Upregulation of COX-1 and COX-2 in nasal polyps in cystic fibrosis.

BACKGROUND

Since abnormalities in prostanoid metabolism occur in the lower airway of patients with cystic fibrosis (CF), it is likely that they could also be detected in the nose.

METHODS

The degree of mRNA and protein expression of cyclo-oxygenase (COX) enzymes 1 (COX-1) and 2 (COX-2) was examined using quantitative reverse competitive polymerase chain reaction (RT-PCR) and Western blot analysis in the nasal polyps from 10 patients with CF, nasal polyps from 10 non-CF patients and 11 nasal mucosa specimens. The results are presented as 10(6) cDNA molecules/mug total RNA and the densitometric ratio between protein and beta-actin.

RESULTS

COX-1 mRNA levels were significantly higher in CF nasal polyps (median 2.34, 25-75th percentiles 1.6-3.2) than in the nasal mucosa (0.78, 0.11-1.21), while there was no difference with non-CF nasal polyps (1.11, 0.80-3.15). COX-1 protein levels were significantly higher in CF nasal polyps (3.63, 2.71-4.27) than in nasal mucosa (1.55, 0.66-2.33) and non-CF nasal polyps (2.19, 1.72-3.68). COX-2 mRNA was significantly higher in CF nasal polyps (3.34, 2.42-7.05) than in nasal mucosa (1.69, 0.19-3.50). No differences were found in COX-2 mRNA expression between CF and non-CF polyps (1.38, 0.12-6.07). COX-2 protein levels were also significantly higher in CF nasal polyps (0.23, 0.04-0.34) than in non-CF nasal polyps (0.011, 0.009-0.016) or nasal mucosa (0.014, 0.014-0.016).

CONCLUSIONS

Upregulation in the expression of COX-1 and COX-2 could explain the high production of prostanoids reported in CF. These findings raise questions regarding the potential use of selective or non-selective COX-2 non-steroidal anti-inflammatory treatment in CF.