Effects of Age and Smoking on the Disaturated Phosphatidylcholine Content of Broncho-Alveolar Lavage Fluid

Abstract

The effects of age and smoking on the pulmonary surfactant content were examined by measuring the disaturated phosophatidylcholine (DSPC) content of the 27, 000×g precipitate of bronchoalveolar lavage fluid (BALF) obtained from 64 normal men aged 20 to 26 years old and 152 male patients aged 30 to 78 years old who had a localized lung disease.
The DSPC content of BALF was almost the same in nonsmokers aged 20-69 years old, but tended to decrease with aging in smokers of 20-78 years old. A negative correlation between age and DSPC content of BALF was found only in the smokers (r, -0.648). There was no significant difference betwen the DSPC content of nonsmokers and smokers aged between 20 and 49 years old, but that of smokers was significantly lower than that of nonsmokers in the 50-60 age group. The DSPC content of nonsmokers aged 70-78 years old was about half of that of nonsmokers aged 20-26 years old, and not significantly different from that of smokers of the same age. The decrease of DSPC content was found only in subjects with a significant decrease in V25/Ht.
It is concluded that the pulmonary surfactant content of BALF is influenced by both smoking and aging but influenced more by smoking than by aging, and its decrease in smokers is closely related to the length of their smoking history. It is suggested that the decrease becomes detectable in subjects with prominent pathologic changes in the lung by smoking and aging.