Effects of vitamin E on neurodegenerative diseases: an update

Mehmet Arif Icer, Neslihan Arslan, Makbule Gezmen-Karadag

Acta Neurobiol Exp (Wars) . 2021;81(1):21-33. doi: 10.21307/ane-2021-003.

Abstract

Vitamin E deficiency is associated with many neurological problems. Although the mechanisms of vitamin E action in neurodegenerative diseases are not clear, there are many possible mechanisms. Examples of such mechanisms are the protective effects of vitamin E against oxidative stress damage and its suppressive role in the expression of many genes involved in the development of neurodegeneration. Many studies have evaluated the relationship between vitamin E intake or vitamin E levels in body fluids and neurodegenerative diseases. Some studies concluded that vitamin E can play a protective role in neurodegeneration with respect to diseases such as Alzheimer’s disease (AD), Parkinson’s disease (PD), stroke and amyotrophic lateral sclerosis (ALS). Vitamin E supplementation was also associated with risk factors for some neurodegenerative diseases. In this review, we discuss the possible effects of vitamin E on the development and course of AD, PD, stroke and ALS, and the potential mechanisms involved.

Vitamin E deficiency is associated with many neurological problems. Although the mechanisms of vitamin E action in neurodegenerative diseases are not clear, there are many possible mechanisms. Examples of such mechanisms are the protective effects of vitamin E against oxidative stress damage and its suppressive role in the expression of many genes involved in the development of neurodegeneration. Many studies have evaluated the relationship between vitamin E intake or vitamin E levels in body fluids and neurodegenerative diseases. Some studies concluded that vitamin E can play a protective role in neurodegeneration with respect to diseases such as Alzheimer’s disease (AD), Parkinson’s disease (PD), stroke and amyotrophic lateral sclerosis (ALS). Vitamin E supplementation was also associated with risk factors for some neurodegenerative diseases. In this review, we discuss the possible effects of vitamin E on the development and course of AD, PD, stroke and ALS, and the potential mechanisms involved.

Read More

Tocotrienols Activate Nrf2 Nuclear Translocation and Increase the Antioxidant- Related Hepatoprotective Mechanism in Mice Liver

Ahmed Atia, Nadia S Alrawaiq, Azman Abdullah

Curr Pharm Biotechnol . 2021;22(8):1085-1098. doi: 10.2174/1389201021666200928095950.

Abstract

Background: The most common preparation of tocotrienols is the Tocotrienol-Rich Fraction (TRF). This study aimed to investigate whether TRF induced liver Nrf2 nuclear translocation and influenced the expression of Nrf2-regulated genes.

Methods: In the Nrf2 induction study, mice were divided into control, 2000 mg/kg TRF and diethyl maleate treated groups. After acute treatment, mice were sacrificed at specific time points. Liver nuclear extracts were prepared and Nrf2 nuclear translocation was detected through Western blotting. To determine the effect of increasing doses of TRF on the extent of liver nuclear Nrf2 translocation and its implication on the expression levels of several Nrf2-regulated genes, mice were divided into 5 groups (control, 200, 500 and 1000 mg/kg TRF, and butylated hydroxyanisole-treated groups). After 14 days, mice were sacrificed and liver RNA was extracted for qPCR assay.

Results: 2000 mg/kg TRF administration initiated Nrf2 nuclear translocation within 30 min, reached a maximum level of around 1 h and dropped to half-maximal levels by 24 h. Incremental doses of TRF resulted in dose-dependent increases in liver Nrf2 nuclear levels, along with concomitant dosedependent increases in the expressions of Nrf2-regulated genes.

Conclusion: TRF activated the liver Nrf2 pathway resulting in increased expression of Nrf2-regulated cytoprotective genes.

Read More

Effect of vitamin E on periodontitis: Evidence and proposed mechanisms of action

Saminathan Shadisvaaran, Kok-Yong Chin, Mohd-Said Shahida, Soelaiman Ima-Nirwana, Xin-Fang Leong

J Oral Biosci . 2021 Jun;63(2):97-103. doi: 10.1016/j.job.2021.04.001. Epub 2021 Apr 20.

