Glycocalyceal bodies--a marker for different epithelial cell types in human airways

The surface epithelium of the mucosa of the nose, sinus maxillaris, trachea and bronchi of the human respiratory tract has been investigated with respect to surface differentiations, glycocalyx and glycocalyceal bodies. The luminal surface mainly is formed by ciliated, undifferentiated, and secretory cells; occasionally metaplastic epithelial regions, composed of flattened squamous cells are found. Ciliated cells as well as differentiating progenitor cells, recognizable by branched, microvillus-like surface differentiations - 'cytofila' which on mature ciliated cells are interposed between the cilia, exhibit a delicate glycocalyx. On the contrary, secretory, undifferentiated, and metaplastic squamous cells possess unbranched microvilli of different length and diameter, and exhibit a prominent glycocalyx of varying, individual expression. These latter cell types, in healthy control persons as well as in patients suffering from different diseases, showed glycocalyceal bodies. By means of the high number of investigated samples, more than 350, the occurrence and distribution of glycocalyceal bodies could be defined more exactly: in all investigated regions of the human respiratory tract--nose, sinus maxillaris, trachea, and bronchi--glycocalyceal bodies were found at the apical surface of undifferentiated cells, secretory cells, and metaplastic squamous cells; ciliated cells and their differentiating progenitor cells never showed glycocalyceal bodies; glycocalyceal bodies were found likewise in healthy control persons as well as in patients suffering from different diseases of the airways.