| Summary: | <p>Abstract</p> <p>Background</p> <p>The xanthophyll carotenoids lutein (L) and zeaxanthin (Z) are found in and around the macula of the primate retina, where they are termed macular pigment (MP). Dietary L and Z are absorbed with fat in the gut and transported on lipoproteins to the retina. Both MP and serum lipoproteins have been related to risk for neurodegenerative diseases such as age-related macular degeneration (AMD). L and Z are carried on both HDL (related to reduced risk of AMD) and LDL (related to increased risk). The purpose of this set of studies was to analyze the relation between L and Z in the serum and retina with the circulating lipid profile.</p> <p>Methods</p> <p>In all experiments, lipoproteins were measured enzymatically from plasma, and MP optical density (MPOD) was measured using customized heterochromatic flicker photometry. <it>Experiment 1: Relations between serum L and Z, MPOD and lipoprotein levels</it>. 108 young, healthy subjects (<it>M </it>= 23.2, <it>SD = </it>4.12 years) participated. Lipoprotein levels and MPOD were measured. In a subset of 66 participants, serum L and Z levels were also measured using high-performance liquid chromatography. <it>Experiment 2: Relations between lipoprotein levels and MPOD in statin users</it>. 20 subjects (<it>M </it>= 58.05, <it>SD = </it>11.08 years) taking statin medication and 20 subjects (<it>M </it>= 57.95, <it>SD </it>= 11.03 years) not taking satin were recruited for participation. MPOD and lipoprotein levels were measured. <it>Experiment 3: lowering lipoprotein levels to impact MPOD</it>. One individual (aged 41 years) with high MP density adhered first to an atorvastatin regimen, then, after a wash-out period, to a rosuvastatin regimen.</p> <p>Results</p> <p><it>Experiment 1</it>: HDL were significantly (<it>p </it>< 0.05) related to MPOD (<it>r </it>= 0.33), to serum L (<it>r </it>= 0.36) and to serum Z (<it>r </it>= 0.26). MPOD was also significantly related to total cholesterol (<it>r </it>= 0.19). <it>Experiment 2</it>: MPOD was not lower in statin users when compared to matched non-statin users, but MPOD decreased significantly with increased duration of statin use (<it>r </it>= −0.63). <it>Experiment 3</it>: Administration of a statin regimen reduced MPOD with atorvastatin (<it>p </it>< 0.05) but not with rosuvastatin.</p> <p>Conclusions</p> <p>Serum xanthophylls, retinal xanthophylls and lipoprotein concentrations are significantly related, and changing lipoprotein levels may impact levels of retinal xanthophylls.</p>
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