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Cui A, Xiao P, Wang P, Wang H, Cong Y, Fan Z, Wei X, Zhuang Y. No genetic causal association between circulating alpha-tocopherol levels and osteoarthritis, a two-sample Mendelian randomization analysis. Sci Rep 2024; 14:10099. [PMID: 38698019 PMCID: PMC11066079 DOI: 10.1038/s41598-024-60676-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 04/25/2024] [Indexed: 05/05/2024] Open
Abstract
The causal association between vitamin E status and osteoarthritis (OA) remains controversial in previous epidemiological studies. We employed a Mendelian randomization (MR) analysis to explore the causal relationship between circulating alpha-tocopherol levels (main forms of vitamin E in our body) and OA. The instrumental variables (IVs) of circulating alpha-tocopherol levels were obtained from a Genome-wide association study (GWAS) dataset of 7781 individuals of European descent. The outcome of OA was derived from the UK biobank. Two-sample MR analysis was used to estimate the causal relationship between circulating alpha-tocopherol levels and OA. The inverse-variance weighted (IVW) method was the primary analysis in this analysis. We used the MR-Egger method to determine horizontal pleiotropic in this work. The heterogeneity effect of instrumental IVs was detected by MR-Egger and IVW analyses. Sensitivity analysis was performed by removing single nucleotide polymorphism (SNP) one by one. Three SNPs (rs964184, rs2108622, and rs11057830) (P < 5E-8) strongly associated with circulating alpha-tocopherol levels were used in this analysis. The IVW-random effect indicated no causal relationship between circulating alpha-tocopherol levels and clinically diagnosed OA (OR = 0.880, 95% CI 0.626, 1.236, P = 0.461). Similarly, IVW analysis showed no causal association between circulating alpha-tocopherol levels and self-reported OA (OR = 0.980, 95% CI 0.954, 1.006, P = 0.139). Other methods of MR analyses and sensitivity analyses revealed consistent findings. MR-Egger and IVW methods indicated no significant heterogeneity between IVs. The MR-Egger intercept showed no horizontal pleiotropic. The results of this linear Mendelian randomization study indicate no causal association between genetically predicted alpha-tocopherol levels and the progression of OA. Alpha-tocopherol may not provide beneficial and more favorable outcomes for the progression of OA. Further MR analysis based on updated GWASs with more IVs is required to verify the results of our study.
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Affiliation(s)
- Aiyong Cui
- Department of Orthopaedics, Honghui Hospital, Xi'an Jiao Tong University, Xi'an, 710000, China
| | - Peilun Xiao
- Department of Orthopaedics, The Fifth Affiliated Hospital of Sun Yat-Sen University, Zhuhai, 519000, Guangdong, China
| | - Pengfei Wang
- Department of Orthopaedics, Honghui Hospital, Xi'an Jiao Tong University, Xi'an, 710000, China
| | - Hu Wang
- Department of Orthopaedics, Honghui Hospital, Xi'an Jiao Tong University, Xi'an, 710000, China
| | - Yuxuan Cong
- Department of Orthopaedics, Honghui Hospital, Xi'an Jiao Tong University, Xi'an, 710000, China
| | - Zhiqiang Fan
- Department of Orthopaedics, Honghui Hospital, Xi'an Jiao Tong University, Xi'an, 710000, China.
| | - Xing Wei
- Department of Orthopaedics, Honghui Hospital, Xi'an Jiao Tong University, Xi'an, 710000, China.
| | - Yan Zhuang
- Department of Orthopaedics, Honghui Hospital, Xi'an Jiao Tong University, Xi'an, 710000, China.
