Increased uptake of monocyte-treated low density lipoproteins by aortic endothelium in vivo.
A new technique was elaborated for measuring LDL uptake by rat aortic endothelial cells in vivo, using a fluorescent marker (Dil)-labelled LDL and quantifying the fluorescence in cells selectively removed from the aorta. This technique was used to study the endothelial uptake of LDL modified by activated human monocytes (LDL-A) in comparison with native LDL (LDL-N) protected from oxidation by vitamin E during the preparation. Incubation of LDL with activated monocytes increased endothelial uptake in vivo by 9.3-fold and also by 4.4-fold in cultured confluent porcine endothelium. In contrast, only a 1.5-fold increase in uptake of LDL-A was observed in sparse cultures. Cytotoxicity of monocyte-altered or native LDL did not differ as measured by the [3H]deoxyglucose-release test on cultured endothelium. Our results suggest that modification of LDL in the circulation by monocytes may make an important contribution to atherogenesis.
D000818:Animals; D001011:Aorta / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D001161:Arteriosclerosis / Q000097:blood / Q000209:etiology; D002478:Cells, Cultured; D004727:Endothelium / Q000378:metabolism*; D006651:Histocytochemistry; D006801:Humans; D066298:In Vitro Techniques; D008077:Lipoproteins, LDL / Q000378:metabolism*; D008297:Male; D003012:Microbial Collagenase / Q000494:pharmacology; D009000:Monocytes / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D013552:Swine
D008077:Lipoproteins, LDL; D003012:Microbial Collagenase