Multimodality imaging in macular telangiectasia 2: A clue to its pathogenesis

Macular telangiectasia type 2 also known as idiopathic perifoveal telangiectasia and juxtafoveolar retinal telangiectasis type 2A is an acquired bilateral neurodegenerative macular disease that manifests itself during the fifth or sixth decades of life. It is characterized by minimal dilatation of the parafoveal capillaries with graying of the retinal area involved, a lack of lipid exudation, right-angled retinal venules, refractile deposits in the superficial retina, hyperplasia of the retinal pigment epithelium, foveal atrophy, and subretinal neovascularization (SRNV). Our understanding of the disease has paralleled advances in multimodality imaging of the fundus. Optical coherence tomography (OCT) images typically demonstrate the presence of intraretinal hyporeflective spaces that are usually not related to retinal thickening or fluorescein leakage. The typical fluorescein angiographic (FA) finding is a deep intraretinal hyperfluorescent staining in the temporal parafoveal area. With time, the staining may involve the whole parafoveal area but does not extend to the center of the fovea. Long-term prognosis for central vision is poor, because of the development of SRNV or macular atrophy. Its pathogenesis remains unclear but multimodality imaging with FA, spectral domain OCT, adaptive optics, confocal blue reflectance and short wave fundus autofluorescence implicate Müller cells and macular pigment. Currently, there is no known treatment for this condition.     

The Relationship between Lutein and Zeaxanthin Status and Body Fat

The objective of this project was to investigate the relationships between total and regional distribution of body fat and tissue lutein (L) and zeaxanthin (Z) status. Healthy men and women (N = 100; average age: 22.5 year, average BMI: 23.4 kg/m²) were evaluated. Total body and regional fat mass were assessed by dual-energy X-ray absorptiometry (Hologic Delphi A). Serum LZ was measured using reverse phase high-performance liquid chromatography, and retinal LZ (referred to as macular pigment optical density; MPOD) was measured using heterochromatic flicker photometry. Body fat percentage (total and regional) was inversely related to MPOD (p < 0.01) but no significant relationship was found for serum LZ. Higher body fat percentage, even within relatively healthy limits, is associated with lower tissue LZ status. The results indicate that adiposity may affect the nutritional state of the retina. Such links may be one of the reasons that obesity promotes age-related degenerative conditions of the retina.     

Low plasma levels of oxygenated carotenoids in patients with coronary artery disease

Background and aimsLow circulating levels of carotenoids have been associated with cardiovascular disease. The distribution of different carotenoids in blood may have an impact on the cardioprotective capacity. The aim of the present study was to determine the plasma levels of 6 major carotenoids in patients with coronary artery disease (CAD) and relate the findings to clinical, metabolic and immune parameters.Methods and resultsPlasma levels of oxygenated carotenoids (lutein, zeaxanthin, β-cryptoxanthin) and hydrocarbon carotenoids (α-carotene, β-carotene, lycopene) were determined in 39 patients with acute coronary syndrome, 50 patients with stable CAD and 50 controls. Serological assays for inflammatory activity and flow cytometrical analysis of lymphocyte subsets were performed. Both patient groups had significantly lower plasma levels of oxygenated carotenoids, in particular lutein + zeaxanthin, compared to controls. Low levels of oxygenated carotenoids were associated with smoking, high body mass index (BMI), low high density lipoprotein (HDL) cholesterol and, to a minor degree, inflammatory activity. Plasma levels of lutein + zeaxanthin were independently associated with the proportions of natural killer (NK) cells, but not with other lymphocytes, in blood.ConclusionAmong carotenoids, lutein + zeaxanthin and β-cryptoxanthin were significantly reduced in CAD patients independent of clinical setting. The levels were correlated to a number of established cardiovascular risk factors. In addition, the relationship between NK cells and lutein + zeaxanthin may indicate a particular role for certain carotenoids in the immunological scenario of CAD.     

