scholarly journals Scavenging of Retinoid Cation Radicals by Urate, Trolox, and α-, β-, γ-, and δ-Tocopherols

2019 ◽  
Vol 20 (11) ◽  
pp. 2799 ◽  
Author(s):  
Malgorzata Rozanowska ◽  
Ruth Edge ◽  
Edward J. Land ◽  
Suppiah Navaratnam ◽  
Tadeusz Sarna ◽  
...  

Retinoids are present in human tissues exposed to light and under increased risk of oxidative stress, such as the retina and skin. Retinoid cation radicals can be formed as a result of the interaction between retinoids and other radicals or photoexcitation with light. It has been shown that such semi-oxidized retinoids can oxidize certain amino acids and proteins, and that α-tocopherol can scavenge the cation radicals of retinol and retinoic acid. The aim of this study was to determine (i) whether β-, γ-, and δ-tocopherols can also scavenge these radicals, and (ii) whether tocopherols can scavenge the cation radicals of another form of vitamin A—retinal. The retinoid cation radicals were generated by the pulse radiolysis of benzene or aqueous solution in the presence of a selected retinoid under oxidizing conditions, and the kinetics of retinoid cation radical decays were measured in the absence and presence of different tocopherols, Trolox or urate. The bimolecular rate constants are the highest for the scavenging of cation radicals of retinal, (7 to 8) × 109 M−1·s−1, followed by retinoic acid, (0.03 to 5.6) × 109 M−1·s−1, and retinol, (0.08 to 1.6) × 108 M−1·s−1. Delta-tocopherol is the least effective scavenger of semi-oxidized retinol and retinoic acid. The hydrophilic analogue of α-tocopherol, Trolox, is substantially less efficient at scavenging retinoid cation radicals than α-tocopherol and urate, but it is more efficient at scavenging the cation radicals of retinoic acid and retinol than δ-tocopherol. The scavenging rate constants indicate that tocopherols can effectively compete with amino acids and proteins for retinoid cation radicals, thereby protecting these important biomolecules from oxidation. Our results provide another mechanism by which tocopherols can diminish the oxidative damage to the skin and retina and thereby protect from skin photosensitivity and the development and/or progression of changes in blinding retinal diseases such as Stargardt’s disease and age-related macular degeneration (AMD).

2021 ◽  
pp. 112067212110026
Author(s):  
Pablo Gili ◽  
Leyre Lloreda Martín ◽  
José-Carlos Martín-Rodrigo ◽  
Naon Kim-Yeon ◽  
Laura Modamio-Gardeta ◽  
...  

Purpose: To identify the association between single-nucleotide polymorphisms (SNPs) in CFH, ARMS2, HTRA1, CFB, C2, and C3 genes and exudative age-related macular degeneration (AMD) in a Spanish population. Methods: In 187 exudative AMD patients and 196 healthy controls (61% women, mean age 75 years), 12 SNPs as risk factors for AMD in CFH (rs1410996, rs1061170, r380390), ARMS2 (rs10490924, rs10490923), HTRA1 (rs11200638), CFB (rs641153), C2 (rs547154, rs9332739), and C3 (rs147859257, rs2230199, rs1047286) genes were analyzed. Results: The G allele was the most frequent in CFH gene (rs1410996) with a 7-fold increased risk of AMD (OR 7.69, 95% CI 3.17–18.69), whereas carriers of C allele in CFH (rs1061170) showed a 3-fold increased risk for AMD (OR 3.22, 95% CI 1.93–5.40). In CFH (rs380390), the presence of G allele increased the risk for AMD by 2-fold (OR 2.52, 95% CI 1.47–4.30). In ARMS2 (rs10490924), the T-allele was associated with an almost 5-fold increased risk (OR 5.49, 95% CI 3.23–9.31). The A allele in HTRA1 (rs11200638) was more prevalent in AMD versus controls (OR 6.44, 95% CI 3.62–11.47). In C2 gene (rs9332739) the presence of C increased risk for AMD by 3-fold (OR 3.10, 95% CI 1.06–9.06). Conclusion: SNPs in CFH, ARMS2, HTRA1, and C2 genes were associated in our study with an increased risk for exudative AMD in Spanish patients.


Metabolites ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 183
Author(s):  
Kevin M Mendez ◽  
Janice Kim ◽  
Inês Laíns ◽  
Archana Nigalye ◽  
Raviv Katz ◽  
...  

