Abstract:Background: Fibroblasts from nasal polyps (NP) of asthma patients have reduced expression of cyclooxygenase 2 (COX-2) and production of prostaglandin E 2 (PGE 2 ). We hypothesized that the reported alterations are due to alterations in the availability of arachidonic acid (AA). Objective: The objective was to determine the fatty acid composition of airway fibroblasts from healthy subjects and from asthma patients with and without aspirin intolerance. Methods: We analyzed the fatty acid composition of cultured fibroblasts from non-asthmatics (n = 6) and from aspirin-tolerant (n = 6) and aspirin-intolerant asthmatics (n = 6) by gas chromatography-flame ionization detector. Fibroblasts were stimulated with acetyl salicylic acid (ASA). Results: The omega-6 fatty acids dihomo-gamma-linolenic acid (C20:3) and AA (C20:4), and omega-3 fatty acids docosapentaenoic acid (DPA) (C22:5) and docosahexaenoic acid (DHA) (C22:6) were significantly higher in NP fibroblasts than in fibroblasts derived from nasal mucosa. The percentage composition of the fatty acids palmitic acid (C16:0) and palmitoleic acid (C16:1) was significantly higher in fibroblasts from patients with NP and aspirin intolerance than in fibroblasts derived from the nasal NP of aspirin-tolerant patients. ASA did not cause changes in either omega-3 or omega-6 fatty acids. Conclusions. Our data do not support the hypothesis that a reduced production of AA in NP fibroblasts can account for the reported low production of PGE 2 in nasal polyps. Whether the increased proportion of omega-3 fatty acids can contribute to reduced PGE 2 production in nasal polyps by competitively inhibiting COX-2 and reducing the amount of AA available to the COX-2 enzyme remains to be elucidated.