Future treatments for chronic obstructive pulmonary disease and its comorbidities.

The recognition that patients with chronic obstructive pulmonary disease (COPD) may have systemic manifestations and often suffer from comorbid conditions has important implications for therapy that require further research. The most likely link between COPD and extrapulmonary effects is that inflammation in the lung periphery "spills over" into the systemic circulation and effects on other organs that may also be affected by the systemic effects of cigarette smoking. The peripheral lung inflammation of COPD and systemic inflammatory effects could be treated by systemic antiinflammatory treatments, but this may have a high risk of systemic side effects, or by inhaled administration of antiinflammatory treatments that suppress inflammation in the lung and prevent the spillover of inflammatory mediators into the systemic circulation. Current therapies for COPD, including inhaled corticosteroids, long-acting beta(2)-agonists, and theophylline, have the potential to reduce systemic features of COPD and comorbid diseases. Treatments for comorbid diseases, such as statins, angiotensin-converting enzyme inhibitors, and peroxisome proliferator-activated agonist agonists, may also have beneficial effects on COPD inflammation. Novel antiinflammatory treatments, such as phosphodiesterase-4, nuclear factor-kappaB, and p38 mitogen-activated protein kinase inhibitors, may provide benefits in both COPD and comorbidities, but have a high risk of adverse effects when given systemically, and may need to be given by inhalation. Increased oxidative stress may be an important mechanism linking COPD inflammation, systemic effects, and comorbid disease, so the development of antioxidants, including nuclear factor erythroid-2-related factor 2 activators, is a priority. Accelerated aging may be associates in common to COPD and several comorbidities, prompting the development of antiaging molecules, such as sirtuin 1 agonists, which may also be effective in reducing the risk of lung cancer.