Objective:
To clarify the possibility that midband lp in ldl fractions might act as an atherogenic lipoprotein in their interaction with macrophages.
Design and methods:
Low density lipoproteins (ldl) isolated by zonal ultracentrifugation from midband lipoprotein-positive serum in type lib hyperlipidemics were subjected to polyacrylamide gel disc electrophoresis.
Results:
A part of midband lipoprotein was observed between pre beta-and beta-band, in addition to the main beta-band. we named this midband lipoprotein "slow beta-migrating lp (slow beta-lp)." the larger ldl subfraction from midband-lipoprotein positive serum on sepharose 2b column chromatography contained much slow beta-lp, named slow beta-lp-rich ldl. the smaller ldl subfraction contained a little slow beta-lp, named slow beta-lp-poor ldl. slow beta-lp-rich ldl had similar composition to the control ldl except for apolipoprotein e. the uptake of [3h]cholesteryl linoleate-labeled slow beta-lp-rich ldl by j774 macrophages was higher than that of control ldl. the cholesterol ester content of j774 macrophages incubated with slow beta-lp-rich ldl increased significantly compared with slow beta-lp-poor ldl, beta-vldl, and control ldl.
Conclusion:
These results suggest that slow beta-lp in type llb might generate foam cells from macrophages in atherosclerotic lesions.