The effects of tocotrienols intake on obesity, blood pressure, inflammation, liver and glucose biomarkers: a meta-analysis of randomized controlled trials

Fengxiang Li, Biao Xu, Samira Soltanieh, Fernando Zanghelini, Ahmed Abu-Zaid, Jian Sun

Crit Rev Food Sci Nutr . 2021 Apr 28;1-14. doi: 10.1080/10408398.2021.1911926. Online ahead of print.

Abstract

The objective of this study is to accomplish a systematic review and meta-analysis of all randomized controlled trials that dissected the influence of tocotrienol supplementation on various anthropometric and cardiometabolic indices in all individuals, irrespective of health condition. This research was carried out in line with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement guidelines. 17 eligible articles were included in the final quantitative analysis. Current study revealed that tocotrienol consumption was not associated with CRP, WC, MDA, BMI, IL-6, HbA1C, ALT, AST, creatinine TNF-α, FPG, BW, DBP, and SBP. We did observe an overall increase in BW (SMD: 0.063 kg, 95% CI: -0.200, 0.327, p = 0.637) and DBP (SMD: 0.249 mmHg, 95% CI: 0.053, 0.446, p = 0.013). In addition, a significant reduction in SBP was observed (SMD: -0.616 mmHg, 95% CI: -1.123, -0.110, p = 0.017). In summary, our meta-analysis revealed that tocotrienol consumption was associated with increase in BW and DBP and decrease in SBP. Significant associations were not observed for other outcomes.

Wajiha Mahjabeen, Dilshad Ahmed Khan, Shakeel Ahmed Mirza, Muhammad Amjad Pervez

Phytother Res . 2021 Apr 25. doi: 10.1002/ptr.7113. Online ahead of print.

Abstract

The study aimed to ascertain the effects of delta-tocotrienol (δT3) supplementation on glycemic control, oxidative stress, inflammation and related micro-ribonucleic acid (miRNA) expression in patients with type 2 diabetes mellitus (T2DM). Total 110 patients of T2DM on oral hypoglycemic agents, were randomly divided into tocotrienol and placebo groups and given 250 mg δT3 or cellulose soft gel capsule once daily respectively for 24 weeks. Glycemic control, oxidative stress, inflammatory biomarkers, and miRNAs expression were measured in serum at baseline and end of the intervention by using standard laboratory methods. Compared to the placebo, δT3 supplementation resulted in a significant (p ≤ .05) reduction [mean difference (95% confidence interval)] in plasma glucose [-0.48 (-0.65, -0.30)], insulin [-1.19 (-1.51, -0.87)], homeostatic model assessment of insulin resistance [-0.67 (-0.86, -0.49)], glycosylated hemoglobin [-0.53 (-0.79, -0.28)], malondialdehyde [-0.34 (-0.45, -0.22)], high sensitive-C-reactive protein[-0.35 (-0.54, -0.16)], tumor necrosis factor-alpha [-1.22 (-1.62, -0.83)], and interleukin-6[-2.30 (-2.91, -1.68)]. More than twofold downregulation in miRNA-375, miRNA-34a, miRNA-21, and upregulation in miRNA-126, miRNA-132 expression was observed in the δT3 group compared to the placebo. The study demonstrated that δT3 supplementation in addition to oral hypoglycemic agents, improved glycemic control, inflammation, oxidative stress, and miRNA expression in T2DM without any adverse effect. Thus, δT3 might be considered as an effective dietary supplement to prevent long-term diabetic complications.

A M Shamseldeen, M Hamzawy, N A Mahmoud, L Rashed, S S Kamar, L A Harb, N Sharawy

J Biol Regul Homeost Agents . Mar-Apr 2021;35(2):457-471. doi: 10.23812/20-693-A.

