Airway Wall Liquid

Sources and Role as an Amplifier of Bronchoconstriction

¹ From the Physiology Program, Department of Environmental Science and Physiology, Harvard School of Public Health, Boston; Bioengineering Laboratory, Mechanical Engineering Department, University of California, Berkeley
² From the Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge
³ From the Physiology Program, Department of Environmental Science and Physiology, Harvard School of Public Health, Boston

Airway liquid balance in asthma is largely determined by active plasma exudation from tracheobronchial microvessels into the interstitial spaces of the mucosa, submucosa, and/or adventitia, and from there into the luminal space. This exuded plasma is rich in proteins and cell mediators capable of initiating several events, including activation of sensory neural pathways, plasma protein cleavage, inflammatory cell recruitment, and inhibition of surfactant function. It can act to amplify the bronchoconstrictor response by increasing mucosal and/or submucosal thickness, altering mechanical properties of airway wall compartments, decoupling the airway wall from parenchymal attachments. filling airway interstices, and by creating an additional inward force because of surface tension, resulting in further airway constriction and possibly closure and thereby significantly increasing airways resistance.