Figure 1.

Sources of inflammatory mediators in COPD. CS: cigarette smoking. Oxidants from cigarette smoking and other environmental contaminants activate the lung epithelial and immune cells, leading to more oxidants from the immune cells, resulting in local oxidative stress. Oxidative stress initiates a series of activities that ultimately lead to local inflammation. The accumulated pro-inflammatory mediators in the lungs can leak into the blood, causing systemic inflammation. Pro-inflammatory mediators in COPD can also originate from the gut and adipose tissues.