Graefes Arch Clin Exp Ophthalmol. 2005 May;243(5):497-500. Epub 2004 Nov 18.
Disturbed visual system function in methionine synthase deficiency.
Isolated functional methionine synthase deficiency occurs in the cblE and cblG defects of methylcobalamin metabolism and is one of a number of causes of severely elevated plasma homocysteine. Clinical features are predominantly of a neurological nature but also include functional restriction of the visual system manifesting as loss of visual acuity and nystagmus. As yet, the origin and pathogenesis of impaired vision have not been explained.
We investigated a patient who was proven by complementation analysis in cultured fibroblasts to belong to the cblG complementation group. Ganzfeld electroretinograms (ERG) and flash visual evoked potentials (VEP) were recorded over a period of 4 years.
Amplitudes of all International Society for Clinical Electrophysiology of Vision (ISCEV) standard responses were below normal. The greatest reductions were of rod response to 24 microV, of standard combined response (SC) b-wave to 120 microV, of oscillatory potentials (OP) to 5 microV, of cone response b-wave to 35 microV, and of 30 Hz flicker response to 8 microV. Except for SC and cone a-waves at age 2.5 and 3.5 years, as well as cone b-wave at 3.5 years, amplitudes remained at a subnormal level at follow-up examinations. Implicit times were slightly prolonged (SC b-wave 6 ms, OPs 2 ms, cone b-wave 2 ms, 30 Hz flicker 4 ms) or fell within the normal range. Responses of the flash VEP were severely deformed but reproducible.
This is the first report of detailed investigations of the visual system in a patient with isolated methionine synthase deficiency. Reduced oscillatory potentials suggest microvascular damage to the retina through homocysteine. Decreased photoreceptor function as well as ganglion cell loss as indicated by pathological flash VEPs may reflect a cytotoxic impact of homocysteine on neurons of the visual pathway.
Ophthalmology. 2013 Nov;120(11):2317-23. doi: 10.1016/j.ophtha.2013.07.039. Epub 2013 Aug 21.
CFH and ARMS2 genetic polymorphisms predict response to antioxidants and zinc in patients with age-related macular degeneration.
The Age-Related Eye Disease Study (AREDS) demonstrated that antioxidant and zinc supplementation decreases progression to advanced age-related macular degeneration (AMD) in patients with moderate to severe disease. We evaluated the interaction of genetics and type of nutritional supplement on progression from moderate to advanced AMD.
Genetic analysis of a randomized, prospective clinical trial.
White patients with AREDS category 3 AMD in 1 eye and AREDS categories 1 through 4 AMD in the fellow eye enrolled in the AREDS with available peripheral blood-derived DNA (995).
Subjects were evaluated for known AMD genetic risk markers and treatment category. The progression rate to advanced AMD was analyzed by genotypes and AREDS treatment group using Cox regression.
The effect of inherited gene polymorphisms on treatment group-specific rate of progression to advanced AMD.
Over an average of 10.1 years, individuals with 1 or 2 complement factor H (CFH) risk alleles derived maximum benefit from antioxidants alone. In these patients, the addition of zinc negated the benefits of antioxidants. Treatment with zinc and antioxidants was associated with a risk ratio (RR) of 1.83 with 2 CFH risk alleles (P = 1.03E-02), compared with outcomes for patients without CFH risk alleles. Patients with age-related maculopathy sensitivity 2 (ARMS2) risk alleles derived maximum benefit from zinc-containing regimens, with a deleterious response to antioxidants in the presence of ARMS2 risk alleles. Treatment with antioxidants was associated with an RR of 2.58 for those with 1 ARMS2 risk allele and 3.96 for those with 2 ARMS2 risk alleles (P = 1.04E-6), compared with patients with no ARMS2 risk alleles. Individuals homozygous for CFH and ARMS2 risk alleles derived no benefit from any category of AREDS treatment.
Individuals with moderate AMD could benefit from pharmacogenomic selection of nutritional supplements. In this analysis, patients with no CFH risk alleles and with 1 or 2 ARMS2 risk alleles derived maximum benefit from zinc-only supplementation. Patients with one or two CFH risk alleles and no ARMS2 risk alleles derived maximum benefit from antioxidant-only supplementation; treatment with zinc was associated with increased progression to advanced AMD. These recommendations could lead to improved outcomes through genotype-directed therapy.
Copyright © 2013. Published by Elsevier Inc.
PLoS One. 2011;6(12):e29245. doi: 10.1371/journal.pone.0029245. Epub 2011 Dec 22.
