Topical oropharyngeal application of lecithin reduces sensitivity to airway challenge in asthmatics

Aim: To determine whether topical application of lecithin to the oropharyngeal mucosa attenuates responses to airway challenge in asthmatics. Methods: Ten adult asthmatics (FEV1 = 93 ± 14 % predicted; mean ± 1 SD) received airway challenges (Aridol™ mannitol inhalers) 15 min after gargling and expectorating either 100 mL of water or 100 mL of aqueous suspension of soy lecithin containing 1680 mg of the phospholipid phosphatidylcholine. Water and lecithin studies were performed with identical airway challenges on separate test days carried out in random order within 1 week of each other. Results: The Figure shows mean FEV1 changes (+ or -1 SD) for 1 h after airway challenge (top curve is lecithin). FEV1 was higher after lecithin for the first 30 min post-challenge (P < 0.05, paired t tests). Conclusion: Topical application of soy lecithin to the oropharynx protected against airway challenge. This suggests that oropharyngeal receptors help regulate airway function in asthmatics, and that phospholipids may have therapeutic potential by masking these receptors.