RELATION OF SMOKING TO IMMUNOREACTIVE ENDOTHELIN IN THE BRONCHIOLAR EPITHELIAL-CELLS

Background - Endothelin is a potent bronchoconstrictor which appears t o be important in asthma. To ascertain whether cigarette smoking is as sociated with any alteration in the proportion of bronchiolar epitheli al cells which express endothelin immunoreactivity, the airways in the lungs of non-smokers and smokers were analysed. Since an increase in immunoreactivity has been found in the bronchial epithelial cells of a sthmatic subjects, cigarette smokers with and without evidence of airw ay hyperresponsiveness were also selected. Methods - A point counting method which examined the proportion of endothelin immunoreactive epit helial cells in membranous and respiratory bronchioles was used. Resul ts - Neither smoking itself nor evidence of airway hyperresponsiveness the percentage of endothelin immunoreactive epithelial cells in the m embraneous and respiratory bronchioles. Conclusions - Cigarette smoke does not induce endothelin production in bronchiolar epithelial cells, and the airway hyperresponsiveness seen in some patients with lung di sease induced by cigarette smoking is not related to exaggerated endot helin production in epithelial cells.