Cellular, molecular and clinical aspects of vitamin E on atherosclerosis prevention

Association of independent dietary antioxidant intake, and CDAI level with risks of all-cause and cardiovascular-cause death among population with cardiovascular disease

BACKGROUND

Antioxidants have been investigated for their potential to prevent cardiovascular disease (CVD); however, their association with mortality risk in patients with CVD has not been thoroughly evaluated. The aim of this study was to assess the relationship between individual antioxidants and the composite dietary antioxidant index (CDAI) with the risk of death in patients with CVD.

METHODS

This study included 1,395 participants with CVD from the National Health and Nutrition Examination Survey (2001-2010). Cox proportional hazards models were employed to estimate the hazard ratios (HRs) and 95% confidence intervals （CIs） for individual antioxidants (including vitamins A, vitamins C, vitamins E, selenium, carotenoids and zinc) and CDAI levels in relation to all-cause mortality and cardiovascular death. Additionally, restricted cubic splines (RCS) were utilized to further investigate potential nonlinear relationships.

RESULTS

Individual antioxidants, including vitamin C and vitamin E, were inversely associated with both all-cause and CVD-cause mortality in patients with CVD. As for CDAI, compared to participants in the first tertile(T1) of CDAI, the fully adjusted HR for all-cause mortality in the third tertile (T3) was 0.62 (95% CI: 0.46, 0.85). For CVD mortality, individuals with T3 of CDAI also exhibited a significantly reduced risk, with an HR of 0. 58 (95% CI: 0. 35,0.97). RCS analysis revealed a linear relationship between CDAI and all-cause mortality, while a non-linear, inverted L-shaped relationship was observed for CVD mortality.

CONCLUSION

Higher levels of dietary antioxidants are associated with a reduced risk of both all-cause and cardiovascular-cause mortality in patients with CVD. These findings suggest that increasing antioxidant intake may serve as a potential strategy for improving outcomes in this population.

Coenzyme Q10 in atherosclerosis

Atherosclerotic disease is a chronic disease that predominantly affects the elderly and is the most common cause of cardiovascular death worldwide. Atherosclerosis is closely related to processes such as abnormal lipid transport and metabolism, impaired endothelial function, inflammation, and oxidative stress. Coenzyme Q10 (CoQ10) is a key component of complex Ⅰ in the electron transport chain and an important endogenous antioxidant that may play a role in decelerating the progression of atherosclerosis. Here, the different forms of CoQ10 presence in the electron transport chain are reviewed, as well as its physiological role in regulating processes such as oxidative stress, inflammatory response, lipid metabolism and cellular autophagy. It was also found that CoQ10 plays beneficial effects in atherosclerosis by mitigating lipid transportation, endothelial inflammation, metabolic abnormalities, and thrombotic processes from the perspectives of molecular mechanisms, animal experiments, and clinical evidence. Besides, the combined use of CoQ10 with other drugs has better synergistic therapeutic effects. It seems reasonable to suggest that CoQ10 could be used in the treatment of atherosclerotic cardiovascular diseases while more basic and clinical studies are needed.

Association Between Nutrients and Cardiovascular Diseases

Cardiovascular diseases (CVD) constitute a leading cause of global mortality. Inflammation and oxidative stress are key molecular underpinnings of CVD pathogenesis. This comprehensive review explores the multifaceted role of nutrients in cardiovascular health beyond their impact on cardiac events. The manuscript examines the influence of macronutrients such as fats and carbohydrates, as well as micronutrients including vitamins and folate, on CVD. Additionally, the interplay between dietary supplements and CVD risk reduction is investigated. The purpose of this manuscript is to provide a comprehensive overview of the diverse mechanisms through which nutrients contribute to cardiovascular well-being, addressing both cardioprotective effects and their broader implications. Through an analysis of pertinent studies, we illuminate the complex relationship between nutrition, lifestyle, and cardiovascular health, underscoring the significance of a holistic approach to CVD prevention and management.

The effect of almond intake on cardiometabolic risk factors, inflammatory markers, and liver enzymes: A systematic review and meta-analysis

Almond intake may be correlated with improvements in several cardiometabolic parameters, but its effects are controversial in the published literature, and it needs to be comprehensively summarized. We conducted a systematic search in several international electronic databases, including MEDLINE, EMBASE, Scopus, Web of Science, Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov until April 2021 to identify randomized controlled trials that examined the effects of almond consumption on cardiometabolic risk factors, inflammatory markers, and liver enzymes. Data were pooled using the random-effects model method and presented as standardized mean differences (SMDs) with 95% confidence intervals (CIs). Twenty-six eligible trials were analyzed (n = 1750 participants). Almond intake significantly decreased diastolic blood pressure, total cholesterol, triglyceride, low-density lipoprotein (LDL), non-high-density lipoprotein (HDL), and very LDL (p < 0.05). The effects of almond intake on systolic blood pressure, fasting blood glucose, insulin, hemoglobin A1c, homeostatic model assessment of insulin resistance, C-peptide, alanine aminotransferase, aspartate aminotransferase, gamma-glutamyl transferase, C-reactive protein (CRP), hs-CRP (high sensitivity C-reactive protein), interleukin 6, tumor necrosis factor-α, ICAM (Intercellular Adhesion Molecule), VCAM (Vascular Cell Adhesion Molecule), homocysteine, HDL, ox-LDL, ApoA1, ApoB, and lipoprotien-a were not statistically significant (p > .05). The current body of evidence supports the ingestion of almonds for their beneficial lipid-lowering and antihypertensive effects. However, the effects of almonds on antiinflammatory markers, glycemic control, and hepatic enzymes should be further evaluated via performing more extensive randomized trials.

Dietary Factors Associated with Asthma Development: A Narrative Review and Summary of Current Guidelines and Recommendations

Asthma is a complex disease, caused by a combination of genetic and environmental factors. The prevalence of asthma is increasing too rapidly to be attributable to genetic factors alone. Thus, environmental factors are becoming increasingly recognized as the cause of asthma. Modifying these environmental factors may be a simple approach for asthma prevention. To date, dietary intervention is an interesting modifiable factor because it can be implemented at the population level. The modification of systemic inflammation, oxidation, and microbial composition might be a mechanistic basis for prevention. This review summarizes the mechanistic basis and evidence from clinical studies on the association between dietary factors and asthma development. We also summarize the recommendations from many organizations and regional guidelines to assist the practicing physician to improve patient care.

The Pathogenic Role of Foam Cells in Atherogenesis: Do They Represent Novel Therapeutic Targets?

BACKGROUND

Foam cells, mainly derived from monocytes-macrophages, contain lipid droplets essentially composed of cholesterol in their cytoplasm. They infiltrate the intima of arteries, contributing to the formation of atherosclerotic plaques.