Age-related macular degeneration (AMD) is associated with lipofuscin accumulation whereas the content of melanosomes decreases. Melanosomes are the main storage of zinc in the pigmented tissues. Since the elderly population, as the most affected group for AMD, is prone to zinc deficit, we investigated the chemical and ultrastructural effects of zinc deficiency in pigmented rat eyes after a six-month zinc penury diet.
Adult Long Evans (LE) rats were investigated. The control animals were fed with a normal alimentation whereas the zinc-deficiency rats (ZD-LE) were fed with a zinc deficient diet for six months. Quantitative Energy Dispersive X-ray (EDX) microanalysis yielded the zinc mole fractions of melanosomes in the retinal pigment epithelium (RPE). The lateral resolution of the analysis was 100 nm. The zinc mole fractions of melanosomes were significantly smaller in the RPE of ZD-LE rats as compared to the LE control rats. Light, fluorescence and electron microscopy, as well as immunohistochemistry were performed. The numbers of lipofuscin granules in the RPE and of infiltrated cells (Ø>3 µm) found in the choroid were quantified. The number of lipofuscin granules significantly increased in ZD-LE as compared to control rats. Infiltrated cells bigger than 3 µm were only detected in the choroid of ZD-LE animals. Moreover, the thickness of the Bruch’s membrane of ZD-LE rats varied between 0.4-3 µm and thin, rangy ED1 positive macrophages were found attached at these sites of Bruch’s membrane or even inside it.
In pigmented rats, zinc deficiency yielded an accumulation of lipofuscin in the RPE and of large pigmented macrophages in the choroids as well as the appearance of thin, rangy macrophages at Bruch’s membrane. Moreover, we showed that a zinc diet reduced the zinc mole fraction of melanosomes in the RPE and modulated the thickness of the Bruch’s membrane.
© 2011 Julien et al.
Invest Ophthalmol Vis Sci. 1999 May;40(6):1238-44.
To determine the effect of moderate zinc deficiency on antioxidant defenses and measures of oxidative stress in the retina and retinal pigment epithelium (RPE) of Brown Norway Rats.
Twenty-four rats were housed individually and divided into three groups of 8 rats each. Group 1 was fed ad libitum a semipurified control diet formulated to contain 50 parts per million [ppm] total zinc; group 2 was fed ad libitum an identical diet but containing 5 ppm total zinc; and group 3 was pair-fed the control diet but restricted in amount to that consumed by group 2. Food intake was measured daily and the rats weighed weekly. After 6 weeks, the rats were killed and the following measurements were made: serum zinc, serum alkaline phosphatase, retinal zinc, RPE-choroid zinc, RPE-choroid catalase, liver metallothionein (MT), retinal MT, RPE-choroid MT, retinal catalase, and retinal thiobarbituric reactive substances (TBARS).
The following showed statistically significant differences between groups 2 and 3, respectively: serum Zn (1216 micro/l versus 1555 microg/l, P < or = 0.01), serum alkaline phosphatase (3.75 U/mg versus 5.10 U/mg, P < or = 0.05), liver MT (4.3 microg/mg protein versus 16.7 microg/mg, P < or = 0.0001), RPE-choroid MT (1.3 microg/mg protein versus 2.2 microg/mg, P < or = 0.02), retinal MT (0.85 microg/mg protein versus 2.8 microg/mg, P < or = 0.05), and retinal TBARS (6.2 nM/mg protein versus 2.2 nM/mg, P < or = 0.05).
The results show that retinal MT and RPE MT concentrations are very sensitive to intake of dietary zinc. The increase in retinal TBARS in group 2 indicates that moderate zinc deficiency increases oxidative stress to the retina. The results also suggest that MT is protective against lipid peroxidation of retinal membranes.
Eur J Ophthalmol. 2012 Mar-Apr;22(2):216-25. doi: 10.5301/ejo.5000069.
The high concentration of carotenoids in the macula, plus evidence linking oxidative stress to age-related macular degeneration (AMD) and carotenoids to antioxidation, generated the hypothesis that higher antioxidant intakes can prevent AMD. The aim of this study was to determine whether nutritional supplementation with a targeted nutritional supplement improves visual acuity and visual function in AMD.
In this multicenter, prospective open-label randomized study, 145 patients were randomly assigned to 2 different treatment groups. Interventions were lutein (10 mg), zeaxanthin (1 mg), astaxanthin (4 mg; AZYR SIFI, Catania, Italy), and antioxidants/vitamins supplementation formula or no dietary supplementation for 2 years. Primary outcome was mean changes in visual acuity (VA) at 12 and 24 months. Other measures included contrast sensitivity (CS) and National Eye Institute visual function questionnaire (NEI VFQ-25) scores at 12 and 24 months.
