Exercise-induced bronchoconstriction is due to the airway epithelium’s osmotic stimulus and leads to a cascade of biomarker release from several inflammatory cells. Several type 2 (T2) mediators have been linked to exercise-induced bronchoconstriction, but the T2 response per se has not been described during exercise. Therefore, this study aimed to investigate T2 biomarkers in plasma and urine from subjects with asthma and healthy controls before and after an exercise challenge.

Twenty-two subjects with mild asthma and 18 healthy controls performed an exercise challenge test on a treadmill, and fractional exhaled NO (FeNO) was measured at baseline. Blood and urine samples were collected repeatedly 60 min after the test, and Interleukin-13 (IL-13), thymus and activation-related chemokine (TARC), periostin, and leukotrienes were measured.

Asthmatics and controls showed similar levels of IL-13, TARC, periostin, and Cys-LT in plasma at baseline, and there were no differences in baseline levels between subjects with a negative and positive exercise challenge. After exercise, there was an overall increase in interleukin-13 (IL-13) plasma in all subjects, with a peak at 10 min after exercise challenge in both groups. An increase in TARC in plasma was also seen (p< 0.001), but only in the control subjects. In contrast, Cys-LT in plasma showed an overall decrease in all subjects (p< 0.001), while periostin in plasma did not change. In conjunction with plasma, the level of IL-13 was increased in urine 30 min after exercise challenge (p=0.002) and decreased at 60 min. Similarly, leukotriene E4 (LTE4) was increased in urine samples, with a peak at 60 min and most pronounced in asthmatic subjects (p< 0.001) but was also seen in controls (p=0.008).

In conclusion, circulating levels of IL-13 are increased after exercise to the same extent in asthmatics and healthy control subjects, which indicates a physiological rather than a pathophysiological response. Also, the levels of TARC and leukotrienes were affected after exercise.

Ref: https://www.dovepress.com/type-2-inflammatory-biomarker-response-after-exercise-challenge-testin-peer-reviewed-article-JAA