Botulinum toxin: a novel therapeutic option for bronchial asthma?

Two components are essential for the development of an attack of bronchial asthma: inflammation and bronchoconstriction, the latter being mediated by smooth muscle contraction. Despite the efficacy of chronic therapy, many asthmatics relapse. Measures to inhibit contraction of the airway smooth muscle, such as vagotomy and thermoablation, may decrease the bronchoconstrictor component of the asthma attack and help to decrease morbidity and mortality from the disease. Botulinum toxin acts to weaken skeletal and smooth muscle by preventing the docking of the acetylcholine vesicle on the inner surface of the presynaptic membrane, thus causing chemical denervation and paresis of skeletal or smooth muscle. We explore the possibility that administration of botulinum toxin may achieve the same effect in bronchial asthma and examine the evidence to support this hypothesis.