|Snodderly, D max|
Submitted to: Nutritional Neuroscience
Publication Type: Peer reviewed journal
Publication Acceptance Date: 5/22/2012
Publication Date: 7/9/2012
Citation: Vishwanathan, R., Neuringer, M., Snodderly, D., Schalch, W., Johnson, E.J. 2012. Macular lutein and zeaxanthin are related to brain lutein and zeaxanthin in primates. Nutritional Neuroscience. DOI: 10.1179/14768230512Y.0000000024. Interpretive Summary: Compared to other dietary carotenoids (plant pigments) lutein (L) and zeaxanthin (Z) preferentially accumulate in the central or macular region of the retina. There they form macular pigment, protecting the retina from damage. L and Z also accumulate in brain tissue. The objective of the study was to evaluate the relationship between levels of these carotenoids in the retina and brain. Study animals were rhesus monkeys. L in the retina was significantly related to L levels in the various regions of the brain. Z in the retina was significantly related to Z levels in the frontal cortex, while the relationship was weaker in the cerebellum, occipital cortex and pons. These data suggest that macular pigment, which can be measured safely and noninvasively in humans, could be used as an indicator for brain L and Z levels.
Technical Abstract: The xanthophyll pigments lutein and zeaxanthin cross the blood-retina barrier to preferentially accumulate in the macular region of the neural retina. There they form macular pigment, protecting the retina from blue light damage and oxidative stress. Lutein and zeaxanthin also accumulate in brain tissue. The objective of the study was to evaluate the relationship between retinal and brain levels of these xanthophylls in non-human primates. Study animals included rhesus monkeys reared on diets devoid of xanthophylls that were subsequently fed pure lutein or pure zeaxanthin (both at 3.9 micro micromoles/kg*d, n=6/group) and normal rhesus monkeys fed a stock diet (0.26 micromoles/kg*d lutein and 0.24 micromoles/kg*d zeaxanthin, n=5). Retina (4 mm macular punch, 4-8 mm annulus and periphery) and brain tissue (cerebellum, frontal cortex, occipital cortex and pons) from the same animals were analyzed by reverse phase HPLC. Lutein in the macula and annulus were significantly related to lutein levels in the cerebellum and frontal and occipital cortices, both in bivariate analysis and after adjusting for covariates (age, sex and n–3 fatty acid status). The relationship to brain levels was weaker for lutein in the retinal periphery. Macular zeaxanthin was significantly related to zeaxanthin in the frontal cortex, while the relationship was marginally significant (P>0.05<0.1) in the cerebellum, occipital cortex and pons. These data suggest that macular pigment optical density, which can be measured noninvasively, could be used as a biomarker for brain lutein and zeaxanthin status.