Methods: Study group consisted of 15 competitive athletes (5 speed skaters and 10 swimmers) aged 15-25. Control groups comprised 10 mild-to-moderate asthmatics aged 19-39 (asthma controls, AC) and 7 healthy, non-smoking subjects aged 21-27 (healthy controls, HC). Control subjects were not performing sports on a reglar basis. Athletes were assessed in two time-points: in-training (period 1) and out-of-training (period 2) depending on individual training schedule. Treadmill exercise challenge was conducted according to the ATS guidelines. EBC was collected immediately before and 30 minutes after exercise. Periostin levels in EBC were assessed by ELISA.
Results: Periostin EBC levels before and after exercise challenge were significantly decreased in athletes during in-training period as compared with out-of-training period (1.87±0.69 vs 2.36±0.77 ng/ml, mean±SD, p<0.02) and with AC subjects (1.87±0.69 vs 2.72±0.62 ng/ml, p<0.01) . Exercise challenge did not induce significant changes in EBC periostin in any of the groups. In athletes during training period, significant positive correlation was observed between baseline EBC periostin levels and mean daily air temperature on the assessment day (day 0) (R=0.57; p=0.02), mean temperature during 7 days preceding the assessment (R=0.56, p=0.02), dew point temperature on day 0 (R=0.60, p<0.02) and mean dew point temperature during 7 days preceding the assessment (R=0.57, p=0.02). In asthmatics a significant negative correlation was observed between baseline EBC periostin and mean daily air temperature on day 0 (R=-0.58; p=0.04). No correlations were observed in athletes during off-training period and in HC subjects.
Conclusions: Regular exercise may contribute to decreased expression airway periostin level. Ambient conditions seem to influence periostin release into the airways.