Tocopherols, tocotrienols and tocomonoenols: Many similar molecules but only one vitamin E

The aim of this article is to correct a very general error in scientific articles, in textbooks and in the Internet that has become an accepted fact. In this literature, the term "vitamin E″ is used for several similar molecules (both tocopherols and tocotrienols) that have never been shown to have vitamin property, i.e. a protective effect against the human deficiency disease. In fact, the name "vitamin E″ should only be used to define molecules that prevent the human deficiency disease "Ataxia with Vitamin E Deficiency" (AVED). Only one such molecule is known, α-tocopherol. This error may confuse consumers as well as medical doctors, who prescribe vitamin E without realizing that the current use of the name includes molecules of unknown, if not unwanted functions.

Inhibition of Osteocyte Membrane Repair Activity via Dietary Vitamin E Deprivation Impairs Osteocyte Survival

Osteocytes experience plasma membrane disruptions (PMD) that initiate mechanotransduction both in vitro and in vivo in response to mechanical loading, suggesting that osteocytes use PMD to sense and adapt to mechanical stimuli. PMD repair is crucial for cell survival; antioxidants (e.g., alpha-tocopherol, also known as Vitamin E) promote repair while reactive oxygen species (ROS), which can accumulate during exercise, inhibit repair. The goal of this study was to determine whether depleting Vitamin E in the diet would impact osteocyte survival and bone adaptation with loading. Male CD-1 mice (3 weeks old) were fed either a regular diet (RD) or Vitamin E-deficient diet (VEDD) for up to 11 weeks. Mice from each dietary group either served as sedentary controls with normal cage activity, or were subjected to treadmill exercise (one bout of exercise or daily exercise for 5 weeks). VEDD-fed mice showed more PMD-affected osteocytes (+ 50%) after a single exercise bout suggesting impaired PMD repair following Vitamin E deprivation. After 5 weeks of daily exercise, VEDD mice failed to show an exercise-induced increase in osteocyte PMD formation, and showed signs of increased osteocytic oxidative stress and impaired osteocyte survival. Surprisingly, exercise-induced increases in cortical bone formation rate were only significant for VEDD-fed mice. This result may be consistent with previous studies in skeletal muscle, where myocyte PMD repair failure (e.g., with muscular dystrophy) initially triggers hypertrophy but later leads to widespread degeneration. In vitro, mechanically wounded MLO-Y4 cells displayed increased post-wounding necrosis (+ 40-fold) in the presence of H₂O₂, which could be prevented by Vitamin E pre-treatment. Taken together, our data support the idea that antioxidant-influenced osteocyte membrane repair is a vital aspect of bone mechanosensation in the osteocytic control of PMD-driven bone adaptation.

Chronic vitamin E deficiency impairs cognitive function in adult zebrafish via dysregulation of brain lipids and energy metabolism

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 function, but the biological rationale for this action remains unknown. In the present study, we investigated behavioral perturbations due to chronic VitE deficiency in adult zebrafish fed from 45 days to 18-months of age diets that were either VitE-deficient (E-) or VitE-sufficient (E+). We hypothesized that E- zebrafish would display cognitive impairments associated with elevated lipid peroxidation and metabolic disruptions in the brain. Quantified VitE levels at 18-months in E- brains (5.7 ± 0.1 nmol/g tissue) were ~20-times lower than in E+ (122.8 ± 1.1; n = 10/group). Using assays of both associative (avoidance conditioning) and non-associative (habituation) learning, we found E- vs E+ fish were learning impaired. These functional deficits occurred concomitantly with the following observations in adult E- brains: decreased concentrations of and increased peroxidation of polyunsaturated fatty acids (especially docosahexaenoic acid, DHA), altered brain phospholipid and lysophospholipid composition, as well as perturbed energy (glucose/ketone), phosphatidylcholine and choline/methyl-donor metabolism. Collectively, these data suggest that chronic VitE deficiency leads to neurological dysfunction through multiple mechanisms that become dysregulated secondary to VitE deficiency. Apparently, the E- animals alter their metabolism to compensate for the VitE deficiency, but these compensatory mechanisms are insufficient to maintain cognitive function.

Vitamin E deficiency during embryogenesis in zebrafish causes lasting metabolic and cognitive impairments despite refeeding adequate diets

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 deficiency followed by dietary remediation. Adult zebrafish maintained on VitE-deficient (E-) or sufficient (E+) diets were spawned to obtained E- and E+ embryos, respectively, which we evaluated up to 12 days post-fertilization (dpf). The E- group suffered significantly increased morbidity and mortality as well as altered DNA methylation status through 5 dpf when compared to E+ larvae, but upon feeding with a VitE-adequate diet from 5 to 12 dpf both the E- and E+ groups survived and grew normally; the DNA methylation profile also was similar between groups by 12 dpf. However, 12 dpf E- larvae still had behavioral defects. These observations coincided with sustained VitE deficiency in the E- vs. E+ larvae (p < 0.0001), despite adequate dietary supplementation. We also found in E- vs. E+ larvae continued docosahexaenoic acid (DHA) depletion (p < 0.0001) and significantly increased lipid peroxidation. Further, targeted metabolomics analyses revealed persistent dysregulation of the cellular antioxidant network, the CDP-choline pathway, and glucose metabolism. While anaerobic processes were increased, aerobic metabolism was decreased in the E- vs. E+ larvae, indicating mitochondrial damage. Taken together, these outcomes suggest embryonic VitE deficiency causes lasting behavioral impairments due to persistent lipid peroxidation and metabolic perturbations that are not resolved via later dietary VitE supplementation.