Macular pigment and serum zeaxanthin levels with Goji berry supplement in early age-related macular degeneration

AIM: To evaluate the efficacy of Goji berry supplementation on improving macular pigment, serum zeaxanthin levels and visual acuity in patients with early age-related macular degeneration (AMD). METHODS: A total of 114 patients (aged from 51 to 92y, mean age 69.53±8.41y) with early AMD were enrolled in our prospective, randomized controlled study. The included patients were assigned randomly to the Goji group (n=57) with 25 g of Goji berries supplementation per day for 90d and the control group (n=57) with their normal diet for 90d. Macular pigment optical density (MPOD) was measured using heterochromatic flicker photometry (HFP). The levels of serum lutein (L)/zeaxanthin (Z) were analyzed using high-performance liquid chromatography (HPLC). MPOD, serum L/Z levels and best corrected visual acuity (BCVA) were recorded at baseline and 90d. RESULTS: In the Goji group, there were no statistically significant differences in the serum L levels between the baseline (0.199±0.149 μmol/mL) and 90d (0.203±0.181 μmol/mL) (t=-0.186, P=0.850); however the serum Z levels were increased at 90d (0.101±0.087 μmol/mL) compared with those at the baseline (0.029±0.032 μmol/mL) (t=6.412, P<0.001). Patients treated with Goji berry for 90d showed an elevated MPOD (0.877±0.202 DU) from the baseline (0.731±0.205 DU) (t=-4.741, P=0.000). In contrast to the control group, the serum Z levels and MPOD were higher in the Goji group at 90d (both P<0.05). At 90d, patients with Goji berry supplementation had a relative decrease in BCVA (0.21±0.18 logMAR) compared with the baseline (0.27±0.20) (t=2.397, P=0.020). CONCLUSION: Overall, daily supplementation with Goji berry for 90d improves MPOD by increasing serum Z levels rather than serum L levels in early AMD patients. Goji berry may be an effective therapeutic intervention for preventing the progression of early AMD.     

Investigation of the effect of simulated lens yellowing, transparency loss and refractive error on in vivo resonance Raman spectroscopy

PURPOSE: To separately investigate the impact of simulated age-related lens yellowing, transparency loss and refractive error on measurements of macular pigment (MP) using resonance Raman spectroscopy. METHODS: Two healthy young subjects with clear media underwent Raman spectroscopy under the following conditions: age-related lens yellowing was simulated using seven broad-band yellow filters with transmittance at 488 nm ranging from 0.54 to 0.90; cataract was simulated using five white filters of increasing opacity (scatter filters), the transmittance of which ranged from 0.42 to 0.86, each of which reduced peak contrast sensitivity by approximately 0.1 log units over the previous filter. Refractive error up to +6.25 D was achieved using soft contact lenses. RESULTS: The Raman signal declined steadily to an average value of 43% of the starting value with the densest yellow filter in place. The white scatter filters produced a progressive linear reduction in signal resulting in almost complete signal loss with the densest filter. Refractive error resulted in an initial slight improvement in Raman count up to a value of +2.00 D followed by a decline thereafter. CONCLUSIONS: These results imply that lens yellowing and increasing scatter has an influence on the Raman signal and suggest that studies using this technology to estimate MP levels in older populations should carefully account for the status of the lens.     

The protective effect of zeaxanthin on human limbal and conjunctival epithelial cells against UV-induced cell death and oxidative stress

AIM: To explore the protective effect of zeaxanthin on human limbal and conjunctival epithelial cells against UV-radiation and excessive oxidative stress. METHODS: Human limbal and conjunctival epithelial cells were isolated from cadaver and cultured in vitro. They were challenged with UVB radiation and H2O2 with and without zeaxanthin pretreatment. Cell viability, p38 and c-JUN NH(2)-terminal kinase (JNK) phosphorylation, IL-6, IL-8 and MCP-1 secretion and malondialdehyde (MDA) content were measured. RESULTS: Zeaxanthin had no measurable cytotoxicity on limbal or conjunctival epithelial cells when used at concentrations of 5 μg/mL and below. At 30 mJ/cm2 UVB, the pretreatment of zeaxanthin increased the percentage of live cells from 50% to 69% (P=0.01) and from 66% to 75% (P=0.05) for limbal and conjunctival epithelial cells, respectively. The concentrations of IL-6, IL-8 and MCP-1 in the culture medium reduced to 66% (for IL-6 and MCP-1) and 56% (for IL-8) of the levels without zeaxanthin. This was accompanied by reduced p38 and JNK protein phosphorylation. Pretreatment of zeaxanthin also reduced intracellular MDA content caused by H2O2 stimulation from 0.86 μmol/L to 0.52 μmol/L (P=0.02) in limbal epithelial cells and from 0.96 μmol/L to 0.56 μmol/L in conjunctival epithelial cells (P=0.03). However, zeaxanthin did not have significant effect on H2O2-induced cell death in limbal or conjunctival epithelial cells. CONCLUSION: Zeaxanthin is an effective reagent in reducing the detrimental effect of UV-radiation and oxidative stress on ocular surface epithelial cells.     