PATHOGENESIS

Foam cells damage the arterial cell wall via the release of proinflammatory cytokines, free radicals, and matrix metalloproteinases, enhancing the plaque size up to its rupture.

THERAPY

A correct dietary regimen seems to be the most appropriate therapeutic approach to minimize obesity, which is associated with the formation of foam cells. At the same time, different types of antioxidants have been evaluated to arrest the formation of foam cells, even if the results are still contradictory. In any case, a combination of antioxidants seems to be more efficient in the prevention of atherosclerosis.

The ameliorating effects of Vitamin E on hepatotoxicity of ecstasy

Background:

The production of stress oxidative condition in body which is caused by consumption of ecstasy (3,4-methylenedioxymethamphetamine [MDMA]) leads to a liver damage. As an antioxidant, Vitamin E can protect cells and tissues against the deleterious effects of free radicals. This study evaluates the protective effects of Vitamin E on MDMA induced liver toxicity.

Materials and Methods:

Twenty-eight male albino mice were randomly assigned to four equal groups. Group 1 received saline (control), Group 2 received MDMA and saline, Group 3 received MDMA, and Vitamin E and Group 4 received Vitamin E. MDMA was injected with single daily dose, three sequential days/week for 5 weeks. At the end of the period, blood samples were collected for a biochemical analysis and then the mice were sacrificed by cervical dislocation for histopathological and biochemical examinations of liver.

Results:

The administration of Vitamin E attenuated the increased levels of alanine transaminase, aspartate transaminase, and alkaline phosphatase enzymes in serum. Vitamin E treatments significantly restored endogenous antioxidant enzymes (reduced glutathione and superoxide dismutase enzyme) activities as compared with MDMA-treated animals. Histological examination of liver revealed significant morphological tissue injuries in hepatocytes after MDMA being used, but in coadministration of vitamin E and MDMA, these morphological alterations reduced.

Conclusion:

The study showed that MDMA administration has adverse effects on the liver. Vitamin E lessened the deleterious impact considerably.

Cytokine storm in aged people with CoV-2: possible role of vitamins as therapy or preventive strategy

BACKGROUND

In December 2019, a novel human-infecting coronavirus, SARS-CoV-2, had emerged. The WHO has classified the epidemic as a "public health emergency of international concern". A dramatic situation has unfolded with thousands of deaths, occurring mainly in the aged and very ill people. Epidemiological studies suggest that immune system function is impaired in elderly individuals and these subjects often present a deficiency in fat-soluble and hydrosoluble vitamins.

METHODS

We searched for reviews describing the characteristics of autoimmune diseases and the available therapeutic protocols for their treatment. We set them as a paradigm with the purpose to uncover common pathogenetic mechanisms between these pathological conditions and SARS-CoV-2 infection. Furthermore, we searched for studies describing the possible efficacy of vitamins A, D, E, and C in improving the immune system function.

RESULTS

SARS-CoV-2 infection induces strong immune system dysfunction characterized by the development of an intense proinflammatory response in the host, and the development of a life-threatening condition defined as cytokine release syndrome (CRS). This leads to acute respiratory syndrome (ARDS), mainly in aged people. High mortality and lethality rates have been observed in elderly subjects with CoV-2-related infection.

CONCLUSIONS

Vitamins may shift the proinflammatory Th17-mediated immune response arising in autoimmune diseases towards a T-cell regulatory phenotype. This review discusses the possible activity of vitamins A, D, E, and C in restoring normal antiviral immune system function and the potential therapeutic role of these micronutrients as part of a therapeutic strategy against SARS-CoV-2 infection.

The Effect of Vitamin Supplementation on Subclinical Atherosclerosis in Patients without Manifest Cardiovascular Diseases: Never-ending Hope or Underestimated Effect?

Micronutrients, especially vitamins, play an important role in the evolution of cardiovascular diseases (CVD). It has been speculated that additional intake of vitamins may reduce the CVD burden by acting on the inflammatory and oxidative response starting from early stages of atherosclerosis, when the vascular impairment might still be reversible or, at least, slowed down. The current review assesses the role of major vitamins on subclinical atherosclerosis process and the potential clinical implications in patients without CVD. We have comprehensively examined the literature data for the major vitamins: A, B group, C, D, and E, respectively. Most data are based on vitamin E, D and C supplementation, while vitamins A and B have been scarcely examined for the subclinical atherosclerosis action. Though the fundamental premise was optimistic, the up-to-date trials with vitamin supplementation revealed divergent results on subclinical atherosclerosis improvement, both in healthy subjects and patients with CVD, while the long-term effect seems minimal. Thus, there are no conclusive data on the prevention and progression of atherosclerosis based on vitamin supplementation. However, given their enormous potential, future trials are certainly needed for a more tailored CVD prevention focusing on early stages as subclinical atherosclerosis.

Effect of atherosclerosis and the protective effect of the antioxidant vitamin E on the rabbit cerebellum

BACKGROUND

Atherosclerosis is a major cardiovascular disease and one of the commonest causes of mortality in the world. Speech, balance, fine motor control and cognition are affected by atherosclerosis of cerebellar arteries. This study investigated the protective role of vitamin E against induced atherosclerosis in the rabbit cerebellum.

MATERIALS AND METHODS

Forty Rex New Zealand adult male rabbits were randomly divided into four groups (10 rabbits each). Group I was designated as the control and received an ordinary diet. Group II received an ordinary diet, but with vitamin E (12 mg/kg/day) added. Group III were given an ordinary diet along with 1% cholesterol powder for 6 weeks. Finally, group IV received an ordinary diet with both 1% cholesterol powder and vitamin E (12 mg/kg/day). Cerebellum samples were stained with haematoxylin and eosin and examined using light microscopy, along with quantitative immunohistochemical assessments of the expression of caspase-3, glial fibrillary acidic protein (GFAP) and inducible nitric oxide synthase (iNOS).

RESULTS

Cerebellum sections from cholesterol-treated rabbits showed ischaemic changes as fibre density decreased, with vacuolation of the molecular layer, and deformed and shrunken Purkinje cells. A significant increase in caspase-3, GFAP and iNOS immunoreactivity was found. However, vitamin E administration reduced these ischaemic manifestations.

CONCLUSIONS

The results demonstrate the neurological protective role of vitamin E therapy in atherosclerosis.

