Human airway mucosa

These observations demonstrate how rapidly edema can form in the human airway mucosa, but it is unknown how the changes relate to those found in asthmatics exposed to inhaled allergens. For example, there is a report that allergens applied directly to the airway mucosa increase the amounts of protein and inflammatory cells in BAL fluid more than do inhaled allergens (Calhoun etal., 1993). 

Hauber H-P, Goldmann T, Vollmer E et al (2007) Effect of dexamethasone and ACC on bacteria-induced mucin expression in human airway mucosa. Am J Respir Cell Mol Biol 37(5) 606-616... 

Macs are ubiquitous throughout the respiratory tract, and discrete populations can be discerned in the airway mucosa, the lung parenchyma ( interstitial macrophages IMs), the luminal surface of the alveoli (pulmonary alveolar macrophages PAMs) and the conducting airways, and in the vascular bed ( intravascular macrophages IVMs). The latter represent a stable marginated population, intimately associated with the endothelial basement membrane they are most common in ruminants (Winkler, 1989) but also occur in humans. 

The airways receive their blood supply from the systemic circulation via laryngeal, tracheal and bronchial arteries. In the trachea and large bronchi of humans and other large mammals, branches of arterioles deep in the airway wall supply the airway mucosa. In some peripheral airways, mucosal vessels may be supplied by the pulmonary circulation through vascular anastomoses. The airway mucosa has a rich blood supply, with a p>articularly extensive vascular network located immediately beneath the epithelium. Mucosal capillaries are tributaries of an extensive system of venules. In humans, a superficial plexus of venules connects with another plexus of venules located deeper in the mucosa. 

The increase in vascular permeability associated with inflammation often is accompanied by the emigration of leukocytes out of the micro vasculature. Neutrophils and eosinophils are found in the airways of guinea-pigs, rabbits, dogs and humans after allergen challenge they are also in the airway mucosa of patients who have died from asthma (Williams et al., 1991). What then is the relationship between vascular permeability and neutrophil migration ... 

Figure 10.4 (a) Resistance of bovine tracheai mucosa to injury eiicited by ionophore activated human neutrophils, and (b) susceptibility of bronchial mucosa under identical conditions. Injury, In this case cell detachment, was measured indirectly by measuring the permeability of the airway mucosa to serum albumin. Cells were applied to the basolateral surface and the vector of solute movement was basolateral-apical. 

Lamb JP, Sparrow MP (2002) Three-dimensional mapping of sensory innervation with substance p in porcine bronchial mucosa comparison with human airways. Am J Respir Crit Care Med 166 1269-1281... 

Local effects of SEB inhalation in the bronchial mucosa cannot be tested experimentally in humans, but have been in mice [69-71]. Low doses of SEB were sufficient to cause some of the characteristic signs (e.g. eosinophilia) and symptoms (bronchial hypersensitivity and airway hyperresponsiveness) of asthma. 

Duan et al. (1998) studied a newborn/erret tracheal model to probe the contribution of tracheal submucosal gland stem cells to repopulating the surface mucosa. They used this model since it shows a very similar anatomy of submucosal gland distribution to that in humans. Mice have no submucosal glands in the lower cartilaginous airways. 

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