Maret Traber

Maret Traber
Oregon State University | OSU · Linus Pauling Institute

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398
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Publications

Publications (398)
Article
Although vitamin E acetate (VEA) is suspected to play a causal role in the development of electronic-cigarette, or vaping, product use-associated lung injury (EVALI), the underlying biological mechanisms of pulmonary injury are yet to be determined. Additionally, no study has replicated the systemic inflammation observed in humans in a murine EVALI...
Chapter
Vitamin E, a fat-soluble antioxidant, is required from the diet but amounts in excess of requirements have not been demonstrated to decrease chronic disease risk. Vitamin E is a chain-breaking, peroxyl radical scavenger that halts lipid peroxidation and protects polyunsaturated fatty acids. This antioxidant activity serves to protect the nervous sy...
Article
α-Tocopherol (α-T) is a required dietary nutrient for humans and thus is a vitamin. This narrative review focuses on vitamin E structures, functions, biological determinants and its deficiency symptoms in humans. The mechanisms for the preferential α-T tissue enrichment in the human body include the α-T transfer protein (TTPA) and the preferential...
Article
This review discusses why the embryo requires vitamin E (VitE) and shows that its lack causes metabolic dysregulation and impacts morphological changes at very early stages in development, which occur prior to when a woman knows she is pregnant. VitE halts the chain reactions of lipid peroxidation (LPO). Metabolomic analyses indicate that thiols be...
Article
Full-text available
The vitamin E regulatory protein, the alpha-tocopherol transfer protein (Ttpa), is necessary for zebrafish embryo development. To evaluate zebrafish embryo Ttpa function, we generated a fluorescent-tagged zebrafish transgenic line using CRISPR-Cas9 technology. One-cell stage embryos (from Casper (colorless) zebrafish adults) were injected the mScar...
Article
An evaluation of the impact of vitamin E deficiency on expression of the alpha-tocopherol transfer protein (α-TTP) and related CRAL_TRIO genes was undertaken using livers from adult zebrafish based on the hypothesis that increased lipid peroxidation would modulate gene expression. Zebrafish were fed either a vitamin E sufficient (E+) or deficient (...
Article
Full-text available
Vitamin E (VitE) is essential for vertebrate embryogenesis, but the mechanisms involved remain unknown. To study embryonic development, we fed zebrafish adults (>55 days) either VitE sufficient (E+) or deficient (E–) diets for >80 days, then the fish were spawned to generate E+ and E– embryos. To evaluate the transcriptional basis of the metabolic...
Article
Full-text available
Vitamin E (α-tocopherol, VitE) was discovered as a nutrient essential to protect fetuses, but its molecular role in embryogenesis remains undefined. We hypothesize that the increased lipid peroxidation due to VitE deficiency drives a complex mechanism of overlapping biochemical pathways needed to maintain glutathione (GSH) homeostasis that is depen...
Article
Background Human vitamin E (α-tocopherol) catabolism is a mechanism for regulating whole-body α-tocopherol. Objectives To determine the roles of the intestine and liver on α-tocopherol catabolism as affected by fat or fasting, 2 deuterium-labeled (intravenous d6- and oral d3-) forms of α-tocopherol were used. Methods Healthy women received intrav...
Article
Full-text available
Vitamin E (VitE) deficiency results in embryonic lethality. Knockdown of the gene ttpa encoding for the VitE regulatory protein [α-tocopherol transfer protein (α-TTP)] in zebrafish embryos causes death within 24 h post-fertilization (hpf). To test the hypothesis that VitE, not just α-TTP, is necessary for nervous system development, adult 5D strain...
Article
Full-text available
Background: α-Lipoic acid (LA) is a dietary supplement for maintaining energy balance, but well-controlled clinical trials in otherwise healthy, overweight adults using LA supplementation are lacking. Objectives: The primary objective was to evaluate whether LA supplementation decreases elevated plasma triglycerides in overweight or obese adults...
Article
Full-text available
BACKGROUND We hypothesized that obesity-associated hepatosteatosis is a pathophysiological chemical depot for fat-soluble vitamins and altered normal physiology. Using α-tocopherol (vitamin E) as a model vitamin, pharmacokinetics and kinetics principles were used to determine whether excess liver fat sequestered α-tocopherol in women with obesity-a...
