Objective To evaluate the expression of cyclooxygenase (COX) and lipoxygenase (LO) enzymes in nasal polyp specimens from aspirin-sensitive (AS) and aspirin-tolerant (AT) patients.
Design Immunohistochemical staining of archived tissue.
Subjects Specimens from 26 patients (11 AS and 15 AT) with nasal polyps were analyzed; specimens from 4 patients were used as controls.
Interventions Immunohistochemical techniques were used to evaluate the expression of the enzymes COX-1, COX-2, 5-LO, 12-LO, and 15-LO in nasal polyp tissue specimens from AS and AT patients. The results were compared with those of a control group of patients without a history of nasal polyposis or rhinosinusitis.
Results Characteristic staining patterns of epithelium and submucosal glands were noted for each enzyme. Statistically significant (P<.05) differences in staining of columnar epithelium were noted for COX-1 (basal cell layer cytoplasm), COX-2 (apical cell layer cytoplasm), and 12-LO (full-thickness cytoplasm and nucleus). Increased 15-LO (full-thickness cytoplasm) expression in columnar epithelium was noted only in the AT group. Significant differences in the staining of submucosal glands were noted for COX-2 (plasma membrane and cytoplasm), 12-LO (cytoplasm), and 15-LO (cytoplasm) between control and AS patients as well as between control and AT patients (P<.05). The only significant difference noted between the AS and AT groups was cytoplasm staining for 5-LO in submucosal glands, which was greater in the AS group. No epithelial staining differences were noted between AT and AS patients.
Conclusions There were significant differences in the expression of COX and LO enzymes between patients with nasal polyps and controls, irrespective of aspirin sensitivity. With 1 exception, there were no significant differences between AS and AT groups.
