Figure 2From: The genetics of chronic obstructive pulmonary diseaseOxidative stress and its effects. Oxidants contained within cigarette smoke irritate epithelial cells (1), releasing activating cytokines that prompt the recruitment of neutrophils and the release of cell derived oxidants (2) and proteases (3). Antioxidants inhibit oxidant mediated damage to the lung (4), but when an imbalance arises (perhaps because of gene polymorphisms) oxidative stress results (5). The consequences of oxidative stress include activation of macrophages (6), leading to the production of more proteases, mucus hypersecretion, epithelial cell apoptosis, inflammation and inhibition of the action of antiproteases.Back to article page