The role of iron in pulmonary pathology

Respiratory disease accounts for a large proportion of emergency admissions to hospital and diseaseassociated mortality. Genetic association studies demonstrate a link between iron metabolism and pulmonary disease phenotypes. IREB2 is a gene that produces iron regulatory protein 2 (IRP2), which has a key role in iron homeostasis. This review addresses pathways involved in iron metabolism, particularly focusing on the role of IREB2. In addition to this, environmental factors also influence phenotypic variation in respiratory disease, for example inhaled iron from cigarette smoke is deposited in the lung and causes tissue damage by altering iron homeostasis. The effects of cigarette smoke are detailed in this article, particularly in relation to lung conditions that favour the upper lobes, such as emphysema and lung cancer. Clinical applications of iron homeostasis are also discussed in this review, especially looking at the pathophysiology of chronic obstructive pulmonary disease, lung cancer, pulmonary infections and acute respiratory distress syndrome. Promising new treatments involving iron are also covered.