Lipoprotein concentrations in serum and in biopsy samples of arterial intima: a quantitive comparison.

Lipoprotein concentrations were compared in serum and in samples of arterial intima obtained during cardiovascular surgery. The interval between blood sampling and surgery did not exceed 48 hours. Apolipoproteins B and C, the major proteins of low density lipoprotein (LDL) and very low density lipoprotein (VLDL) respectivity, were detectable by immuno-assay in all arterial specimens. Highly significant positive correlations existed between the levels of lipoproteins in the intima and in serum. In patients with elevated serum VLDL levels (Type IV hyperlipoproteinaemia) arterial concentrations of apolipoproteins B and C were increased about two-fold; in those with raised LDL levels in serum (Type II), with or without concomitant elevation of VLDL levels, the concentration of apolipoprotein B was increased almost 5-fold in the arterial intima. The arterial wall therefore contains lipoproteins or their immunologically-similar metabolites at concentrations which are determined in part by serum lipoprotein levels.