Abstract

Background: Periodontitis is a noncommunicable inflammatory disease of the soft tissue and bone surrounding the teeth in the jaw, which affects susceptible individuals with poor oral hygiene. A growing interest has been seen in the use of dietary supplements and natural products for the treatment and prevention of periodontitis. Vitamin E consists of two major groups, namely tocopherols and tocotrienols, which are botanical lipophilic compounds with excellent anti-inflammatory and antioxidant properties.

Highlight: This review aimed to summarize the preclinical and clinical findings on the effects of vitamin E on periodontitis. The current literature suggests that vitamin E could improve the periodontal status by correcting redox status imbalance, reducing inflammatory responses, and promoting wound healing, thus highlighting the potential of vitamin E in the management of periodontitis.

Conclusion: Direct evidence for the use of vitamin E supplementation or treatment of periodontitis in humans is still limited. More well-designed and controlled studies are required to ascertain its effectiveness.

Read More

Protective role of vitamin E in testicular development of mice exposed to valproic acid

Daniel Conei, Mariana Rojas, Luis Santamaría, Jennie Risopatrón

Andrologia . 2021 Jun 21;e14140. doi: 10.1111/and.14140. Online ahead of print.

Abstract

Valproic acid (VPA) is a teratogenic antiepileptic, causing alterations in oxidative stress in prenatal development, being altered the development of the male reproductive system. The purpose of this study was to determine the protective effect of vitamin E (VE) on the testicular development in embryos, foetuses and pubertal mice exposed to VPA, VPA+VE and only VE. Sixty pregnant adult female mice were used, to which they were administered 600 mg/kg of VPA (VPA groups), 600 mg/kg of VPA and 200 IU of VE (VPA+VE groups), 200 IU VE (VE groups) and 0.3 ml of 0.9% physiological solution (control groups), showing at 12.5 days post-coital (dpc), 17.5 dpc and 6 weeks postnatal testicular development, and proliferative and apoptotic indices. The groups treated with VPA presented a smaller testicular volume, with greater interstitial space and a delay in the conformation of the testicular cords, shorter lengths and diameters of the germinal epithelium, a smaller number of germline and somatic cells, an increase in cells apoptotic and less proliferation, with significant differences. VE-treated groups behaved similarly to controls. In conclusion, VE reduces the effects caused by VPA throughout testicular development, from embryonic stages, continuing until pubertal stages.

Read More

Associations between vitamin E, oxidative stress markers, total homocysteine levels, and physical activity or cognitive capacity in older adults

Ahmad H Alghadir, Sami A Gabr, Shahnawaz Anwer, Heng Li

Sci Rep . 2021 Jun 18;11(1):12867. doi: 10.1038/s41598-021-92076-4.

Abstract

This study examined the associations between vitamin E, oxidative stress markers, total homocysteine levels, and physical activity or cognitive capacity in older adults. One hundred and six older adults (62 men, 44 women) within the age range of 56-81 years participated. The Global Physical Activity Questionnaire and the Loewenstein Occupational Therapy Cognitive Assessment were used to assess physical activity and cognitive function, respectively. Vitamin E (e.g., α-tocopherol and γ-tocopherol), oxidative stress markers (e.g., total antioxidant capacity and nitric oxide), and total homocysteine were estimated. There were significant associations between physical activity (high versus moderate versus poor) and all biomarkers (all p = 0.000, and p = 0.010 for γ-tocopherol). While total homocysteine and total antioxidant capacity were significantly associated with cognitive capacity (p = 0.000), vitamin E levels (e.g., α-tocopherol and γ-tocopherol) and nitric oxide (p = 0.354, 0.103 and 0.060, respectively) were not related to cognitive capacity in older adults. This study concludes that physical activity was associated with Vitamin E, oxidative stress markers, total homocysteine, and cognitive capacity in older adults. Although cognitive capacity was associated with total homocysteine and total antioxidant capacity, it was unrelated to vitamin E levels and nitric oxide in older adults.

