Researchers here demonstrate that comparatively simple stem cell transplants may be effective in regenerating lung injuries: "Human stem cells administered intravenously can restore alveolar epithelial tissue to a normal function in a novel ex vivo perfused human lung after E. coli endotoxin-induced acute lung injury (ALI) ... ALI is a common cause of respiratory failure in the intensive care units, often leading to death. It can be caused by both direct injury such as aspiration and pneumonia, and indirect injury such as sepsis and from trauma. ... Yearly, ALI affects approximately 200,000 patients in the US and has a 40 percent mortality rate despite extensive investigations into its causes and pathophysiology. Innovative therapies are desperately needed. ... we found that intravenous infusion of [stem cells] preferentially homed to the injured areas of the lung, which means that the cells find their way from the bloodstream to the sites in the lung of injury. ... In addition to having restored function of alveolar epithelial cells, lungs treated with [stem cells] showed a reduction in inflammatory [cytokine] levels suggesting a favorable shift away from a proinflammatory environment in the injured alveolus."