Alveolar Type I Epithelial Cells: The Forgotten Cells in Fetal Lung Development and Lung Injury
Journal Title: Pulmonary Research and Respiratory Medicine – Open Journal - Year 2015, Vol 2, Issue 4
Abstract
The alveolar surface of the lung is covered by large flat type I epithelial cells. Even though type I cells represent only around 10% of the cells present in the alveolus; they cover much of the surface area in the developed lung.1 Given their thinness and proximity to the capillary endothelium; it is well accepted that type I cells play an important role in gas exchange.2 In addition, these cells are important to maintain adequate fluid balance in the alveolus3 via the tight junctions,4 ion transport channels5 and aquaporin-5.6 Recent studies also indicate that type I cells participate in innate immunity; they express toll-like receptor 4 and produce proinflammatory cytokines.7,8 Studies from T1α knockout mice indicate that alveolar type I cells may be critical for normal lung development. T1α, a lung type I cell differentiation gene, is developmentally regulated and expressed only in type I cells. T1α knockout mice died at birth of respiratory failure. Histologic analysis show fewer alveolar type I cells and decreased alveoli.9 All together, these investigations suggest a critical role for type I cells in gas exchange, alveolar fluid hemostasis, immunity and fetal lung development.
Authors and Affiliations
Juan Sanchez-Esteban
Keywords
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- EP ID EP549964
- DOI 10.17140/PRRMOJ-2-e003
- Views 143
- Downloads 0
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