EFFECT OF LOW-DENSITY-LIPOPROTEIN FATTY-ACID COMPOSITION ON COPPER-INDUCED PEROXIDATION - H-1-NUCLEAR MAGNETIC-RESONANCE ANALYSIS

Oxidation of low density lipoprotein (LDL) has been implicated in athe rogenesis. An increased content of oleic acid in LDL and the substitut ion of monounsaturated for polyunsaturated fatty acids in the diet red uce LDL oxidation, With H-1-NMR analysis, all LDL modifications, inclu ding the production of copper-induced aldehyde products, can be evalua ted simultaneously. The aim of the present study was to investigate wh ether the fatty acid composition of LDL affected the NMR evaluation of aldehyde compounds, The LDL of the samples utilized were rich in olei c fatty acid (26.9%). After 48 h of exposure to copper sulfate, the me an production of malonyldialdehyde (MDA) by LDL was 31.2 nmol/mg of pr otein. Moreover, in the present study NMR did not reveal large amounts of peroxidative compounds since the nanomolar amounts of MDA produced after exposure to copper sulfate could not be detected. This study al so demonstrated that the: fatty acid composition (i.e. the oleic:linol eic acid ratio) must be taken into account in the evaluation of LDL pe roxidation by NMR. In particular, a high concentration of oleic acid m ay limit the formation of large amounts of peroxidative compounds gene rated after exposure to the oxidant copper sulfate. (C) 1997 Elsevier Science B.V.