Abstract
Quantitative histochemical analyses of multiple layers of the atherosclerotic human aortic wall — cut from the inside to the outside of the vessel — show that (1) the sphingomyelin/lecithin ratio is much higher than that in plasma; (2) this ratio remains relatively constant throughout the various layers of the aorta; (3) there is no falling gradient in phospholipid concentration from the inside to the outside of the vessel wall; and (4) that there is little phospholipid in the innermost layer of the aorta.
These results support the view that phospholipid is synthesized within the arterial wall and does not infiltrate there from the plasma. These analyses are consistent with previous qualitative histochemical studies on the distribution and nature of phospholipids in the human aortic wall.