Vitamin E and NF‐κB Activation: A Review

Antioxidant Metabolism Pathways in Vitamins, Polyphenols, and Selenium: Parallels and Divergences

Free radicals (FRs) are unstable molecules that cause reactive stress (RS), an imbalance between reactive oxygen and nitrogen species in the body and its ability to neutralize them. These species are generated by both internal and external factors and can damage cellular lipids, proteins, and DNA. Antioxidants prevent or slow down the oxidation process by interrupting the transfer of electrons between substances and reactive agents. This is particularly important at the cellular level because oxidation reactions lead to the formation of FR and contribute to various diseases. As we age, RS accumulates and leads to organ dysfunction and age-related disorders. Polyphenols; vitamins A, C, and E; and selenoproteins possess antioxidant properties and may have a role in preventing and treating certain human diseases associated with RS. In this review, we explore the current evidence on the potential benefits of dietary supplementation and investigate the intricate connection between SIRT1, a crucial regulator of aging and longevity; the transcription factor NRF2; and polyphenols, vitamins, and selenium. Finally, we discuss the positive effects of antioxidant molecules, such as reducing RS, and their potential in slowing down several diseases.

Alpha-tocopherol-loaded polycaprolactone nanoparticles improve the inflammation and systemic oxidative stress of arthritic rats

Background and aim

The present study investigated the effects of orally administered α-tocopherol-loaded polycaprolactone nanoparticles on the articular inflammation and systemic oxidative status of middle-aged Holtzman rats with Freund's adjuvant-induced polyarthritis, a model for rheumatoid arthritis. Intraperitoneally administered free α-tocopherol provided the reference for comparison.

Experimental procedure

Two protocols of treatment were followed: intraperitoneal administration of free α-tocopherol (100 mg/kg i.p.) or oral administration of free and nanoencapsulated α-tocopherol (100 mg/kg p.o.). Animals were treated during 18 days after arthritis induction.

Results

Free (i.p.) and encapsulated α-tocopherol decreased the hind paws edema, the leukocytes infiltration into femorotibial joints and the mRNA expression of pro-inflammatory cytokines in the tibial anterior muscle of arthritic rats, but the encapsulated compound was more effective. Free (i.p.) and encapsulated α-tocopherol decreased the high levels of reactive oxygen species in the brain and liver, but only the encapsulated compound decreased the levels of protein carbonyl groups in these organs. Both free (i.p.) and encapsulated α-tocopherol increased the α-tocopherol levels and the ratio of reduced to oxidized glutathione in these organs.

Conclusion

Both intraperitoneally administered free α-tocopherol and orally administered encapsulated α-tocopherol effectively improved inflammation and systemic oxidative stress in middle-aged arthritic rats. However, the encapsulated form should be preferred because the oral administration route does not be linked to the evident discomfort that is caused in general by injectable medicaments. Consequently, α-tocopherol-loaded polycaprolactone nanoparticles may be a promising adjuvant to the most current approaches aiming at rheumatoid arthritis therapy.

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Oxidative stress is systemically increased in rats with adjuvant-induced arthritis.

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Arthritic rats were orally treated with α-tocopherol-loaded polycaprolactone nanoparticles.

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Treatment decreased the paw edema and articular inflammation of arthritic rats.

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Treatment improved the oxidative stress in the liver and brain arthritic rats.

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The content of α-tocopherol was increased in the brain and liver of treated rats.