The purpose of this study was to analyze the association between plasma metabolite levels and dark adaptation (DA) in age-related macular degeneration (AMD). This was a cross-sectional study including patients with AMD (early, intermediate, and late) and control subjects older than 50 years without any vitreoretinal disease. Fasting blood samples were collected and used for metabolomic profiling with ultra-performance liquid chromatography–mass spectrometry (LC-MS). Patients were also tested with the AdaptDx (MacuLogix, Middletown, PA, USA) DA extended protocol (20 min). Two measures of dark adaptation were calculated and used: rod-intercept time (RIT) and area under the dark adaptation curve (AUDAC). Associations between dark adaption and metabolite levels were tested using multilevel mixed-effects linear modelling, adjusting for age, gender, body mass index (BMI), smoking, race, AMD stage, and Age-Related Eye Disease Study (AREDS) formulation supplementation. We included a total of 71 subjects: 53 with AMD (13 early AMD, 31 intermediate AMD, and 9 late AMD) and 18 controls. Our results revealed that fatty acid-related lipids and amino acids related to glutamate and leucine, isoleucine and valine metabolism were associated with RIT (p < 0.01). Similar results were found when AUDAC was used as the outcome. Fatty acid-related lipids and amino acids are associated with DA, thus suggesting that oxidative stress and mitochondrial dysfunction likely play a role in AMD and visual impairment in this condition.


2014 ◽  
Vol 111 (9) ◽  
pp. 1673-1679 ◽  
Author(s):  
Bamini Gopinath ◽  
Victoria M. Flood ◽  
Jimmy C. Y. Louie ◽  
Jie Jin Wang ◽  
George Burlutsky ◽  
...  

Habitual consumption of dairy products has been shown to play an important role in the prevention of several chronic diseases. We aimed to prospectively assess the relationship between the change in dairy product consumption (both regular fat and low/reduced fat) and the 15-year incidence of age-related macular degeneration (AMD). In the Blue Mountains Eye Study, 2037 participants aged 49 years or above at baseline were re-examined at follow-up in 1997–9, 2002–4 and/or 2007–9. AMD was assessed from retinal photographs. Dietary data were collected using a semi-quantitative FFQ, and servings of dairy product consumption calculated. Over the 15-year follow-up, there were 352, 268 and eighty-four incident cases of any, early and late AMD, respectively. After adjusting for age, sex, current smoking, white cell count and fish consumption, a significant linear trend (Pfor trend = 0·003) was observed with decreasing consumption of total dairy foods and the 15-year incidence of late AMD, comparing the lowestv.highest quintile of intake (OR 2·80, 95 % CI 1·21, 3·04). Over the 15 years, decreased consumption of reduced-fat dairy foods was associated with an increased risk of incident late AMD, comparing the lowest to highest quintile of intake (OR 3·10, 95 % CI 1·18, 8·14,Pfor trend = 0·04). Decreasing total dietary Ca intake over the 15 years was also associated with an increased risk of developing incident late AMD (multivariable-adjustedPfor trend = 0·03). A lower consumption of dairy products (regular and low fat) and Ca was independently associated with a higher risk of developing incident late AMD in the long term. Additional cohort studies are needed to confirm these findings.


2018 ◽  
Vol 59 (4) ◽  
pp. AMD12 ◽  
Author(s):  
Moritz Lindner ◽  
Sebastian Kosanetzky ◽  
Maximilian Pfau ◽  
Jennifer Nadal ◽  
Lukas A. Gördt ◽  
...  

Author(s):  
Liv Tybjærg Nordestgaard ◽  
Anne Tybjærg-Hansen ◽  
Ruth Frikke-Schmidt ◽  
Børge Grønne Nordestgaard

