Expression of cyclo-oxygenase 1 and 2 proteins in upper respiratory mucosa

Cyclo-oxygenases 1 (Cox-1) and 2 (Cox-2) catalyse the conversion of arachidonic acid to prostaglandin endoperoxides, leading to the formation of prostaglandin and thromboxane mediators of inflammation. The involvement of these enzymes in inflammatory disorders such as sinusitis and nasal polyps is unknown although this may be relevant to their pathophysiology.

We studied Cox-1 and Cox-2 immunoreactivities in nasal polyp, maxillary sinus, and turbinate biopsies obtained from eight patients with chronic allergic rhinitis and sinusitis and/or nasal polyps, 15 patients with chronic non-allergic rhinitis and sinusitis and/or nasal polyps and five control subjects (patients requiring nose surgery not related to sinusitis or nasal polyps).

Both Cox- and Cox-2 were mainly expressed in the epithelium (basal, ciliated) and were found in 16/28 and 25/28 subjects for Cox-1 and Cox-2 respectively. We did not find any differences between the patient populations. There were no correlations between any of the clinical parameters studied nor the pathological patterns and the presence and characteristics of the Cox immunoreactivities.

Both cyclo-oxygenase enzymes are expressed in normal human upper respiratory epithelium and are not upregulated in chronic sinusitis nor in nasal polyposis, possibly suggesting that Cox products do not have an important role as mediators of the chronic upper airway inflammation.