Article
Full-text available
Background: Determining the human vitamin E [α-tocopherol (α-T)] requirement is difficult, and novel approaches to assess α-T absorption and trafficking are needed. Objective: We hypothesized that the dual-isotope technique, using 2 deuterium-labeled [intravenous (IV) d6- and oral d3-] α-T, would be effective in determining α-T fractional absorp...
Article
To determine optimal conditions for blood collection during clinical trials, where sample handling logistics might preclude prompt separation of erythrocytes from plasma, healthy subjects (n=8, 6 M/2F) were recruited and non-fasting blood samples were collected into tubes containing different anticoagulants (ethylenediaminetetra-acetic acid (EDTA),...
Article
Full-text available
Metabolic syndrome (MetS) is a constellation of cardiometabolic risk factors, which together predict increased risk of more serious chronic diseases. We propose that one consequence of dietary overnutrition is increased abundance of Gram-negative bacteria in the gut that cause increased inflammation, impaired gut function, and endotoxemia that furt...
Article
Lipid peroxidation is the process by which oxygen combines with lipids to generate lipid hydroperoxides via intermediate formation of peroxyl radicals. Vitamin E and coenzyme Q10 react with peroxyl radicals to yield peroxides, and then these oxidized lipid species can be detoxified by glutathione and glutathione peroxidase 4 (GPX4) and other compon...
Article
Hazelnut kernels obtained from the commercial processes were analyzed for proximate composition, bioactive compounds, lipid oxidation, and enzyme (lipase, peroxidase, and polyphenol oxidase) activities and compared among three cultivars (Barcelona, Yamhill, and Jefferson) and two agricultural practices (with and without fertigation for Jefferson)....
Article
Contamination of soil and water by waste from abandoned uranium mines has led to chronic exposures to metal mixtures in Native American communities. Our previous work demonstrated that community exposures to mine waste increase the likelihood of developing cardiovascular disease, as well as the likelihood of developing multiple chronic diseases inc...
Article
Zebrafish (Danio rerio) are a recognized model for studying the pathogenesis of cognitive deficits and the mechanisms underlying behavioral impairments, including the consequences of increased oxidative stress within the brain. The lipophilic antioxidant vitamin E (α-tocopherol; VitE) has an established role in neurological health and cognitive fun...
Article
Vitamin E (α-tocopherol, VitE) was discovered in 1922 because it prevented rat fetal resorption. We investigated the mechanisms causing lethality using targeted metabolomic analyses of zebrafish VitE-deficient embryos daily from 1 to 5 days by which time 80% experienced increased morbidity or mortality. VitE deficiency caused lipid peroxidation of...
Article
Vitamin E (α-tocopherol; VitE) is a lipophilic antioxidant required for normal embryonic development in vertebrates, but the long-term effects of embryonic VitE deficiency, and whether they are ameliorated by feeding VitE–adequate diets, remain unknown. We addressed these questions using a zebrafish (Danio rerio) model of developmental VitE deficie...
Article
High levels of alpha-tocopherol, the usual vitamin E supplement, are reported to decrease bone mass in rodents; however, the effects of other vitamin E forms on the skeleton are unknown. To test the hypothesis that high intakes of various vitamin E forms or the vitamin E metabolite, carboxyethyl hydroxy chromanol, were detrimental to bone status, S...
Article
Full-text available
The data herein is in support of our research article by McDougall et al. (2017) [1], in which we used our zebrafish model of embryonic vitamin E (VitE) deficiency to study the consequences of VitE deficiency during development. Adult 5D wild-type zebrafish (Danio rerio), fed defined diets without (E–) or with VitE (E+, 500mg RRR-α-tocopheryl aceta...
Article
Full-text available
Electric conductivity in plasma is the balance between oxidized and reduced molecules (static Oxidation-Reduction Potential, sORP) and the amount of readily oxidizable molecules (capacity ORP, cORP). Adults with metabolic syndrome (MetS) have increased inflammation, dyslipidemia and oxidative stress; therefore, participants with MetS were hypothesi...
