Association of plasma trace element levels with neovascular age-related macular degeneration.

Although the triggers causing angiogenesis in the context of neovascular age-related macular degeneration (nAMD) are not fully understood, oxidative stress is likely involved. Oxidative stress in the eye can occur through exposure of macular tissues to sunlight and local or systemic exposure to oxidative stressors associated with environmental or lifestyle factors. Because trace elements have been implicated as regulators of oxidative stress and cellular antioxidant defense mechanisms, we hypothesized that they may play a role as a risk factor, modifying the progression toward nAMD. Herein, we determined whether levels of human plasma trace elements are different in 236 individuals with nAMD compared to 236 age-matched controls without AMD. Plasma levels of 16 trace elements including arsenic, barium, calcium, cadmium, cobalt, chromium, copper, iron, magnesium, manganese, molybdenum, lead, antimony, selenium, vanadium and zinc were measured using inductively coupled plasma mass spectrometry. Associations of trace elements with demographic, environmental and lifestyle factors and AMD-associated genetic variants were assessed. Elevated levels of barium and cadmium and reduced levels of chromium were observed in nAMD patients compared to controls. Mean plasma concentrations of barium were 1.35 µg/L (standard deviation [SD] 0.71) in nAMD and 1.15 µg/L (SD 0.63) in controls (P = 0.001). Mean levels of chromium were 0.37 µg/L (SD 0.22) in nAMD and 0.46 µg/L (SD 0.34) in controls (P = 0.001). Median levels for cadmium, which were not normally distributed, were 0.016 µg/L (interquartile range [IQR] 0.001-0.026) in nAMD and 0.012 µg/L (IQR 0.001-0.022) in controls (P = 0.002). Comparison of the Spearman's correlation coefficients between nAMD patients and controls identified a difference in correlations for 8 trace elements. Cadmium levels were associated with the smoking status (P < 0.001), while barium levels showed a trend of association with the usage of antihypertensive drugs. None of the AMD-associated genetic variants were associated with any trace element levels. In conclusion, in this case-control study we detected elevated plasma levels of barium and cadmium and reduced plasma levels of chromium in nAMD patients. An imbalance in plasma trace elements, which is most likely driven by environmental and lifestyle factors, might have a role in the pathogenesis of AMD. These trace elements may be incorporated as biomarkers into models for prediction of disease risk and progression. Additionally, population-based preventive strategies to decrease Cd exposure, especially by the cessation of smoking, could potentially reduce the burden of nAMD. Future studies are warranted to investigate whether supplementation of Cr would have a beneficial effect on nAMD.

Plasma long-chain omega-3 polyunsaturated fatty acids and macular pigment in subjects with family history of age-related macular degeneration: the Limpia Study.

PURPOSE: In numerous epidemiological studies, omega-3 polyunsaturated fatty acids (PUFAs) have been associated with a decreased risk of age-related macular degeneration (AMD). Beyond their structural, functional and neuroprotective roles, omega-3 PUFAs may favour the retinal accumulation of lutein and zeaxanthin and thus increase macular pigment optical density (MPOD). We examined the associations of MPOD with plasma omega-3 PUFAs in subjects with family history of AMD. METHODS: The Limpia study is a double-blind, placebo-controlled, prospective randomized clinical trial performed in 120 subjects. Subjects with at least one parent treated for neovascular AMD, aged 40-70, with a best corrected visual acuity (BCVA) >20/25, free of late AMD and other major eye conditions and with no use of supplement containing lutein or zeaxanthin the preceding year were recruited in Bordeaux and Dijon, France. At baseline, MPOD within 1° of eccentricity was measured by modified Heidelberg retinal analyser (Heidelberg, Germany) and plasma omega-3 PUFAs by gas chromatography. Medical history and lifestyle data were collected from a standardized questionnaire. Associations of MPOD with plasma omega-3 PUFAs were assessed at the baseline examination, using mixed linear models adjusted for age, gender, centre, body mass index, smoking, plasma high-density lipoprotein (HDL) cholesterol and lutein+zeaxanthin. RESULTS: After multivariate adjustment, high MPOD was significantly associated with higher level of plasma docosapentaenoic acid (DPA) (ß = 0.029, 95% CI: 0.003, 0.055; p = 0.03). Plasma alpha linolenic, eicosapentaenoic and docosahexaenoic acids were not significantly associated with MPOD. CONCLUSION: In the Limpia study, high MPOD within 1° was significantly associated with higher plasma levels of omega-3 DPA.

