Isolation and Culture of Human Alveolar Epithelial Cells

The human lung comprises more than 40 different cell types. The morphology and function of constituent cells of the proximal, conducting airway epithelium differ drastically from those of the more distal, alveolar epithelium. This chapter will concentrate on the isolation and culture of human alveolar epithelial cells that line the peripheral gas exchange region of the lung. Whereas immortalized cell lines emanating mostly from the different cells of the tracheal/bronchial epithelium of human and other animals’ lungs are available (1 ), no cell lines that possess significant functional properties of alveolar epithelial cells (AEC) are reported to date (1 ). Primary culture of AEC is, therefore, used for most in vitro studies of alveolar epithelial function (e.g., transport and various metabolic pathways). The primary culture of human AEC involves isolation, purification, and culture of alveolar epithelial type II (ATII) cells from human tissue obtained after lung resections. These ATII cells, when plated on permeable supports or plasticware, acquire the type 1 cell-like phenotype and morphology under appropriate culture conditions (3 ). Owing to the lack of availability of human tissue and some ethical issues pertaining to use of human tissues in certain countries, most studies were based on isolation and culture of cells from the lungs of small laboratory animals including mouse, rat, and rabbit (4 -8 ). However, not much information on species differences in this specific area of cellular research has been systematically studied yet.