Read More

Protective Effects of Vitamin E on Chemotherapy-Induced Peripheral Neuropathy: A Meta-Analysis of Randomized Controlled Trials

Huikai Miao, Rongzhen Li, Dongni Chen, Jia Hu, Youfang Chen, Chunmei Xu, Zhesheng Wen

Ann Nutr Metab . 2021 Jun 18;1-11. doi: 10.1159/000515620. Online ahead of print.

Abstract

Introduction: Chemotherapy-induced peripheral neuropathy (CIPN) is a common symptom, but prophylactic measures cannot still be carried out effectively. In addition, the efficacy of vitamin E in preventing peripheral neurotoxicity caused by chemotherapy is inconclusive. Therefore, we collected the relevant randomized controlled trials (RCTs) and performed a meta-analysis to examine whether the vitamin E has a positive effect in CIPN.

Methods: We searched PubMed, EMBASE, Cochrane, and other databases in December 2019 for eligible trials. Two reviewers conducted the analysis independently when studies were homogeneous enough.

Results: Eight RCTs, involving 488 patients, were identified. Upon pooling these RCTs, patients who received vitamin E supplementation of 600 mg/day had a lower incidence of CIPN (risk ratio [RR] 0.31; 95% confidence interval [CI] 0.14-0.65; p = 0.002) than the placebo group. Vitamin E played a key role in decreasing the incidence of peripheral neuropathy in the cisplatin chemotherapy group (RR 0.28; 95% CI 0.14-0.54; p = 0.0001). Moreover, vitamin E supplementation significantly decreased patients’ sural amplitude after 3 rounds of chemotherapy (RR -2.66; 95% CI -5.09 to -0.24; p = 0.03) in contrast with that of placebo supplementation, while no significant difference was observed when patients were treated with vitamin E after 6 rounds of chemotherapy. In addition, the vitamin E-supplemented group had better improvement in the neurotoxicity score and lower incidence of reflexes and distal paraesthesias than the control group.

Conclusion: Available data in this meta-analysis showed that vitamin E supplementation can confer modest improvement in the prevention of CIPN.

Read More

The chemoprotective effects of IFN-α-2b on rat hepatocarcinogenesis are blocked by vitamin E supplementation

Marina C Vera, Alvaro Lucci, Anabela C Ferretti, Adriano A Abbondanzieri, Carla G Comanzo, Florencia Lorenzetti, Gerardo B Pisani, María P Ceballos, Maria de L Alvarez, María C Carrillo, Ariel D Quiroga

J Nutr Biochem . 2021 Jun 17;108806. doi: 10.1016/j.jnutbio.2021.108806. Online ahead of print.

Abstract

Many cancer patients receive their classical therapies together with vitamin supplements. However, the effectiveness of these strategies is on debate. Here we aimed to evaluate how vitamin E supplementation affects the anticancer effects of interferon (IFN-α) using an early-model of liver cancer development (initiation-promotion, IP). Male Wistar rats subjected to this model were divided as follows: untreated (IP), IP treated with recombinant IFN-α-2b (6.5 × 105 U/kg), IP treated with vitamin E (50 mg/kg), and IP treated with combination of vitamin E and IFN-α-2b. After treatments rats were fasted and euthanized and plasma and livers were collected. Combined administration of vitamin E and IFN-α-2b induced body weight drop, increased liver apoptosis and low levels of hepatic lipid levels. Interestingly, vitamin E and IFN-α-2b combination also induced an increase in altered hepatic foci number, but not in size. It seems that vitamin E acts on its antioxidant capability in order to block the oxidative stress induced by IFN-α-2b, blocking in turn its beneficial effects on preneoplastic livers, leading to harmful final effects. In conclusion, this study shows that vitamin E supplementation in IFN-α-2b-treated rats exerts unwanted effects; and highlights that in spite of being natural, nutritional supplements may not always exert beneficial outcomes when used as complementary therapy for the treatment of cancer.

Read More

Association Between Vitamin E and Handgrip Strength in the Korean General Population in KNHANES VII (2018

Nodam Park, Soo A Kim, Kiyoung Oh, Yuntae Kim, Siha Park, Joon Yeop Kim, Namhun Heo

Ann Rehabil Med . 2021 Jun 14. doi: 10.5535/arm.21038. Online ahead of print.

Abstract

Objective: To investigate the association between vitamin E and handgrip strength (HGS) with multiple factors.

