Immunomodulatory Effects of α-Tocopherol on the H1N1 Influenza Vaccine: Improving the Potency and Efficacy of the Influenza Vaccine in Aged Mice

Yasaman Eshraghi, Yasaman Vahdani, Pegah Karimi, Meghdad Abdollahpour-Alitappeh, Asghar Abdoli, Morteza Taghizadeh 8, Mehdi Mahdavi

Viral Immunol . 2022 Apr;35(3):244-253. doi: 10.1089/vim.2021.0154.


Declined immune response is the main cause of decreased potency of the influenza vaccine in the elderly, regardless of virus mutations. Herein, we hypothesized that the addition of α-tocopherol to the influenza vaccine formulation might increase vaccine potency and efficacy. Hemagglutinin of the H1N1 virus was formulated in Alum and α-tocopherol, and then aged (16-20-month-old) and young (6-8-week-old) mice were immunized subcutaneously two times with 2-week intervals with 5 μg of different vaccine formulations. Two weeks after the final boosting, IFN-γ and IL-4 cytokines were assessed by using ELISA. Humoral immune responses were assessed by hemagglutination inhibition (HI). In addition, vaccine efficacy was determined by intranasal viral challenge of mice using mouse-adapted H1N1 virus. Our results showed that the new vaccine formulation improved IFN-γ and IL-4 responses in the experimental mice. However, the increase was evident mainly in the aged group and, to some extent, in the young group. Results from the HI assay showed that α-tocopherol in the vaccine formulation could increase HI activity in both young and aged mice. Furthermore, α-tocopherol, as an adjuvant, increased the protectivity of the influenza vaccine in both aged and young groups through the decreased lung viral load and increased survival rate of the experimental mice. In conclusion, it seems that α-tocopherol can not only be used as an appropriate adjuvant for aged people, but also empower old and worn out cells to increase the effectiveness of the vaccine in the elderly.

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Metabolomic analysis of serum alpha-tocopherol among men in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study

Eur J Clin Nutr . 2022 Mar 23. doi: 10.1038/s41430-022-01112-7. Online ahead of print.

Wayne R Lawrence, Jung-Eun Lim, Jiaqi Huang, Joshua N Sampson, Stephanie J Weinstein, Demetrius Albanes


Background/objectives: The role of vitamin E in chronic disease risk remains incompletely understood, particularly in an un-supplemented state, and evidence is sparse regarding the biological actions and pathways involved in its influence on health outcomes. Identifying vitamin-E-associated metabolites through agnostic metabolomics analyses can contribute to elucidating the specific associations and disease etiology. This study aims to investigate the association between circulating metabolites and serum α-tocopherol concentration in an un-supplemented state.

Subjects/methods: Metabolomic analysis of 4,294 male participants was conducted based on pre-supplementation fasting serum in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study. The associations between 1,791 known metabolites measured by ultra-high-performance LC-MS/GC-MS and HPLC-determined α-tocopherol concentration were estimated using multivariable linear regression. Differences in metabolite levels per unit difference in α-tocopherol concentration were calculated as standardized β-coefficients and standard errors.

Results: A total of 252 metabolites were associated with serum α-tocopherol at the Bonferroni-corrected p value (p < 2.79 × 10-5). Most of these metabolites were of lipid and amino acid origin, with the respective subclasses of dicarboxylic fatty acids, and valine, leucine, and isoleucine metabolism, being highly represented. Among lipids, the strongest signals were observed for linoleoyl-arachidonoyl-glycerol (18:2/20:4)[2](β = 0.149; p = 8.65 × 10-146) and sphingomyelin (D18:2/18:1) (β = 0.035; p = 1.36 × 10-30). For amino acids, the strongest signals were aminoadipic acid (β = 0.021; p = 5.01 × 10-13) and l-leucine (β = 0.007; p = 1.05 × 10-12).

Conclusions: The large number of metabolites, particularly lipid and amino acid compounds associated with serum α-tocopherol provide leads regarding potential mechanisms through which vitamin E influences human health, including its role in cardiovascular disease and cancer.

