Cell number and distribution in human and rat airways.

Abstract

Morphometric procedures were used to determine the number of cells, cell volume, cell diameter, and surface areas of the airways in human and rat lungs. Nuclear sizes of epithelial cells from human bronchi were significantly larger than other lung cell nuclei. The average volume of human ciliated cell nuclei was 310 +/- 30 microns 3 and 167 +/- 12 microns 3 in bronchi and bronchioles, respectively. The smaller nuclei of human bronchioles were comparable to those of alveolar cells. In the pseudostratified epithelium of human bronchi, basal cells had a large surface area in contact with the basement membrane (51.3 +/- 4.6 microns 2 per cell) when compared with ciliated (1.1 +/- 0.1 microns 2), goblet (7.6 +/- 1.2 microns 2), or other secretory cells (12.0 +/- 2.1 microns 2). In the first four airway generations distal to the trachea, basal cells account for 30% of the cells in human airway epithelium and 2% of the cells in rat airway epithelium. Total airway surface area from trachea to bronchioles was 2,471 +/- 320 and 27.2 +/- 1.7 cm2 in human and rat lungs, respectively. These direct measurements of airway surface area are less than half of the estimates based on current lung models. The total number of airway epithelial cells were 10.5 x 10(9) for human and 0.05 x 10(9) for rat lungs. For both species, there were 18 times more alveolar cells than bronchial epithelial cells.

Cytotoxicity and Characterization of Particles Collected From an Indium–Tin Oxide Production Facility

“…The human lung burden was determined based on the 50-μg/ml dose being approximately 15 μg/cm 2 (accounting for well volumes and surface areas) and the estimated surface area of the human airways being approximately 2300 cm 2 (Mercer et al, 1994). Therefore:…”

Molecular Mechanisms of Metaplasia, Differentiation and Hyperplasia of Goblet Cellin Allergic Asthma

“…Also Sox2 is required for proliferation and differentiation of Clara and basal cells that serve as the progenitor cells from which Clara, ciliated, and goblet cells are derived. The existence of such an early progenitor population is still hypothetical, but these cells might correspond to some of the 'indeterminate' or 'intermediate' epithelial cells that have been described in human airways [87].…”

The Glandular Stem/Progenitor Cell Niche in Airway Development and Repair

“…Unlike mice, ferrets and humans share a remarkably similar proximal airway cytoarchitecture (11)(12)(13). As in humans, SMGs in the ferret are distributed throughout the cartilaginous airways (12,14).…”