Monthly Archives: October 2018

Tocotrienol from palm may slow the progression of diabetic kidney disease, says new study

Supplementation with a full-spectrum palm tocotrienol complex may slow the progression of diabetic kidney disease in those with type 2 diabetes, a new study published in Nutrients1 found. Patients with diabetic kidney disease have an increased risk of cardiovascular disease events, hospitalization, cognitive dysfunction, and poor quality of life, say the researchers. In the randomized, double-blind, placebo-controlled trial, 45 patients who have had type 2 diabetes for an average of 18.5 years, and diabetic kidney disease, were assigned to receive either placebo or the tocotrienol complex (400 mg/day) for eight weeks.

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An evaluation of crude palm oil (CPO) and tocotrienol rich fraction (TRF) of palm oil as percutaneous permeation enhancers using full-thickness human skin

Singh I, Nair RS, Gan S, Cheong V, Morris A

Pharm Dev Technol. 2018 Oct 3:1-7. doi: 10.1080/10837450.2018.1509347. [Epub ahead of print]

Abstract

The drawbacks associated with chemical skin permeation enhancers such as skin irritation and toxicity necessitated the research to focus on potential permeation enhancers with a perceived lower toxicity. Crude palm oil (CPO) is obtained by direct compression of the mesocarp of the fruit of the oil palm belonging to the genus Elaeis. In this research, CPO and tocotrienol-rich fraction (TRF) of palm oil were evaluated for the first time as skin permeation enhancers using full-thickness human skin. The in vitro permeation experiments were conducted using excised human skin mounted in static upright ‘Franz-type’ diffusion cells. The drugs selected to evaluate the enhancing effects of these palm oil derivatives were 5-fluorouracil, lidocaine and ibuprofen: compounds covering a wide range of Log p values. It was demonstrated that CPO and TRF were capable of enhancing the percutaneous permeation of drugs across full-thickness human skin in vitro. Both TRF and CPO were shown to significantly enhance the permeation of ibuprofen with flux values of 30.6 µg/cm2 h and 23.0 µg/cm2 h respectively, compared to the control with a flux of 16.2 µg/cm2 h. The outcome of this research opens further scope for investigation on the transdermal penetration enhancement activity of pure compounds derived from palm oil.

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Tocopherol suppresses 24(S)-hydroxycholesterol-induced cell death via inhibition of CaMKII phosphorylation

Kimura Y, Asa M, Urano Y, Saito Y, Nishikawa K, Noguchi N

Biochimie. 2018 Oct;153:203-209. doi: 10.1016/j.biochi.2018.07.004. Epub 2018 Jul 7.

Abstract

Although 24(S)-hydroxycholesterol (24S-OHC) plays an important role to maintain homeostasis of cholesterol in the brain, it induces neuronal cell death at high concentrations. 24S-OHC-induced cell death was suppressed by γ-tocopherol (γ-Toc) but not by γ-tocotrienol (γ-Toc3) in a similar way to α-tocopherol (α-Toc) and α-tocotrienol (α-Toc3) in human neuroblastoma SH-SY5Y cells. Both γ-Toc and γ-Toc3 significantly inhibited cumene hydroperoxide-induced cell death, as previously shown in the case of α-Toc and α-Toc3. Lipid droplet-like structure formation induced by 24S-OHC was suppressed by neither γ-Toc nor γ-Toc3. The phosphorylation of calcium/calmodulin-dependent protein kinase II (CaMKII) was induced by 24S-OHC, which was suppressed by CaMKII phosphorylation-site inhibitor mM3 but not by calmodulin-binding-site inhibitor KN62. A calcium chelator, BAPTA-AM, inhibited calcium ionophore A23187-induced CaMKII phosphorylation but not 24S-OHC-induced CaMKII phosphorylation. Receptor-interacting protein kinase 1 (RIPK1) phosphorylation induced by 24S-OHC was not inhibited by either mM3 or KN62, suggesting that CaMKII activation does not affect RIPK1 phosphorylation. Knockdown of RIPK1 using siRNA induced not only inhibition of CaMKII phosphorylation but also reduction of total CaMKII protein levels, suggesting that RIPK1 may regulate CaMKII signalling. 24S-OHC-induced RIPK1 phosphorylation was inhibited by neither α-Toc nor α-Toc3. In contrast, CaMKII phosphorylation induced by 24S-OHC was significantly suppressed by α-Toc but not by α-Toc3. These results suggest that CaMKII activation is involved in the mechanism of 24S-OHC-induced cell death and that Toc inhibits the cell death via inhibition of CaMKII activation through a RIPK1 phosphorylation-independent pathway.