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Contents and isomers distribution of vitamin E in human mature breast milk from six regions of China in 2018-2019

Zeru Lou, Ke Wu, Yizi Xu, Xiaokun Cai, Fang Tian, Yingyi Mao, Yanrong Zhao, Meiqin Cai

Wei Sheng Yan Jiu . 2021 Nov;50(6):914-918. doi: 10.19813/j.cnki.weishengyanjiu.2021.06.007.


Objective: The study aimed to investigate the contents and isomer composition of vitamin E in mature milk in different regions of China.

Methods: Simultaneously recruited 604 lactating mothers aged(29.58±3.43) from Shanghai, Guangzhou, Tianjin, Chengdu, Lanzhou and Changchun cities. They were mainly primiparas with good education background. A total number of 604 mature milk samples was collected. The contents of α-, γ-, δ-tocopherols and the stereoisomers of α-tocopherol were determined by high performance liquid chromatography(HPLC).

Results: The M(P25, P75) concentrations of α-tocopherol, RRR-α-tocopherol, γ-tocopherol and δ-tocopherol in Chinese mature milk were 3.16(2.29, 4.16)mg/L, 2.57(1.77, 3.48)mg/L, 0.89(0.58, 1.27)mg/L and 0.17(0.09, 0.27)mg/L, respectively. The total α-TE level was 3.09(2.22, 4.10)mg/L with statistically regional differences(P&lt;0.001). RRR-α-tocopherol was the predominated stereoisomers of α-tocopherol, accounting for 83.17%(76.36%, 88.43%). The proportion of RRR in Tianjin mature milk was significantly lower than that in Lanzhou(77.11% vs. 86.16%, P&lt;0.001) while breast milk samples from other regions had similar RRR-α-tocopherol proportions(82.82%-85.39%).

Conclusion: Vitamin E content in mature milk was mainly composed of α-tocopherol. Even though the contents of tocopherols have large regional differences, RRR-α-tocopherol was predominated form in all breast milk samples. It is suggested that RRR-α-tocopherol was the main active form of vitamin E in the early stage of life.

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Formulation and In Vivo Evaluation of a Solid Self-Emulsifying Drug Delivery System Using Oily Liquid Tocotrienols as Model Active Substance

You Zhuan Lee, Eng Kwong Seow, Sheau Chin Lim, Kah Hay Yuen, Nurzalina Abdul Karim Khan

Pharmaceutics . 2021 Oct 25;13(11):1777. doi: 10.3390/pharmaceutics13111777.


Self-emulsifying drug delivery systems (SEDDS) can improve the oral bioavailability of poorly water-soluble drugs. Solid self-emulsifying drug delivery systems (s-SEDDS) offer several advantages including improved drug stability, ease of administration, and production. Most compounds employed in developing s-SEDDS are solid in nature, with a high amount of surfactants added. The aim of this study was to develop an s-SEDDS using a tocotrienol-rich fraction (TRF) as the model liquid active substance via a simple adsorption method. The solid formulation was developed using magnesium aluminosilicate as the carrier with 70% TRF and 30% surfactants (poloxamer and Labrasol®). The formulation showed good self-emulsification efficiency with stable emulsion formed, excellent powder flowability, and small emulsion droplet size of 210-277 nm. The s-SEDDS with combined surfactants (poloxamer and Labrasol®) showed a faster absorption rate compared to preparations with only a single surfactant and enhanced oral bioavailability (3.4-3.8 times higher) compared to the non-self-emulsifying oily preparation when administered at a fasted state in rats. In conclusion, an s-SEDDS containing a high amount of TRF was successfully developed. It may serve as a useful alternative to a liquid product with enhanced oral bioavailability and the added advantage of being a solid dosage form.

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Vitamin E: How much is enough, too much and why!

Maret G Traber, Brian Head

Free Radic Biol Med . 2021 Oct 23;177:212-225. doi: 10.1016/j.freeradbiomed.2021.10.028. Online ahead of print.


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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Absorption, transportation, and distribution of vitamin E homologs

Chikako Kiyose

Free Radic Biol Med . 2021 Oct 20;S0891-5849(21)00766-8. doi: 10.1016/j.freeradbiomed.2021.10.016. Online ahead of print.


