POSSIBLE ROLE FOR ELASTIN LIGANDS IN THE PROTEOLYTIC DEGRADATION OF ARTERIAL ELASTIC LAMELLAE IN THE RABBIT

Thoracic aortae of normal rabbits were perfused with pancreatic elastase in vitro at 37°C and 70 mm Hg pressure in the presence of absence of elastin ligands previously shown to stimulate or inhibit the enzymatic degradation of elastin. Perfusion with elastase results in an average of 3.6 lamellae degraded, whereas addition of sodium linoleate before and during the perfusion with elastase increases this value to 7.9 (P<0.001). Conversely, perfusion with the cationic detergent, dodecyltrimethylammonium chloride, completely prevents the degradation of elastic lamellae by elastase. These effects do not reflect alterations of the intrinsic catalytic activity of elastase, but apparently indicate the formation of complexes between the elastin ligands and arterial elastic lamellae, as is consistent with prior studies indicating such interactions between fatty acids or detergents and purified elastin. These studies suggest that agent such as fatty acids may significantly alter the metabolic susceptibility of elastin in vivo and possible contribute to the degradation of elastic lamellae seen in arteries with advanced atherosclerosis.