A General Review of the Current Knowledge of Stem Cell Therapy for Lung Disorders

An increasing number of studies suggest that cell therapy approaches may be powerful tools for repair of injured or diseased lungs as well as for understanding mechanisms involved in both lung development and lung repair. This rapidly progressing field encompasses a number of disciplines and conceptual approaches including the study of endogenous stem and progenitor cells resident in the lung, and investigations utilizing exogenously administered cells for the repair of injured lung. Moreover, the field has undergone several conceptual shifts over recent years. For example, the initial focus on engraftment of exogenously administered cells as airway or alveolar epithelium has been shifted to the current emphases on immunomodulation of inflammatory and immune pathways in the lung by stem cells, and on bioengineering approaches to grow functional lung tissue ex vivo for subsequent use in in vivo implantation for destructive lung diseases, such as emphysema. Furthermore, it has become apparent that the variety of candidate stem and progenitor cell types can have different actions in the lung. Each of these areas is the focus of a comprehensive chapter in this book. The goal of this introductory chapter is to provide an overview of the field to date.