Antioxidants and Atherosclerosis: Mechanistic Aspects

Atherosclerosis is a chronic inflammatory disease which is a major cause of coronary heart disease and stroke in humans. It is characterized by intimal plaques and cholesterol accumulation in arterial walls. The side effects of currently prescribed synthetic drugs and their high cost in the treatment of atherosclerosis has prompted the use of alternative herbal medicines, dietary supplements, and antioxidants associated with fewer adverse effects for the treatment of atherosclerosis. This article aims to present the activity mechanisms of antioxidants on atherosclerosis along with a review of the most prevalent medicinal plants employed against this multifactorial disease. The wide-ranging information in this review article was obtained from scientific databases including PubMed, Web of Science, Scopus, Science Direct and Google Scholar. Natural and synthetic antioxidants have a crucial role in the prevention and treatment of atherosclerosis through different mechanisms. These include: The inhibition of low density lipoprotein (LDL) oxidation, the reduction of reactive oxygen species (ROS) generation, the inhibition of cytokine secretion, the prevention of atherosclerotic plaque formation and platelet aggregation, the preclusion of mononuclear cell infiltration, the improvement of endothelial dysfunction and vasodilation, the augmentation of nitric oxide (NO) bioavailability, the modulation of the expression of adhesion molecules such as vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) on endothelial cells, and the suppression of foam cell formation.

Asymmetric Dimethylarginine Predicts One-year Recurrent Cardiovascular Events: Potential Biomarker of "Toxin Syndrome" in Coronary Heart Disease

OBJECTIVE

To examine the prognostic value of serum levels of asymmetric dimethylarginine (ADMA) in patients with stable coronary heart disease (CHD) thus explore a potential biomarker of "toxin syndrome" in CHD.

METHODS

In this prospective nested case-control study, 36 of 1,503 Chinese patients with stable CHD experienced at least 1 recurrent cardiovascular event (RCE) during 1-year follow-up. Serum levels of ADMA at the start of follow-up were compared between these 36 cases and 36 controls which matched to cases in terms of gender, age, history of hypertension, and myocardial infarction.

RESULTS

Based on the crude model, subjects in the 2 highest ADMA quartiles showed significantly higher risk of developing RCE than those in the lowest ADMA quartile [odds ratio (OR) 4.09, 95% confidence interval (CI) 1.01 to 16.58; OR 6.76, 95% CI 1.57 to 29.07]. This association was also observed in the case-mix model (OR 5.51, 95% CI 1.23 to 24.61; OR 7.83, 95% CI 1.68 to 36.41) and multivariable model (OR 6.64, 95% CI 1.40 to 31.49: OR 13.14, 95% CI 2.28 to 75.71) after adjusting for confounders. The multivariable model which combined ADMA and high-sensitivity C-reactive protein (hsCRP) showed better predictive power with areas under the receiver operator characteristic curves (0.779) than the model of either ADMA (0.694) or hsCRP (0.636).

CONCLUSION

Serum ADMA level may be a potential biomarker of "toxin syndrome" in CHD which shows favorable prognostic value in predicting 1-year RCE in patients with stable CHD. [The registration number is ChiCTR-PRNRC-07000012].

Vitamin E: Regulatory Role on Signal Transduction

Vitamin E modulates signal transduction pathways by several molecular mechanisms. As a hydrophobic molecule located mainly in membranes it contributes together with other lipids to the physical and structural characteristics such as membrane stability, curvature, fluidity, and the organization into microdomains (lipid rafts). By acting as the main lipid-soluble antioxidant, it protects other lipids such as mono- and poly-unsaturated fatty acids (MUFA and PUFA, respectively) against chemical reactions with reactive oxygen and nitrogen species (ROS and RNS, respectively) and prevents membrane destabilization and cellular dysfunction. In cells, vitamin E affects signaling in redox-dependent and redox-independent molecular mechanisms by influencing the activity of enzymes and receptors involved in modulating specific signal transduction and gene expression pathways. By protecting and preventing depletion of MUFA and PUFA it indirectly enables regulatory effects that are mediated by the numerous lipid mediators derived from these lipids. In recent years, some vitamin E metabolites have been observed to affect signal transduction and gene expression and their relevance for the regulatory function of vitamin E is beginning to be elucidated. In particular, the modulation of the CD36/FAT scavenger receptor/fatty acids transporter by vitamin E may influence many cellular signaling pathways relevant for lipid homeostasis, inflammation, survival/apoptosis, angiogenesis, tumorigenesis, neurodegeneration, and senescence. Thus, vitamin E has an important role in modulating signal transduction and gene expression pathways relevant for its uptake, distribution, metabolism, and molecular action that when impaired affect physiological and patho-physiological cellular functions relevant for the prevention of a number of diseases. © 2018 IUBMB Life, 71(4):456-478, 2019.

CD36 expression in peripheral blood mononuclear cells reflects the onset of atherosclerosis

Together with complex genetic and environmental factors, increased serum cholesterol and ox-LDL levels are considered as major triggering factors of atherosclerosis. Mononuclear cell infiltration to the arterial wall and uptake of ox-LDL, which is facilitated by CD36 receptor through an uncontrolled manner, play a key role in foam cell formation followed by atherogenesis development. The aim of this study was to analyze if CD36 expression in peripheral blood mononuclear cells reflect its aortic tissue level in hypercholesterolemia. In this study, CD36 protein expression was evaluated in aortic specimens of cholesterol or cholesterol plus Vitamin E treated animals in relation to the immunohistochemical analyses for the HNE-protein adducts, as well as for smooth muscle actin and vimentin. The CD36 mRNA expression was determined by RT-PCR in PBMC of hypercholesterolemic rabbits and hypercholesterolemic versus normocholesterolemic individuals. Immunohistochemistry findings revealed that smooth muscle actin, smooth muscle vimentin, HNE-protein conjugates, and CD36 protein expressions were significantly increased in aorta of hypercholesterolemic group where foam cells were present. High cholesterol diet significantly induced CD36 mRNA expression in both rabbit aorta and PBMCs, while positive correlation between aortic and PBMC CD36 expression has been found. In addition, consistent with the rabbit model, CD36 mRNA expression levels in human PBMCs were significantly higher in hypercholesterolemic patients than in normocholesterolemic individuals. Taken together, these results demonstrate that the CD36 mRNA levels of PBMCs could reflect the CD36 mRNA levels in aorta and could be used as a biomarker for diagnosis of atherosclerotic burden. © 2018 BioFactors, 44(6):588-596, 2018.

Therapeutic effect of vitamin D3-containing nanostructured lipid carriers on inflammatory bowel disease

The active form of vitamin D₃, 1,25(OH)₂D₃ has been found to exert multiple effects on the suppression of progression of inflammatory bowel disease (IBD). Vitamin D₃ has been gathering attention as a therapy for IBD. However, the clinical trials conducted to date revealed that a relatively high dosage of vitamin D₃ was required to see a significant therapeutic effect. Thus, effective formulation and delivery of vitamin D₃ to colonic inflammatory lesions will be required. Herein we describe the preparation of a nanostructured lipid carrier (NLC) for the encapsulation of 1,25(OH)₂D₃ for colonic delivery via oral administration. The optimized fabrication procedure enabled the incorporation of 1,25(OH)₂D₃ in the NLC by minimizing the destruction of chemically unstable 1,25(OH)₂D₃. The obtained NLCs orally delivered 1,25(OH)₂D₃ to the colon in mice and maintained a high concentration of 1,25(OH)₂D₃ in the colonic tissue for at least 12 h. The NLC showed multiple effects on the suppression of symptoms of colitis induced by dextran sodium sulfate, namely maintaining crypt structure, reducing the tissue concentration of inflammatory cytokines, suppressing the infiltration of polymorphonuclear leukocytes, and augmenting anti-inflammatory CX₃CR1^high macrophages. Our NLCs containing 1,25(OH)₂D₃ may be an alternative treatment for IBD therapy.