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2
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Duncan RS, Hurtado DT, Hall CW, Koulen P. Differential Mechanisms of Action and Efficacy of Vitamin E Components in Antioxidant Cytoprotection of Human Retinal Pigment Epithelium. Front Pharmacol 2022; 12:798938. [PMID: 35058783 PMCID: PMC8764263 DOI: 10.3389/fphar.2021.798938] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 11/17/2021] [Indexed: 12/21/2022] Open
Abstract
The purpose of this study was to determine if different vitamin E components exhibit similar efficacy and mechanism of action in protecting Retinal pigment epithelium (RPE) cells from oxidative damage. We hypothesized that α-tocopherol (αT) is unique among vitamin E components in its cytoprotective mechanism of action against oxidative stress in RPE cells and that it requires protein synthesis for optimal antioxidant effect. We used cell viability assays, fluorescent chemical labeling of DNA and actin and immuno-labeling of the antioxidant proteins Nrf2 and Sod2 and of the tight junction protein, ZO-1, and confocal microscopy to determine the effects of αT and γT against oxidative stress in immortalized human RPE cells (hTERT-RPE). Using the four main vitamin E components, αT, γT, δ-tocopherol (δT) and α-tocotrienol (αTr), we ascertained that they exhibit similar, but not identical, antioxidant activity as αT when used at equimolar concentrations. In addition, we determined that the exposure time of RPE cells to α-tocopherol is critical for its ability to protect against oxidative damage. Lastly, we determined that αT, but not γT, partially requires the synthesis of new proteins within a 24-h period and prior to exposure to tBHP for optimal cytoprotection. We conclude that, unlike γT and δT, αT appears to be unique in its requirement for transport and/or signaling for it to be an effective antioxidant. As a result, more focus should be paid to which vitamin E components are used for antioxidant interventions.
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Affiliation(s)
- R Scott Duncan
- Vision Research Center, Department of Ophthalmology, School of Medicine, University of Missouri-Kansas City, Kansas City, MO, United States
| | - Daniel T Hurtado
- Department of Biomedical Sciences, School of Medicine, University of Missouri-Kansas City, Kansas City, MO, United States
| | - Conner W Hall
- Vision Research Center, Department of Ophthalmology, School of Medicine, University of Missouri-Kansas City, Kansas City, MO, United States
| | - Peter Koulen
- Vision Research Center, Department of Ophthalmology, School of Medicine, University of Missouri-Kansas City, Kansas City, MO, United States.,Department of Biomedical Sciences, School of Medicine, University of Missouri-Kansas City, Kansas City, MO, United States
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3
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Traber MG, Head B. Vitamin E: How much is enough, too much and why! Free Radic Biol Med 2021; 177:212-225. [PMID: 34699937 DOI: 10.1016/j.freeradbiomed.2021.10.028] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 09/08/2021] [Accepted: 10/11/2021] [Indexed: 12/12/2022]
Abstract
α-Tocopherol (α-T) is a required dietary nutrient for humans and thus is a vitamin. This narrative review focuses on vitamin E structures, functions, biological determinants and its deficiency symptoms in humans. The mechanisms for the preferential α-T tissue enrichment in the human body include the α-T transfer protein (TTPA) and the preferential metabolism of non-α-T forms. Potential new α-T biomarkers, pharmacokinetic data, and whether there are better approaches to evaluate and set the α-T dietary requirement are discussed. Finally, the possible role of α-T supplements in delay of chronic diseases and the evaluation of vitamin E safety are considered.
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Affiliation(s)
- Maret G Traber
- Linus Pauling Institute, USA; School of Biological and Population Health Sciences, College of Public Health and Human Sciences, USA.
| | - Brian Head
- Linus Pauling Institute, USA; Molecular and Cell Biology Program, Oregon State University, Corvallis, OR, USA
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4
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Szewczyk K, Chojnacka A, Górnicka M. Tocopherols and Tocotrienols-Bioactive Dietary Compounds; What Is Certain, What Is Doubt? Int J Mol Sci 2021; 22:6222. [PMID: 34207571 PMCID: PMC8227182 DOI: 10.3390/ijms22126222] [Citation(s) in RCA: 61] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 06/02/2021] [Accepted: 06/05/2021] [Indexed: 12/13/2022] Open
Abstract
Tocopherols and tocotrienols are natural compounds of plant origin, available in the nature. They are supplied in various amounts in a diet, mainly from vegetable oils, some oilseeds, and nuts. The main forms in the diet are α- and γ-tocopherol, due to the highest content in food products. Nevertheless, α-tocopherol is the main form of vitamin E with the highest tissue concentration. The α- forms of both tocopherols and tocotrienols are considered as the most metabolically active. Currently, research results indicate also a greater antioxidant potential of tocotrienols than tocopherols. Moreover, the biological role of vitamin E metabolites have received increasing interest. The aim of this review is to update the knowledge of tocopherol and tocotrienol bioactivity, with a particular focus on their bioavailability, distribution, and metabolism determinants in humans. Almost one hundred years after the start of research on α-tocopherol, its biological properties are still under investigation. For several decades, researchers' interest in the biological importance of other forms of vitamin E has also been growing. Some of the functions, for instance the antioxidant functions of α- and γ-tocopherols, have been confirmed in humans, while others, such as the relationship with metabolic disorders, are still under investigation. Some studies, which analyzed the biological role and mechanisms of tocopherols and tocotrienols over the past few years described new and even unexpected cellular and molecular properties that will be the subject of future research.
