Synthesis of Phospholipid by Foam Cells Isolated from Rabbit Atherosclerotic Lesions

Abstract

In a preliminary study, foam cells from atherosclerotic lesions have been isolated by incubation of the intima with collagenase and elastase. The composition and metabolism of homogeneous preparations of foam cells obtained in this way have been compared with other parts of the atherosclerotic intima. About 1% of the cholesterol and phospholipid of the intima was present in the cells obtained. The phospholipids of the foam cells contained a lower percentage of lecithin and of sphingomyelin and a higher percentage of "phosphatidyl ethanolamine" than the other parts of the intima. The isolated foam cells incubated in vitro incorporated P 32 -phosphate into phospholipid at a rate of about 0.5 mµmoles/10 6 cells/hr. The P 32 was incorporated mainly into lecithin and phosphatidyl inositol with smaller amounts incorporated into phosphatidyl ethanolamine, sphingomyelin and lysolecithin. The amount of P 32 incorporated into phospholipid by the foam cells was compared with that incorporated into phospholipid by other portions of the intima when the aorta was incubated in vitro prior to disruption. Up to 6.8% of the phospholipid synthesis was brought about by isolated cells. The significance of the findings in relation to phospholipid synthesis in the atherosclerotic lesion was discussed.