Effects of Cadmium Exposure on the Immune System and Immunoregulation

Cadmium (Cd), a biologically non-essential heavy metal, is widespread in the environment, including the air, water, and soil, and is widely present in foods and quantum dot preparations. Cd enters the body primarily through inhalation and ingestion. Its biological half-life in humans is 10-35 years; therefore, Cd poses long-term health risks. While most studies on Cd toxicity have focused on organ and tissue damage, the immunotoxicity of Cd has drawn increasing attention recently. Cd accumulates in immune cells, modulates the function of the immune system, triggers immunological responses, and leads to diverse health problems. Cd acts as an immunotoxic agent by regulating the activity and apoptosis of immune cells, altering the secretion of immune cytokines, inducing reactive oxygen species (ROS) production and oxidative stress, changing the frequency of T lymphocyte subsets, and altering the production of selective antibodies in immune cells. This review summarizes the immunological toxicity of Cd, elucidates the mechanisms underlying Cd toxicity in terms of innate immunity and adaptive immunity, and discusses potential strategies to alleviate the adverse effects of Cd on the immune system.

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.

Cholecystokinin-8 attenuates methamphetamine-induced inflammatory activation of microglial cells through CCK2 receptor

Methamphetamine (METH) exposure reportedly promotes microglial activation and pro-inflammatory cytokines secretion. Sustained inflammation in abusers of psychostimulant drugs further induces neural damage. Cholecystokinin-8 (CCK-8) is a gut-brain peptide which exerts a wide range of biological activities in the gastrointestinal tract and central nervous system. We previously found that pre-treatment with CCK-8 inhibited behavioural and histologic changes typically induced by repeated exposure to METH. Here, we aimed to estimate the effects of CCK-8 on METH-induced neuro-inflammation, which is markedly characterized by microglia activation and increased pro-inflammatory cytokines production in vivo and in vitro. Moreover, we assessed the subtypes of the CCK receptor mediating the regulatory effects of CCK-8, and the changes in the NF-κB signalling pathway. We found that CCK-8 inhibited METH-induced microglial activation and IL-6 and TNF-α generation in vivo and in vitro in a dose-dependent manner. Furthermore, co-treatment of CCK-8 with METH significantly attenuated the activation of the NF-κB signalling pathway by activating the CCK2 receptor subtype in N9 cells. In conclusion, our findings indicated the inhibitory effect of CCK-8 on METH-induced neuro-inflammation in vivo and in vitro, and suggested the underlying mechanism may involve the activation of the CCK2 receptor, which downregulated the NF-κB signalling pathway induced by METH stimulation.

Protective effect of hypothermia and vitamin E on spermatogenic function after reduction of testicular torsion in rats

This study was designed to investigate the protective effect of hypothermia and vitamin E on spermatogenic function after reduction of testicular torsion in rats. Ninety-six pure inbred male SD rats were divided into group A, B, C and D according to the principle of body weight and birth similarity, with 24 rats in each group. Four groups of rats were respectively twisted on the left testis to establish unilateral testicular torsion rats. Rats in groups A, B, C, D were respectively given normal saline, hypothermia therapy, vitamin E therapy, and hypothermia and vitamin E therapy. The superoxide dismutase (SOD) activity and malondialdehyde (MDA) content of the four groups were detected, and the correlation levels of inflammatory factors IL-1β, hs-CRP and related sex hormones luteinizing hormone (LH), follicle-stimulating hormone (FSH), total testosterone (T) were detected by ELISA. Apoptosis of spermatogenic cells of testis in the four groups was detected by flow cytometry. SOD activity and MDA content in groups B, C and D were significantly higher than those in group A, MDA content was significantly lower than that in group A (P<0.05), SOD activity in group D was higher than that in groups B and C, while MDA content was lower than that in groups B and C (P<0.05). The levels of IL-1β and hs-CRP in group A were much higher than those in groups B, C and D (P<0.05). LH and FSH levels in group A were significantly higher than those in groups B, C and D (P<0.05), and in group D were significantly lower than those in groups B and C (P<0.05). Apoptosis rate of spermatogenic cells in group A was significantly higher than that in groups B, C and D (P<0.05). Hypothermia combined with vitamin E can reverse testicular injury in rats and reduce the apoptosis rate of spermatogenic cells.