Nutritional Supplementation Inhibits the Increase in Serum Malondialdehyde in Patients with Wet Age-Related Macular Degeneration.

Purpose. To compare serum levels of malondialdehyde (MDA) in patients with wet age-related macular degeneration (wAMD), patients with dry AMD (dAMD), and patients without AMD and to evaluate the efficacy of nutritional supplementation for treating elevated serum MDA in patients with wAMD. Methods. MDA levels were measured in sera from 20 patients with wAMD, 20 with dAMD, and 24 without AMD. Patients with wAMD were randomized to receive or not receive nutritional supplementation (10 patients in each group), and MDA levels were measured after 3 months of treatment. Results. MDA levels in patients with wAMD were significantly greater compared with patients without AMD. In eyes with wAMD, there was a significant correlation between MDA levels and choroidal neovascularization lesion area. Serum MDA levels decreased in most patients that received supplementation and significantly increased in those who did not. Conclusion. Baseline serum MDA levels were elevated in patients with wAMD, and MDA levels were directly correlated with choroidal neovascularization lesion area. In addition, nutritional supplementation appeared to exert a protective effect against oxidative stress in patients with wAMD.

Dietary Intakes of Eicosapentaenoic Acid and Docosahexaenoic Acid and Risk of Age-Related Macular Degeneration.

PURPOSE: To evaluate the associations between intakes of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) and the intermediate and advanced stages of age-related macular degeneration (AMD). DESIGN: Prospective cohort study. PARTICIPANTS: We followed 75 889 women from the Nurses' Health Study and 38 961 men from the Health Professionals Follow-Up Study who were at least 50 years old, from 1984 to 2012 and 1986 to 2010, respectively. Cohort participants are mostly white (≥95%). METHODS: We assessed dietary intake by a validated food frequency questionnaire (FFQ) at baseline and every 4 years. We calculated cumulative average intakes of EPA and DHA from FFQs and also computed predicted erythrocyte and plasma scores directly from food intake using regression models. Cox proportional hazards models were used to compute the associations with AMD outcomes. MAIN OUTCOME MEASURES: We confirmed 1589 incident intermediate and 1356 advanced AMD cases (primarily neovascular AMD) with a visual acuity of 20/30 or worse, owing primarily to AMD, by medical record review. RESULTS: For intermediate AMD, the pooled hazard ratio (HR) between the 2 cohorts for DHA comparing the extreme quintiles of intake was 0.78 (95% confidence interval [CI], 0.66-0.92; P trend, 0.008) and for EPA + DHA was 0.83 (95% CI, 0.71-0.98; P trend, 0.03). The pooled HR for fatty fish, comparing ≥5 servings per week to almost never, was 0.61 (95% CI, 0.46-0.81; P trend, <0.001). For advanced AMD, the pooled HR for DHA was 1.01 (95% CI, 0.84-1.21; P trend, 0.75) and for fatty fish was 0.80 (95% CI, 0.59-1.08; P trend, 0.11). Secondary analyses using predicted erythrocyte and plasma scores of EPA and DHA yielded slightly stronger inverse associations for intermediate AMD and similar results for advanced AMD. CONCLUSIONS: Higher intakes of EPA and DHA may prevent or delay the occurrence of visually significant intermediate AMD. However, the totality of current evidence for EPA and DHA and advanced AMD is discordant, though there was no association with advanced AMD in the present study.