Vitamin E deficiency depressed fish growth, disease resistance, and the immunity and structural integrity of immune organs in grass carp (Ctenopharyngodon idella): Referring to NF-κB, TOR and Nrf2 signaling

This study investigated the effects of dietary vitamin E on growth, disease resistance and the immunity and structural integrity of head kidney, spleen and skin in grass carp (Ctenopharyngodon idella). The fish were fed six diets containing graded levels of vitamin E (0, 45, 90, 135, 180 and 225 mg/kg diet) for 10 weeks. Subsequently, a challenge test was conducted by injection of Aeromonas hydrophila. The results showed that compared with optimal vitamin E supplementation, vitamin E deficiency caused depressed growth, poor survival rates and increased skin lesion morbidity in grass carp. Meanwhile, vitamin E deficiency decreased lysozyme and acid phosphatase activities, complement component 3 and complement component 4 contents in the head kidney, spleen and skin of grass carp (P < 0.05). Moreover, vitamin E deficiency down-regulated antimicrobial peptides (Hepcidin, liver-expressed antimicrobial peptide-2A, -2B, β-defensin), IL-10, TGFβ1, IκBα, TOR and S6K1 mRNA levels (P < 0.05) and up-regulated IL-1β, IL-6, IL-8, IFN-γ2 and TNFα, NF-κB p65, IKKα, IKKβ and 4EBP1 (not in the head kidney) mRNA levels (P < 0.05). In addition, vitamin E deficiency caused oxidative damage, decreased superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT) and glutathione reductase (GR) activities, and down-regulated the mRNA levels of antioxidant enzymes and signaling molecules Nrf2 (P < 0.05). Vitamin E deficiency also induced apoptosis by up-regulating capase-2, -3, -7, and -8 mRNA levels in the head kidney, spleen and skin of grass carp. In conclusion, this study indicated that dietary vitamin E deficiency depressed fish growth, impaired the immune function and disturbed the structural integrity of the head kidney, spleen and skin in grass carp, but optimal vitamin E supplementation can reverse those negative effects in fish. The optimal vitamin E requirements for young grass carp (266.39-1026.63 g) to achieve optimal growth performance and disease resistance based on the percent weight gain (PWG) and skin lesion morbidity were estimated to be 116.2 and 130.9 mg/kg diet, respectively. Meanwhile, based on immune indicator (LA activity in the head kidney) and antioxidant indicator (protection of spleen against MDA), the optimal vitamin E requirements for young grass carp were estimated to be 123.8 and 136.4 mg/kg diet, respectively.

Vitamin E-deficiency did not exacerbate partial skin reactions in mice locally irradiated with X-rays

We previously showed that free radicals and oxidative stress are involved in radiation-induced skin reactions. Since vitamin E (VE) is a particularly important lipophilic antioxidant, VE-deficient mice were used to examine its effects on radiation-induced skin damage. The VE content of the skin was reduced to one fourth of levels of normal mice. Neither the time of onset nor the extent of the reactions quantified with a scoring system differed between normal and VE-deficient mice after local X-irradiation (50 Gy). Similarly, there was no difference in the levels of the ascorbyl radical between the groups, although they were higher in irradiated skin than non-irradiated skin. X-irradiation increased the amount of Bax protein in the skin of normal mice both in the latent and acute inflammatory stages, time- and dose-dependently. The increase was associated with an increase in cytochrome c in the cytosolic fraction, indicating that apoptosis was also promoted by the irradiation. The increase in Bax protein correlated well with the thickness of the skin. Although a deficiency in VE should lower resistance to free radicals in the mitochondrial membrane and thus enhance radiation-induced Bax expression and apoptosis, it actually attenuated the increase in Bax protein caused by irradiation.

Correlation between neurological dysfunction with vitamin E deficiency and gastrectomy

OBJECTIVE

We previously reported on vitamin E malabsorption after gastrectomy. In this study, we focused on neurological dysfunction due to serum vitamin E decrease during the postgastrectomy period in lager number of patients.

METHODS

We examined the type of gastrectomy, type of reconstruction, serum vitamin E level, and neurological status for 96 gastrectomy patients.

RESULTS

Low serum vitamin E levels were observed in 20 patients, and 10 of those patients suffered some neurological symptoms, i.e., peripheral neuropathy, limb or truncal ataxia. Vitamin E levels tended to decrease with time after gastrectomy, and the number of patients with low serum vitamin E levels increased at about 50 months after gastrectomy. This relationship was stronger in total gastrectomy patients than in subtotal gastrectomy patients. Ten patients were given oral vitamin E, and serum vitamin E levels normalized in 9 of the patients and neurological abnormalities improved in 8 patients. An oral intake of 300 mg or more of vitamin E was necessary for normalization of vitamin E levels.

CONCLUSIONS

Gastrectomy should be considered a risk for vitamin E deficiency and neurological disturbance over the long-term clinical course. An oral vitamin E supply can improve serum vitamin E levels and neurological symptoms.

Dietary vitamin E deficiency increases anxiety-related behavior in rats under stress of social isolation

It has been demonstrated that vitamin E deficiency from birth increases anxiety-related behavior using knockout animals with no vitamin E transfer proteins. The current study was undertaken to elucidate the effect of dietary vitamin E deficiency on anxiety-related behavior of rats in different housing conditions. Male Wistar strain rats were divided into two groups during the weaning period and fed a control or vitamin E-deficient diet. All rats were housed in groups (three rats per cage) for 3 weeks. In the fourth week, half of the rats in each dietary treatment were kept in social housing and the other half were kept in individual housing. Before sacrifice, rota-rod and elevated plus-maze (EPM) tests were performed to measure motor coordination and anxiety, respectively. The EPM test revealed that vitamin E-deficient rats spent less time in the open arms and showed more stretch-out posture than the control rats, showing that anxiety increased with dietary vitamin E deficiency. Furthermore, vitamin E deficiency-induced anxiety behavior was observed more prominent in individual housed rats than in social housed rats. On the basis of these results, we conclude that dietary vitamin E deficiency induces anxiety in rats especially under stress of social isolation.

