Alveolar epithelial cells: master regulators of lung homeostasis

Int J Biochem Cell Biol. 2013 Nov;45(11):2568-73. doi: 10.1016/j.biocel.2013.08.009. Epub 2013 Aug 27.


The lung interfaces with the environment across a continuous epithelium composed of various cell types along the proximal and distal airways. At the alveolar structure level, the epithelium, which is composed of type I and type II alveolar epithelial cells, represents a critical component of lung homeostasis. Indeed, its fundamental role is to provide an extensive surface for gas exchange. Additional functions that act to preserve the capacity for such unique gas transfer have been progressively identified. The alveolar epithelium represents a physical barrier that protects from environmental insults by segregating inhaled foreign agents and regulating water and ions transport, thereby contributing to the maintenance of alveolar surface fluid balance. The homeostatic role of alveolar epithelium relies on the regulated/controlled production of the pulmonary surfactant, which is not only a key determinant of alveolar mechanical stability but also a complex structure that participates in the cross-talk between local cells and the lung immune and inflammatory response. In regard to these critical functions, a major point is the maintenance of alveolar surface integrity, which relies on the renewal capacity of type II alveolar epithelial cells, and the contribution of progenitor populations within the lung.

Keywords: Alveoli; Epithelium; Lung.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Alveolar Epithelial Cells / pathology*
  • Alveolar Epithelial Cells / physiology
  • Animals
  • Cell Lineage
  • Homeostasis*
  • Humans
  • Lung / pathology*
  • Lung / physiopathology
  • Lung Diseases / pathology
  • Lung Diseases / physiopathology
  • Models, Biological