QUANTITATIVE STUDIES OF HUMAN LUNG AIRSPACE WALL IN RELATION TO COLLAGEN AND ELASTIN CONTENT

Biochemical determinations of the collagen and elastin content in 50 m m3 samples of human lung are presented in relation to morphometric mea surements of lung structure, as the amount of alveolar wall surface ar ea per unit volume (AWUV), on adjacent slices. There were no differenc es in AWUV values, collagen content (determined as hydroxyproline) or elastin content (determined as isodesmosine) between upper and lower l obes within a single lung. In a study of 102 samples from 9 smokers lu ngs with no evidence of macro- or microscopic emphysema (as estimated by AWUV measurement), there was a negative correlation between AWUV an d the amounts of collagen or elastin per unit volume of inflated lung. The correlation was stronger when collagen and elastin content were e xpressed per unit area of alveolar wall. The negative correlation is i nterpreted as representing either the anatomical variation within the complex hierarchy of normal lung structure or possibly low levels of f ibrosis in response to cigarette smoking.