Methods: A total of 1,814 participants were included (822 men and 981 women) from the Korean subjects of the 7th Korea National Health and Nutrition Examination Survey in 2018. Data were analyzed using multiple logistic regression to determine the correlation between vitamin E and HGS with potential confounding factors.

Results: In the multiple logistic regression model, only the young age group (19-40 years) of men showed a positive relationship between vitamin E and HGS. However, in older age groups (41-80 years) of men and all age groups of women, there was no statistically significant result. After adjusting for confounding factors, young men showed higher vitamin E levels and higher HGS. Conversely, women and older age groups did not show significant results after adjusting for confounding factors.

Conclusion: In this study, the serum vitamin E level had a positive effect on HGS in young men (<40 years). Further research is needed on this topic regarding vitamin E intake and other objective measures.

Read More

The effect of vitamin E treatment on selected immune and oxidative parameters in Kivircik ewes suffering from transport stress

Erdem Danyer, Tanay Bilal, Ayşen Altiner, İsmail Aytekin, Hasan Atalay

J Anim Physiol Anim Nutr (Berl) . 2021 Jun 11. doi: 10.1111/jpn.13560. Online ahead of print.

Abstract

The study aimed to investigate the effects of vitamin E injection for the prevention of transport stress on ewes. Kivircik ewes (2-3 years old, n = 24) were randomly separated into three groups; G1 (Control) and G2 treated with 14 ml. saline as the placebo, G3 treated with 2100 IU/ind. DL-alpha-tocopherol acetate prior to transport. G2 and G3 were transported at 80 km/h for 4 h on a truck. Serum samples were obtained before (T0) and after (T1) transport. Serum cortisol, catalase, IgG, ceruloplasmin, C-reactive protein, complement component 4, interleukin-1 beta, tumour necrosis factor-alpha, glutathione peroxidase (GPx), superoxide dismutase, malondialdehyde analyses performed by ELISA, and serum alpha-tocopherol concentrations were evaluated by HPLC-UV. Wilcoxon and Kruskal-Wallis tests were used for statistical assessments (p < 0.05). Alpha-tocopherol concentrations were founded 1.22 ± 0.82, 0.27 ± 0.14 and 0.14 ± 0.07 µmol/L, respectively, in G1, G2 and G3 at T1. Alpha-tocopherol concentration decreased significantly in G2 between T0 and T1. GPx concentrations were increased twofold in G2 and G3 between T0 and T1 (p < 0.01). As a result, G2 alpha-tocopherol concentrations decreased but, the stress and oxidative parameters tested in this study were not affected by treating 2100 IU/ind. DL-alpha-tocopherol acetate before transport.

Read More

Vitamin A and Vitamin E: Will the Real Antioxidant Please Stand Up?

William S Blaner, Igor O Shmarakov, Maret G Traber

Annu Rev Nutr . 2021 Jun 11. doi: 10.1146/annurev-nutr-082018-124228. Online ahead of print.

Abstract

Vitamin A, acting through its metabolite, all-trans-retinoic acid, is a potent transcriptional regulator affecting expression levels of hundreds of genes through retinoic acid response elements present within these genes. However, the literature is replete with claims that consider vitamin A to be an antioxidant vitamin, like vitamins C and E. This apparent contradiction in the understanding of how vitamin A acts mechanistically within the body is a major focus of this review. Vitamin E, which is generally understood to act as a lipophilic antioxidant protecting polyunsaturated fatty acids present in membranes, is often proposed to be a transcriptional regulator. The evaluation of this claim is another focus of the review. We conclude that vitamin A is an indirect antioxidant, whose indirect function is to transcriptionally regulate a number of genes involved in mediating the body’s canonical antioxidant responses. Vitamin E, in addition to being a direct antioxidant, enables the increase of peroxidized lipids that alter both metabolic pathways and gene expression profiles within tissues and cells. However, there is little compelling evidence that vitamin E has a direct transcriptional mechanism like that of vitamin A. Thus, we propose that the term antioxidant not be applied to vitamin A, and we discourage the use of the term transcriptional mediator when discussing vitamin E.

Read More