Pathogenesis of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a respiratory disease characterized by permanent and progressive airway obstruction. Cigarette smoking is the main cause responsible for COPD although only 15 to 25 % of smokers develop COPD. Mechanisms underlying COPD pathogenesis are not fully understood. Structural abnormalities in small airways (bronchioles < 2 mm in diameter) ore the main determinants of airway obstruction, obstruction of these bronchioles is related to increase in airway wall thickness (associated with peribronchiolar fibrosis) and to plugging by mucus exudates. Alveolar wall destruction (emphysema) also contributes to airway obstruction and to gas exchange abnormalities. Current knowledge related to molecular and cellular mechanisms responsible for these structural modifications are reviewed.