Twins' Macular Pigment Optical Density Assessment and Relation with SCARB1 Gene Polymorphism.

THE AIM OF THE STUDY: to assess the influence of genetic and environmental factors using twin studies and evaluate the associations of SCARB1 gene variants (rs11057841) with AMD and MPOD. MATERIAL AND METHODS: a total of 108 healthy twins (56 MZ and 52 DZ twins) were tested in this study. The MPOD was measured using the one-wavelength reflectometry method. Fundus reflectance (Visucam 500, reflectance of a single 460 nm wavelength) was used to measure the MPOD levels, MPOD parameters including max and mean optical density (OD), and area and volume. Real-time polymerase chain reaction was used to detect single nucleotide polymorphisms. RESULTS: we detected a positive correlation of MPOD in the right and left eyes in MZ twin pairs (r = 0.830 and r = 0.860, respectively) (p < 0.0001) and a negative correlation of MPOD in the right and left eyes in DZ twin pairs (r = 0.314 and r = 0.408, respectively) (p < 0.05). The study was able to identify statistically significant differences in mean MPOD values in the right and left eyes between subjects with a wild-type CC genotype and a CT genotype with a risk allele. A decrease in the mean MPOD value was observed in group II with a CT genotype (0.110 d.u.) compared with the CC genotype (0.117 d.u.) in the right eye (p = 0.037) and in the left eye with a CT genotype (0.109 d.u.) compared with a CC genotype in the subjects (0.114 d.u.) (p = 0.038). In the right eye, in group II (0.101-0.128 d.u.), those with a CT genotype (n = 6) with one risk allele had a statistically significantly lower (0.110 d.u.) mean average MPOD value compared with those with a wild-type CC genotype (n = 25) (0.117 d.u.) (p = 0.037). CONCLUSION: this twin study showed a strong heritability of the retina pigment, which was 86% prevalent in Lithuania. Individuals with a CT genotype of the SCARB1 rs11057841 with a risk allele had statistically significantly lower mean MPOD values in both eyes compared to subjects with a wild-type CC genotype.

Evaluation of serum SLCO1B1 levels and genetic variants of SLCO1B1 rs4149056 and rs2306283 in patients with early and exudative age-related macular degeneration.

PURPOSE: To determine SLCO1B1 rs4149056 and rs2306283 gene polymorphisms and SLCO1B1 serum levels in patients with early and exudative age-related macular degeneration. MATERIALS AND METHODS: The study enrolled 206 patients with exudative AMD, 253 patients with early AMD and 301 control subjects. DNA was extracted from peripheral venous blood leukocytes using commercial kits. Genotyping of SLCO1B1 rs4149056 and rs2306283 was carried out using a real-time polymerase chain reaction (RT-PCR) method. Serum SLCO1B1 levels were measured using SLCO1B1 ELISA kit. RESULTS: We found statistically significant differences in genotype (T/T, T/C and C/C) distribution of SLCO1B1 rs4149056 variant between the patients with exudative AMD and control group (52.4%, 47.6% and 0% vs. 64.8%, 31.6% and 13.7%, respectively, p < 0.001). Univariate binary logistic regression analysis showed that age was a risk factor for exudative AMD development. Also, T/C variant was associated with 1.9-fold increased Odds ratio of exudative AMD development under a codominant model (OR = 1.863; 95% CI: 1.290;2.689; p < 0.001). The results remained of the same statistical significance after multivariate analysis. On the other hand, C allele was associated with 1.6-fold increased odds ratio of exudative AMD development (OR = 1.563; 95% CI: 1.035;2.359; p = 0.034) only after adjustment for age. No significant associations were found in analysis of genotypes and alleles at rs2306283. Serum SLCO1B1 concentration was significantly higher in early AMD patients than in healthy controls (median, IQR: 2.92 ng/ml, 5.01 ng/ml versus 1.26 ng/ml, 2.63 ng/ml, respectively, p = 0.025), as well as in exudative AMD patients than in controls (median, IQR: 2.72 ng/ml, 5.71 ng/ml versus 1.26 ng/ml, 2.63 ng/ml, respectively, p = 0.002). Furthermore, subjects with rs4149056 T/C genotype had higher SLCO1B1 serum levels than those with T/T genotype (median, IQR: 3.73 ng/ml, 3.14 ng/ml versus 1.23 ng/ml, 1.47 ng/ml, respectively, p = 0.037). CONCLUSION: Our study determined that SLCO1B1 (c.521 T > C) rs4149056 T/C genotype and C allele may be associated with exudative age-related macular degeneration, as well as with elevated serum SLCO1B1 levels. Also, higher serum SLCO1B1 levels were found to be associated with early and exudative age-related macular degeneration.