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Vitamin E Analogue Protects Red Blood Cells against Storage-Induced Oxidative Damage

Antosik A, Czubak K, Cichon N, Nowak P, Zbikowska H

Transfus Med Hemother. 2018 Oct;45(5):347-354. doi: 10.1159/000486605. Epub 2018 Mar 9

Abstract

BACKGROUND:

To investigate i) the effects of Trolox® or mannitol, which represent two different classes of antioxidants, on oxidative changes generated in manually isolated red blood cells (RBCs) from citrate-phosphate-dextrose (CPD) preserved whole blood, followed by up to 20 days refrigerated storage, and ii) whether Trolox supplemented to the blood bank-manufactured saline-adenine-glucose-mannitol (SAGM) preserved RBC units would offer better storage conditions compared with SAGM alone.

METHODS:

The percentage of hemolysis and extracellular activity of lactate dehydrogenase (LDH) was measured to assess RBC membrane integrity. Lipid peroxidation, reduced glutathione (GSH) levels and total antioxidant capacity (TAC) were quantified by thiobarbituric acid-reactive substances (TBARS), Ellman’s reagent and 2, 2′-azinobis-(3-ethylbenzothiazoline-6-sulfonate) (ABTS.+) based assay, respectively.

RESULTS:

Trolox was little more effective than mannitol in protecting against progressive RBC hemolysis. Trolox (0.125-3.125 mmol/l) inhibited storage-induced leakage of LDH, lipid peroxidation, and to a lesser extent GSH depletion. Mannitol at these concentrations neither inhibited TBARS formation nor prevented GSH depletion. RBC units stored in SAGM-Trolox had significantly lower hemolysis, LDH leakage, and lipid peroxidation level compared to RBCs stored in SAGM.

CONCLUSION:

There is evidence of the beneficial effects of supplementing RBC-additive solutions with membrane-interacting antioxidants such as vitamin E analogues.

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Effects of Vitamin E more diverse than thought

At the University of Innsbruck, a pharmacy team has been inquiring about normal items for their anti-inflammatory impacts for quite a while. The investigations will be done together with a worldwide consortium with the cooperation of scientists from Germany, France, and Italy. In these investigations, information rose that indicated vitamin E and related structures as an on-screen character in the inflammatory procedure.

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Induction of peroxisomal changes in oligodendrocytes treated with 7-ketocholesterol: Attenuation by α-tocopherol

Nury T, Sghaier R, Zarrouk A, Ménétrier F, Uzun T, Leoni V, Caccia C, Meddeb W, Namsi A, Sassi K, Mihoubi W, Riedinger JM, Cherkaoui-Malki M, Moreau T, Vejux A, Lizard G

Biochimie. 2018 Oct;153:181-202. doi: 10.1016/j.biochi.2018.07.009. Epub 2018 Jul 19.

Abstract

The involvement of organelles in cell death is well established especially for endoplasmic reticulum, lysosomes and mitochondria. However, the role of the peroxisome is not well known, though peroxisomal dysfunction favors a rupture of redox equilibrium. To study the role of peroxisomes in cell death, 158 N murine oligodendrocytes were treated with 7-ketocholesterol (7 KC: 25-50 μM, 24 h). The highest concentration is known to induce oxiapoptophagy (OXIdative stress + APOPTOsis + autoPHAGY), whereas the lowest concentration does not induce cell death. In those conditions (with 7 KC: 50 μM) morphological, topographical and functional peroxisome alterations associated with modifications of the cytoplasmic distribution of mitochondria, with mitochondrial dysfunction (loss of transmembrane mitochondrial potential, decreased level of cardiolipins) and oxidative stress were observed: presence of peroxisomes with abnormal sizes and shapes similar to those observed in Zellweger fibroblasts, lower cellular level of ABCD3, used as a marker of peroxisomal mass, measured by flow cytometry, lower mRNA and protein levels (measured by RT-qPCR and western blotting) of ABCD1 and ABCD3 (two ATP-dependent peroxisomal transporters), and of ACOX1 and MFP2 enzymes, and lower mRNA level of DHAPAT, involved in peroxisomal β-oxidation and plasmalogen synthesis, respectively, and increased levels of very long chain fatty acids (VLCFA: C24:0, C24:1, C26:0 and C26:1, quantified by gas chromatography coupled with mass spectrometry) metabolized by peroxisomal β-oxidation. In the presence of 7 KC (25 μM), slight mitochondrial dysfunction and oxidative stress were found, and no induction of apoptosis was detected; however, modifications of the cytoplasmic distribution of mitochondria and clusters of mitochondria were detected. The peroxisomal alterations observed with 7 KC (25 μM) were similar to those with 7 KC (50 μM). In addition, data obtained by transmission electron microcopy and immunofluorescence microscopy by dual staining with antibodies raised against p62, involved in autophagy, and ABCD3, support that 7 KC (25-50 μM) induces pexophagy. 7 KC (25-50 μM)-induced side effects were attenuated by α-tocopherol but not by α-tocotrienol, whereas the anti-oxidant properties of these molecules determined with the FRAP assay were in the same range. These data provide evidences that 7 KC, at concentrations inducing or not cell death, triggers morphological, topographical and functional peroxisomal alterations associated with minor or major mitochondrial changes.

