Role of growth factors in lung repair and diseases

A number of growth factors have been identified that participate in lung growth and repair. The early stages of the repair cascade are important in preventing the later development of fibrosis. Both transforming growth factor-beta and basic fibroblast growth factor can have beneficial effects when given early in some injury models. Keratinocyte growth factor stimulates type II cell hyperplasia in vitro but has not yet been studied in a lung injury model. Excessive production of growth factors such as transforming growth factor-alpha and transforming growth factor-beta can lead to fibrosis. Granulocyte-macrophage colony-stimulating factor is implicated in asthma, but now that knockout mice have been shown to have a histologic picture similar to pulmonary alveolar proteinosis, a new role for this factor in pulmonary disease has been suggested. Increasing our understanding of the diverse actions and interactions of growth factors in the lung will bring us closer to therapeutic interventions that can prevent some chronic lung diseases.