Oxidatively modified low density lipoprotein in mononuclear cells detected by laser-induced fluorescence spectroscopy

Hyperlipidemic states are associated with focal accumulations in arterial walls of oxidatively modified low density lipoprotein (LDL) and monocyte-derived lipid4aden macrophages, biochemical and cellular hallmarks of atheromatous lesions. Mechanisms underlying the generation and cellular uptake of oxidized LDL are still incompletely understood. We have used laser4nduced fluorescence spectroscopy to monitor the formation, intracellular accumulation, and tissue distribution of oxidized LDL. Oxidatively modified LDL excited by a XeC1 excimer laser (308 nm) exhibits unique spectral characteristics that distinguish it from native (non-oxidized) LDL. The same spectral characteristics were demonstrated in lipid-rich atheromatous lesions, macrophages after incubation with oxidized LDL, and peripheral blood monocytes from hyperlipidemic, but not normolipidemic subjects. Detection of oxidized LDL in peripheral blood monocytes and arterial tissue may provide information on the atherogenic activity of hyperlipidemic states and serve as a novel risk factor for the assessment of atherosclerosis.