Vitamin E has eight different naturally occurring forms: four tocopherols and four tocotrienols. Because α-tocopherol has three asymmetric carbons, both natural α-tocopherol (RRR-α-tocopherol) and synthetic α-tocopherol (all-rac-α-tocopherol) are utilized in both pharmaceutical products and food additives. Therefore, determining the distribution of vitamin E in the body is very important. With regard to absorption, and transportation of vitamin E, it is suggested that the pathways mediated by three proteins (CD36, SR-BI, and NPC1L1) as well as passive diffusion affect absorption of vitamin E. Vitamin E homologs are mainly transported by very low-density lipoprotein (VLDL) with the α-tocopherol being recognized by the α-tocopherol transfer protein in liver. However, it is also suggested that chylomicrons (CMs) and high-density lipoprotein (HDL) are involved in transportation of vitamin E homologs from the small intestine to each section of peripheral tissue. In particular, it is speculated that vitamin E homologs transportation by CMs and HDL from enterocytes to peripheral tissues such as adipose tissue greatly affects the distribution of vitamin E homologs, excluding α-tocopherol. However, how lipoprotein lipase affects the incorporation of vitamin E homologs containing lipoprotein into peripheral tissues is unclear. Whether there is biodiscrimination when vitamin E homologs are incorporated into peripheral tissues from lipoprotein is an interesting question. It is likely that future research will reveal how individual vitamin E homologs are incorporated into peripheral tissue, especially the brain, adipose tissue, and skin.

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Cytotoxicity, cellular uptake, and metabolism to short-chain metabolites of 11′-α-tocomonoenol is similar to RRR-α-tocopherol in HepG2 cells

Alexander Montoya-Arroyo, Tanja Wagner, Nadine Sus, Marco Müller, Alexander Kröpfl, Walter Vetter, Jan Frank

Free Radic Biol Med . 2021 Oct 16;S0891-5849(21)00768-1. doi: 10.1016/j.freeradbiomed.2021.10.018. Online ahead of print.


Contrary to the major vitamin E congener α-tocopherol, which carries a saturated sidechain, and α-tocotrienol, with a threefold unsaturated sidechain, little is known about the intracellular fate of α-tocomonoenol, a minor vitamin E derivative with a single double bond in C11′-position of the sidechain. We hypothesized that, due to structural similarities, the uptake and metabolism of α-tocomonoenol will resemble that of α-tocopherol. Cytotoxicity, cellular uptake of α-tocomonoenol, α-tocopherol and α-tocotrienol and conversion into the short-chain metabolites αCEHC and αCMBHC were studied in HepG2 cells. α-Tocomonoenol did not show significant effects on cell viability and its uptake was similar to that observed for α-tocopherol and significantly lower than for α-tocotrienol. α-Tocomonoenol was mainly metabolized to αCMBHC in liver cells, but to a lower extent than α-tocotrienol, while α-tocopherol was not metabolized in quantifiable amounts at all. In summary, the similarities in the cytotoxicity, uptake and metabolism of α-tocomonoenol and α-tocopherol suggest that this minor vitamin E congener deserves more attention in future research with regard to its potential vitamin E activity.

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α-tocopherol, a slow-binding inhibitor of acetylcholinesterase

Irina Zueva, Sofya Lushchekina, Polina Shulnikova, Oksana Lenina, Konstantin Petrov, Elena Molochkina, Patrick Masson

Chem Biol Interact . 2021 Oct 1;348:109646. doi: 10.1016/j.cbi.2021.109646. Epub 2021 Sep 8.


Acetylcholinesterase (AChE) is reversibly inhibited by α-tocopherol (α-T). Steady state kinetic analysis shows that α-T is a mixed slow-binding inhibitor of type A of human enzyme (Kci = 0.49 μM; Kui = 1.6 μM) with a residence time of 2 min on target. Molecular dynamics (MD) simulations support this mechanism, and indicate that α-T first forms multiple non-specific interactions with AChE surface near the gorge entrance, then binds to the peripheral side with alkylene chain slowly sliding down the gorge, inducing no significant conformational change. α-T slightly modulates the progressive inhibition of AChE by the cyclic organophosphorus, cresyl saligenylphosphate, accelerating the fast pseudo-first order process of phosphorylation. A moderate accelerating effect of α-T on phosphorylation by paraoxon was also observed after pre-incubation of AChE in the presence of α-T. This accelerating effect of α-T on ex vivo paraoxon-induced diaphragm muscle weakness was also observed. The effect of α-T on AChE phosphylation was interpreted in light of molecular modeling results. From all results it is clear that α-T does not protect AChE against phosphylation by organophosphorus.