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Affiliation(s)
- Kacper Szewczyk
- Institute of Human Nutrition Sciences, Warsaw University of Life Sciences (SGGW-WULS), 159C Nowoursynowska Street, 02-787 Warsaw, Poland
| | - Aleksandra Chojnacka
- Institute of Human Nutrition Sciences, Warsaw University of Life Sciences (SGGW-WULS), 159C Nowoursynowska Street, 02-787 Warsaw, Poland
| | - Magdalena Górnicka
- Institute of Human Nutrition Sciences, Warsaw University of Life Sciences (SGGW-WULS), 159C Nowoursynowska Street, 02-787 Warsaw, Poland
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Nie R, Zhang Y, Zhang H, Jin Q, Wu G, Wang X. Effect of different processing methods on physicochemical properties, chemical compositions and in vitro antioxidant activities of Paeonia lactiflora Pall seed oils. Food Chem 2020; 332:127408. [PMID: 32619944 DOI: 10.1016/j.foodchem.2020.127408] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2020] [Revised: 06/20/2020] [Accepted: 06/21/2020] [Indexed: 11/25/2022]
Abstract
A research was performed to determine and compare the physicochemical properties, chemical compositions and in vitro antioxidant activities of Paeonia lactiflora Pall seed oils with ultrasonic-assisted solvent extraction, pressing and supercritical fluid extraction. Paeonia lactiflora Pall seed oil contained a high percentage of polyunsaturated fatty acids and monounsaturated fatty acids, especially oleic (31.62-32.88%) and α-linolenic acids (37.55-39.95%). The beneficial multiple dietary phytochemicals (tocopherol, phytosterols and squalene) and in vitro antioxidant activity were significantly influenced by the hull and processing method (P<0.05). However, higher tocopherol (596.67-738.76 mg/kg) and phytosterols (5775.01-6055.62 mg/kg) contents were found in supercritical fluid extraction oils. Additionally, ten individual polyphenols were quantified, and significantly influenced by the hull and processing method (P<0.05), with the content of benzoic acid and several individual flavonoids being the higher. According to the results, pressing might be the best process for extracting oil with a high number of polyphenols.
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Affiliation(s)
- Rong Nie
- State Key Laboratory of Food Science and Technology, Jiangnan University, China; National Engineering Research Center for Functional Food, Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, School of Food Science and Technology, Jiangnan University, China
| | - Yiren Zhang
- Department of Chemistry, School of Physical Science, University of Liverpool, China
| | - Hui Zhang
- State Key Laboratory of Food Science and Technology, Jiangnan University, China; National Engineering Research Center for Functional Food, Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, School of Food Science and Technology, Jiangnan University, China
| | - Qingzhe Jin
- State Key Laboratory of Food Science and Technology, Jiangnan University, China; National Engineering Research Center for Functional Food, Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, School of Food Science and Technology, Jiangnan University, China
| | - Gangcheng Wu
- State Key Laboratory of Food Science and Technology, Jiangnan University, China; National Engineering Research Center for Functional Food, Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, School of Food Science and Technology, Jiangnan University, China.
