher expression of IL-1beta (3.74 vs. 0.14; P<0.005), ICAM-1 (1.91 vs. 0.29; P<0.05) and p65 (0.70 vs. 0.16; P<0.05) before treatment. Following treatment, IL-1beta (4.18 vs. 0.42; P<0.005) and GR-beta (0.95 vs. 0.28; P<0.05) mRNA expression was higher in this group.
Conclusion: Topical budesonide reduced the expression of TNF-alpha, eotaxin-2 and p65. Poor responders to topical budesonide exhibit higher levels of IL-1beta, ICAM-1 and nuclear factor (NF)-kappaB at diagnosis and higher expression of both IL-1beta and GR-beta after treatment. These results emphasize the anti-inflammatory action of topical budesonide at the molecular level and its importance in the treatment of NP. Nevertheless, IL-1beta, ICAM-1 and NF-kappaB may be associated with primary resistance to glucocorticoids in NP, whereas higher expression of GR-beta in poor responders only after glucocorticoid treatment may represent a secondary drug resistance mechanism in this disease.