Asymptomatic HIV People Present Different Profiles of sCD14, sRAGE, DNA Damage, and Vitamins, according to the Use of cART and CD4+ T Cell Restoration

We aimed to analyze markers of immune activation, inflammation, and oxidative stress in 92 asymptomatic HIV-infected patients according to the adequate (AR, >500 cells/mm³) or inadequate (IR, <500 cells/mm³) CD4⁺ T recovery and the presence or absence of antiretroviral treatment (cART). In relation to those newly diagnosed, they were divided into two groups, cART-naïve IR (nIR) and cART-naïve AR (nAR). Among those diagnosed more than five years ago, the following division was made: the cART-naïve long-term nonprogressors (LTNP); patient under cART and AR (tAR); and patients under cART and IR (tIR). We investigated the expression of soluble receptor for advanced glycation end products (sRAGE), high-mobility group-box protein −1 (HMGB1), soluble CD14 (sCD14), IL-8, IL-10, 8-isoprostane, vitamins, and DNA damage. We observed higher levels of sRAGE in tAR as compared to nIR, nAR, LTNP, and more sCD14 than in nIR and nAR. As for IL-10 levels, we found nIR > nAR > LTNP > tAR > tIR. Higher levels of 8-isoprostane were observed in nIR. LTNP presented a higher retinol dosage than tAR and less genotoxic damage induced by oxidative stress than the other groups. We suggest that the therapy, despite being related to lesser immune activation and inflammation, alters the vitamin profile and consequently increases the oxidative stress of patients. In addition, the lowest genotoxic index for LTNP indicates that both VL and cART could be responsible for the increased DNA damage. More studies are needed to understand the influence of cART on persistent immune activation and inflammation.

Water-Soluble Vitamin E-Tocopheryl Phosphate

The hydrophobicity of vitamin E poses transport and metabolic challenges to regulate its bioavailability and to prevent its accumulation in lipid-rich tissues such as adipose tissue, brain, and liver. Water-soluble precursors of vitamin E (α-tocopherol, αT), such as its esters with acetate (αTA), succinate (αTS), or phosphate (αTP), have increased solubility in water and stability against reaction with free radicals, but they are rapidly converted during their uptake into the lipid-soluble vitamin E. Therefore, the bioavailability of these precursors as intact molecules is low; nevertheless, at least for αTS and αTP, the recent research has revealed unique regulatory effects on signal transduction and gene expression and the modulation of cellular events ranging from proliferation, survival/apoptosis, lipid uptake and metabolism, phagocytosis, long term potentiation, cell migration, telomere maintenance, and angiogenesis. Moreover, water-soluble derivatives of vitamin E including some based on αTP are increasingly used as components of nanocarriers for enhanced and targeted delivery of drugs and other molecules (vitamins, including αT and αTP itself, vitamin D3, carnosine, caffeine, docosahexaenoic acid (DHA), insulin) and cofactors such as coenzyme Q10. In this review, the chemical characteristics, transport, metabolic pathways, and molecular mechanisms of action of αTP in cells and tissues are summarized and put into perspective with its possible role in the prevention of a number of diseases.

Analysis of the Effects of δ-Tocopherol on RAW264.7 and K562 Cells Based on 1H NMR Metabonomics

δ-Tocopherol (δ-TOH) is a form of vitamin E with higher bioactivity. In this study, we studied the bioactivity of δ-TOH using the IC₅₀ of δ-TOH on RAW264.7 (80 μM) and K562 (110 μM) cells. We compared the differential metabolites from the cell lines with and without δ-TOH treatment by ¹H NMR metabonomics analysis. It was found that δ-TOH affected the protein biosynthesis, betaine metabolism, and urea cycle in various ways in both cell lines. Metabolic levels of the cell lines were changed after treatment with δ-TOH as differential metabolites were produced. The betaine level in RAW264.7 cells was reduced significantly, while the l-lactic acid level in K562 cells was significantly enhanced. The metabolic changes might contribute to the switch of the respiration pattern from aerobic respiration to anaerobic respiration in K562 cells. These results are helpful in further understanding the subtoxicity of δ-TOH.

Simultaneous analysis of tert-butylhydroquinone, tert-butylquinone, butylated hydroxytoluene, 2-tert-butyl-4-hydroxyanisole, 3-tert-butyl-4-hydroxyanisole, α-tocopherol, γ-tocopherol, and δ-tocopherol in edible oils by normal-phase high performance liquid chromatography

A normal-phase high performance liquid chromatography method for the simultaneous determination of tert-butylhydroquinone, tert-butylquinone, butylated hydroxytoluene, 2-tert-butyl-4-hydroxyanisole, 3-tert-butyl-4-hydroxyanisole, α-tocopherol, γ-tocopherol, and δ-tocopherol in edible oils was investigated. A silica column was used to separate the analytes with the gradient elution. An ultraviolet-visible detector was set at dual wavelengths mode (280 and 310nm). The column temperature was 30°C. The analytes were directly extracted with methanol. Results showed that the normal-phase high performance liquid chromatography method performed well with wide liner ranges (0.10∼500.00μg/mL, R²>0.9998), low limits of detection and quantitation (below 0.40 and 1.21μg/mL, respectively), and good recoveries (81.38∼102.34% in soybean oils and 83.03∼100.79% in lard, respectively). The reduction of tert-butylquinone caused by the reverse-phase high performance liquid chromatography during the injection was avoided with the current normal-phase method. The two isomers of butylated hydroxyanisole can also be separated with good resolution.

