Metabolism of lipid in the human fatty streak lesion.

The composition and synthesis of lipid have been examined in normal intima and adjacent fatty streak lesions of human arterial segments which were incubated with [2-(14)C]acetate. The incorporation of acetate into lipid was greater in fatty streaks than in normal intima. There was increased acetate incorporation into all major lipid groups in the fatty streak, with the greatest relative increase in the cholesteryl ester fraction. The major radiolabeled arterial fatty acid was a long-chain polyenoic fatty acid with chromatographic properties of a C22:4 acid. The content of fatty acid in the fatty streaks differed from that in normal intima, with substantial increases in the C18:1 acid and decreases in C16:0, C18:0, and C18:2 acids of the fatty streak. It is concluded that lipid synthesis is increased in the human fatty streak lesion and that the local metabolism of lipid contributes to its accumulation within the fatty streak.