Article
Vitamin E (α-tocopherol, VitE) was discovered in 1922 for its role in preventing embryonic mortality. We investigated the underlying mechanisms causing lethality using targeted metabolomics analyses of zebrafish VitE-deficient embryos over five days of development, which coincided with their increased morbidity and mortality. VitE deficiency result...
Article
Background: Vitamin E supplementation improves liver histology in patients with nonalcoholic steatohepatitis, which is a manifestation of the metabolic syndrome (MetS). We reported previously that α-tocopherol bioavailability in healthy adults is higher than in those with MetS, thereby suggesting that the latter group has increased requirements....
Article
Vitamin E (VitE), a lipophilic antioxidant, prevents fetal resorption in VitE-deficient pregnant rodents. However, the mechanism for this requirement is unknown. We explored the underlying cause of mortality during developmental VitE deficiency using an embryonic zebrafish model. Adult 5D zebrafish (Danio rerio) fed defined diets without (E-) or wi...
Article
Full-text available
We hypothesized that vitamin E (α-tocopherol) is required by the developing embryonic brain to prevent depletion of highly polyunsaturated fatty acids, especially docosahexaenoic acid (DHA, 22:6), the loss of which we predicted would underlie abnormal morphological and behavioral outcomes. Therefore, we fed adult 5D zebrafish (Danio rerio) defined...
Article
Full-text available
Background: Increasing dietary fat intake is expected to improve α-tocopherol bioavailability, which could be beneficial for improving α-tocopherol status, especially in cohorts at high cardiometabolic risk who fail to meet dietary α-tocopherol requirements. Objective: Our objective was to assess dose-dependent effects of dairy fat and metabolic...
Article
Full-text available
We hypothesized that brains from vitamin E-deficient (E-) zebrafish (Danio rerio) would undergo increased lipid peroxidation because they contain highly polyunsaturated fatty acids, thus susceptible lipids could be identified. Brains from zebrafish fed for 9 months defined diets without (E-) or with added vitamin E (E+, 500 mg RRR-α-tocopheryl acet...
Article
Full-text available
Background: Little is known about α-tocopherol’s bioavailability as a constituent of food or its dependence on a subject’s age. Objective: To evaluate the α-tocopherol bioavailability from food, we used collard greens grown in deuterated water (²H collard greens) as a source of deuterium-labeled (²H) α-tocopherol consumed by younger and older adult...
Article
We have shown previously that alpha-lipoic acid, a naturally-occurring dithiol compound, inhibits atherosclerotic lesion development and body weight gain and lowers serum triglycerides in apoE-/-and apoE-/-LDLR-/-mice. In addition, we found that alpha-lipoic acid stimulates triglyceride clearance and inhibits liver triglyceride secretion in ZDF rat...
Article
Full-text available
Nicotine replacement therapy (NRT) improves the long-term success rate of smoking cessation, but induces oxidative stress and inflammatory responses that may delay the restoration of vascular endothelial function (VEF). No studies have examined co-therapy of NRT-assisted smoking abstinence with γ-tocopherol (γ-T), a vitamin E form with antioxidant...
Article
Full-text available
Dairy cows have increased nutritional requirements for antioxidants postpartum. Supranutritional organic Se supplementation may be beneficial because selenoproteins are involved in regulating oxidative stress and inflammation. Our objective was to determine whether feeding Se-yeast above requirements to Se-replete dairy cows during late gestation a...
Article
ScopeThe influence of excess α-tocopherol (α-T) on tissue depletion of phylloquinone (PK) and menaquinone-4 (MK-4) was evaluated.Methods and resultsRats (n = 5 per group) were fed deuterium-labeled PK (2 μmol/kg diet) for 17 days, thereby labeling the conversion from deuterium-labeled PK to d4-MK-4. Then they were injected subcutaneously daily for...
Article
The composition of the typical commercial diet fed to zebrafish can dramatically vary. By utilizing defined diets we sought to answer two questions: 1) How does the embryonic zebrafish transcriptome change when the parental adults are fed a commercial lab diet compared with a sufficient, defined diet (E +)? 2) Does a vitamin E-deficient parental di...