Diversity of Chromanol and Chromenol Structures and Functions: An Emerging Class of Anti-Inflammatory and Anti-Carcinogenic Agents

Natural chromanols and chromenols comprise a family of molecules with enormous structural diversity and biological activities of pharmacological interest. A recently published systematic review described more than 230 structures that are derived from a chromanol ortpd chromenol core. For many of these compounds structure-activity relationships have been described with mostly anti-inflammatory as well as anti-carcinogenic activities. To extend the knowledge on the biological activity and the therapeutic potential of these promising class of natural compounds, we here present a report on selected chromanols and chromenols based on the availability of data on signaling pathways involved in inflammation, apoptosis, cell proliferation, and carcinogenesis. The chromanol and chromenol derivatives seem to bind or to interfere with several molecular targets and pathways, including 5-lipoxygenase, nuclear receptors, and the nuclear-factor "kappa-light-chain-enhancer" of activated B-cells (NFκB) pathway. Interestingly, available data suggest that the chromanols and chromenols are promiscuitively acting molecules that inhibit enzyme activities, bind to cellular receptors, and modulate mitochondrial function as well as gene expression. It is also noteworthy that the molecular modes of actions by which the chromanols and chromenols exert their effects strongly depend on the concentrations of the compounds. Thereby, low- and high-affinity molecular targets can be classified. This review summarizes the available knowledge on the biological activity of selected chromanols and chromenols which may represent interesting lead structures for the development of therapeutic anti-inflammatory and chemopreventive approaches.

Role of NF-κB in Platelet Function

Platelets are megakaryocyte-derived fragments lacking nuclei and prepped to maintain primary hemostasis by initiating blood clots on injured vascular endothelia. Pathologically, platelets undergo the same physiological processes of activation, secretion, and aggregation yet with such pronouncedness that they orchestrate and make headway the progression of atherothrombotic diseases not only through clot formation but also via forcing a pro-inflammatory state. Indeed, nuclear factor-κB (NF-κB) is largely implicated in atherosclerosis and its pathological complication in atherothrombotic diseases due to its transcriptional role in maintaining pro-survival and pro-inflammatory states in vascular and blood cells. On the other hand, we know little on the functions of platelet NF-κB, which seems to function in other non-genomic ways to modulate atherothrombosis. Therein, this review will resemble a rich portfolio for NF-κB in platelets, specifically showing its implications at the levels of platelet survival and function. We will also share the knowledge thus far on the effects of active ingredients on NF-κB in general, as an extrapolative method to highlight the potential therapeutic targeting of NF-κB in coronary diseases. Finally, we will unzip a new horizon on a possible extra-platelet role of platelet NF-κB, which will better expand our knowledge on the etiology and pathophysiology of atherothrombosis.

Cell Type-Specific Roles of NF-κB Linking Inflammation and Thrombosis

The transcription factor NF-κB is a central mediator of inflammation with multiple links to thrombotic processes. In this review, we focus on the role of NF-κB signaling in cell types within the vasculature and the circulation that are involved in thrombo-inflammatory processes. All these cells express NF-κB, which mediates important functions in cellular interactions, cell survival and differentiation, as well as expression of cytokines, chemokines, and coagulation factors. Even platelets, as anucleated cells, contain NF-κB family members and their corresponding signaling molecules, which are involved in platelet activation, as well as secondary feedback circuits. The response of endothelial cells to inflammation and NF-κB activation is characterized by the induction of adhesion molecules promoting binding and transmigration of leukocytes, while simultaneously increasing their thrombogenic potential. Paracrine signaling from endothelial cells activates NF-κB in vascular smooth muscle cells and causes a phenotypic switch to a “synthetic” state associated with a decrease in contractile proteins. Monocytes react to inflammatory situations with enforced expression of tissue factor and after differentiation to macrophages with altered polarization. Neutrophils respond with an extension of their life span—and upon full activation they can expel their DNA thereby forming so-called neutrophil extracellular traps (NETs), which exert antibacterial functions, but also induce a strong coagulatory response. This may cause formation of microthrombi that are important for the immobilization of pathogens, a process designated as immunothrombosis. However, deregulation of the complex cellular links between inflammation and thrombosis by unrestrained NET formation or the loss of the endothelial layer due to mechanical rupture or erosion can result in rapid activation and aggregation of platelets and the manifestation of thrombo-inflammatory diseases. Sepsis is an important example of such a disorder caused by a dysregulated host response to infection finally leading to severe coagulopathies. NF-κB is critically involved in these pathophysiological processes as it induces both inflammatory and thrombotic responses.

