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Preventing bronchoconstriction in exercise-induced asthma with inhaled heparin
1Division of Pulmonary Disease, University of Miami School of Medicine, FL.
The New England Journal of Medicine
|July 8, 1993
Summary
Inhaled heparin effectively prevents exercise-induced asthma by modulating mediator release, not by affecting smooth muscle directly. This treatment offers a new approach for managing exercise-induced asthma.
Area of Science:
- Pulmonary Medicine
- Allergy and Immunology
- Pharmacology
Background:
- Previous studies showed inhaled heparin prevents allergic bronchoconstriction and inhibits histamine release from mast cells.
- Mediator release is implicated in exercise-induced asthma, prompting investigation into heparin's efficacy.
Purpose of the Study:
- To investigate if inhaled heparin can attenuate bronchoconstriction in exercise-induced asthma.
- To determine if heparin's effect is due to direct action on airway smooth muscle or mediator modulation.
Main Methods:
- 12 subjects with exercise-induced asthma underwent exercise challenges after pretreatment with inhaled heparin, cromolyn sodium, or placebo in a crossover design.
- Specific airway conductance was measured to assess bronchoconstriction; histamine provocation tests were conducted to evaluate direct smooth muscle effects.
Main Results:
- Inhaled heparin and cromolyn sodium attenuated exercise-induced decreases in specific airway conductance compared to placebo.
- Heparin did not alter baseline airway conductance, partial-thromboplastin time, or histamine-induced bronchoconstriction.
Conclusions:
- Inhaled heparin effectively prevents exercise-induced asthma.
- Heparin's action is likely through modulating mediator release rather than direct effects on airway smooth muscle.