Article
Retained placenta (RP), defined as fetal membranes not being expelled within 24 h after calving, is a costly disease in multiparous dairy cows that has been linked to immune suppression, infections, elevated lipid mobilization, and depleted status of antioxidants including α-tocopherol, and that increases the risk of other diseases (OD) in early la...
Article
The purpose of this study was to determine the system-wide consequences of deficiencies in two essential micronutrients, vitamin C and E, on the proteome using zebrafish (Danio rerio) as one of the few vertebrate models that similar to humans cannot synthesize vitamin C. We describe a label-free proteomics workflow to detect changes in protein abun...
Article
Oxidative stress and low-grade systemic inflammation may contribute to the pathogenesis of obesity-induced comorbidities, including nonalcoholic fatty liver disease. Increasing intake of dietary antioxidants might be beneficial, but there are few data in obese children. To examine the effect of antioxidant supplementation on biomarkers of oxidative...
Article
Oxidative stress and low-grade systemic inflammation may contribute to the pathogenesis of obesity-induced comorbidities, including nonalcoholic fatty liver disease. Increasing intake of dietary antioxidants might be beneficial, but there are few data in obese children. To examine the effect of antioxidant supplementation on biomarkers of oxidative...
Article
Full-text available
Nonalcoholic steatohepatitis (NASH) is a progressive form of nonalcoholic fatty liver disease and a risk factor for cirrhosis, hepatocellular carcinoma and liver failure. Previously, we reported that dietary docosahexaenoic acid (DHA, 22:6,n-3) was more effective than eicosapentaenoic acid (EPA, 20:5,n-3) at reversing western diet (WD) induced NASH...
Article
Full-text available
To test the hypothesis that embryogenesis depends upon α-tocopherol (E) to protect embryo polyunsaturated fatty acids (PUFAs) from lipid peroxidation, new methodologies were applied to measure α-tocopherol and fatty acids in extracts from saponified zebrafish embryos. A solid phase extraction method was developed to separate the analyte classes, us...
Article
Full-text available
While vitamin E has been used for decades in cattle diets, the principle form used traditionally is the synthetic α-isoform acetate or succinate and largely no data exist on the biological partitioning or functionality of the major naturally occurring γ- and δ-isoforms in cattle. Using tyrosine 3’-nitrated protein (pNT) as a biomarker of nitrosativ...
Article
Oxidative stress and inflammation persist years after smoking cessation thereby limiting the restoration of vascular endothelial function (VEF). Although short-term smoking cessation improves VEF, no studies have examined co-therapy of antioxidants in combination with smoking cessation to improve VEF. We hypothesized that improvements in γ-tocopher...
Article
High dietary α-tocopherol levels reportedly result in osteopenia in growing rats, while α-tocopherol deficiency in α-tocopherol transfer protein knockout (α-TTP KO) mice results in increased cancellous bone mass. Since osteoporosis is a disease associated primarily with aging, we hypothesized that age-related bone loss would be attenuated in α-TTP...
Article
α-Tocopherol is a lipid-soluble antioxidant that is specifically required for reproduction and embryogenesis. However, since its discovery, α-tocopherol's specific biologic functions, other than as an antioxidant, and the mechanism(s) mediating its requirement for embryogenesis, remain unknown. As an antioxidant, α-tocopherol protects polyunsaturat...
Article
Scope: The objective of this study was to investigate the initial catabolic step of vitamin E and K metabolism, the ω-hydroxylation by human cytochrome P450 4F2 (CYP4F2). Methods and results: Tocopherol (T) metabolism was compared using rat liver slices incubated with deuterated (d₆)-RRR-α-T (d₆-α-T), racemic 2S-α-T (2S, 4'RS, 8'RS α-T, 2S-α-T),...
Article
We hypothesized that zebrafish (Danio rerio) undergoing long-term vitamin E deficiency with marginal vitamin C status would develop myopathy resulting in impaired swimming. Zebrafish were fed for 1 y a defined diet without (E-) and with (E+) vitamin E (500mg α-tocopherol/kg diet). For the last 150days, dietary ascorbic acid concentrations were decr...
