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Brief exercise increases circulating myeloperoxidase in boys with maturational influences observed at baseline
Author(s) -
Schwindt Christina Danell,
Zaldivar Frank,
Cooper Dan
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.670.20
Subject(s) - medicine , bronchoconstriction , myeloperoxidase , endocrinology , cycle ergometer , asthma , inflammation , heart rate , blood pressure
Rationale: Circulating myeloperoxidase (cMPO) is elevated in asthmatics suggesting leukocytes are inordinately activated in these individuals and may play a role in wheezing. Intriguingly, MPO is increased in response to exercise in non‐asthmatic adults, and exercise is a major trigger for bronchoconstriction in asthmatics. We hypothesized that exercise would increase cMPO in children and the response to exercise would be greater in asthmatics. Methods: Thirty‐one boys [9‐asthmatic late pubertal (AL), mean age 16.1 years; 8‐asthmatic early pubertal (AE), mean age 10.6 years; and 14 healthy control late pubertal (CL), mean age 17.0 years] performed 6–8 minutes of moderate exercise on a cycle ergometer. Blood was sampled at pre‐exercise (PE) and end‐exercise (EE). Results: CMPO did not differ between groups at PE (AL 8.0±1.6 ng/mL, AE 9.8±1.7 ng/mL, and CL 5.8±1.3 ng/mL); however, in 3 asthmatics PE cMPO was >2SD above normal. All groups demonstrated a significant increase from PE to EE [AE Δ =3.9±1.5 ng/mL, p=0.013; AL Δ =4.5±1.4 ng/mL, p=0.0032; and CL Δ =5.0±1.1 ng/mL, p=0.0001] without a significant difference among groups. There was no correlation (|r|<0.4) in PE cMPO or ΔcMPO to leukocytes, lung function, or fitness (BMI%, max VO2, VO2/kg). There was a significant negative correlation (r=0.54, p<0.02) between PE cMPO and age in controls. Conclusions: Baseline cMPO may be influenced by maturational status. Brief exercise led to significant increases in cMPO in all children. The magnitude of difference was not related to asthma. We speculate that exercise‐induced asthma may result from an exaggerated response to leukocyte activation that occurs normally in children even with brief exercise.