Oxidized low-density lipoproteins induce apoptosis in aortic and endocardial endothelial cells.
OBJECTIVE
To examine whether oxidized low-density lipoproteins (ox-LDL) might induce apoptosis in bovine aortic and endocardial endothelial cells (BAEC and BEEC).


METHODS
Low-density lipoproteins (LDL) were isolated from healthy human plasma by ultracentrifugation and oxidized by CuSO4 10 mumol.L-1. BAEC and BEEC were incubated in a medium containing ox-LDL, LDL, or phosphate-buffer solution (PBS) as control. DNA fragmentation was visualized by agarose gel electrophoresis and determined quantitatively using Hoechst-33258 fluorochrome.


RESULTS
Ox-LDL, not LDL, elicited typical apoptotic changes and DNA fragmentation in BAEC and BEEC. In BAEC, dextran sulfate, and cicloheximide (Cic) exhibited no effect on DNA fragmentation induced by ox-LDL. Butylated hydroxytoluene (BHT) 20 mumol.L-1 completely inhibited Cu(2+)-mediated oxidation of LDL as well as the apoptosis-inducing effect of Cu(2+)-exposed LDL. Lysophosphatidylcholine (LPC) did not elicit DNA fragmentation in BAEC and in BEEC. DNA fragmentation induced by ox-LDL in BAEC and in BEEC was blocked by chelating the calcium of the culture medium by egtazic acid.


CONCLUSIONS
Ox-LDL induces apoptosis in BAEC and BEEC without involving the LPC.
D000818:Animals; D001011:Aorta / Q000166:cytology; D017209:Apoptosis / Q000187:drug effects*; D002417:Cattle; D002478:Cells, Cultured; D053938:DNA Fragmentation / Q000187:drug effects*; D004699:Endocardium / Q000166:cytology*; D004730:Endothelium, Vascular / Q000166:cytology*; D006801:Humans; D008077:Lipoproteins, LDL / Q000494:pharmacology*; D010084:Oxidation-Reduction