Alveolar Epithelial Type II Cells and Their Microenvironment in the Caveolin‐1‐Deficient Mouse

Caveolin‐1 (Cav‐1) is highly expressed in alveolar epithelial type I (AE1) and endothelial cells of the alveolar region of the lung. Interestingly, alveolar epithelial type II (AE2) cells that are progenitors of the AE1 cells do not express Cav‐1. We investigated whether genetic Cav‐1 deficiency alters the phenotype of AE2 cells and their microenvironment using stereology. Total number, mean volume, and subcellular composition of the AE2 cells were not altered in Cav‐1 ^?/? when compared with wild‐type mice. The alveolar septa were thickened and contained a significantly greater volume of extracellular matrix. Thus, AE2 cells as progenitors of AE1 cells are not critically involved in the severe pulmonary phenotype in Cav‐1‐deficient mice. Anat Rec, 2012. © 2011 Wiley Periodicals, Inc.