Roles of eosinophils and catecholamines in pathophysiology of exercise‐induced asthma

Abstract

To study the roles of eosinophils and catecholamines in the pathophysiology of exercise-induced asthma (EIA), an exercise challenge test was performed in 22 asthmatic children, using a bicycle ergometer, and the changes in lung function, plasma norepinephrine (NE), epinephrine (E) and eosinophil cationic protein (ECP) levels with exercise were evaluated. Subjects were classified into three groups from the results of lung function test, respectively: EIA-negative group. EIA-positive groups with good recovery and poor recovery. Eosinophil counts before exercise in the EIA-positive groups were significantly higher than those in the EIA-negative group. The ECP levels rose with exercise in all groups. Five minutes after exercise, ECP values fell to the pre-exercise level in the EIA-negative group, but rose to higher levels in EIA-positive groups. Plasma E levels rose with exercise and showed 4-fold increase in the EIA-negative group, whereas only 1.5-fold increase of plasma E levels was observed in the EIA-positive group with poor recovery. From these findings, a possible contribution of sympathoadrenal hypofunction and a probable involvement of eosinophils in the pathophysiology of EIA have been suggested.

Prolonged Endurance Challenge at Moderate Altitude

“…Venge et al 9 also observed an initial short-term rise in serum ECP in patients with exercise-induced asthma (EIA) after exercise challenge, but no change in serum ECP levels in asthmatics without EIA. Tsuda et al 10 found that ECP levels in asthmatic children may rise during exercise and that this increase may even continue after exercise, but only in the EIA-positive group. Dufaux et al 11 found an increase in ECP release after short, maximal bicycle exercise in healthy subjects, providing strong evidence that blood eosinophils may be activated after a short bout of maximal exercise.…”

Changes in blood levels of eosinophil cationic protein and tryptase after exercise challenge in adolescents with exercise-induced asthma

“…It is conceivable that an initial rise might have occurred before the subsequent fall. Similarly, Tsuda et al (32) in their own study on children observed that ECP levels after an initial rise following exercise fell 15 minutes later in EIA positive group but not in EIA negative group. They suggested a possible involvement of eosinophils in the pathophysiology of EIA.…”

Preventive effect of 2 and 10 mg of sodium cromoglycate on exercise-induced bronchoconstriction

“…Venge and colleagues [33] demonstrated that enhanced activity of eosinophils was one prerequisite for the development of EIA. An increase in eosinophilic mediators after exercise, such as eosinophil cationic protein, eosinophil peroxidase and EPX in serum, has previously been reported in patients with EIA [30,33]. Following exercise in children with EIA, an increase of 9a,11b-PGF 2 in urine, a mediator generated in small amounts by eosinophils, has been observed [17,22].…”