Vitamin E Modifies High-Fat Diet-Induced Increase of DNA Strand Breaks, and Changes in Expression and DNA Methylation of Dnmt1 and MLH1 in C57BL/6J Male Mice

Obesity is associated with low-grade inflammation, increased ROS production and DNA damage. Supplementation with antioxidants might ameliorate DNA damage and support epigenetic regulation of DNA repair. C57BL/6J male mice were fed a high-fat (HFD) or a control diet (CD) with and without vitamin E supplementation (4.5 mg/kg body weight (b.w.)) for four months. DNA damage, DNA promoter methylation and gene expression of Dnmt1 and a DNA repair gene (MLH1) were assayed in liver and colon. The HFD resulted in organ specific changes in DNA damage, the epigenetically important Dnmt1 gene, and the DNA repair gene MLH1. Vitamin E reduced DNA damage and showed organ-specific effects on MLH1 and Dnmt1 gene expression and methylation. These results suggest that interventions with antioxidants and epigenetic active food ingredients should be developed as an effective prevention for obesity—and oxidative stress—induced health risks.

Effect of vitamin E succinate on inflammatory cytokines induced by high-intensity interval training

Aim and Scope:

The anti-inflammatory effect of vitamin E under moderate exercises has been evaluated. However, the effect of vitamin E succinate, which has more potent anti-inflammatory effect than other isomers of vitamin E has not been evaluated. Therefore, the aim of the present study was to evaluate the effects of vitamin E succinate on tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) production induced by high-intensity interval training (HIIT).

Materials and Methods:

In the present study, 24 rats were randomly divided into control (C), supplementation (S), HIIT, and HIIT + supplementation (HIIT+S) groups. HIIT training protocol on a treadmill (at a speed of 40–54 m/min) and vitamin E succinate supplementation (60 mg/kg/day) was conducted for 6 weeks.

Results:

Serum IL-6 in the HIIT group significantly increased compared with the C group (350.42 ± 123.31 pg/mL vs 158.60 ± 41.96 pg/mL; P = 0.002). Also, serum TNF-α concentrations significantly enhanced (718.15 ± 133.42 pg/mL vs 350.87 ± 64.93 pg/mL; P = 0.001) in the HIIT group compared with the C group. Treatment of the training group with vitamin E numerically reduced IL-6 and TNF-α when compared with the HIIT group (217.31 ± 29.21 and 510.23 ± 217.88, respectively, P > 0.05). However, no significant changes were observed in serum TNF-α (P = 0.31) and IL-6 (P = 0.52) concentrations in the HIIT + S group compared with the C group.

Conclusion:

HIIT-induced IL-6 and TNF-α decreased by administration of Vitamin E succinate.

A Plasma α-Tocopherome Can Be Identified from Proteins Associated with Vitamin E Status in School-Aged Children of Nepal

BACKGROUND

The term vitamin E describes a family of 8 vitamers, 1 of which is α-tocopherol, that is essential for human health. Vitamin E status remains largely unknown in low-income countries because of the complexity and cost of measurement. Quantitative proteomics may offer an approach for identifying plasma proteins for assessing vitamin E status in these populations.

OBJECTIVE

To improve options for vitamin E status assessment, we sought to detect and quantify a set of plasma proteins associated with α- and γ-tocopherol concentrations in a cohort of 500 rural Nepalese children aged 6-8 y and, based on nutrient-protein associations, to predict the prevalence of vitamin E deficiency (α-tocopherol <12 μmol/L).

