Effects of hyperlipidemic sera and lipoproteins on prostacyclin synthesis by rabbit aortic smooth muscle cells.

The effects of various hyperlipidemic sera and serum high density lipoproteins (HDL) and low density lipoproteins (LDL) on the synthesis of prostacyclin (PGI2) by rabbit aortic smooth muscle cells in culture were studied. Data show that HDL induces a dose-dependent increase in the synthesis of PGI2 in smooth muscle cells. Although LDL at comparable cholesterol concentrations to HDL also results in an increase of PGI2 synthesis in a dose-dependent pattern, the extent of this increase is much less than that induced by HDL. Smooth muscle cells incubated with hyperlipidemic serum and hyperlipidemic + aspirin-treated sera synthesize less PGI2 as compared to normal serum, but cells incubated with hyperlipidemic + 8501-treated serum generate an amount of PGI2 similar to that seen with normal serum. We suggest that 8501 may directly stimulate PGI2 synthetase in smooth muscle cells.