Lung remodeling associated with recovery from acute lung injury

Acute respiratory distress syndrome (ARDS) is a disease with a variety of causes and is defined by severe hypoxemia. Whereas ARDS carries a mortality of approximately 30 %, patients that survive may ultimately regain near normal pulmonary physiology. The critical pathophysiological processes in ARDS are alveolar barrier dysfunction and overwhelming inflammation. This encompasses damage to the epithelial and endothelial layers, thickening of the interstitial matrix, edema with inactivation of pulmonary surfactant at the alveolar surface and marked inflammation mediated by infiltrating neutrophils and pro-inflammatory macrophages. For patients that survive the disease, these are the critical processes that require repair and remodeling to allow for the recovery of ARDS. As such, the current review focuses on the experimental studies that have begun to elucidate the mechanisms involved in restoring the alveolar barrier following injury.