Montelukast Attenuates AHR In Ice Rink Athletes Exposed To PM1 During Exercise

Abstract

1803 Airborne particulate matter (PM1) emitted from fossil-fueled ice resurfacing equipment may be causal to the increased airway hyperresponsiveness (AHR) and reduced resting lung function observed in ice rink athletes. Cysteinyl-leukotrienes (LT) are mediators involved in asthma and may be important in PM1-associated AHR. PURPOSE: To evaluate the efficacy of a single-dose LT receptor antagonist (montelukast sodium, ML) in treating AHR positive (+) athletes during high and low [PM1] exposure exercise. METHODS: Eight male AHR+ subjects (age: 19.25 ± 1.28) performed 2 high intensity 6-min cycle ergometer challenges in both low [PM1] and high [PM1] (∼70-fold above low [PM1]) conditions. Subjects ingested either placebo (PL) or 10 mg ML 6 h prior to each trial. Order was randomized and double-blinded with at least 48 h between trials. Spirometry was performed pre-and post-challenge. RESULTS: Peak fall in FEV1 was significantly attenuated by ML treatment over PL in high [PM1] (1.95 ± 6.13 vs. 18.12 ± 10.09; p<0.001). ML improved lung function compared to PL at 5, 10, 15 min post-exercise (change in FEV1 from baseline; −1.3 ± 5.92 vs.-10.3 ± 6.59, 0.5 ± 7.06 vs.-15.7 ± 9.15, and 2.3 ± 6.69 vs.-12.3 ± 11.46, respectively; p<0.01). In low [PM1], ML provided modest but non-significant protection (8.96 ± 11.07 vs. 16.15 ± 18.56 fall in FEV1). CONCLUSION: ML provided substantially better protection against AHR from high PM1 exposure exercise than from low PM1 exercise. The precise mechanism by which airborne PM1 affects AHR remains unclear, but the response appears to be highly mediated by LT which is different than that observed in a low [PM1] cold air challenge. Supported by Merck & Co. Inc. Grant # SING-US-63–01.