Histochromatographical determination of cholesteryl ester composition in the human atherosclerotic aorta

In 14 human aortas, the cholesteryl ester (CE) composition of fatty spots was investigated histochromatographically. By a special method the intracellular lipid (foam cells) lying in the inner intima could be separated from the extracellular lipid found in the depth of the intima in many cases. The fatty acid pattern of CE of the intracellular lipid differed from that of the extracellular lipid by a relative increase in monoenoic acids (M) and trienoic acids (Tr) as well as by a relative decrease in linoleic acid (D), tetraenoic acids (Ar), and saturated fatty acids (S). In every case, the sum of the polyunsaturated fatty acids (PU) of CE (with 2 to 6 double bonds) was lower in the intracellular than in the extracellular lipid (highest difference: 23,2%, lowest difference: 5,7%). High differences of the PU-values between intra- and extracellular CE were associated with high or low D-values and with low values for Tr, Ar, and HU (high unsaturated fatty acids with more than 4 double bonds) of intracellular CE. Low differences of the PU-values between intra- and extracellular CE were accompanied with high D-values and medium or high values for Tr, Ar, and HU of intracellular CE. The results suggest that the cholesteryl esters in the intracellular lipid lose polyunsaturated fatty acids by the processes of hydrolysis and reesterification which are possibly used for other metabolic processes.