Vitamin E: the shrew waiting to be tamed

Vitamin E is the last of all vitamins whose essentiality is not yet understood. Its widely accepted role as a lipophilic antioxidant has been questioned, since proof of its in vivo relevance remained scarce. The influence of vitamin E on biomarkers of oxidative stress in vivo is inconsistent and metabolites of vitamin E having reacted as an antioxidant are hardly detectable. Novel functions of vitamin E include the regulation of enzymes, most of which are membrane bound or activated by membrane recruitment. Also, expression of genes responds to vitamin E. The search for a transcription factor common to all regulated genes failed so far and a receptor that specifically binds vitamin E has not yet been identified. According to microarray data, pathways preferentially affected by the vitamin E status are the inflammatory response and cellular traffic. A role of vitamin E in cellular trafficking could best explain the neurological symptoms seen in vitamin E deficiency. Emerging knowledge on vitamin E is compiled here with the perspective to unravel the molecular mechanisms that could more likely explain the essentiality of the vitamin than its ability to scavenge free radicals.

Folate deprivation increases presenilin expression, gamma-secretase activity, and Abeta levels in murine brain: potentiation by ApoE deficiency and alleviation by dietary S-adenosyl methionine

Folate deficiency has been associated with age-related neurodegeneration. One direct consequence of folate deficiency is a decline in the major methyl donor, S-adenosyl methionine (SAM). We demonstrate herein that dietary deficiency in folate and vitamin E, coupled pro-oxidant stress induced by dietary iron, increased presenilin-1 expression, gamma-secretase activity, and Abeta levels in normal adult mice. These increases were potentiated by apolipoprotein E deficiency as shown by treatment of transgenic mice homozygously lacking murine apolipoprotein E. Dietary supplementation with SAM in the absence of folate attenuated or alleviated these deleterious consequences. These findings link nutritional and genetic risk factors for age-related neurodegeneration and underscore that dietary supplementation with SAM may be useful to augment therapeutic approaches.

Supplementation with apple juice attenuates presenilin-1 overexpression during dietary and genetically-induced oxidative stress

Gain-of-function mutations in the presenilin-1 (PS-1) promote Alzheimer's disease (AD) by increasing reactive oxygen species, at least part of which is derived by an accompanying increase in generation of amyloid-beta (Abeta). Additional studies indicate that impaired Apolipoprotein E function, which also increases oxidative stress and is also associated with AD, potentiates the deleterious activity of PS-1. Folate deficiency is also associated with AD and potentiates the impact of both ApoE deficiency and beta exposure. More recently, folate deficiency has been shown to increase PS-1 expression. Since dietary supplementation with apple juice provides neuroprotection against ApoE deficiency, Abeta exposure and folate deficiency, we examined the impact of apple juice on PS-1 overexpression. Herein, we demonstrate that dietary deficiency in folate and vitamin E increased PS-1 expression in juvenile and adult normal C57B1/6J and ApoE-/- mice and in aged normal mice. Supplementation with apple juice concentrate (AJC) attenuated or prevent these increases. Prior studies demonstrate that impaired DNA methylation resulting from a deficiency in S-adenosylmethionine (SAM, which is rapidly depleted following folate deprivation) leads to PS-1 overexpression, and that direct supplementation with SAM attenuates PS-1 overexpression. We determined that AJC contained levels of SAM comparable to those capable of suppressing PS-1 overexpression, suggesting that the SAM content of AJC represents a potential mechanism for preventing PS-1 overexpression, and further highlighting the possibility that AJC provides neuroprotection by mechanisms in addition to its antioxidant potential.

Clinical features and molecular genetics of autosomal recessive cerebellar ataxias

Among the hereditary ataxias, autosomal recessive spinocerebellar ataxias comprise a diverse group of neurodegenerative disorders. Clinical phenotypes vary from predominantly cerebellar syndromes to sensorimotor neuropathy, ophthalmological disturbances, involuntary movements, seizures, cognitive dysfunction, skeletal anomalies, and cutaneous disorders, among others. Molecular pathogenesis also ranges from disorders of mitochondrial or cellular metabolism to impairments of DNA repair or RNA processing functions. Diagnosis can be improved by a systematic approach to the categorisation of these disorders, which is used to direct further, more specific, biochemical and genetic investigations. In this Review, we discuss the clinical characteristics and molecular genetics of the more common autosomal recessive ataxias and provide a framework for assessment and differential diagnosis of patients with these disorders.

Deletion of vitamin E enhances phenotype of Alzheimer disease model mouse

Increased oxidative damage is a prominent and early feature in Alzheimer disease (AD). However, whether it is a primary cause or merely a downstream consequence in AD pathology is still unknown. We previously generated alpha-tocopherol transfer protein knockout (Ttpa-/-) mice, in which lipid peroxidation in the brain was significantly increased by complete depletion of alpha-tocopherol (alpha-Toc). Here we crossed AD transgenic (APPsw) model mice (Tg2576) with Ttpa-/- mice. The resulting double-mutant (Ttpa-/- APPsw) mice showed earlier and more severe cognitive dysfunction in the Morris water maze, novel-object recognition, and contextual fear conditioning tests. They also showed increased amyloid beta-peptide (Abeta) deposits in the brain by immunohistochemical analysis, which was ameliorated with alpha-Toc supplementation. In this report we provide clear evidence indicating that chronic lipid peroxidation due to alpha-Toc depletion enhances AD phenotype in a mouse model.

