Mechanisms of respiratory tissue injury from cigarette smoking

Cigarette smoking can be viewed as a chronic inflammatory disorder of the lower airways. Two of the major lung injuries that can result are chronic bronchitis and emphysema. Chronic bronchitis is characterized by chronic mucus hypersecretion and cough; emphysema is a destructive process of the alveolar spaces. Tissue injury may result from the actions of degradative enzymes derived from such inflammatory cells as neutrophils and monocytes. In addition, oxidative injury from inflammatory cells and from oxidants in smoke may participate in the pathogenesis of these smoking-related illnesses.