Article
Full-text available
The liver is at the nexus of the regulation of lipoprotein uptake, synthesis, and secretion; and the site of xenobiotic detoxification by cytochrome P450 oxidation systems (phase I), conjugation systems (phase II) and transporters (phase III). These two major regulatory systems control vitamin E status. The mechanisms for the preference for α-tocop...
Article
Full-text available
Cows with left displaced abomasum (LDA), a costly disease occurring primarily in multiparous dairy cows during early lactation, have been reported to have 40% lower circulating concentrations of vitamin E. It is unknown, however, whether the lower circulating α-tocopherol concentrations precede LDA or remain after LDA. Using a nested case-control d...
Article
Full-text available
While vitamin E has been used for decades in cattle diets, the principle form used traditionally is the synthetic α-isoform acetate or succinate and largely no data exist on the biological partitioning or functionality of the major naturally occurring γ- and δ-isoforms in cattle. Using tyrosine 3’-nitrated protein (pNT) as a biomarker of nitrosativ...
Article
Full-text available
More than 20,000 burn injury victims suffer from smoke inhalation injury in the United States annually. In an ovine model of acute lung injury, γ-tocopherol had a beneficial effect when nebulized into the airway. We hypothesize that γ-tocopherol scavenges reactive oxygen species (ROS) and reactive nitrogen species resulting from burn and smoke inha...
Article
Vitamin E (α-tocopherol) was discovered nearly 100 years ago because it was required to prevent fetal resorption in pregnant, vitamin E-deficient rats fed lard-containing diets that were easily oxidizable. The human diet contains eight different vitamin E-related molecules synthesized by plants; despite the fact that all of these molecules are pero...
Article
Full-text available
The hepatic α-tocopherol transfer protein (TTP) is required for optimal α-tocopherol bioavailability in humans; mutations in the human TTPA gene result in the heritable disorder ataxia with vitamin E deficiency (AVED, OMIM #277460). TTP is also expressed in mammalian uterine and placental cells and in the human embryonic yolk-sac, underscoring TTP'...
Data
Putative peptide products. A. TTP transcript is depicted, with EXC morpholinos (green lines), marked. B. The proper mature mRNA and associated full-length protein. C. A naturally occurring splice-variant (inclusion of intron 1–2), recorded as “non-coding”, if translated, results in a truncated protein product due to a frame shift. D. The exclusion...
Data
EXC MO concentration efficacy validation. Embryos were injected using the noted concentrations at 1–2 cell stage with the exon-exclusion (EXC) MOs, which are complementary to either end of the second exon (Upper rows). MO-injected embryos were observed at 24 hpf for gross morphologic effects. Results shown are from three separate injection trials....
Data
MO splice-blocking confirmation. PCR products created using primers flanking exon 2 in the TTP mRNA sequence are shown. Products from EXC injected embryos (EXC) display an aberrant transcript when compared to the other TTP knockdown (TRN), or the control groups (CTR and NON). The loss of exon 2 creates a single 346 base pair (bp) product, the prope...
Data
Splice blocking MO cause decreased TTP mRNA. At 12 hpf, prior to overt malformations, TTP transcripts are significantly reduced in EXC embryos compared to the CTR embryos. This ∼10-fold reduction in TTP mRNA is likely due to nonsense mediated decay of the aberrant transcript (Gene-tools, personal communication). The qPCR amplicon does not include t...
Data
TTP knockdown time-lapse video. Representative embryo with TTP knockdown from 4–24 hpf (TRN). Loss of TTP causes notable malformations beginning at ∼12 hpf. The rostral and caudle parts of the embryo fail to develop, while somitogenesis continues unabated. Arrow appears next to beginning eye-spot at ∼12 hpf. (MP4)
Data
Control injected embryo time lapse. Representative control (CTR) MO-injected embryo from 4–17 hpf. Embryo development proceeds in proper fashion regardless of the injection process, as compared to non-injected, not shown. Arrow appears next to beginning eye-spot at ∼12 hpf. (MP4)