Patients in the treated group showed stabilization of VA with significantly (p=0.003) better VA scores (81.4 ± 7.2) compared to the nontreated group (76.8 ± 8.9) at 24-month follow-up. An improvement in CS (p=0.001) and final mean NEI VFQ-25 composite scores at 12 and 24 months higher in treated group compared to nontreated group were also shown (p<0.001).
Patients treated with lutein/zeaxanthin and astaxanthin together with other nutrients were more likely to report clinically meaningful stabilization/improvements in VA, CS, and visual function through 24 months compared with nontreated subjects. Further studies are needed with more patients and for longer periods of time.
Graefes Arch Clin Exp Ophthalmol. 2013 Dec;251(12):2711-23. doi: 10.1007/s00417-013-2376-6. Epub 2013 May 22.
The primary objective of LUTEGA is to determine the long-term effect of a supplementation with fixed combination of lutein, zeaxanthin, omega-3-longchain-polyunsaturated-fatty-acids (O-3-LCPUFAs) and antioxidants on macular pigment optical density (MPOD) in patients with non-exudative age-related macular degeneration (AMD).
The LUTEGA study is a double-blind, placebo-controlled clinical trial. 172 patients with non-exudative AMD were enrolled and randomized to three treatment arms. Supplementation included either once (dosage D1) or twice daily (dosage D2) of 10 mg L / 1 mg Z/ O-3-LCPUFAs (thereof 100 mg DHA, 30 mg EPA)/ antioxidants, or placebo (P). After best-corrected visual acuity (BCVA) test, blood sample was collected and MPOD was measured using the 1-wavelength-reflection method and recording reflection images at 480 nm (modified Visucam(NM/FA), Carl Zeiss Meditec, Germany). During 1 year of intervention, AMD patients were followed up after 1, 3, 6 and 12 months. 145 AMD patients (D1 = 50, D2 = 55, P = 40) completed the study.
After 12 months of intervention, the MPOD parameters (volume, area, maxOD, meanOD) increased significantly in treatment arms D1 and D2 (p < 0.001). Volume of MPOD showed the highest within-group difference and increased significantly in D1 and D2, and decreased significantly in P (p = 0.041). Between-group comparison of absolute changes of all MPOD parameters were significantly different between D1 and P as well as D2 and P with p < 0.001 at end point (t = 12). BCVA, measured in log MAR, improved in D1 and in D2 (p < 0.001). After 12 months of intervention, the mean improvement in BCVA was significant in D2 (p = 0.006) and D1 (p = 0.038) compared to P.
The supplementation of L, Z, O-3-LCPUFAs and antioxidants resulted in considerable increase in MPOD. There was no difference in accumulation of MPOD between both dosages. Thus, we believe that the used supplementation with L and Z seems to reach a saturation level in retinal cell structure. Additionally, the constant supplementation of L, Z, O-3-LCPUFAs and antioxidants in AMD patients seems to be useful, because MPOD reduces without supplementation. We conclude that the supplementation caused an increase of MPOD, which results in an improvement and stabilization in BCVA in AMD patients. Thus, a protective effect on the macula in AMD patients is assumed.
Arch Ophthalmol. 2007 Sep;125(9):1225-32.
To evaluate the relationship of dietary carotenoids, vitamin A, alpha-tocopherol, and vitamin C with prevalent age-related macular degeneration (AMD) in the Age-Related Eye Disease Study (AREDS).
Demographic, lifestyle, and medical characteristics were ascertained on 4519 AREDS participants aged 60 to 80 years at enrollment. Stereoscopic color fundus photographs were used to categorize participants into 4 AMD severity groups and a control group (participants with < 15 small drusen). Nutrient intake was estimated from a self-administered semiquantitative food frequency questionnaire at enrollment. Intake values were energy adjusted and classified by quintiles. The relationship between diet and AMD status was assessed using logistic regression analyses.
Dietary lutein/zeaxanthin intake was inversely associated with neovascular AMD (odds ratio [OR], 0.65; 95% confidence interval [CI], 0.45-0.93), geographic atrophy (OR, 0.45; 95% CI, 0.24-0.86), and large or extensive intermediate drusen (OR, 0.73; 95% CI, 0.56-0.96), comparing the highest vs lowest quintiles of intake, after adjustment for total energy intake and nonnutrient-based covariates. Other nutrients were not independently related to AMD.
Higher dietary intake of lutein/zeaxanthin was independently associated with decreased likelihood of having neovascular AMD, geographic atrophy, and large or extensive intermediate drusen.
Optometry. 2004 Apr;75(4):216-30.