METHODS

Study children were born to mothers enrolled in an earlier antenatal micronutrient trial in Sarlahi District, Nepal. Plasma α- and γ-tocopherol concentrations were measured by high-performance liquid chromatography. Plasma aliquots were depleted of 6 high-abundance proteins, digested with trypsin, labeled with isobaric mass tags, and assessed for relative protein abundance by tandem mass spectrometry. Linear mixed-effects models were used to evaluate the association between α-tocopherol status and relative protein abundance and to predict deficiency.

RESULTS

We quantified 982 plasma proteins in >10% of all child samples, of which 119 correlated with α-tocopherol (false discovery rate, q < 0.10). Proteins were primarily involved in lipid transport, coagulation, repair, innate host defenses, neural function, and homeostasis. Six proteins [apolipoprotein (apo)C-III; apoB; pyruvate kinase, muscle; forkhead box 04; unc5 homolog C; and regulator of G-protein signaling 8] explained 71% of the variability in plasma α-tocopherol, predicting an in-sample population prevalence of vitamin E deficiency of 51.4% (95% CI: 46.4%, 56.3%) compared with a measured prevalence of 54.8%. Plasma γ-tocopherol was associated with 12 proteins (q < 0.10), 2 of which (apoC-III and Misato 1) explained 20% of its variability.

CONCLUSIONS

In this undernourished population of children in South Asia, quantitative proteomics identified a large plasma α-tocopherome from which 6 proteins predicted the prevalence of vitamin E deficiency. The findings illustrate that protein biomarkers, once absolutely quantified, can potentially predict micronutrient deficiencies in populations. The maternal micronutrient supplementation trial from which data were derived as a follow-up activity was registered with clinicaltrials.gov as NCT00115271.

Vitamin E: Curse or Benefit in Alzheimer's Disease? A Systematic Investigation of the Impact of α-, γ- and δ-Tocopherol on Aß Generation and Degradation in Neuroblastoma Cells

OBJECTIVES

The E vitamins are a class of lipophilic compounds including tocopherols, which have high antioxidative properties. Because of the elevated lipid peroxidation and increased reactive oxidative species in Alzheimer's disease (AD) many attempts have been made to slow down the progression of AD by utilizing the antioxidative action of vitamin E. Beside the mixed results of these studies nothing is known about the impact of vitamin E on the mechanisms leading to amyloid-β production and degradation being responsible for the plaque formation, one of the characteristic pathological hallmarks in AD. Here we systematically investigate the influence of different tocopherols on Aβ production and degradation in neuronal cell lines.

MEASUREMENTS

Beside amyloid-β level the mechanisms leading to Aβ production and degradation are examined.

RESULTS

Surprisingly, all tocopherols have shown to increase Aβ level by enhancing the Aβ production and decreasing the Aβ degradation. Aβ production is enhanced by an elevated activity of the involved enzymes, the β- and γ-secretase. These secretases are not directly affected, but tocopherols increase their protein level and expression. We could identify significant differences between the single tocopherols; whereas α-tocopherol had only minor effects on Aβ production, δ-tocopherol showed the highest potency to increase Aβ generation. Beside Aβ production, Aβ clearance was decreased by affecting IDE, one of the major Aβ degrading enzymes.

CONCLUSIONS

Our results suggest that beside the beneficial antioxidative effects of vitamin E, tocopherol has in respect to AD also a potency to increase the amyloid-β level, which differ for the analysed tocopherols. We therefore recommend that further studies are needed to clarify the potential role of these various vitamin E species in respect to AD and to identify the form which comprises an antioxidative property without having an amyloidogenic potential.

