Adult Lung Stem Cells

Over the past decade a wealth of information has been divulged on stem cells present in the lung both in the pulmonary vasculature and the respiratory tract. Cells have been identified with the capability of repopulating the lung and others that contribute to the pathogenesis or, conversely, have therapeutic benefit in pulmonary vascular disease. The isolation of a single-resident lung stem cell capable of repopulating any lung epithelium still remains elusive. What is currently known about stem and progenitor cells in the lung suggests that a non-classical stem cell hierarchy exists with a novel array of cellular mechanisms controlling proliferation and differentiation of such cells. This chapter serves to provide an up-to-date review of what is currently known about stem and progenitor cells within the lung.