α-Tocopheryl Phosphate Induces VEGF Expression via CD36/PI3Kγ in THP-1 Monocytes

The CD36 scavenger receptor binds several ligands and mediates ligand uptake and ligand-dependent signal transduction and gene expression, events that may involve CD36 internalization. Here we show that CD36 internalization in THP-1 monocytes is triggered by α-tocopherol (αT) and more strongly by α-tocopheryl phosphate (αTP) and EPC-K1, a phosphate diester of αTP and L-ascorbic acid. αTP-triggered CD36 internalization is prevented by the specific covalent inhibitor of selective lipid transport by CD36, sulfo-N-succinimidyl oleate (SSO). Moreover, SSO inhibited the CD36-mediated uptake of 14C-labelled αTP suggesting that αTP binding and internalization of CD36 is involved in cellular αTP uptake, whereas the uptake of αT was less affected. Similar to that, inhibition of selective lipid transport of the SR-BI scavenger receptor resulted mainly in reduction of αTP and not αT uptake. In contrast, uptake of αT was mainly inhibited by Dynasore, an inhibitor of clathrin-mediated endocytosis, suggesting that the differential regulatory effects of αTP and αT on signaling may be influenced by their different routes of uptake. Interestingly, αTP and EPC-K1 also reduced the neutral lipid content of THP-1 cells and the phagocytosis of fluorescent Staphylococcus aureus bioparticles. Moreover, induction of the vascular endothelial growth factor (VEGF) promoter activity by αTP occurred via CD36/PI3Kγ/Akt, as it could be inhibited by specific inhibitors of this pathway (SSO, Wortmannin, AS-605240). These results suggest that αTP activates PI3Kγ/Akt signaling leading to VEGF expression in monocytes after binding to and/or transport by CD36, a receptor known to modulate angiogenesis in response to amyloid beta, oxLDL, and thrombospondin. J. Cell. Biochem. 118: 1855-1867, 2017. © 2017 Wiley Periodicals, Inc.

ABCG1 is involved in vitamin E efflux

Vitamin E membrane transport has been shown to involve the cholesterol transporters SR-BI, ABCA1 and NPC1L1. Our aim was to investigate the possible participation of another cholesterol transporter in cellular vitamin E efflux: ABCG1. In Abcgl-deficient mice, vitamin E concentration was reduced in plasma lipoproteins whereas most tissues displayed a higher vitamin E content compared to wild-type mice. α- and γ-tocopherol efflux was increased in CHO cells overexpressing human ABCG1 compared to control cells. Conversely, α- and γ- tocopherol efflux was decreased in ABCG1-knockdown human cells (Hep3B hepatocytes and THP-1 macro- phages). Interestingly, α- and γ-tocopherol significantly downregulated ABCG1 and ABCA1 expression levels in Hep3B and THP-1, an effect confirmed in vivo in rats given vitamin E for 5 days. This was likely due to reduced LXR activation by oxysterols, as Hep3B cells and rat liver treated with vitamin E displayed a significantly reduced content in oxysterols compared to their respective controls. Overall, the present study reveals for the first time that ABCG1 is involved in cellular vitamin E efflux.

Human cytomegalovirus infection is associated with essential hypertension in Kazakh and Han Chinese populations

Background

We aimed to study the association between cytomegalovirus (CMV) infection and hypertension in Kazakh and Han populations from Xinjiang Province, China.

Material/Methods

We analyzed data on 800 Kazakhs (467 hypertension patients and 333 healthy control participants) and 800 Hans (482 hypertension patients and 318 healthy control participants) aged 18–84 years old. ELISA and real-time quantitative PCR coupled with restriction fragment length polymorphism analysis were applied for determining CMV infection and glycoprotein B (gB) genotypes, respectively.

Results

Serologic evidence of CMV infection was obtained for 95.4% and 90.1% of the Kazakhs and Hans, respectively. The CMV seroprevalence rates among the Kazakh and Han participants with hypertension were 96.8% and 89.8%, respectively. Multiple logistic regression analyses revealed statistically significant independent associations between CMV seropositivity and hypertension in Kazakh males and between CMV antibody titers and hypertension in Hans; significant relationships also existed between CMV antibody titers and blood pressure in Hans. In Kazakhs, 3 CMV gB genotypes were identified: gB2 and genotype mixtures gB1+gB2 and gB2+gB3. In Hans, 4 CMV gB genotypes were identified: gB1, gB2, gB1+gB2, and gB2+gB3. Of the 4 studied genotypes, gB2+gB3 showed a significant independent association with hypertension in Kazakh females.

Conclusions

CMV infection is associated with essential hypertension in Kazakh males and Hans in Xinjiang. CMV seropositivity is associated with hypertension in Kazakh males, and CMV antibody titers are associated with blood pressure and hypertension in Han males and females. Moreover, the CMV gB2+gB3 genotype mixture is associated independently with essential hypertension in Kazakh females.

Effects of vitamin E on peroxisome proliferator-activated receptor γ and nuclear factor-erythroid 2-related factor 2 in hypercholesterolemia-induced atherosclerosis

Atherosclerosis and associated cardiovascular complications such as stroke and myocardial infarction are major causes of morbidity and mortality. We have previously reported a significant increase in mRNA levels of the scavenger receptor CD36 in aortae of cholesterol-fed rabbits and shown that vitamin E treatment attenuated increased CD36 mRNA expression. In the present study, we further investigated the redox signaling pathways associated with protection against atherogenesis induced by high dietary cholesterol and correlated these with CD36 expression and the effects of vitamin E supplementation in a rabbit model. Male albino rabbits were assigned to either a control group fed with a low vitamin E diet alone or a test group fed with a low vitamin E diet containing 2% cholesterol in the absence or presence of daily intramuscular injections of vitamin E (50mg/kg). To elucidate the mechanisms by which vitamin E supplementation alters the effects of hypercholesterolemia in rabbit aortae, we measured peroxisome proliferator-activated receptor γ (PPARγ), ATP-binding cassette transporter A1 (ABCA1), and matrix metalloproteinase-1 (MMP-1) mRNA levels by quantitative RT-PCR and the expression of MMP-1, nuclear factor-erythroid 2-related factor 2 (Nrf2), and glutathione S-transferase α (GSTα) protein by immunoblotting. The increased MMP-1 and decreased GSTα expression observed suggests that a cholesterol-rich diet contributes to the development of atherosclerosis, whereas vitamin E supplementation affords protection by decreasing MMP-1 and increasing PPARγ, GSTα, and ABCA1 levels in aortae of rabbits fed a cholesterol-rich diet. Notably, protein expression of Nrf2, the antioxidant transcription factor, was increased in both the cholesterol-fed and the vitamin E-supplemented groups. Although Nrf2 activation can promote CD36-mediated cholesterol uptake by macrophages, the increased induction of Nrf2-mediated antioxidant genes is likely to contribute to decreased lesion progression. Thus, our study demonstrates that Nrf2 can mediate both pro- and antiatherosclerotic effects.