The association between macular pigment optical density and CFH, ARMS2, C2/BF, and C3 genotype

Age-related macular degeneration (AMD) is the most common cause of blindness in older people in developed countries, and risk for this condition may be classified as genetic or environmental, with an interaction between such factors predisposing to this disease. This study investigated the relationship between AMD risk genes, macular pigment optical density (MPOD), which may protect against AMD, and serum concentrations of the macular carotenoids, lutein (L) and zeaxanthin (Z). This was a cross-sectional study of 302 healthy adult subjects. Dietary intake of L and Z was assessed by food frequency questionnaire, and MPOD was measured by customized heterochromatic flicker photometry. We also calculated MPOD Area as the area of MP under the spatial profile curve, to reflect MP across the macula. Serum L and Z were measured by HPLC. Genotyping of tag SNPs in the genes CFH, ARMS2, C3, C2 and BF was undertaken with multiplex polymerase chain reaction (PCR) and primer extension methodology (ABI Snapshot, ABI Warrington UK) on DNA extracted from peripheral blood. The mean ± SD (range) age of the subjects in this study was 48 ± 11 (21–66) years. There was a statistically significant association between CFH genotype and family history of AMD, with subjects having two non-risk CFH haplotypes (n = 35), or one non-risk and one protective CFH haplotype (n = 33), being significantly more likely to have a negative family history of AMD (Pearson Chi square: p = 0.001). There was no significant association between the AMD risk genes investigated and either MPOD (One way ANOVA: p > 0.05) or serum concentrations of L or Z (One way ANOVA: p > 0.05, for both). Subjects who were homozygous for risk alleles of both CFH and ARMS2 (n = 4) had significantly lower MPOD at 0.5° and 1° retinal eccentricity (Independent samples t test: p < 0.05) and lower MPOD Area which approached statistical significance (Independent samples t test: p = 0.058), compared to other subjects (n = 291). In conclusion, this study did not detect an association between individual AMD risk genotypes and the putatively protective MP, or serum concentrations of its constituent carotenoids. However, the combination of homozygous risk alleles at both CFH and ARMS2 loci was associated with significantly lower MPOD centrally, despite comparable serum concentrations of the macular carotenoids. These findings suggest that the maculae of subjects at very high genetic risk of AMD represent a hostile environment for accumulation and/or stabilization of MP.     

EURRECA: EURopean micronutrient RECommendations Aligned. Preparing the way

Background There is increasing evidence that higher intakes of carotenoids could protect against oxidative and light damage in premature infants and may promote other health benefits in both mothers during pregnancy and lactation and in newborn infants. Aim of the study To develop and validate a brief quantitative food frequency questionnaire (FFQ) aimed at assessing lutein and zeaxanthin intake in women. Methods In this cross-sectional study, estimates of lutein and zeaxanthin intake from the FFQ were compared with a 7-day dietary record and with plasma concentrations of these carotenoids. This primary care study was conducted in Pavia, Italy. Subjects were all female volunteers, aged 20–25 years (mean age 22.7 ± 2.1 years), university students. Of the 110 women initially recruited, 87 completed diet questionnaires and donated a blood sample. Dietary intake was assessed by the FFQ by interview and 7-day dietary records chosen as a reference standard, using photographic estimations of portion sizes. Plasma concentrations of lutein and zeaxanthin were measured by HPLC. Pearson’s correlation coefficient and Bland Altman Regression analysis were used. Results Mean dietary lutein and zeaxanthin intakes were 1,107 ± 113 μg/day from the FFQ questionnaire and 1,083 ± 116 μg/day from the 7 day dietary records. The mean difference in intake assessed by the two methods (−24.5 ± 38.3 μg/day) did not differ significantly from zero. Dietary intake of lutein and zeaxanthin measured with the FFQ and plasma nutrient concentration among this sample were significantly correlated (r = 0.76, P < 0.0001). Mean plasma lutein and zeaxanthin concentrations were 0.33 ± 0.09 μmol/l. Conclusions This FFQ could be used to assess lutein and zeaxanthin intake in adult women.     

