Comparative studies of the elastin content of normal and emphysematous human lungs with special regard to antitrypsin deficiency.

The elastin content and the amino acid composition of elastin in emphysematous and healthy control lung tissues were comparatively studied. Decreased lung elastin content was found in the emphysematous patients of both normal and reduced trypsin inhibitor activity compared to normal control subjects. In the emphysematous patients with reduced inhibitor level a more significantly decreased elastin level was found than in those emphysematous patients with normal inhibitor level. There was no difference between the two groups in either the amino acid composition of elastin or the ratio of nonpolar to polar amino acid components. There was no significant correlation demonstrable between the age and the elastin content of the lung. This applied to the control group as well as to the emphysematous patients with normal trypsin inhibitor activity. The results indicate that no genetically abnormal pulmonary elastin structure is a predisposing risk factor but the reduced elastin content induced by elastase enzymes leading to changed mechanical properties is responsible for the development of pulmonary emphysema.