Numerous studies in experimental animal models provide compelling evidence for the beneficial effects of stem cell therapy approaches for a wide variety of adult lung diseases ( Table 2) , including acute lung injury/acute respiratory distress syndrome, pulmonary hypertension, asthma, and chronic obstructive pulmonary disease (including emphysema). [65] [66] [67] Of the many different stem/progenitor cell therapies that have been used in experimental models, MSCs appear to be the most extensively examined cell type.