Central Retinal Enrichment Supplementation Trials (CREST): Design and Methodology of the CREST Randomized Controlled Trials

Abstract

Purpose: The Central Retinal Enrichment Supplementation Trials (CREST) aim to investigate the potential impact of macular pigment (MP) enrichment, following supplementation with a formulation containing 10?mg lutein (L), 2?mg zeaxanthin (Z) and 10?mg meso-zeaxanthin (MZ), on visual function in normal subjects (Trial 1) and in subjects with early age-related macular degeneration (AMD; Trial 2).

Methods: CREST is a single center, double-blind, randomized clinical trial. Trial 1 (12-month follow-up) subjects are randomly assigned to a formulation containing 10?mg?L, 10?mg MZ and 2?mg Z (n?=?60) or placebo (n?=?60). Trial 2 (24-month follow-up) subjects are randomly assigned to a formulation containing 10?mg?L, 10?mg MZ, 2?mg Z plus 500?mg vitamin C, 400?IU vitamin E, 25?mg zinc and 2?mg copper (Intervention A; n?=?75) or 10?mg?L and 2?mg Z plus 500?mg vitamin C, 400?IU vitamin E, 25?mg zinc and 2?mg copper (Intervention B; n?=?75). Contrast sensitivity (CS) at 6 cycles per degree represents the primary outcome measure in each trial. Secondary outcomes include: CS at other spatial frequencies, MP, best-corrected visual acuity, glare disability, photostress recovery, light scatter, cognitive function, foveal architecture, serum carotenoid concentrations, and subjective visual function. For Trial 2, AMD morphology, reading speed and reading acuity are also being recorded.

Conclusions: CREST is the first study to investigate the impact of supplementation with all three macular carotenoids in the context of a large, double-blind, randomized clinical trial.     

The selective retention of lutein, meso-zeaxanthin and zeaxanthin in the retina of chicks fed a xanthophyll-free diet

Lutein and zeaxanthin are pigmented oxygenated carotenoids, or xanthophylls, derived from plants and concentrated in the retina of primates and birds. We investigated the transport, distribution and depletion of lutein and zeaxanthin in the plasma and tissues of newly hatched chicks fed xanthophyll-free diets. One-day-old Leghorn chicks were randomly divided into two groups. A control group was fed a diet containing lutein and zeaxanthin (5.2 and 1.7 mg/kg diet, respectively) for 28 days. An experimental group was fed a diet containing no lutein and zeaxanthin for 28 days. Plasma and tissues were analyzed for lutein and zeaxanthin at 28 days (control) and on days 1, 14 and 28 (experimental). At hatching, lutein and zeaxanthin were the predominant carotenoids present in the blood and tissues. As indicated by their similar mass contents, there was complete transfer of these carotenoids from egg yolk to chick. Lutein and zeaxanthin concentrations in the plasma and tissues of chicks fed the xanthophyll-free diet decreased rapidly to almost zero (with a depletion time of seven days [t(1/2)]). In contrast, the retina retained its initial concentrations of lutein and zeaxanthin similar to the control group. meso-Zeaxanthin and cis-zeaxanthin were identified only in the retina. The retina concentrated zeaxanthin over lutein. Lutein and zeaxanthin were selectively retained in the retinas of chicks fed a xanthophyll-free diet. In contrast, the plasma and other tissues lost up to 90% of their original content of xanthophylls. These data emphasize the relative stability of lutein and zeaxanthin in the cone-rich retina where they are present as esters in oil droplets. The tissue depletion suggests the need for a regular dietary intake of lutein and zeaxanthin because of rapid depletion in the body. It is clear that these xanthophylls may have an essential role in the cone-rich retina of the chick as evidenced by their selective retention.