Vitamin E isoforms as modulators of lung inflammation

Asthma and allergic diseases are complex conditions caused by a combination of genetic and environmental factors. Clinical studies suggest a number of protective dietary factors for asthma, including vitamin E. However, studies of vitamin E in allergy commonly result in seemingly conflicting outcomes. Recent work indicates that allergic inflammation is inhibited by supplementation with the purified natural vitamin E isoform α-tocopherol but elevated by the isoform γ-tocopherol when administered at physiological tissue concentrations. In this review, we discuss opposing regulatory effects of α-tocopherol and γ-tocopherol on allergic lung inflammation in clinical trials and in animal studies. A better understanding of the differential regulation of inflammation by isoforms of vitamin E provides a basis towards the design of clinical studies and diets that would effectively modulate inflammatory pathways in lung disease.

Two faces of vitamin E in the lung

Asthma and allergic lung disease occur as complex environmental and genetic interactions. Clinical studies of asthma indicate a number of protective dietary factors, such as vitamin E, on asthma risk. However, these studies have had seemingly conflicting outcomes. In this perspective, we discuss opposing regulatory effects of tocopherol isoforms of vitamin E, mechanisms for tocopherol isoform regulation of allergic lung inflammation, association of vitamin E isoforms with outcomes in clinical studies, and how the variation in global prevalence of asthma may be explained, at least in part, by vitamin E isoforms.

Isoforms of Vitamin E Differentially Regulate PKC α and Inflammation: A Review

Vitamin E regulation of disease has been extensively studied but most studies focus on the α-tocopherol isoform of vitamin E. These reports indicate contradictory outcomes for anti-inflammatory functions of the α-tocopherol isoform of vitamin E with regards to animal and clinical studies. These seemingly disparate results are consistent with our recent studies demonstrating that purified natural forms of vitamin E have opposing regulatory functions during inflammation. In this review, we discuss that α-tocopherol inhibits whereas γ-tocopherol elevates allergic inflammation, airway hyperresponsiveness, leukocyte transendothelial migration, and endothelial cell adhesion molecule signaling through protein kinase Cα. Moreover, we have demonstrated that α-tocopherol is an antagonist and γ-tocopherol is an agonist of PKCα through direct binding to a regulatory domain of PKCα. In summary, we have determined mechanisms for opposing regulatory functions of α-tocopherol and γ-tocopherol on inflammation. Information from our studies will have significant impact on the design of clinical studies and on vitamin E consumption.

Fat-soluble vitamins and atopic disease: what is the evidence?

The prevalence of asthma and other atopic disorders continues to increase worldwide. Examination of the epidemiologic patterns has revealed that this rise has occurred primarily in western, industrialised countries and countries transitioning to this lifestyle. While many changes have occurred in human populations over the years, it has been hypothesised that some of the relevant changes that have led to the rise in asthma and atopic disorders have been the changes from a traditional diet to a more western diet consisting of decreased intake of fruits and vegetables (sources of antioxidant vitamins and carotenoids) leading to decreased intakes of vitamins E and A, and a decrease in sun exposure (e.g. greater time spent indoors and heavy use of sunscreen) leading to decreased circulating levels of vitamin D. This review will examine the evidence for an effect of fat-soluble vitamins (vitamins A, D and K) on the development and severity of asthma and allergies. While observational studies suggest that these vitamins may play a salutary role in asthma and allergies, large, well-designed clinical trials are lacking. Of the fat-soluble vitamins, vitamin D holds great promise as an agent for primary and secondary prevention of disease. Ongoing clinical trials will help determine whether results of observational studies can be applied to the clinical setting.

Vascular cell adhesion molecule-1 expression and signaling during disease: regulation by reactive oxygen species and antioxidants

The endothelium is immunoregulatory in that inhibiting the function of vascular adhesion molecules blocks leukocyte recruitment and thus tissue inflammation. The function of endothelial cells during leukocyte recruitment is regulated by reactive oxygen species (ROS) and antioxidants. In inflammatory sites and lymph nodes, the endothelium is stimulated to express adhesion molecules that mediate leukocyte binding. Upon leukocyte binding, these adhesion molecules activate endothelial cell signal transduction that then alters endothelial cell shape for the opening of passageways through which leukocytes can migrate. If the stimulation of this opening is blocked, inflammation is blocked. In this review, we focus on the endothelial cell adhesion molecule, vascular cell adhesion molecule-1 (VCAM-1). Expression of VCAM-1 is induced on endothelial cells during inflammatory diseases by several mediators, including ROS. Then, VCAM-1 on the endothelium functions as both a scaffold for leukocyte migration and a trigger of endothelial signaling through NADPH oxidase-generated ROS. These ROS induce signals for the opening of intercellular passageways through which leukocytes migrate. In several inflammatory diseases, inflammation is blocked by inhibition of leukocyte binding to VCAM-1 or by inhibition of VCAM-1 signal transduction. VCAM-1 signal transduction and VCAM-1-dependent inflammation are blocked by antioxidants. Thus, VCAM-1 signaling is a target for intervention by pharmacological agents and by antioxidants during inflammatory diseases. This review discusses ROS and antioxidant functions during activation of VCAM-1 expression and VCAM-1 signaling in inflammatory diseases.

Multiple aberrations in shared inflammatory and oxidative & nitrosative stress (IO&NS) pathways explain the co-association of depression and cardiovascular disorder (CVD), and the increased risk for CVD and due mortality in depressed patients

There is evidence that there is a bidirectional relationship between major depression and cardiovascular disorder (CVD): depressed patients are a population at risk for increased cardiac morbidity and mortality, and depression is more frequent in patients who suffer from CVD. There is also evidence that inflammatory and oxidative and nitrosative stress (IO&NS) pathways underpin the common pathophysiology of both CVD and major depression. Activation of these pathways may increase risk for both disorders and contribute to shared risk. The shared IO&NS pathways that may contribute to CVD and depression comprise the following: increased levels of pro-inflammatory cytokines, like interleukin-1β (IL-1β), IL-2, IL-6, IL-8, IL-12, tumor necrosis factor-α, and interferon-γ; T cell activation; increased acute phase proteins, like C-reactive protein, haptoglobin, fibrinogen and α1-antitrypsin; complement factors; increased LPS load through bacterial translocation and subsequent gut-derived inflammation; induction of indoleamine 2,3-dioxygenase with increased levels of tryptophan catabolites; decreased levels of antioxidants, like coenzyme Q10, zinc, vitamin E, glutathione and glutathione peroxidase; increased O&NS characterized by oxidative damage to low density lipoprotein (LDL) and phospholipid inositol, increased malondialdehyde, and damage to DNA and mitochondria; increased nitrosative stress; and decreased ω3 polyunsaturated fatty acids (PUFAs). The complex interplay between the abovementioned IO&NS pathways in depression results in pro-atherogenic effects and should be regarded as a risk factor to future clinical CVD and due mortality. We suggest that major depression should be added as a risk factor to the Charlson "comorbidity" index. It is advised that patients with (sub)chronic or recurrent major depression should routinely be assessed by serology tests to predict if they have an increased risk to cardiovascular disorders.