Age-related macular degeneration (ARMD) is the leading cause of vision loss in aging Westem societies. The objective of the lutein antioxidant supplementation trial (LAST) is to determine whether nutritional supplementation with lutein or lutein together with antioxidants, vitamins, and minerals, improves visual function and symptoms in atrophic ARMD.
The study was a prospective, 12-month, randomized, double-masked, placebo-controlled trial conducted at an urban midwestern Veterans Administration Hospital from August 1999 to May 2001. Ninety patients with atrophic ARMD were referred by ophthalmologists at two Chicago-area veterans medical facilities. Patients in Group 1 received lutein 10 mg (L); in Group 2, a lutein 10 mg/antioxidants/vitamins and minerals broad spectrum supplementation formula (L/A); and in Group 3, a maltodextrin placebo (P) over 12 months.
In Groups 1 L and 2 L/A, mean eye macular pigment optical density increased approximately 0.09 log units from baseline, Snellen equivalent visual acuity improved 5.4 letters for Group 1 L and 3.5 letters for Group 2 L/A, and contrast sensitivity improved. There was a net subjective improvement in Amsler grid in Group 1 L. VFO-14 questionnaires conceming subjective glare recovery were nearly significant at 4 months for Group 2 L/A. Patients who received the placebo (Group 3) had no significant changes in any of the measured findings.
In this study, visual function is improved with lutein alone or lutein together with other nutrients. Further studies are needed with more patients, of both genders, and for longer periods of time to assess long-term effects of lutein or lutein together with a broad spectrum of antioxidants, vitamins, and minerals in the treatment of atrophic age-related macular degeneration.
Maturitas. 2016 Jun;88:101-12. doi: 10.1016/j.maturitas.2016.04.002. Epub 2016 Apr 2.
Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.
Age-related macular degeneration; Eye; Meta-analysis; Neuroendocrinology; Older adults; Vitamin D
PLoS One. 2013 Jul 29;8(7):e70948. doi: 10.1371/journal.pone.0070948. Print 2013.
To evaluate potential differences in plasma 25-hydroxyvitamin in subtypes of age-related macular degeneration (AMD), and in patients in Clinical Age-Related Maculopathy Staging (CARMS) group 5 with or without subretinal fibrosis.
This single-center cross-sectional study included 178 participants during a period of 20 months. Ninety-five patients belonged to CARMS 5; twelve belonged to CARMS 4; twenty-two belonged to CARMS 2 or 3; and 49 individuals did not have AMD (CARMS 1). Following a structured interview, a detailed bilateral retinal examination was performed and participants were allocated to their respective subgroups in accordance with the Clinical Age-Related Maculopathy Staging system. Plasma 25-hydroxyvitamin D2 and D3 were analyzed using liquid chromatography-tandem mass spectrometry. Genomic DNA was extracted from leukocytes and genotyped for single nucleotide polymorphisms (SNPs) in the vitamin D metabolism. Differences in plasma 25-hydroxyvitamin D were determined in the subgroups as well as between patients in CARMS 5 with or without subretinal fibrosis.
Plasma 25-hydroxyvitamin D was comparable in patients across CARMS groups 1 to 5 (p = 0.83). In CARMS 5, the presence of subretinal fibrosis was associated with significantly lower concentrations of 25-hydroxyvitamin D as compared to the absence of subretinal fibrosis (47.2 versus 75.6 nmol/L, p<0.001). Patients in CARMS 5 with subretinal fibrosis were more likely to have insufficient levels of 25-hydroxyvitamin D compared to patients without subretinal fibrosis (p = 0.006). No association was found between the SNPs rs10877012, rs2228570, rs4588, or rs7041 and AMD subgroups or plasma 25-hydroxyvitamin levels.
This study suggests that the presence of subretinal fibrosis in patients belonging to CARMS 5 may be associated with a poor vitamin D status. Our observations warrant further investigation into the role of vitamin D in the development of subretinal fibrosis.
Ophthalmic Res. 2015;53(3):109-16. doi: 10.1159/000369824. Epub 2015 Feb 7.
The aim of this study was to investigate the effects of quercetin on vascular endothelial growth factor (VEGF)-induced choroidal and retinal angiogenesis in vitro using a rhesus macaque choroid-retinal endothelial (RF/6A) cell line.
RF/6A cells were cultured in Dulbecco’s modified Eagle’s medium containing 10% fetal bovine serum. Then the cells were treated with different concentrations (from 0 to 100 μM) of quercetin and 100 ng/ml VEGF. The cell proliferation was assessed using cholecystokinin octapeptide dye. The cell migration was investigated by a Transwell assay. The tube formation was measured on Matrigel. Furthermore, the impact of quercetin’s effects on VEGF-induced activation of VEGF receptor 2 (VEGFR-2) downstream signal pathways was tested by Western blot analysis.
