A new fluorescence method for the continuous determination of surface lipid oxidation in lipoproteins and plasma.
We report on a new method for the determination of lipid oxidation in lipoproteins and plasma. The biological lipid system is preloaded with a fluorescent analog of phosphatidylcholine containing diphenylhexatriene (DPH) propionic acid covalently linked to the sn-2 position. When externally added, the respective phospholipid label (DPHPC) localizes to the surface monolayer of a lipoprotein. Under oxidative conditions (e.g. in the presence of Cu2+ ions) the fluorophore undergoes decomposition, resulting in a continuous decrease of fluorescence intensity which reflects the oxidation of a chemically defined phospholipid molecule with well defined localization. When incorporated into LDL particles, the kinetics of the decrease in DPHPC fluorescence intensity upon exposure to Cu2+ us very similar to that of conjugated diene accumulation. Furthermore, our assay can be applied to follow the oxidation of lipids in diluted serum and may also be developed into a suitable test system for clinical studies of susceptibility of plasma lipids to oxidation.
D004161:Diphenylhexatriene; D005456:Fluorescent Dyes; D006801:Humans; D015227:Lipid Peroxidation; D008055:Lipids / Q000097:blood; D008074:Lipoproteins / Q000378:metabolism*
D005456:Fluorescent Dyes; D008055:Lipids; D008074:Lipoproteins; D004161:Diphenylhexatriene