Plasma LDL and HDL Subspecies Are Heterogenous in Particle Content of Tocopherols and Oxygenated and Hydrocarbon Carotenoids Relevance to Oxidative Resistance and Atherogenesis

Abstract Epidemiological data indicate that dietary tocopherols and carotenoids can exert cardioprotective effects, which may be mediated by their antioxidant actions. The oxidative modification of LDL underlies the atherogenicity of these cholesterol-rich particles. The resistance of LDL to oxidation is influenced by several endogenous factors, among which the content of tocopherols and carotenoids is prominent. Of the exogenous factors, HDL inhibits oxidation of LDL via several mechanisms. In view of the paucity of data on the distribution of diverse tocopherol and carotenoid components among the apoB- and apoA-I–containing lipoproteins of human plasma, we evaluated the quantitative and qualitative features of the LDL and HDL particle subspecies in normolipidemic subjects. The bulk of tocopherols and hydrocarbon carotenoids (lycopene, α- and β-carotene) was transported in LDL (45% and 76%, respectively), in contrast to the oxygenated carotenoids (lutein/zeaxanthin, canthaxanthin, and β-cryptoxanthin), w...