Quercetin inhibits RF/6A cell proliferation in a dose-dependent fashion: 22.7, 31.5 and 36.7% inhibition on treatment with 10, 50 and 100 μM quercetin, respectively. VEGF-induced migration and tube formation of RF/6A cells were also significantly inhibited by quercetin in a dose-dependent manner. Quercetin inhibits VEGF-induced VEGFR-2 downstream signal pathways of RF/6A.
The results show that quercetin inhibits VEGF-induced cell proliferation, migration and tube formation of RF/6A. We suggest that quercetin inhibits VEGF-induced choroidal and retinal angiogenesis in vitro. Collectively, the findings in the present study suggest that quercetin inhibits VEGF-induced choroidal and retinal angiogenesis by targeting the VEGFR-2 pathway. This suggests that quercetin is a choroidal and retinal angiogenesis inhibitor.
© 2015 S. Karger AG, Basel.
Exp Eye Res. 2016 Apr;145:1-9. doi: 10.1016/j.exer.2015.10.005. Epub 2015 Oct 22.
Oxidative stress and inflammation play key roles in the light damage (LD) model of photoreceptor degeneration, as well as in age-related macular degeneration (AMD). We sought to investigate whether Berberine (BBR), an antioxidant herb extract, would protect the retina against light-induced degeneration. To accomplish this, Balb/c mice were treated with BBR or PBS via gavage for 7 days, and then were placed in constant cool white light-emitting diode (LED) light (10,000 lux) for 4 h. Retinal function and degeneration were evaluated by histology, electroretinography (ERG) and optical coherence tomography (OCT) at 7d after LD. Additionally, mRNA levels of cell-type specific, antioxidant, and inflammatory genes were compared 7d after LD. Photoreceptor DNA fragmentation was assessed via the terminal deoxynucleotidyl transferase dUTP nick end-labeling (TUNEL) assay. LD resulted in substantial photoreceptor-specific cell death. Histological analysis using plastic sections showed dosing with BBR preserved photoreceptors. The ERG analysis demonstrated functional protection by BBR in rod-b, -a, and cone-b waves. In OCT images, mice receiving PBS showed severe thinning and disorganization of the photoreceptor layer 7 days after LD, whereas mice treated with BBR had significantly less thinning and disorganization. Consistent with OCT results, the mRNA levels of Rho in the NSR, and Rpe65 and Mct3 in the RPE, were significantly higher in mice treated with BBR. The numbers of TUNEL-positive photoreceptors were significantly decreased in BBR-treated mice. The retinal mRNA levels of oxidative stress genes, the number of microglia/macrophages, and the malondialdehyde (MDA) immunolabeling were significantly lower in BBR-treated mice compared to controls 48 h after LD, which indicates oxidative stress was reduced by BBR in light-damaged eyes. In conclusion, systemic BBR is protective against light-induced retinal degeneration associated with diminished oxidative stress in the retina. These results suggest that BBR may be protective against retinal diseases involving oxidative stress.
Copyright © 2015 Elsevier Ltd. All rights reserved.
Berberine; Light damage; Oxidative stress; Photoreceptor degeneration; Retina
Proc Natl Acad Sci U S A. 2014 Apr 8;111(14):E1402-8. doi: 10.1073/pnas.1400530111. Epub 2014 Mar 24.
Accumulation of lipofuscin bisretinoids (LBs) in the retinal pigment epithelium (RPE) is the alleged cause of retinal degeneration in genetic blinding diseases (e.g., Stargardt) and a possible etiological agent for age-related macular degeneration. Currently, there are no approved treatments for these diseases; hence, agents that efficiently remove LBs from RPE would be valuable therapeutic candidates. Here, we show that beta cyclodextrins (β-CDs) bind LBs and protect them against oxidation. Computer modeling and biochemical data are consistent with the encapsulation of the retinoid arms of LBs within the hydrophobic cavity of β-CD. Importantly, β-CD treatment reduced by 73% and 48% the LB content of RPE cell cultures and of eyecups obtained from Abca4-Rdh8 double knock-out (DKO) mice, respectively. Furthermore, intravitreal administration of β-CDs reduced significantly the content of bisretinoids in the RPE of DKO animals. Thus, our results demonstrate the effectiveness of β-CDs to complex and remove LB deposits from RPE cells and provide crucial data to develop novel prophylactic approaches for retinal disorders elicited by LBs. PMID: 24706818