Recent advances in vitamin E metabolism and deficiency

Alpha-, beta-, gamma- and delta-tocopherol are present in many foods and are, in the absence of fat malabsorption, well absorbed from the gut. Their anti-oxidant property is well known and protects arteries and capillaries as well as blood lipids and nervous tissue against oxidative stress. In contrast to beta-, gamma- and delta-tocopherol, alpha-tocopherol is preferentially conserved by the discriminating action of the liver alpha-tocopherol transfer protein, which also maintains plasma alpha-tocopherol concentration within a range of 20 to 40 microM. In the circulation, alpha-tocopherol, in association with the transfer-protein, is assembled into the very low-density lipoprotein and low-density lipoprotein particles and released for use by the peripheral tissues. Recent data suggest that alpha-tocopherol is not only an anti-oxidant but also a regulator of gene expression through its binding to nuclear receptors. The precise mechanism of regulating gene expression, however, is still unknown. The four tocopherols are ultimately degraded by omega-oxidation and subsequent beta-oxidations followed by the elimination of the metabolites in the bile and in the urine. Patients with a defect of the alpha-tocopherol transfer protein are unable to maintain their alpha-tocopherol reserves and progressively lose tendon reflexes and have signs and symptoms of spinocerebellar ataxia while plasma vitamin E level drops below 2 microg/ml.

Genetic vitamin E deficiency does not affect MPTP susceptibility in the mouse brain

Oxidative stress is involved in the degeneration of the nigrostriatal dopaminergic system in Parkinson's disease (PD). Vitamin E (alpha-tocopherol) is a potent antioxidant in the cell membrane that can trap free radicals and prohibit lipid peroxidation. The retention and secretion of vitamin E are regulated by alpha-tocopherol transfer protein (TTP) in the brain and liver. Dysfunction of TTP results in systemic deficiency of vitamin E in humans and mice, and increased oxidative stress in mouse brain. In this study, we investigated the effect of vitamin E deficiency in PD development by generating an 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of PD using TTP knockout (TTP-/-) mice. Vitamin E concentration in the brains of TTP+/- mice was half that in TTP+/+ mice, and in TTP-/- mice, was undetectable. MPTP treatment tended to decrease striatal dopamine, but the effect was comparable and not significant in any of the three genotypes. Furthermore, the extent of loss of dopaminergic cell bodies in the substantia nigra did not differ among the groups. One the other hand, oral administration of vitamin E resulted in the partial protection of striatal dopaminergic terminals against MPTP toxicity. Our results suggest that vitamin E does not play a major protective role in MPTP-induced nigrostriatal dopaminergic neurodegeneration in the brain.

Appearance of amyloid beta-like substances and delayed-type apoptosis in rat hippocampus CA1 region through aging and oxidative stress

To elucidate whether oxidative stress induces cognitive deficit, and whether nerve cells in the hippocampus, which modulates learning and memory functions in the brain, are damaged by oxidative stress and during aging, the influence of hyperoxia as oxidative stress on either the cognitive function of rats or the oxidative damage of nerve cells was investigated. Young rats showed better learning ability than both old rats and vitamin E-deficient young rats. Vitamin E- supplemented young rats showed similar ability to young control rats. After they learned the location of the platform in the Morris water maze test, the young rats and vitamin E-supplemented young rats were subjected to oxidative stress for 48 h, and the old rats and vitamin E-deficient young rats were kept in normal atmosphere. The memory function of the old rats and vitamin E-deficient young rats declined even when they were not subjected to oxidative stress for 48 h. In contrast, the young rats maintained their memory function for 4 days after the oxidative stress. However, their learning abilities suddenly declined toward that of the normal old rats after 5 days. At this point, nerve cell loss and apoptosis were observed in the hippocampal CA 1 region of young rats. Vitamin E-supplementation in the young rats prevented either memory deficit or the induction of delayed-type apoptosis. The old rats and vitamin E-deficient young rats kept in normal atmosphere for 48 h also showed apoptosis in the hippocampus. Also, 10 days after oxidative stress, amyloid beta-like substances appeared in the CA-1 region of control young rats; these substances were also observed in the CA-1 region of the old rats and vitamin E- deficient young rats. These results suggest that reactive oxygen species (ROS) generated by oxidative stress induced amyloid beta-like substances and delayed-type apoptosis in the rat hippocampus, resulting in cognitive deficit. Since amyloid beta in Alzheimer's disease characterized by cognitive deficit induces neuronal cell death, it is reasonable to consider that amyloid beta deposition in the brain may be associated with memory dysfunction. The results of this study imply that age-related hippocampal neuronal damage is prevented by vitamin E supplementation due to the antioxidant effect of vitamin E.

Effects on Neural Function of Repleting Vitamin E–Deficient Rats With α-Tocopherol

A severe and chronic deficiency of vitamin E (α-tocopherol) is associated with a characteristic neurological syndrome with typical “clinical,” neuropathological, and electrophysiological abnormalities in both humans and experimental animals. Repletion of vitamin E–deficient human subjects with α-tocopherol typically halts the progression of the neural signs and symptoms, and in some cases, can result in objective improvement. Electrophysiological parameters provide an objective measure of neural and visual function and improvement of some of these measures has been reported after repletion with vitamin E in humans. In this longitudinal study, the effects of repleting rats with a diet containing 36 mg/kg all-rac-α-tocopheryl acetate for 20 wk after they had been receiving a vitamin E–deficient diet for 38 wk was studied. We report significant improvements in growth and a number of electrophysiological parameters of both neural and visual function after repletion. These results confirm the validity of the vitamin E–deficient rat as a model of vitamin E deficiency in humans.