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δ-Tocotrienol, Isolated from Rice Bran, Exerts an Anti-Inflammatory Effect via MAPKs and PPARs Signaling Pathways in Lipopolysaccharide-Stimulated Macrophages

Shen J, Yang T, Xu Y, Luo Y, Zhong X, Shi L, Hu T, Guo T, Nie Y, Luo F, Lin Q

Int J Mol Sci. 2018 Oct 4;19(10). pii: E3022. doi: 10.3390/ijms19103022.

Abstract

δ-Tocotrienol, an important component of vitamin E, has been reported to possess some physiological functions, such as anticancer and anti-inflammation, however their molecular mechanisms are not clear. In this study, δ-tocotrienol was isolated and purified from rice bran. The anti-inflammatory effect and mechanism of δ-tocotrienol against lipopolysaccharides (LPS) activated pro-inflammatory mediator expressions in RAW264.7 cells were investigated. Results showed that δ-tocotrienol significantly inhibited LPS-stimulated nitric oxide (NO) and proinflammatory cytokine (TNF-α, IFN-γ, IL-1β and IL-6) production and blocked the phosphorylation of c-Jun N-terminal kinase (JNK) and extracellular regulated protein kinases 1/2 (ERK1/2). δ-Tocotrienol repressed the transcriptional activations and translocations of nuclear factor-kappa B (NF-κB) and activator protein-1 (AP-1), which were closely related with downregulated cytokine expressions. Meanwhile, δ-tocotrienol also affected the PPAR signal pathway and exerted an anti-inflammatory effect. Taken together, our data showed that δ-tocotrienolinhibited inflammation via mitogen-activated protein kinase (MAPK) and peroxisome proliferator-activated receptor (PPAR) signalings in LPS-stimulated macrophages.

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The Effect of Magnesium and Vitamin E Co-Supplementation on Glycemic Control and Markers of Cardio-Metabolic Risk in Women with Polycystic Ovary Syndrome: A Randomized, Double-Blind, Placebo-Controlled Trial

Jamilian M, Sabzevar NK, Asemi Z

Horm Metab Res. 2018 Oct 4. doi: 10.1055/a-0749-6431. [Epub ahead of print]

Abstract

Data on the effects of magnesium and vitamin E co-supplementation on glycemic control and markers of cardio-metabolic risk of patients with polycystic ovary syndrome (PCOS) were collected. This investigation was conducted to evaluate the effects of magnesium and vitamin E co-supplementation on glycemic control and markers of cardio-metabolic risk in women with PCOS. This randomized, double-blind, placebo-controlled trial was carried out on 60 women with PCOS, aged 18-40 years old. Participants were randomly divided into two groups to receive 250 mg/day magnesium plus 400 mg/day vitamin E supplements or placebo (n=30 each group) for 12 weeks. Fasting blood samples were taken at baseline and after the 12-week intervention to quantify related variables. After the 12-week intervention, compared with the placebo, magnesium and vitamin E co-supplementation led to a significant reduction in serum insulin levels (-1.1±3.0 vs. +1.6±3.7 μIU/ml, p=0.003) and homeostatic model of assessment for insulin resistance (-0.2±0.7 vs. +0.4±0.9, p=0.002), and a significant increase in the quantitative insulin sensitivity check index (+0.01±0.01 vs. -0.009±0.02, p=0.003). Furthermore, magnesium plus vitamin E supplementation significantly decreased serum triglycerides (-15.0±24.4 vs. +6.7±22.2 mg/dl, p=0.001) and VLDL-cholesterol concentrations (-3.0±4.9 vs. +0.6±2.4 mg/dl, P=0.01) compared with the placebo. A trend toward a greater decrease in total cholesterol levels was observed in magnesium plus vitamin Egroup compared to placebo group (-7.0±32.6 vs. +8.1±26.6 mg/dl, p=0.05). In conclusion, magnesium and vitamin E co-supplementation for 12 weeks to PCOS women had beneficial effects on parameters of insulin metabolism and few markers of cardio-metabolic risk.

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Why vitamin E effect is often a matter of luck until now

Vitamin E’s positive effects often fail to manifest themselves as strongly as expected, but sometimes administering vitamin E actually has detrimental effects. An international team has now found a possible cause for this. It has shown that the effect of vitamin E, which is taken as a tablet or capsule, is not based on the vitamin itself, but rather on the effect of a metabolite. This socalled alpha-carboxychromanol has e. g. a promising anti-inflammatory effect.

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