Lung physiology and defense

The lung is a rhythmic organ and pulmonary outputs show circadian variation. Intrinsic timers within multiple different pulmonary cell types exert circadian organization onto homeostatic lung functions, such as gas exchange and expression of drug targets. Asthma and chronic obstructive pulmonary disease show diurnal variation in their symptoms, and evidence is emerging demonstrating the importance of the circadian clock in regulating inflammatory pathways underlying these chronic inflammatory conditions as well as lung fibrosis. Conversely, the lung clock is sensitive to local and systemic environmental changes, such as inflammation and therapeutic glucocorticoids. This in turn may have negative effects on circadian control of lung physiology. This review discusses recent research in the field of circadian control of lung physiology and defense.