Isoforms of vitamin E differentially regulate inflammation

Vitamin E regulation of disease has been extensively studied in humans, animal models and cell systems. Most of these studies focus on the α-tocopherol isoform of vitamin E. These reports indicate contradictory outcomes for anti-inflammatory functions of the α-tocopherol isoform of vitamin E, especially with regards to clinical studies of asthma and atherosclerosis. These seemingly disparate clinical results are consistent with recently reported unrecognized properties of isoforms of vitamin E. Recently, it has been reported that physiological levels of purified natural forms of vitamin E have opposing regulatory functions during inflammation. These opposing regulatory functions by physiological levels of vitamin E isoforms impact interpretations of previous studies on vitamin E. Moreover, additional recent studies also indicate that the effects of vitamin E isoforms on inflammation are only partially reversible using physiological levels of a vitamin E isoform with opposing immunoregulatory function. Thus, this further influences interpretations of previous studies with vitamin E in which there was inflammation and substantial vitamin E isoforms present before the initiation of the study. In summary, this review will discuss regulation of inflammation by vitamin E, including alternative interpretations of previous studies in the literature with regards to vitamin E isoforms.

Vitamin E transport, membrane incorporation and cell metabolism: Is alpha-tocopherol in lipid rafts an oar in the lifeboat?

Vitamin E is composed of closely related compounds, including tocopherols and tocotrienols. Studies of the last decade provide strong support for a specific role of alpha-tocopherol in cell signalling and the regulation of gene expression. It produces significant effects on inflammation, cell proliferation and apoptosis that are not shared by other vitamin E isomers with similar antioxidant properties. The different behaviours of vitamin E isomers might relate, at least in part, to the specific effects they exert at the plasma membrane. alpha-Tocopherol is not randomly distributed throughout the phospholipid bilayer of biological membranes, and as compared with other isomers, it shows a propensity to associate with lipid rafts. Distinct aspects of vitamin E transport and metabolism is discussed with emphasis on the interaction between alpha-tocopherol and lipid rafts and the consequences of these interactions on cell metabolism.

alpha-Tocopheryl phosphate--an active lipid mediator?

The vitamin E (alpha-tocopherol, alphaT) derivative, alpha-tocopheryl phosphate (alphaTP), is detectable in small amounts in plasma, tissues, and cultured cells. Studies done in vitro and in vivo suggest that alphaT can become phosphorylated and alphaTP dephosphorylated, suggesting the existence of enzyme(s) with alphaT kinase or alphaTP phosphatase activity, respectively. As a supplement in animal studies, alphaTP can reach plasma concentrations similar to alphaT and only a part is dephosphorylated; thus, alphaTP may act both as pro-vitamin E, but also as phosphorylated form of vitamin E with possibly novel regulatory activities. Many effects of alphaTP have been described: in the test tube alphaTP modulates the activity of several enzymes; in cell culture alphaTP affects proliferation, apoptosis, signal transduction, and gene expression; in animal studies alphaTP prevents atherosclerosis, ischemia/reperfusion injury, and induces hippocampal long-term potentiation. At the molecular level, alphaTP may act as a cofactor for enzymes, as an active lipid mediator similar to other phosphorylated lipids, or indirectly by altering membrane characteristics such as lipid rafts, fluidity, and curvature. In this review, the molecular and cellular activities of alphaTP are examined and the possible functions of alphaTP as a natural compound, cofactor and active lipid mediator involved in signal transduction and gene expression discussed.

Inhibitory effect of PMC, a potent hydrophilic α-tocopherol derivative, on vascular smooth muscle cell proliferation: the pivotal role of PKC-α translocation

CONTENT

Vascular smooth muscle cells (VSMCs) play a major role in the pathogenesis of atherosclerosis and restenosis, and thus the excessive proliferation of VSMCs contributes to neointimal thickening during atherosclerosis and restenosis. PMC (2,2,5,7,8-pentamethyl-6-hydroxychromane) is the most potent hydrophilic derivative of the alpha-tocopherols; it acts as a potent anti-inflammatory and free-radical scavenger.

OBJECTIVE

The present study was designed to examine the inhibitory mechanisms of PMC in VSMC proliferation.

MATERIALS AND METHODS

VSMC proliferation and cytotoxicity were measured by MTT and LDH assays, respectively. The cell cycle and translocation of PKC-alpha in VSMCs were used by flow cytometry and confocal microscope, respectively. To detect PKC-alpha translocation and activation in VSMCs, immunoblotting was performed in the present study.

RESULTS

In this study, we demonstrate an anti-proliferative effect of PMC in VSMCs. Concentration-dependent inhibition of serum-induced VSMC proliferation was observed in PMC (20 and 50 muM)-treated cells. PMC pretreatment also arrested VSMC cell cycle progression at the G2/M phase. Furthermore, PMC exhibited obvious inhibitory effects on phorbol 12-myristate 13-acetate (PMA)-induced protein kinase C (PKC)-alpha translocation and phospho-(Ser/Thr) substrate phosphorylation.

DISCUSSION AND CONCLUSION

The inhibitory mechanisms of PMC on VSMC proliferation is mediated, at least in part, by inhibition of PKC-alpha translocation and causes cell cycle arrest in the G2/M phase. PMC treatment may represent a novel approach for lowering the risk of or improving function in abnormal VSMC proliferation-related vascular diseases.

Micronutrient concentrations and subclinical atherosclerosis in adults with HIV

BACKGROUND

Extremes in micronutrient intakes are common in HIV-infected patients in developed countries and may affect the progression of atherosclerosis in this population.

OBJECTIVE

We completed a cross-sectional study examining the association between serum micronutrient concentrations and surrogate markers of atherosclerosis in a cohort of HIV-infected adults.

DESIGN

We measured serum selenium, zinc, vitamin A, and vitamin E concentrations as well as carotid intima-media thickness (c-IMT) and coronary artery calcium (CAC) in 298 Nutrition for Healthy Living participants. We assessed cardiovascular disease risk factors, c-IMT, and CAC for each micronutrient tertile by using a chi-square test for binary variables and analysis of variance for continuous variables. We performed multivariate regression of c-IMT and CAC with each micronutrient with adjustment for HIV-related and cardiovascular disease risk factors.

RESULTS

In the multivariate analysis, the highest tertile of serum vitamin E concentration was associated with higher common and internal c-IMT and CAC scores (P < 0.05 for c-IMT and CAC). Participants with higher vitamin E concentrations were more likely to have detectable CAC (50% compared with 44% compared with 67% for tertiles 1, 2, and 3, respectively; P = 0.004) and common c-IMT >0.8 mm (5% compared with 4% compared with 17% for tertiles 1, 2, and 3, respectively; P = 0.002). Other than vitamin E, micronutrients had no association with markers of atherosclerosis.