Oxidant stress modulates murine allergic airway responses

The allergic inflammation occurring in asthma is believed to be accompanied by the production of free radicals. To investigate the role of free radicals and the cells affected we turned to a murine model of allergic inflammation produced by sensitization to ovalbumin with subsequent aerosol challenge. We examined oxidant stress by measuring and localizing the sensitive and specific marker of lipid peroxidation, the F2-isoprostanes. F2-isoprostanes in whole lung increased from 0.30 +/- 0.08 ng/lung at baseline to a peak of 0.061 +/- 0.09 ng/lung on the ninth day of daily aerosol allergen challenge. Increased immunoreactivity to 15-F2t-IsoP (8-iso-PGF2alpha) or to isoketal protein adducts was found in epithelial cells 24 h after the first aerosol challenge and at 5 days in macrophages. Collagen surrounding airways and blood vessels, and airway and vascular smooth muscle, also exhibited increased immunoreactivity after ovalbumin challenge. Dietary vitamin E restriction in conjunction with allergic inflammation led to increased whole lung F2-isoprostanes while supplemental vitamin E suppressed their formation. Similar changes in immunoreactivity to F2-isoprostanes were seen. Airway responsiveness to methacholine was also increased by vitamin E depletion and decreased slightly by supplementation with the antioxidant. Our findings indicate that allergic airway inflammation in mice is associated with an increase in oxidant stress, which is most striking in airway epithelial cells and macrophages. Oxidant stress plays a role in the production of airway responsiveness.

Antagonistic Effects of Oxidized Low Density Lipoprotein and α-Tocopherol on CD36 Scavenger Receptor Expression in Monocytes

Vitamin E deficiency increases expression of the CD36 scavenger receptor, suggesting specific molecular mechanisms and signaling pathways modulated by alpha-tocopherol. We show here that alpha-tocopherol down-regulated CD36 expression (mRNA and protein) in oxidized low density lipoprotein (oxLDL)-stimulated THP-1 monocytes, but not in unstimulated cells. Furthermore, alpha-tocopherol treatment of monocytes led to reduction of fluorescent oxLDL-3,3'-dioctadecyloxacarbocyanine perchlorate binding and uptake. Protein kinase C (PKC) appears not to be involved because neither activation of PKC by phorbol 12-myristate 13-acetate nor inhibition by PKC412 was affected by alpha-tocopherol. However, alpha-tocopherol could partially prevent CD36 induction after stimulation with a specific agonist of peroxisome proliferator-activated receptor-gamma (PPARgamma; troglitazone), indicating that this pathway is susceptible to alpha-tocopherol action. Phosphorylation of protein kinase B (PKB) at Ser473 was increased by oxLDL, and alpha-tocopherol could prevent this event. Expression of PKB stimulated the CD36 promoter as well as a PPARgamma element-driven reporter gene, whereas an inactive PKB mutant had no effect. Moreover, coexpression of PPARgamma and PKB led to additive induction of CD36 expression. Altogether, our results support the existence of PKB/PPARgamma signaling pathways that mediate CD36 expression in response to oxLDL. The activation of CD36 expression by PKB suggests that both lipid biosynthesis and fatty acid uptake are stimulated by PKB.

Brown bowel syndrome: case report and review

Brown bowel syndrome is characterized by deposits of lipofuscin in the tunica muscularis of the small intestine. Its etiology is associated with chronic malabsorption resulting in a deficiency of vitamin E. This hypovitaminosis is believed to cause a mitochondrial myopathy secondary to loss of the antioxidant properties of vitamin E, which further worsens the malabsorption and leads to atonic, dilated segments of bowel. Current treatment options involve nutritional supplementation, surgical resection of the affected segments, and intestinal transplantation.

Dietary habits and nutritional biomarkers in Italian type 1 diabetes families: evidence of unhealthy diet and combined-vitamin-deficient intakes

OBJECTIVE

Nutritional status and lifestyle can have profound effects on health. To analyse behaviour patterns in population subgroups of public health importance, we compared lifestyle, dietary intake of energy and selected nutrients, and nutritional biomarkers of type 1 diabetes (T1DM) patients and nondiabetic first-degree relatives against control subjects with no family history of T1DM.

DESIGN

A cross-sectional study.

SETTING

Department of Internal Medicine, University of Pisa, Italy.

SUBJECTS

A total of 209 individuals including 38 type 1 patients, 76 relatives, and 95 healthy subjects.

INTERVENTIONS

We used the European Prospective Investigation of Cancer and Nutrition questionnaires to assess dietary intake and lifestyle. Anthropometric indices and nutritional biomarkers (such as plasma levels of albumin, iron, lipids, homocysteine, vitamin B9 and vitamin B12 as well as urinary outputs of nitrogen, sodium and potassium) were evaluated.

RESULTS

Emerging health issues: (1) In total, 45% of controls were overweight. Increasing age was associated with increasing body mass and decreasing activity in sport in front of an unchanged energy intake. (2) The distribution of energy sources was incorrect. The proportion of caloric intake derived from total fat and cholesterol did not match general guidelines. Total dietary fibre consumption was assessed to be adequate (25 g/day) in only 27% of all the participants. (3) Estimated daily intakes of water-soluble vitamin B9 and fat-soluble vitamin D and vitamin E were deficient in comparison with dietary reference intakes. (4) The prevalence of adoption and maintenance of healthful eating and physical activity habits was higher in women and T1DM patients (probably as a consequence of the medical educational intervention). On the contrary, supportiveness of the family in term of changing the undesirable behaviours at home seemed to fail.

CONCLUSIONS

This study provides first evidence indicating unhealthy dietary behaviours, which could even predispose to the development of diabetes and cardiovascular complications, in subjects living in Pisa. The combination of vitamin B9 and vitamin E deprivation could be deleterious for endothelial function, since these antioxidants have been implicated in the modulation of nitric oxide and eicosanoid signalling.