Abstract

Diet pattern is an emerging risk factor for renal disease. The mechanism by which high-fat high fructose (western) diet mediates renal injury is not yet fully understood. The objective of the present study was to investigate the relationship between endoplasmic reticulum (ER) stress and autophagy in the development of renal impairment and aggravation of the inflammatory response. Eighty male rats were randomly divided into four groups as follows: a standard diet-fed (ConD), a high-fat high fructose diet fed (HFHF-V), ConD fed and orally supplemented with vitamin E (ConD-E), and HFHF fed and orally supplemented vitamin E (HFHF-E). After 12 weeks, either lipopolysaccharide (LPS) or saline was injected. We found that upregulation of endoplasmic reticulum stress-related proteins rendered the cells susceptible to injury induced by dysbiosis and microbiota-derived metabolites. A downregulation of autophagy and upregulation of caspase-12 resulted in the loss of intestinal integrity and renal tubular injury. Maintained ER stress also increased the inflammatory response to LPS. In contrast, vitamin E effectively ameliorated ER stress and promoted autophagy to protect intestinal and renal tissues. Our results provide insight into the influences of sustained ER stress activation and autophagy inhibition on the development of renal injury, which may contribute also to the enhanced inflammatory response.

Anca Ungurianu, Anca Zanfirescu, Georgiana Nițulescu, Denisa Margină

Antioxidants (Basel) . 2021 Apr 21;10(5):634. doi: 10.3390/antiox10050634.

Abstract

Vitamin E, comprising tocopherols and tocotrienols, is mainly known as an antioxidant. The aim of this review is to summarize the molecular mechanisms and signaling pathways linked to inflammation and malignancy modulated by its vitamers. Preclinical reports highlighted a myriad of cellular effects like modulating the synthesis of pro-inflammatory molecules and oxidative stress response, inhibiting the NF-κB pathway, regulating cell cycle, and apoptosis. Furthermore, animal-based models have shown that these molecules affect the activity of various enzymes and signaling pathways, such as MAPK, PI3K/Akt/mTOR, JAK/STAT, and NF-κB, acting as the underlying mechanisms of their reported anti-inflammatory, neuroprotective, and anti-cancer effects. In clinical settings, not all of these were proven, with reports varying considerably. Nonetheless, vitamin E was shown to improve redox and inflammatory status in healthy, diabetic, and metabolic syndrome subjects. The anti-cancer effects were inconsistent, with both pro- and anti-malignant being reported. Regarding its neuroprotective properties, several studies have shown protective effects suggesting vitamin E as a potential prevention and therapeutic (as adjuvant) tool. However, source and dosage greatly influence the observed effects, with bioavailability seemingly a key factor in obtaining the preferred outcome. We conclude that this group of molecules presents exciting potential for the prevention and treatment of diseases with an inflammatory, redox, or malignant component.

Chwan-Li Shen, Sivapriya Ramamoorthy, Gurvinder Kaur, Jannette M Dufour, Rui Wang, Huanbiao Mo, Bruce A Watkins

Nutrients . 2021 Apr 13;13(4):1267. doi: 10.3390/nu13041267.

Abstract

Obesity and its related complications are a world-wide health problem. Dietary tocotrienols (TT) have been shown to improve obesity-associated metabolic disorders, such as hypercholesterolemia, hyperglycemia, and gut dysbiosis. This study examined the hypothesis that the antioxidant capacity of TT alters metabolites of oxidative stress and improves systemic metabolism. C57BL/6J mice were fed either a high-fat diet (HFD control) or HFD supplemented with 800 mg annatto-extracted TT/kg (HFD+TT800) for 14 weeks. Sera from obese mice were examined by non-targeted metabolite analysis using UHPLC/MS. Compared to the HFD group, the HFD+TT800 group had higher levels of serum metabolites, essential amino acids (lysine and methionine), sphingomyelins, phosphatidylcholine, lysophospholipids, and vitamins (pantothenate, pyridoxamine, pyridoxal, and retinol). TT-treated mice had lowered levels of serum metabolites, dicarboxylic fatty acids, and inflammatory/oxidative stress markers (trimethylamine N-oxide, kynurenate, 12,13-DiHOME, and 13-HODE + 9-HODE) compared to the control. The results suggest that TT supplementation lowered inflammation and oxidative stress (oxidized glutathione and GSH/GSSH) and improved macronutrient metabolism (carbohydrates) in obese mice. Thus, TT actions on metabolites were beneficial in reducing obesity-associated hypercholesterolemia/hyperglycemia. The effects of a non-toxic dose of TT in mice support the potential for clinical applications in obesity and metabolic disease.

Yan Yi Koay, Gerald Chen Jie Tan, Sonia Chew Wen Phang, J-Ian Ho, Pei Fen Chuar, Loon Shin Ho, Badariah Ahmad, Khalid Abdul Kadir

Nutrients . 2021 Jan 18;13(1):258. doi: 10.3390/nu13010258.

