Adiponectin: a novel link between adipocytes and COPD.

Adiponectin (APN) is a unique adipokine with multiple salutary effects such as antiapoptotic, anti-inflammatory, and anti-oxidative activities in numerous organs and cells. Chronic obstructive pulmonary disease (COPD), a growing cause of mortality and morbidity worldwide, often results from the smoking habit and is considered a lifestyle-related disease. COPD is frequently complicated with comorbidities, such as cardiovascular disease, diabetes mellitus, and osteoporosis; however, the molecular mechanisms linking COPD and the associated comorbidities are poorly understood. Recent data have revealed a role for APN in the lung; mice lacking APN spontaneously develop a COPD-like phenotype with extrapulmonary effects, including systemic inflammation, body weight loss, and osteoporosis. This finding highlights the key role of APN in lung pathology and the novel cross talk between lung and adipose tissues. This review summarizes recent advances in understanding the physiological and pathological role of APN in the lung.