Inflammation and Nutritional Science for Programs/Policies and Interpretation of Research Evidence (INSPIRE)

An increasing recognition has emerged of the complexities of the global health agenda—specifically, the collision of infections and noncommunicable diseases and the dual burden of over- and undernutrition. Of particular practical concern are both 1) the need for a better understanding of the bidirectional relations between nutritional status and the development and function of the immune and inflammatory response and 2) the specific impact of the inflammatory response on the selection, use, and interpretation of nutrient biomarkers. The goal of the Inflammation and Nutritional Science for Programs/Policies and Interpretation of Research Evidence (INSPIRE) is to provide guidance for those users represented by the global food and nutrition enterprise. These include researchers (bench and clinical), clinicians providing care/treatment, those developing and evaluating programs/interventions at scale, and those responsible for generating evidence-based policy. The INSPIRE process included convening 5 thematic working groups (WGs) charged with developing summary reports around the following issues: 1) basic overview of the interactions between nutrition, immune function, and the inflammatory response; 2) examination of the evidence regarding the impact of nutrition on immune function and inflammation; 3) evaluation of the impact of inflammation and clinical conditions (acute and chronic) on nutrition; 4) examination of existing and potential new approaches to account for the impact of inflammation on biomarker interpretation and use; and 5) the presentation of new approaches to the study of these relations. Each WG was tasked with synthesizing a summary of the evidence for each of these topics and delineating the remaining gaps in our knowledge. This review consists of a summary of the INSPIRE workshop and the WG deliberations.

Egg yolks inhibit activation of NF-κB and expression of its target genes in adipocytes after partial delipidation

How composition of egg yolk (EY) influences NF-κB, a key transcription pathway in inflammation, remains unclear. We performed partial delipidation of EY that removed 20-30% of cholesterol and triglycerides. The resulting polar and nonpolar fractions were termed EY-P and EY-NP. NF-κB activation in response to EY from different suppliers and their fractions was examined in 3T3-L1 adipocytes using a NF-κB response element reporter assay and by analyzing expression of 248 inflammatory genes. Although EY-P and EY contained similar level of vitamins, carotenoids, and fatty acids, only delipidated EY-P fraction suppressed NF-κB via down-regulation of toll like receptor-2 and up-regulation of inhibitory toll interacting protein (Tollip) and lymphocyte antigen 96 (Ly96). Our data suggest that anti-inflammatory activity of lutein and retinol were blunted by nonpolar lipids in EY, likely via crosstalk between SREBP and NF-κB pathways in adipocytes. Thus, moderate delipidation may improve the beneficial properties of regular eggs.

Inflammatory status modulates plasma lipid and inflammatory marker responses to kiwifruit consumption in hypercholesterolaemic men

BACKGROUND AND AIMS

Kiwifruit has the potential to improve markers of metabolic dysfunction, but the response may be influenced by inflammatory state. We aimed to investigate whether inflammatory state would modulate the effect of consuming two green kiwifruit daily on plasma lipids and markers of inflammation.

METHODS AND RESULTS

Eighty-five hypercholesterolaemic men completed a 4-week healthy diet run-in, before randomisation to a controlled cross-over study of two 4-week interventions of two green kiwifruit/day plus healthy diet (intervention) or healthy diet alone (control). Anthropometric measures and fasting blood samples (plasma lipids, serum apolipoproteins A1 and B, high-sensitivity C-reactive protein (hs-CRP) and interleukin (IL)-6, tumour necrosis factor-alpha (TNF-α) and IL-10) were taken at baseline, 4 and 8 weeks. Subjects were divided into low and medium inflammatory groups, using pre-intervention hs-CRP concentrations (hs-CRP <1 and 1-3 mg/L, respectively). In the medium inflammatory group the kiwifruit intervention resulted in significant improvements in plasma high-density lipoprotein cholesterol (HDL-C) (mean difference 0.08 [95% CI: 0.03, 0.12] mmol/L [P < 0.001]), total cholesterol (TC)/HDL-C ratio (-0.29 [-0.45, -0.14] mmol/L [P = 0.001]), plasma hs-CRP (-22.1 [-33.6, -4.97]% [P = 0.01]) and IL-6 (-43.7 [-63.0, -14.1]% [P = 0.01]) compared to control treatment. No effects were seen in the low inflammatory group. There were significant between inflammation group differences for TC/HDL-C (P = 0.02), triglyceride (TG)/HDL-C (P = 0.05), and plasma IL-6 (P = 0.04).