Abstract

Diabetic kidney disease (DKD) is a debilitating complication of diabetes, which develops in 40% of the diabetic population and is responsible for up to 50% of end-stage renal disease (ESRD). Tocotrienols have shown to be a potent antioxidant, anti-inflammatory, and antifibrotic agent in animal and clinical studies. This study evaluated the effects of 400 mg tocotrienol-rich vitamin E supplementation daily on 59 DKD patients over a 12-month period. Patients with stage 3 chronic kidney disease (CKD) or positive urine microalbuminuria (urine to albumin creatinine ratio; UACR > 20-200 mg/mmol) were recruited into a randomized, double-blind, placebo-controlled trial. Patients were randomized into either intervention group (n = 31) which received tocotrienol-rich vitamin E (Tocovid SupraBio^TM; Hovid Berhad, Ipoh, Malaysia) 400 mg daily or a placebo group which received placebo capsules (n = 28) for 12 months. HbA1c, renal parameters (i.e., serum creatinine, eGFR, and UACR), and serum biomarkers were collected at intervals of two months. Tocovid supplementation significantly reduced serum creatinine levels (MD: -4.28 ± 14.92 vs. 9.18 ± 24.96), p = 0.029, and significantly improved eGFR (MD: 1.90 ± 5.76 vs. -3.29 ± 9.24), p = 0.011 after eight months. Subgroup analysis of 37 patients with stage 3 CKD demonstrated persistent renoprotective effects over 12 months; Tocovid improved eGFR (MD: 4.83 ± 6.78 vs. -1.45 ± 9.18), p = 0.022 and serum creatinine (MD: -7.85(20.75) vs. 0.84(26.03), p = 0.042) but not UACR. After six months post washout, there was no improvement in serum creatinine and eGFR. There were no significant changes in the serum biomarkers, TGF-β1 and VEGF-A. Our findings verified the results from the pilot phase study where tocotrienol-rich vitamin E supplementation at two and three months improved kidney function as assessed by serum creatinine and eGFR but not UACR.

Roberto Ambra, Sonia Manca, Guido Leoni, Barbara Guantario, Raffaella Canali, Raffaella Comitato

Molecules . 2020 Dec 31;26(1):163. doi: 10.3390/molecules26010163.

Abstract

We previously demonstrated that apoptosis induced by tocotrienols (γ and δT3) in HeLa cells is preceded by Ca²⁺ release from the endoplasmic reticulum. This event is eventually followed by the induction of specific calcium-dependent signals, leading to the expression and activation of the gene encoding for the IRE1α protein and, in turn, to the alternative splicing of the pro-apoptotic protein sXbp1 and other molecules involved in the unfolded protein response, the core pathway coping with EndoR stress. Here, we showed that treatment with T3s induces the expression of a specific set of miRNAs in HeLa cells. Data interrogation based on the intersection of this set of miRNAs with a set of genes previously differentially expressed after γT3 treatment provided a few miRNA candidates to be the effectors of EndoR-stress-induced apoptosis. To identify the best candidate to act as the effector of the Xbp1-mediated apoptotic response to γT3, we performed in silico analysis based on the evaluation of the highest ∆ in Gibbs energy of different mRNA-miRNA-Argonaute (AGO) protein complexes. The involvement of the best candidate identified in silico, miR-190b, in Xbp1 splicing was confirmed in vitro using T3-treated cells pre-incubated with the specific miRNA inhibitor, providing a preliminary indication of its role as an effector of EndoR-stress-induced apoptosis.

Hui-Fang Guo, Razana Mohd Ali, Roslida Abd Hamid, Sui Kiat Chang, Mohammed Habibur Rahman, Zaida Zainal, Huzwah Khaza'ai

Int J Low Extrem Wounds . 2020 Nov 26;1534734620971066. doi: 10.1177/1534734620971066. Online ahead of print.