| | - Xingguo Wang
- State Key Laboratory of Food Science and Technology, Jiangnan University, China; National Engineering Research Center for Functional Food, Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, School of Food Science and Technology, Jiangnan University, China
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6
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Ma C, Liu Y, He S, Zeng J, Li P, Ma C, Ping F, Zhang H, Xu L, Li W, Li Y. Negative association between antioxidant vitamin intake and non-alcoholic fatty liver disease in Chinese non-diabetic adults: mediation models involving superoxide dismutase. Free Radic Res 2020; 54:670-677. [PMID: 32985285 DOI: 10.1080/10715762.2020.1825705] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
We aimed to explore the association between antioxidant vitamin intake, oxidative stress related markers and non-alcoholic fatty liver disease (NAFLD) by a cross-sectional analysis. A total of 241 non-diabetic participants from a Chinese rural cohort were included. NAFLD was diagnosed by abdominal ultrasound (NAFLD, n = 71; Non-NAFLD, n = 171). Dietary intake was assessed by a 24-h food recall. Plasma oxidative stress related markers superoxide dismutase (SOD), glutathione reductase (GR) and 8-oxo-2'-deoxyguanosine(8-oxo-dG) were measured. The association between dietary antioxidant vitamin intake, oxidative stress related markers and NAFLD were analysed by Spearman correlation analysis and multiple logistic regression analysis. Mediation models were established to examine whether SOD mediated the association between dietary vitamin A or α-tocopherol intake and NAFLD. Spearman correlation analysis indicated that dietary vitamin A and α-tocopherol intake were positively correlated with SOD (p < .05). Multiple logistic regression analysis found plasma SOD, dietary vitamin A and α-tocopherol intake were inversely associated with NAFLD (all p < .05). Mediation analysis indicated that SOD significantly mediated the indirect effect of dietary α-tocopherol (mediated effect = 13.21% total effect) or vitamin A (mediated effect = 3.12% total effect) intake on NAFLD. Our study indicated that dietary vitamin A and α-tocopherol intake may contribute to protect from NAFLD in Chinese non-diabetics, and the associations were partly mediated by SOD. However, SOD only accounted for a minor percentage of the association between vitamin A intake and NAFLD. Thus, other mechanisms underlying antioxidant vitamin' protective effect on NAFLD need further exploration.
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Affiliation(s)
- Chifa Ma
- Department of Endocrinology, Key Laboratory of Endocrinology, Ministry of Health, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Yiwen Liu
- Department of Endocrinology, Key Laboratory of Endocrinology, Ministry of Health, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Shuli He
- Department of Nutrition, Peking Union Medical College Hospital, Beijing, China
| | - Jingbo Zeng
- Department of Endocrinology, Fuxing Hospital, the Eighth Clinical Medical College, Capital Medical University, Beijing, China
| | - Pingping Li
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.,Diabetes Research Center of Chinese Academy of Medical Sciences, Beijing, China
| | - Chunxiao Ma
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.,Diabetes Research Center of Chinese Academy of Medical Sciences, Beijing, China
| | - Fan Ping
- Department of Endocrinology, Key Laboratory of Endocrinology, Ministry of Health, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Huabing Zhang
- Department of Endocrinology, Key Laboratory of Endocrinology, Ministry of Health, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Lingling Xu
- Department of Endocrinology, Key Laboratory of Endocrinology, Ministry of Health, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Wei Li
- Department of Endocrinology, Key Laboratory of Endocrinology, Ministry of Health, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Yuxiu Li
- Department of Endocrinology, Key Laboratory of Endocrinology, Ministry of Health, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
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7
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Rozanowska M, Edge R, Land EJ, Navaratnam S, Sarna T, Truscott TG. Scavenging of Retinoid Cation Radicals by Urate, Trolox, and α-, β-, γ-, and δ-Tocopherols. Int J Mol Sci 2019; 20:ijms20112799. [PMID: 31181693 PMCID: PMC6600601 DOI: 10.3390/ijms20112799] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 06/02/2019] [Accepted: 06/03/2019] [Indexed: 12/17/2022] Open
Abstract
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).
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Affiliation(s)
- Malgorzata Rozanowska
- Cardiff Institute of Tissue Engineering and Repair, Cardiff University, Wales CF10 3AX, UK.
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, Wales CF24 4HQ, UK.
| | - Ruth Edge
- Dalton Cumbrian Facility, The University of Manchester, Westlakes Science Park, Moor Row, Cumbria CA24 3HA, UK.
| | - Edward J Land
- Free Radical Research Facility, Science and Technology Facilities Council (STFC) Daresbury Laboratory, Warrington WA4 4AD, UK.
| | - Suppiah Navaratnam
- Biomedical Sciences Research Institute, University of Salford, Manchester M5 4WT, UK.
| | - Tadeusz Sarna
- Department of Biophysics, Faculty of Biotechnology, Jagiellonian University, 30-387 Krakow, Poland.
| | - T George Truscott
- School of Chemical and Physical Sciences, Lennard-Jones Building, Keele University, Staffordshire ST5 5BG, UK.
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