CONCLUSIONS

Inflammatory state modulated responses to the kiwifruit intervention by improving inflammatory markers and lipid profiles in subjects with modestly elevated CRP, suggesting this group may particularly benefit from the regular consumption of green kiwifruit. Registered 16th March 2010, Australian New Zealand Clinical Trials Registry (no. ACTRN12610000213044), www.ANZCTR.org.au.

Diabetic and metabolic programming: mechanisms altering the intrauterine milieu

A wealth of epidemiological, clinical, and experimental studies have been linked to poor intrauterine conditions as well as metabolic and associated cardiovascular changes postnatal. These are novel perspectives connecting the altered intrauterine milieu to a rising number of metabolic diseases, such as diabetes, obesity, and hypercholesterolemia as well as the Metabolic Syndrome (Met S). Moreover, metabolic associated atherosclerotic diseases are connected to perigestational maternal health. The "Thrifty Phenotype Hypothesis" introduced cross-generational links between poor conditions during gestation and metabolic as well as cardiovascular alterations postnatal. Still, mechanisms altering the intrauterine milieu causing metabolic and associated atherosclerotic diseases are currently poorly understood. This paper will give novel insights in fundamental concepts connected to specific molecular mechanisms "programming" diabetes and associated metabolic as well as cardiovascular diseases.

Supplementation with alpha-tocopherol or beta-carotene reduces serum concentrations of vascular endothelial growth factor-D, but Not -A or -C, in male smokers

Evidence from the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study suggests that vitamin E and β-carotene supplement use may influence the risk of several cancers. Vascular endothelial growth factors (VEGF) are proteins involved in angiogenesis, an important requirement for tumor growth and metastasis. Thus, vitamin E and β-carotene may influence cancer risk through one or more VEGF. The ATBC Study was a randomized, double-blind, placebo-controlled, primary cancer prevention trial in which participants were assigned to 1 of 4 supplementation groups based on a 2 × 2 factorial design: 1) α-tocopherol (vitamin E); 2) β-carotene; 3) both; or 4) placebo. For the present study, 100 cancer-free participants with follow-up serum available were randomly selected from each intervention group. VEGF-A, -C, and -D concentrations were measured by ELISA in serum obtained at baseline and after at least 2 y of supplementation. Differences in change in VEGF levels from baseline to follow-up between intervention groups were assessed using the ANOVA test. Change in VEGF-A and VEGF-C concentrations between baseline and follow-up did not differ by intervention group (P = 0.45 and 0.29, respectively). The decrease in the serum VEGF-D concentration was greater in the men supplemented with α-tocopherol (-9.7 ± 2.5%) or β-carotene (-8.5 ± 2.7%) and tended to be greater in those supplemented with both (-6.8 ± 2.4%) compared to the placebo group, in which there was no change (-0.4 ± 3.0%) (P = 0.03). In this population of male smokers, supplementation with α-tocopherol or β-carotene was associated with a decrease in VEGF-D levels over time. Although the mechanism through which these supplements affect cancer etiolog remains unclear, our results support the hypothesis that vitamin E and β-carotene may influence cancer progression through VEGF-mediated lymphangiogenesis.