Abstract

Our previous study has demonstrated that epidermal growth factor (EGF) with tocotrienol-rich fraction (TRF) cream formulation accelerating postburn wound healing with deep partial-thickness burn in rats. Current study was conducted to determine the gene expression levels related to burn wound healing process. A total of 180 Sprague-Dawley rats were randomly divided into 6 groups: untreated control, treated with Silverdin cream, base cream, base cream with 0.00075% EGF, base cream with 3% TRF or base cream with 0.00075% EGF, and 3% TRF, respectively. Burn wounds were created and the above-mentioned creams were applied once daily. Six animals from each group were sacrificed on days 3, 7, 11, 14, and 21 postburn. RNA was extracted from wound tissues and quantitative real-time polymerase chain reaction was performed to analyze the 9 wound healing-related genes against time postburn. Results demonstrated that topically applied EGF + TRF formulation downregulated the expression levels of IL-6 (interluekin-6), TNF-α (tumor necrosis factor-α) and iNOS (inducible nitric oxide synthase) throughout the whole healing process. TGF-β1 (transforming growth factor-β) and VEGF-A (vascular endothelial growth factor-A) were reduced on day 14 postburn. On the contrary, increased expression of Collagen-1 in the early stage of wound healing was observed with no effects on epidemal growth factor receptor (EGFR). The results showed beneficial application of EGF + TRF cream in the treatment of burn wound since it accelerated wound healing by relieving oxidative stress, decreasing inflammation, and promoting proper tissue modelling in the burn wound.

Minnja S Hartmann, Soraya Mousavi, Stefan Bereswill, Markus M Heimesaat

Eur J Microbiol Immunol (Bp) . 2020 Nov 5. doi: 10.1556/1886.2020.00020. Online ahead of print.

Abstract

The use of antibiotics has provoked an emergence of various multidrug-resistant (MDR) bacteria. Infectious diseases that cannot be treated sufficiently with conventional antibiotic intervention strategies anymore constitue serious threats to human health. Therefore, current research focus has shifted to alternative, antibiotic-independent therapeutic approaches. In this context, vitamin E constitutes a promising candidate molecule due to its multi-faceted modes of action. Therefore, we used the PubMed database to perform a comprehensive literature survey reviewing studies addressing the antimicrobial properties of vitamin E against bacterial pathogens including MDR bacteria. The included studies published between 2010 and 2020 revealed that given its potent synergistic antimicrobial effects in combination with distinct antibiotic compounds, vitamin E constitutes a promising adjunct antibiotic treatment option directed against infectious diseases caused by MDR bacteria such as Pseudomonas aeruginosa, Burkholderia cenocepacia and methicillin-resistant Staphylococcus aureus (MRSA). In conclusion, the therapeutic value of vitamin E for the treatment of bacterial infections should therefore be investigated in future clinical studies.

Lexie Harlan, London T Mena, Latha Ramalingam, Shasika Jayarathne, Chwan-Li Shen, Naima Moustaid-Moussa

Nutrients . 2020 Oct 30;12(11):3356. doi: 10.3390/nu12113356.

Abstract

Chronic low-grade inflammation is a primary characteristic of obesity and can lead to other metabolic complications including insulin resistance and type 2 diabetes (T2D). Several anti-inflammatory dietary bioactives decrease inflammation that accompanies metabolic diseases. We are specifically interested in delta-tocotrienol, (DT3) an isomer of vitamin E, and tart cherry anthocyanins (TCA), both of which possess individual anti-inflammatory properties. We have previously demonstrated that DT3 and TCA, individually, reduced systemic and adipose tissue inflammation in rodent models of obesity. However, whether these compounds have combinatorial effects has not been determined yet. Hence, we hypothesize that a combined treatment of DT3 and TCA will have great effects in reducing inflammation in adipocytes, and that these effects are mediated via the nuclear factor kappa-light-chain-enhancer of activated B cells (NFkB), a major inflammatory transcription factor. We used 3T3-L1 adipocytes and treated them with 1-5 µM doses of DT3 along with tart cherry containing 18-36 µg anthocyanin/mL, to assess effects on inflammation. Neither DT3 nor TCA, nor their combinations had toxic effects on adipocytes. Furthermore, pro-inflammatory markers interleukin-6 (IL-6) and p-65 (subunit of NFkB) were reduced at the protein level in media collected from adipocytes with both individual and combined treatments. Additionally, other downstream targets of NFkB including macrophage inflammatory protein 2 (Mip2), and Cyclooxygenase-2 (Cox2) were also significantly downregulated (p ≤ 0.05) when treated with individual and combined doses of DT3 and TCA with no additional combinatorial effects. In summary, DT3 and TCA individually, are beneficial in reducing inflammation with no additional combinatorial effects.