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Pressurized liquid extraction to obtain chia seeds oils extracts enriched in tocochromanols. Nanoemulsions approaches to preserve the antioxidant potential

Lucía Castro-Vázquez, Virginia Rodríguez-Robledo, María Plaza-Oliver, Manuel J Santander-Ortega, M Victoria Lozano, Joaquín González, Noemí Villaseca, Pilar Marcos, M Mar Arroyo-Jiménez

J Food Sci Technol . 2021 Oct;58(10):4034-4044. doi: 10.1007/s13197-020-04866-9. Epub 2021 Jan 5.


The objective of this study was to use accelerated-solvent-extraction to achieve antioxidant extracts from chia seeds oils, enriched in tocopherols and tocotrienols, namely tocochromanols. Nanotechnology applications have been also incorporated to develop an innovative formulation of chia seeds oil nanoemulsion that preserve its antioxidant potential after conditions of oxidative stress. Chia seeds oils proved to be a valuable source of tocochromanols, from 568.84 to 855.98 μg g-1, depending on the geographical provenance. Quantitative data obtained by LC-DAD-ESI-MS/MS showed outstanding levels of γ-Tocopherol, over 83%, followed far behind by Tocopherols-(α, β, δ) and Tocotrienols-(α, β, δ, γ)-tocotrienols. The characteristic tocochromanols fingerprint of chia seeds oils was positively correlated with the FRAP and DPPH antioxidant activity of the extracts (between 18.81 and 138.48 mg Trolox/g). Formulation of the Chia seeds oils as nanoemulsions did not compromised the antioxidant properties of fresh extracts. Interestingly, nanoemulsions retained about the 80% of the initial antioxidant capacity after UV-induced stress, where the non-emulsified oils displayed a remarkable reduction (50-60%) on its antioxidant capacity under the same conditions. These antioxidant chia seeds formulations can constitute a promising strategy to vectorizing vitamin E isomers, in order to be used for food fortification, natural additives and to increase the self-life of food products during packing.

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Spatiotemporal biodistribution of α-tocopherol is impacted by the source of 13 C-labeled α-tocopherol in mice following a single oral dose

Sookyoung Jeon, Qiyao Li, Katherine M Ranard, Stanislav S Rubakhin, Jonathan V Sweedler, Matthew J Kuchan, John W Erdman

Nutr Res . 2021 Sep;93:79-86. doi: 10.1016/j.nutres.2021.07.005. Epub 2021 Jul 25.


Natural (RRR-) α-tocopherol (αT) is more bioactive than synthetic (all racemic, all rac-) αT, but not enough is known about the tissue kinetics of the 2 αT sources. We examined the time-course bioaccumulation of natural versus synthetic αT in tissues of young, marginally vitamin E-deficient mice using 13C-RRR-αT or 13C-all rac-αT tracers. In experiment 1, 3-week old male wild-type mice were fed a vitamin E-deficient diet for 0, 1, 2, or 3 weeks (n = 5/time point). Tissue αT levels were analyzed by HPLC-PDA. Feeding a vitamin E-deficient diet for up to 3 weeks decreased total αT concentrations in all analyzed tissues except the brain, which maintained its αT level. In experiment 2, a 2-week αT-depletion period was followed by administration of a single oral dose of 0.5 mg of 13C-RRR-αT or 13C-all rac-αT. At 12 hr, 1, 2, and 4 days post-dose, serum and multiple tissues were collected (n = 3/time point). αT was quantified by HPLC-PDA, and 13C-αT enrichment was determined by LC-MS. Both sources of 13C-αT reached maximum serum levels at 12 hr post-dose. 13C-RRR-αT levels were significantly higher than 13C-all rac-αT in serum at 1 d post-dose, and in heart, lungs, and kidney at 2d post-dose. In brain, 13C-RRR-αT concentrations were significantly higher than 13C-all rac-αT at 2 and 4 d post-dose. At 4 d post-dose, 13C-αT levels were similar between the 2 sources in examined tissues except for brain and adipose tissue where 13C-RRR-αT was higher. In conclusion, αT bioaccumulation over time varied substantially depending on αT source and tissue type.

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