In AERD patients, 15-hydroxyeicosatetraenoic acid (15-HETE) plasma levels are associated with response to aspirin desensitization. We investigated changes in 15-HETE and in several other HETE’s in AERD nasal polyp tissue compared to non-AERD polyps in response to aspirin-lysine stimulation in vitro.
Nasal polyps were obtained from twenty-six AERD patients and seven controls (patients with nasal polyps but no AERD). Immediately after surgery, nasal polyps were dissected into pieces of approximately 50mg, then exposed in culture medium for 30 min at 37°C, to aspirin-lysine at 0 mM, 1mM, 3mM, and 10mM. Supernatants were collected and eicosanoids in culture supernatants were isolated by liquid:liquid extraction and their concentrations were measured by liquid chromatography.
In AERD patients, 15-HETE levels in nasal polyp supernatant significantly decreased in response to stimulation by aspirin-lysine (from baseline of 18.6 ng/mL (±2.2) to 13.0 ng/mL (±2.7) at 3 mM of aspirine-lysine, p=0.03, and to 11.4 ng/mL (±2.2) at 10 mM (±1.8), p<0.001). There was no significant change in levels after stimulation with 1mM of aspirin-lysine. Similar decreases were observed in 5-HETE, 11-HETE, 12-HETE levels in AERD polyps (p-values for all <0.01). There was no significant change in 8-HETE or 20-HETE. There was no significant change in HETE levels in non-AERD polyps.
The differential response of HETE metabolites to aspirin stimulation of nasal polyps In AERD patients compared to non-AERD patients with nasal polyps indicates a possible implication of these eicosanoids in the mechanism of AERD.