Pulmonary surfactant and chronic lung disease.

Chronic obstructive bronchitis and emphysema are two chronic lung diseases closely associated with cigarette smoking. Early pathological changes in the lung in asymptomatic smokers affect the alveoli and bronchioli, sites where surfactant production is centred. Bronchial lavage work has demonstrated a reduction of 'free' extra-cellular surfactant in smokers. In this report the interaction between the 'tar' of tobacco smoke and surfactant is described from in vitro studies. Also using an isolated rat lung model tobacco smoke 'tar' appears to increase lung compliance. These observations may help explain why young asymptomatic cigarette smokers have increased lung compliance and suggest the way in which 'tar' interacts with the lung surface.