Abstract Context To enable prevention and treatment of age-related macular degeneration(AMD), understanding risk factors for AMD is important. Objective We tested the hypotheses that elevated plasma apolipoprotein A1 and high-density lipoprotein(HDL) cholesterol, and low levels of low-density lipoprotein(LDL) cholesterol, are associated with increased risk of AMD. Design and Setting From the Danish general population, we studied 106,703 and 16,032 individuals in the Copenhagen General Population Study(CGPS) and the Copenhagen City Heart Study(CCHS) with median follow-up of respectively 9 and 32 years. Main Outcome Measures 1,787 AMD in CGPS and 206 in CCHS. Results Higher concentrations of plasma apolipoprotein A1 and HDL cholesterol, and lower concentrations of LDL cholesterol, were associated with higher risk of AMD in CGPS. After multifactorial adjustment, individuals in the highest versus lowest quartile of plasma apolipoprotein A1 and HDL cholesterol had hazard ratios for AMD of 1.40(95%CI:1.20-1.63) and 1.22(1.03-1.45). Corresponding hazard ratios for individuals in the lowest versus highest quartile of LDL cholesterol were 1.18(1.02-1.37). Per 100 mg/dL higher plasma apolipoprotein A1, 1 mmol/L(39 mg/dL) higher HDL, and 1 mmol/L(39mmol/L) lower LDL cholesterol, the hazard ratios for AMD were 1.53(1.31-1.80), 1.19(1.07-1.32), and 1.05(1.00-1.11), respectively, with similar results across strata of different risk factors. Higher concentrations of HDL cholesterol were also associated with higher risk of AMD in the CCHS. Conclusion Elevated plasma apolipoprotein A1 and HDL cholesterol, and lower LDL cholesterol, are associated with increased risk of age-related macular degeneration.


2021 ◽  
pp. bjophthalmol-2021-319508
Author(s):  
Xianwen Shang ◽  
Zhuoting Zhu ◽  
Yu Huang ◽  
Xueli Zhang ◽  
Wei Wang ◽  
...  

AimsTo examine independent and interactive associations of ophthalmic and systemic conditions with incident dementia.MethodsOur analysis included 12 364 adults aged 55–73 years from the UK Biobank cohort. Participants were assessed between 2006 and 2010 at baseline and were followed up until the early of 2021. Incident dementia was ascertained using hospital inpatient, death records and self-reported data.ResultsOver 1 263 513 person-years of follow-up, 2304 cases of incident dementia were documented. The multivariable-adjusted HRs (95% CI) for dementia associated with age-related macular degeneration (AMD), cataract, diabetes-related eye disease (DRED) and glaucoma at baseline were 1.26 (1.05 to 1.52), 1.11 (1.00 to 1.24), 1.61 (1.30 to 2.00) and (1.07 (0.92 to 1.25), respectively. Diabetes, heart disease, stroke and depression at baseline were all associated with an increased risk of dementia. Of the combination of AMD and a systemic condition, AMD-diabetes was associated with the highest risk for incident dementia (HR (95% CI): 2.73 (1.79 to 4.17)). Individuals with cataract and a systemic condition were 1.19–2.29 times more likely to develop dementia compared with those without cataract and systemic conditions. The corresponding number for DRED and a systemic condition was 1.50–3.24. Diabetes, hypertension, heart disease, depression and stroke newly identified during follow-up mediated the association between cataract and incident dementia as well as the association between DRED and incident dementia.ConclusionsAMD, cataract and DRED but not glaucoma are associated with an increased risk of dementia. Individuals with both ophthalmic and systemic conditions are at higher risk of dementia compared with those with an ophthalmic or systemic condition only.


2020 ◽  
Vol 12 ◽  
pp. 251584142090392
Author(s):  
Constantinos D. Georgakopoulos ◽  
Olga E. Makri ◽  
Athina Pallikari ◽  
Konstantinos Kagkelaris ◽  
Panagiotis Plotas ◽  
...  

Purpose: Treatment with intravitreal injections of anti-vascular endothelial growth factor agents has been associated with an increased risk of arterial thromboembolic events. The aim of the present pilot study was to assess the effect of a single intravitreal injection of aflibercept on coagulation. Methods: Treatment-naïve patients with age-related macular degeneration ( n = 47), who were scheduled to undergo treatment with intravitreal injections of aflibercept, were enrolled. None of the included patients received any anticoagulation therapy or had a history of a recent arterial thromboembolic event. Blood samples were collected before the first intravitreal injection, and at 7 and 30 days after aflibercept administration. We evaluated coagulation parameters, such as platelet count and plasma fibrinogen and D-dimer levels; functional clotting parameters, such as prothrombin time, international normalized ratio, and activated partial thromboplastin time; and anticoagulant parameters, such as the levels of Proteins S and C. Results: The levels of all of the evaluated biomarkers were within the normal range at baseline and at both the time points throughout the study. No statistically significant changes were observed in any of the measured parameters at 1 week and 1 month after aflibercept administration. Conclusion: A single intravitreal injection of aflibercept in treatment-naïve patients with exudative age-related macular degeneration has no statistically significant effect on blood coagulation parameters for up to 1 month after aflibercept administration. Our results also provide an explorative statistical data, and further studies are required to evaluate any significant clinical effects of aflibercept on blood coagulation parameters. ClinicalTrials.gov ID: NCT03509623.


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