Stem cells in lung development, disease, and therapy

The objective of this workshop was to bring together in­ vestigators engaged in basic studies of organ development in order to facilitate discussion on epithelial-cell lineage in the lung. Although the bronchial epithelium and the alve­ olar epithelium contain transiently proliferating cells, it is not known whether there are any more pluripotent stem cells in these two compartments in the adult lung. It is also not known whether all alveolar type II cells and airway basal and secretory cells are capable of division, nor is it known what are the local restrictions or mechanisms of control of cell proliferation in vivo. Cell lineage is impor­ tant for the understanding of lung development, injury, re­ pair, and carcinogenesis. Since a great deal of progress has been made in identi­ fying stem cells in other organ systems, such as neural crest, intestine, liver, pancreas, testes, and the ocular lens, it was hoped that a multidisciplinary discussion of the concepts of epithelial stem-cell biology and a review of the data in these other organ systems might suggest ap­ proaches applicable to the study of pulmonary stem-cell biology.