CONCLUSIONS

Our study showed that elevated serum vitamin E concentrations are associated with abnormal markers of atherosclerosis and may increase the risk of cardiovascular complications in HIV-infected adults.

Dimethylarginine dimethylaminohydrolase regulation: a novel therapeutic target in cardiovascular disease

Asymmetric dimethylarginine (ADMA), an endogenous methylated form of the amino acid L-arginine, inhibits the activity of the enzyme endothelial nitric oxide synthase, with consequent reduced synthesis of nitric oxide. ADMA is metabolised to L-citrulline and dimethylamine by the enzyme dimethylarginine dimethylaminohydrolase (DDAH). The modulation of DDAH activity and expression plays a pivotal role in regulating intracellular ADMA concentrations, with important effects on vascular homeostasis. For example, impairment in DDAH activity, resulting in elevated ADMA concentrations and reduced nitric oxide synthesis, can promote the onset and progression of atherosclerosis in experimental models. This review discusses the current role of ADMA and DDAH in vascular health and disease, the techniques used to assess DDAH activity and expression, and the results of recent studies on pharmacological and biological agents modulating DDAH activity and expression. Suggestions for future basic and clinical research directions are also discussed.

Isoforms of vitamin E have opposing immunoregulatory functions during inflammation by regulating leukocyte recruitment

Reports indicate contradictory outcomes for anti-inflammatory functions of the alpha-tocopherol isoform of vitamin E in clinical studies of asthma and atherosclerosis. These seemingly disparate clinical results are consistent with novel unrecognized properties of isoforms of vitamin E reported in this study. We demonstrate that the isoform d-gamma-tocopherol elevates inflammation in experimental asthma. Moreover, d-gamma-tocopherol, at as little as 10% the concentration of d-alpha-tocopherol, ablates the anti-inflammatory benefit of the d-alpha-tocopherol isoform. A mechanism for these opposing immunoregulatory functions of purified tocopherols at physiological concentrations is not through modulation of expression of several cytokines, chemokines, or adhesion molecules, but is, at least in part, by regulation of endothelial cell signals during leukocyte recruitment. These opposing regulatory functions of vitamin E isoforms have impact on interpretations of vitamin E studies. In summary, our studies with purified tocopherol isoforms alter our understanding of vitamin E regulation of vascular function and asthma.

7-ketocholesterol incorporation into sphingolipid/cholesterol-enriched (lipid raft) domains is impaired by vitamin E: a specific role for alpha-tocopherol with consequences on cell death

Cholesterol oxides, in particular 7-ketocholesterol, are proatherogenic compounds that induce cell death in the vascular wall when localized in lipid raft domains of the cell membrane. Deleterious effects of 7-ketocholesterol can be prevented by vitamin E, but the molecular mechanism involved is unclear. In this study, unlike gamma-tocopherol, the alpha-tocopherol vitamin E form was found to prevent 7-ketocholesterol-mediated apoptosis of A7R5 smooth muscle cells. To be operative, alpha-tocopherol needed to be added to the cells before 7-ketocholesterol, and its anti-apoptotic effect was reduced and even suppressed when added together or after 7-ketocholesterol, respectively. Both pre- and co-treatment of the cells with alpha-tocopherol resulted in the redistribution of 7-ketocholesterol out of the sphingolipid/cholesterol-enriched (lipid raft) domains. In turn, fewer amounts of alpha-tocopherol associated with lipid rafts on 7-ketocholesterol-pretreated cells compared with untreated cells, with no prevention of cell death in this case. In further support of the implication of lipid raft domains, the dephosphorylation/inactivation of Akt-PKB was involved in the 7-ketocholesterol-induced apoptosis. Akt-PKB dephosphorylation was prevented by alpha-tocopherol, but not gamma-tocopherol pretreatment.

Vitamin effects on the immune system: vitamins A and D take centre stage

Vitamins are essential constituents of our diet that have long been known to influence the immune system. Vitamins A and D have received particular attention in recent years as these vitamins have been shown to have an unexpected and crucial effect on the immune response. We present and discuss our current understanding of the essential roles of vitamins in modulating a broad range of immune processes, such as lymphocyte activation and proliferation, T-helper-cell differentiation, tissue-specific lymphocyte homing, the production of specific antibody isotypes and regulation of the immune response. Finally, we discuss the clinical potential of vitamin A and D metabolites for modulating tissue-specific immune responses and for preventing and/or treating inflammation and autoimmunity.

Inflammation at the molecular interface of atherogenesis: an anthropological journey

Despite the multifactorial nature of atherosclerosis, substantial evidence has established inflammation as an often surreptitious, yet critical and unifying driving force which promotes disease progression. To this end, research has defined molecular networks initiated by cytokines, growth factors and other pro-inflammatory molecules which promote hallmarks of atherosclerosis such as endothelial dysfunction, macrophage infiltration, LDL oxidation, cell proliferation and thrombosis. Although commonly associated with risk factors such as dyslipidemia, diabetes and hypertension, the global etiology of atherosclerosis may be alternatively attributed to underlying anthropological pressures. The agricultural, industrial and technological revolutions produced alterations in dietary, social and economic factors which have collectively exaggerated the exposure of the human genome to environmental stimuli. Furthermore, advances in sanitation, nutrition, and medicine have increased the lifespan of humans, effectively prolonging blood vessel exposure to these factors. As a result, the vasculature has become conditioned to respond to injury with what is arguably an overzealous immunological response; thus setting the stage for the prevalence of cardiovascular disease, including atherosclerotic plaque development in Western populations. Evidence suggests that each of these alterations can be linked to specific mediators in the inflammatory process. Integration of these factors with an inflammation-based hypothesis of atherosclerosis has yet to be extrapolated to observations in the realms of basic and clinical sciences and is the focus of this review.

Vitamin E: An overview of major research directions

During the last 90 years since the discovery of vitamin E, research has focused on different properties of this molecule, the focus often depending on the specific techniques and scientific knowledge present at each time. Originally discovered as a dietary factor essential for reproduction in rats, vitamin E has revealed in the meantime many more important molecular properties, such as the scavenging of reactive oxygen and nitrogen species with consequent prevention of oxidative damage associated with many diseases, or the modulation of signal transduction and gene expression in antioxidant and non-antioxidant manners. Research over the last 30 years has also resolved the biosynthesis and occurrence of vitamin E in plants, the proteins involved in the cellular uptake, tissue distribution and metabolism, and defined a congenital recessive neurological disease, ataxia with vitamin E deficiency (AVED), characterized by impaired enrichment of alpha-tocopherol in plasma as a result of mutations in the liver alpha-tocopherol transfer gene. This review is giving a brief introduction about vitamin E by following the major research directions since its discovery with a historical perspective.