[Nonalcoholic steatohepatitis]

Nonalcoholic steatohepatitis (NASH) is a condition characterized by excessive deposition of fat in the liver (steatosis), inflammation and hepatocellular necrosis. While steatosis alone is generally a benign and stable condition, NASH can have a dire prognosis in a minority of patients, mainly because of fibrosis occurrence and progression to cirrhosis. Life-threatening complications such as liver failure and hepatocellular carcinoma have been described in NASH-induced cirrhosis. Insulin resistance is almost universally found in patients with NASH and the main risk factors for this condition are overweight and diabetes. Improvement in insulin sensitivity, whether achieved by diet, exercise and/or pharmacological interventions, results in a dramatic reduction of liver fat and inflammation and fibrosis as well. Therefore NASH should be viewed as the hepatic phenotypic manifestation of insulin resistance and a bona fide component of the metabolic syndrome. Liver injury should be assessed in diabetic and/or obese patients and the mechanisms by which insulin resistance promotes liver damage needs to be elucidated. The encouraging results of the use of PPARgamma agonists and, in particular, rosiglitazone, in human or experimental models of NASH, justifies future large-scale, randomized controlled trials.

[Lactose-induced diarrhea increases oxidative stress and it is more severe in rats deficient in vitamin E]

Diarrhea is the disease with high incidence in the world and causes infant mortality and malnutrition in the developing world. This justifies the study of nutrition and diarrhea. Due to ethical and financial considerations it is difficult to study nutrition and diarrhea in children thus animal models have become a convenient alternative. In previous studies it was shown that lactose induced diarrhea in rats was associated with a reduction in tissue levels of vitamin E and also with evidence of an inflammatory response of the intestine. Accordingly, in this study, in order to determine the effect of this type of diarrhea on the level of oxidative stress, diarrhea was induced in vitamin E sufficient and deficient rats. The results showed that after 23 days the tissue concentration of vitamin E decreased in all the rats with diarrhea but this reduction was substantially greater in the vitamin E deficient group. Moreover, diarrhea was 60% more severe in the vitamin E deficient rats than in the vitamin E sufficient group that also had diarrhea. Both diarrhea and vitamin E deficiency altered malonaldehyde and superoxide dismutase levels in various tissues. However, the most outstanding changes associated with diarrhea were a 100% increment in plasma malonaldehyde and erythrocyte superoxide dismutase activities which were 8 to 11 times higher than those seen in the rats without diarrhea. These non-invasive changes correlated well with the severity of diarrhea. The study shows that vitamin E deficiency results in diarrheas which are more severe and that lactose induced diarrhea is associated with higher levels of oxidative stress.

Nutritional degenerative myopathy in a population of captive bred Uroplatus phantasticus (satanic leaf-tailed geckoes)

Severe generalized degenerative myopathy was diagnosed in a population of captive bred satanic leaf-tailed geckoes (Uroplatus phantasticus). The diagnosis was based on characteristic histological changes and response to dietary therapy. This is the first reported case of nutritional myopathy in the satanic leaf-tailed gecko.

Is low serum tocopherol in Wilson's disease a significant symptom?

BACKGROUND

Free radical mediated injury is increasingly recognized in many metabolic diseases including Wilson's disease (WD). Use of antioxidants as an adjunctive therapy in WD may have therapeutic significance.

AIM

The aim of the study was to correlate serum levels of tocopherols with serum copper and ceruloplasmin and clinical status of these patients.

METHODS

Serum levels of tocopherol of were measured spectrophotometrically using the Emmerie-Engel reaction in 34 patients from a large cohort of WD being followed up at a tertiary care center.

RESULTS

Majority of patients were male (M/F=23:11). The mean serum copper was 43.6+/-26.2 microg/dl (range=10-121 microg/dl) and serum ceruloplasmin was 5.6+/-5.5 mg/dl (range=0-30 mg/dl). The mean serum tocopherol level was 0.68+/-0.18 mg/dl (range=0.23-1.14 mg/dl) and compared to the control (1.07+/-0.17 mg/dl), nearly 59% of patients had decreased levels (p<0.001). No significant correlation was noted between low serum tocopherol levels and serum copper levels, Mini Mental Status Examination (MMSE) scores and CHU staging. However, serum tocopherol levels were lower in patients with relatively short duration of treatment (7.8 years vs. 12.4 years).

CONCLUSION

Decreased levels of serum tocopherol were detected in 59% of patients compared to controls. However, low tocopherol levels did not correlate with clinical status or biochemical parameters of WD, except for relatively shorter duration of treatment. Further studies, especially in newly diagnosed patients, need to be done to validate the role of low tocopherol levels in Wilson's disease.

Vitamin E in Neural and Visual Function

A rat model of vitamin E (alpha-tocopherol) deficiency with similar "clinical," electrophysiological, and neuropathological abnormalities to those seen in man was used to investigate the effects of various amounts and forms of alpha-tocopheryl acetate (alphaTA) on neural and visual function. Electrophysiological techniques provide an objective, non-invasive measure of neural and visual function. These techniques were used in the animal model to determine the minimum dietary requirement of vitamin E necessary to prevent neural and visual abnormalities. They were also used to compare the biological activities of the natural (RRR-) and synthetic (all-rac-) forms of alpha-tocopherol in neural tissues. The results were as follows: (1) Significant differences in neural and visual function were observed between deficient and control rats after approximately 8 months. (2) An intake of 1.0 mg/kg all-rac- or 0.75 mg/kg RRR-alphaTA was observed to marginally protect nerves from vitamin E deficiency. (3) The biological activity of all-rac-alpha-tocopherol in neural tissues was approximately 75% of RRR-alpha-tocopherol. (4) The concentration of free malondialdehyde (an indicator of lipid peroxidation) was significantly increased in tissues from the deficient compared to the control animals. These results are consistent with a deficiency of alpha-tocopherol causing increased lipid peroxidation leading to abnormal neural electrophysiology. They could also be explained by more specific but as yet undefined function(s) of alpha-tocopherol in neural tissues.

