HIGH-DENSITY-LIPOPROTEIN FROM HYPERCHOLESTEROLEMIC ANIMALS HAS PEROXIDIZED LIPIDS AND OLIGOMERIC APOLIPOPROTEIN-A-I - ITS PUTATIVE ROLE IN ATHEROGENESIS

Oxidized lipoproteins have been involved in the pathogenesis of athero sclerosis and atherosclerotic lesions contain oxidized low density lip oprotein. Conversely, the presence of oxidized high density lipoprotei n (HDL) in vivo has not been clearly established. Oxidation of HDL in vitro models produces an increase in peroxidized lipids and the appear ance of apolipoprotein A-I (ape A-I) oligomers. We investigated the ox idative status of HDL in an in vivo model: the hypercholesterolemic ch icken, The HDLs from control and hyperlipemic animals were analyzed fo r the content of lipid peroxides employing spectroscopic and fluoresce nce techniques, for the level of apo A-I oligomerization, and for susc eptibility to in vitro oxidation. HDL from hypercholesterolemic chicke ns was more peroxidized (as detected by fluorescence), had higher amou nt of oligomeric apo A-I, and was oxidized to a greater extent by uv i rradiation than that of control animals. We speculate that apo A-I oli gomerization could be a key step in the atheroma formation. (C) 1997 A cademic Press.