Vitamin E supplementation and hepatic drug metabolism in humans

Meta-analyses studies suggest that high-dose vitamin E may be associated with increased mortality in some populations. Vitamin E may increase the production of CYP3A4 in the liver, and this could lead to an increase in drug metabolism, potentially lowering the efficacy of therapeutic drugs. We hypothesized that upregulation of CYP3A4 by alpha-tocopherol (alpha-TOH) would decrease the plasma concentration of the CYP3A4 substrate midazolam. Baseline metabolism of midazolam (1 mg intravenously) was determined in 12 healthy subjects before randomization into 2 groups of 6 to receive either RRR-alpha-TOH (750 IU/d) or placebo for 3 weeks. At completion, subjects were given an additional 1 mg intravenous bolus of midazolam. Plasma midazolam, 1-hydroxy-midazolam, and urinary alpha-TOH metabolite excretion were measured using gas chromatography mass spectrometry. Serum alpha-TOH was measured using high performance liquid chromatography with electrochemical detection. Serum alpha-TOH increased by 100% (P = 0.002) and urinary alpha-TOH metabolite excretion increased 20-fold in the treatment group versus placebo (P = 0.001). There was no effect on the area under time curve of midazolam in subjects taking alpha-TOH compared with placebo. These findings do not support the hypothesis that alpha-TOH supplementation interferes with hepatic CYP3A4-mediated drug metabolism.

Iron behaving badly: inappropriate iron chelation as a major contributor to the aetiology of vascular and other progressive inflammatory and degenerative diseases

BACKGROUND

The production of peroxide and superoxide is an inevitable consequence of aerobic metabolism, and while these particular 'reactive oxygen species' (ROSs) can exhibit a number of biological effects, they are not of themselves excessively reactive and thus they are not especially damaging at physiological concentrations. However, their reactions with poorly liganded iron species can lead to the catalytic production of the very reactive and dangerous hydroxyl radical, which is exceptionally damaging, and a major cause of chronic inflammation.

REVIEW

We review the considerable and wide-ranging evidence for the involvement of this combination of (su)peroxide and poorly liganded iron in a large number of physiological and indeed pathological processes and inflammatory disorders, especially those involving the progressive degradation of cellular and organismal performance. These diseases share a great many similarities and thus might be considered to have a common cause (i.e. iron-catalysed free radical and especially hydroxyl radical generation).The studies reviewed include those focused on a series of cardiovascular, metabolic and neurological diseases, where iron can be found at the sites of plaques and lesions, as well as studies showing the significance of iron to aging and longevity. The effective chelation of iron by natural or synthetic ligands is thus of major physiological (and potentially therapeutic) importance. As systems properties, we need to recognise that physiological observables have multiple molecular causes, and studying them in isolation leads to inconsistent patterns of apparent causality when it is the simultaneous combination of multiple factors that is responsible.This explains, for instance, the decidedly mixed effects of antioxidants that have been observed, since in some circumstances (especially the presence of poorly liganded iron) molecules that are nominally antioxidants can actually act as pro-oxidants. The reduction of redox stress thus requires suitable levels of both antioxidants and effective iron chelators. Some polyphenolic antioxidants may serve both roles.Understanding the exact speciation and liganding of iron in all its states is thus crucial to separating its various pro- and anti-inflammatory activities. Redox stress, innate immunity and pro- (and some anti-)inflammatory cytokines are linked in particular via signalling pathways involving NF-kappaB and p38, with the oxidative roles of iron here seemingly involved upstream of the IkappaB kinase (IKK) reaction. In a number of cases it is possible to identify mechanisms by which ROSs and poorly liganded iron act synergistically and autocatalytically, leading to 'runaway' reactions that are hard to control unless one tackles multiple sites of action simultaneously. Some molecules such as statins and erythropoietin, not traditionally associated with anti-inflammatory activity, do indeed have 'pleiotropic' anti-inflammatory effects that may be of benefit here.

CONCLUSION

Overall we argue, by synthesising a widely dispersed literature, that the role of poorly liganded iron has been rather underappreciated in the past, and that in combination with peroxide and superoxide its activity underpins the behaviour of a great many physiological processes that degrade over time. Understanding these requires an integrative, systems-level approach that may lead to novel therapeutic targets.