Oxidative stress in colon tissue induced by vitamin E depletion

Inflammatory disorders of the bowel and colon cancer are associated with elevated indices of oxidative stress. Analogous elevations in markers of oxidative stress and loss of cell-membrane integrity are also observed in the colons of rats deficient in vitamin E (D-α-tocopherol), the major lipid-soluble antioxidant in biological systems. The causal relationship between colon pathologies associated with oxidative stress and dietary deficiency in antioxidant vitamins such as vitamin E is still uncertain. Investigation of potential mechanisms by which lack of dietary vitamin E may lead to clinically relevant pathological changes in colon tissue was conducted using gene expression profiling strategies on vitamin E-sufficient and -deficient rats. Morphological changes and increased indices of lipid peroxidation were linked to vitamin E deficiency. These changes in colon tissue are potentially important in disease pathogenesis of the colon linked with oxidative stress or other direct consequences of inadequate levels of vitamin E.

Vitamin E affects cell death in adult rat dentate gyrus

We have previously reported the presence of dying cells in the granule cell layer (GCL) of adult rat dentate gyrus (DG), where neurogenesis occurs. In particular, we found that cell death in the GCL increased in vitamin E deficiency and decreased in vitamin E supplementation. These findings were regarded as related to changes in neurogenesis rate, which in turn was influenced by vitamin E availability; a neuroprotective effect of vitamin E on cell death was also proposed. In order to verify this latter hypothesis, we have studied cell death in all layers of DG in vitamin E-deficient and vitamin E-supplemented rats and in control rats at different ages, using TUNEL and nick translation techniques. The phenotype of TUNEL-positive cells was characterized and the existence of dying BrdU-positive cells was investigated. Dying cells with neuronal phenotype were observed throughout the DG in all experimental groups. The number of TUNEL-positive cells decreased from juvenile to adult age. A higher number of TUNEL-positive cells in vitamin E-deficient rats and a lower number in vitamin E-supplemented rats, with respect to age-matched controls, were found; moreover, in these groups, TUNEL-positive cells had a different percentage distribution in the different layers of the DG. Our results confirm the occurrence of cell death in DG, demonstrate that cell death affects neuronal cells and support the hypothesis that the effect of vitamin E on cell death is not related to neurogenesis.

The S-adenosyl homocysteine hydrolase inhibitor 3-deaza-adenosine prevents oxidative damage and cognitive impairment following folate and vitamin E deprivation in a murine model of age-related, oxidative stress-induced neurodegeneration

Deficiencies in folate promote neurodegeneration and potentiate the influence of other risk factors for neurodegeneration. This is accomplished at least in part by increasing levels of the neurotoxin homocysteine (HC). The S-adenosyl homocysteine (SAH) hydrolase inhibitor 3-deaza-adenosine (DZA) prevents HC accumulation following folate deprivation. We tested the ability of dietary supplementation with DZA to counteract the deleterious influence of folate deprivation. Folate deficiency has previously been shown to potentiate the impact of apolipoprotein E (ApoE); ApoE-/- mice deprived of folate demonstrated increased oxidative damage in brain tissue and impaired cognitive performance as compared to normal mice or to ApoE-/- mice receiving folate. Herein, we demonstrate that dietary supplementation with DZA prevented both the increase in oxidative damage and impaired cognition characteristic of ApoE-/- mice following folate deprivation. These findings suggest that manipulation of the methionine cycle by DZA can counteract folate deficiency. Because folate deprivation, increased HC, and apolipoprotein E deficiency are all risk factors for Alzheimer's disease, these findings also underscore that DZA might be useful in a therapeutic approach to delay neurodegeneration in Alzheimer's disease.

The effects of long-term vitamin E treatment on gene expression and oxidative stress damage in the aging Brown Norway rat epididymis

The male reproductive tract of the Brown Norway rat is profoundly affected by aging. In the epididymis, the site of sperm maturation and storage, aging results in histological and biochemical changes that are suggestive of oxidative stress. Vitamin E is a potent lipid-soluble antioxidant that ameliorates the oxidative stress load associated with some chronic disease conditions. To determine the effects of long-term (18-mo) vitamin E deficiency and supplementation on aging in the epididymis, we assessed gene expression changes using cDNA microarrays and lipid peroxidation using immunohistochemical detection of 4-hydroxynonenal (4-HNE) in 24-mo-old rats. Plasma vitamin E levels were significantly lower in vitamin E-deficient animals and higher in vitamin E-supplemented animals compared with age-matched controls. Vitamin E deficiency resulted in increased expression of oxidative stress-related transcripts along the epididymis. This effect was most marked in the corpus epididymidis, where expression of glutathione S-transferases pi, 8, and mu, as well as superoxide dismutase, increased by over 50%. The effect of vitamin E supplementation on the expression of oxidative stress-related transcripts was primarily decreased expression; however, the magnitude of the gene expression changes was smaller than that observed for vitamin E deficiency. 4-HNE immunostaining was present throughout the epididymis in control animals. Vitamin E deficiency both increased the intensity and altered the distribution of 4-HNE staining, while vitamin E supplementation had no observable effect. In summary, we found that long-term vitamin E treatment alters the expression of oxidative stress-related transcripts. Moreover, long-term vitamin E deficiency exacerbates the effects of age on the accumulation of oxidative stress damage in the epididymis.

