Glycosaminoglycans and apolipoproteins B and A-I in human aortas. Chemical and immunological analysis of lesion-free aortas from children and adults.

To study changes in the contents of plasma lipoproteins in human arteries with age and the relationship of lipoproteins with other arterial constituents, we analyzed the contents of apolipoproteins B (apo B) and A-I (apo A-I), free and esterified cholesterol, and glycosaminoglycans (GAG) in lesion-free aortic intimas of 30 children and adults. The content of apo B increased significantly with age, whereas that of apo A-I remained relatively constant. Apo B and apo A-I had significant positive correlations with the content of chondroitin sulphates A + C (CS A + C), which comprised 35% to 47% of the aortic GAG. The correlations remained significant after correction for the effect of age. Aortic apo B, but not apo A-I, also showed significant positive correlations with the contents of intimal free and esterified cholesterol. The results indicate that: considerable amounts of apo B and apo A-I can be found in lesion-free aortic intimas; there is an age-related rise in the content of apo B and a fall in the ratio of apo A-I to apo B, which are unfavorable developments in the light of current views on atherogenesis; the contents of the apolipoproteins are proportional to that of CS A + C, which might have a role in the retention of lipoproteins in the arteries.