The airway neurogenic inflammation: clinical and pharmacological implications

Bronchial airway microvasculature consists in a developed network of vessels, which plays an important role in normal homeostasis as well as in inflammatory airway processes. Its airway autonomic neural control includes cholinergic and adrenergic innervation, as well as nonadrenergic noncholinergic system. The nerve/vessel interplay is complex and not yet completely clarified. In response to inspired air conditions, the sensory nerves can recruit appropriate reflexes, which can induce different vascular processes, such as vasodilatation, vasoconstriction, plasma extravasation and exudation. Additionally, the stimulation of C fibres may result in an axon local reflex with antidromic conduction down afferent nerve collaterals and release of sensory neuropeptides, which in turn may act on the mucosal vasculature to promote vasodilatation and microvascular leakage. The neurogenic inflammation may play a key role in allergic diseases, such as asthma, as well as in COPD, a smoking-related disease. This review deals with the interactions of vessels and nerves within the airway mucosa under healthy conditions and in inflammatory diseases. The clinical and pharmacological implications are also described.