Why do we not find polyps in the lungs? Bronchial mucosa as a model in the treatment of polyposis

Abstract

The link between lower and upper airways has been reported since the beginning of 1800 s. They share the same pseudostratified ciliated columnar epithelium lining and the concept of one airway, one disease is quite well widespread. Nasal polyposis and asthma share basically the same inflammatory process: predominant infiltration of eosinophils, mucus cell hyperplasia, edema, thickened basal membrane, polarization for Th2 cell immune response, similar pro-inflammatory mediators are increased, for example cysteinyl leukotrienes. If the lower and upper airways share a lot of common epithelial structural features so why is the edema in the nasal mucosa able to increase so much the size of the mucosa to the point of developing polyps? The article tries to underline some differences between the nasal and the bronchial mucosa that could be implicated in this aberrant change from normal mucosa to polyps. This paper creates the concept that there are no polyps with the features of nasal polyposis disease in the lower airway and through it is developed the hypothesis of the nasal polyps origin could partially lie on the difference between the upper and lower airway histology.