The Effect of BCMO1 Gene Variants on Macular Pigment Optical Density in Young Healthy Caucasians

Abstract

Background: Serum lutein (L) and zeaxanthin (Z) positively correlate with macular pigment optical density (MPOD); hence, the latter is a valuable indirect tool for measuring L and Z content in the macula. L and Z have been attributed antioxidant capacity and protection from certain retinal diseases but their uptake within the eye is thought to depend on genetic, age, and environmental factors. In particular, gene variants within beta-carotene monooxygenase (BCMO1) are thought to modulate MPOD in the macula.Objectives: To determine the effect of BCMO1 single nucleotide polymorphisms (SNPs) rs11645428, rs6420424, and rs6564851 on MPOD in a cohort of young healthy participants of Caucasian origin with normal ocular health.Design: In this cohort study, MPOD was assessed in 46 healthy participants (22 male and 24 female) with a mean age of 23.8 ± 4.0 years (range 19–33). The three SNPs, rs11645428, rs6420424, rs6564851 that have established associations with MPOD were determined using MassEXTEND (hME) Sequenom assay. One-way analysis of variance was performed on groups segregated into homozygous and heterozygous BCMO1 genotypes. Correlations between body mass index (BMI), iris color, gender, central retinal thickness (CRT), diet, and MPOD were investigated.Results: Macular pigment optical density neither significantly varied with BCMO1 rs11645428 (F2,41 = 0.70, p = 0.503), rs6420424 (F2,41 = 0.21, p = 0.801) nor rs6464851 homozygous or heterozygous genotypes (F2,41 = 0,13, p = 0.88), in this young healthy cohort. The combination of these three SNPs into triple genotypes based on plasma conversion efficiency did not affect MPOD (F2,41 = 0.07, p = 0.9). There was a significant negative correlation with MPOD and CRT (r = −0.39, p = 0.01) but no significant correlation between BMI, iris color, gender, and MPOD.Conclusion: Our results indicate that macular pigment deposition within the central retina is not dependent on BCMO1 gene variants in young healthy people. We propose that MPOD is saturated in younger persons and/or other gene variant combinations determine its deposition.

The Association between Foveal Morphology and Macular Pigment Spatial Distribution: An Ethnicity Study

“…However, other studies have reported inconsistent findings; a positive correlation between central MPOD and central foveal thickness has been demonstrated [31], whereas others have found no correlation even when taking ethnicity into account [17, 31, 32]. In contrast, a significant negative correlation between central retinal thickness and MPOD at 0.5° (measured by HFP) was determined in a young healthy Caucasian cohort (r = -0.39, P = 0.01) [51]. The role of ethnicity remains unclear.…”

Macular Pigment Optical Density and Measures of Macular Function: Test-Retest Variability, Cross-Sectional Correlations, and Findings from the Zeaxanthin Pilot Study of Response to Supplementation (ZEASTRESS-Pilot)

“…Twin studies have confirmed the importance of genetic factors also in the MPOD response to supplementation [ 69 ]. In recent years, some of the genetic determinants of MPOD (variants in or near the GSTP1, SCARB1, ABCA1, BCG5, LIPC, ELOVL2, FADS1, FADS2, ALDH3A2, and RPE65 genes) have been identified [ 70 , 71 , 72 , 73 , 74 ], leading Meyers et al . to conclude that “MPOD is a multi-factorial phenotype associated with variation in genes related to carotenoid transport, uptake, and metabolism, independent of known dietary and health influences on MPOD” [ 71 ].…”

Fruit and Vegetable Intake and the Macular Pigment Optical Density

“…The values of MPOD are generally in the range of 0.30 -0.40 d.u 6,16,17,19,61 , with certain exceptions found in studies with mean values lower than 0.20 du. 60 or higher 62,63,65,66 . There are also differences observed in the form of expressing the results and, thus, in some cases the MPOD is expressed as a single value and other authors provide data on several loci, which, moreover, differ from one study to another.…”

“…In most of the studies included, the evaluation of the dietary intake of lutein and zeaxanthin measures them jointly and this intake has a mean value of between 1 and 2 mg/day. In some studies, it is the intake of foods that are good sources of lutein and zeaxanthin in the diet, either food groups such as fruit and vegetables [60][61][62] or specific foods such as Chinese wolfberry 63,64 or corn oil 63 , that is assessed in relation to the MPOD. With respect to the methodology utilized to evaluate the MPOD, the approach most widely used is heterochromatic flicker photometry, which has the limitations derived from being a psychophysical methodology, but its reliability has been the subject of a number of studies 49 .…”