VARIATION OF ELASTASE-TYPE PROTEASE ACTIVITY AND ELASTIN BIOSYNTHESIS IN RABBIT AORTA INDUCED BY CHOLESTEROL DIET AND IMMUNIZATION WITH ELASTIN PEPTIDES

  • 1 January 1982
    • journal article
    • research article
    • Vol. 10  (5) , 310-316
Abstract
Elastase-type proteases were shown to be produced by arterial smooth muscle cells and fibroblasts in culture and were probably involved in the development of the arterio-atherosclerotic process. The quantitative determination of the elastase-type enzyme activity in the aortas was carried out in rabbits submitted to 2 different athero-arteriosclerosis inducing treatments: high cholesterol diet and immunization with .kappa.-elastin peptides. Simultaneously, the incorporation of 14C-lysine in cross-linked elastin peptides by the surviving (organ culture) aorta preparations was determined. Elastase-type activity of aorta extracts, determined with a synthetic substrate (Suc-(Ala)3-pNA [succinyl-(Ala)3-p-nitroanilide] increased 2-fold after 1.5-mo. cholesterol diet, and 3-fold after 8 wk of immunization with .kappa.-elastin in complete Freund''s adjuvant. The incorporation of 14C-lysine in cross-linked elastin slightly increased (+20%) in cholesterol-fed aorta explants and strongly decreased (-65%) in the immunized aorta explants, on a DNA basis. Apparently, atherogenic stimuli produce an increase of elastase-type enzyme activity in the arterial wall. This increase appears to be correlated with elastic fiber degradation. It may also be accompanied by a decrease of elastin biosynthesis as in the .kappa.-elastin-induced immuno-arteriosclerosis model.