Ataxia with vitamin E deficiency and severe dystonia: report of a case

Mutation of the gene for alpha-tocopherol transfer protein causes ataxia with isolated vitamin E deficiency, a disorder usually stabilized or improved after vitamin E supplementation. Dystonia has rarely been described in ataxia with isolated vitamin E deficiency (AVED) patients. We present the case of a young boy with AVED, whose neurological and extra-neurological cardinal symptoms of the disease improved after vitamin E supplementation but who progressively developed generalized dystonia.

Effect of vitamin E deficiency on the growth and secretory function of the rat prostatic complex

Increased intake of vitamin E has been suggested to be protective against prostate cancer in men, but the effects of vitamin E on prostate growth and function remain poorly defined. The purpose of this study was to determine the effects of vitamin E deficiency on pubertal growth and maturation of the prostate in the rat. Animals were placed on a vitamin E deficient diet at 28 days of age and were followed for 15 and 26 weeks. Vitamin E deficient rats had a circulating vitamin E level of less than 1% of control animals and experienced a decrease in body and testis weight. The deficiency did not alter the weights of the ventral and dorsal lobes of the prostate. However, there was an increase in weight, DNA, and protein contents of the lateral lobe in control and vitamin E deficient rats from 15 to 26 weeks of treatment, but these increases were significantly lower in vitamin E deficient 26-week treated rats. The volume of secretion per milligram tissue was greater in the ventral than lateral or dorsal lobes. The volume of secretion and activity of the secretory 26 kDa protease in the ventral prostate was lower in vitamin E deficient rats at 15 weeks, but not at 26 weeks of treatment. In contrast, the relative protein content of lateral lobe secretion increased in both control and vitamin E deficient rats from 15 to 26 weeks of treatment. The lateral, but not ventral or dorsal, lobes of both control and vitamin E deficient rats were affected by chronic prostatitis as evidenced by infiltration of inflammatory cells. The lateral lobes also showed markedly elevated activities of the matrix metalloproteinases gelatinase A (MMP-2) and gelatinase B (MMP-9). These data indicate that vitamin E deficiency does not alter the growth of the prostatic lobes, nor the onset and extent of lateral lobe specific prostatitis, but it may delay some differentiated functions such as secretion of specific proteins in the ventral lobe. Thus, the effects of vitamin E in the prostate of the rat appear to be selective.

Vitamin E and transfer proteins

PURPOSE OF REVIEW

Recently, the intracellular transport as well as cellular uptake and excretion of alpha-tocopherol, the major representative of vitamin E, have been elucidated.

RECENT FINDINGS

Alpha-tocopherol transfer protein has been identified as the major intracellular transport protein for vitamin E, mediating alpha-tocopherol secretion into the plasma via a non-Golgi-dependent pathway, while other binding proteins seem to play a less important role. New information has accumulated concerning the role of this protein in the transport and supply of vitamin E to tissues such as the central nervous system and the feto-maternal unit. The scavenger receptor class B type I receptor, a membrane-bound protein, is capable of transferring vitamin E into the cell, while the ATP-binding cassette transporter A1 can excrete vitamin E out of the cell. Advances in the area of vitamin E metabolism have shown that alpha-CEHC (2,5,7,8-tetramethyl-2-(2'-carboxyethyl)-6-hydroxychroman) and gamma-CEHC (2,7,8-trimethyl-2-(2'-carboxyethyl)-6-hydroxychroman) are formed by a cytochrome p450-mediated process, important for alpha and gamma-tocopherol excretion.

SUMMARY

Insights into the regulation of vitamin E transport and metabolism on the cellular level have made enormous advances, showing the complex interplay of influx, trafficking, efflux and metabolism of this crucial antioxidant.

Tocotrienols are needed for normal bone calcification in growing female rats

In this study the effects of vitamin E deficiency and supplementation on bone calcification were determined using 4-month-old female Sprague-Dawley rats. The rats weighed between 180 and 200 g. The study was divided in three parts. In experiment I the rats were given normal rat chow (RC, control group), a vitamin E deficient (VED) diet or a 50% vitamin E deficient (50%VED) diet. In experiment 2 the rats were given VED supplemented with 30 mg/kg palm vitamin E (PVE30), 60 mg/kg palm vitamin E (PVE60) or 30 mg/kg pure alpha-tocopherol (ATF). In experiment 3 the rats were fed RC and given the same supplements as in experiment 2. The treatment lasted 8 months. Vitamin E derived from palm oil contained a mixture of ATF and tocotrienols. Rats on the VED and 50%VED diets had lower bone calcium content in the left femur compared to the RC group (91.6 +/- 13.3 mg and 118.3 +/- 26.0 mg cf 165.7 +/- 15.2 mg; P < 0.05) and L5 vertebra (28.3 +/- 4.0 mg and 39.5 +/- 6.2 mg compared with 51.4 +/- 5.8 mg; P < 0.05). Supplementing the VED group with PVE60 improved bone calcification in the left femur (133.6 +/- 5.0 mg compared with 91.6 +/- 13.3 mg; P < 0.05) and L5 vertebra (41.3 +/- 3.3 mg compared with 28.3 +/- 4.0 mg; P < 0.05) while supplementation with PVE30 improved bone calcium content in the L5 vertebra (35.6 +/- 3.1 mg compared with 28.3 +/- 4.0 mg; P < 0.05). However, supplementation with ATF did not change the lumbar and femoral bone calcium content compared to the VED group. Supplementing the RC group with PVE30, PVE60 or ATF did not cause any significant changes in bone calcium content. In conclusion, vitamin E deficiency impaired bone calcification. Supplementation with the higher dose of palm vitamin E improved bone calcium content, but supplementation with pure ATF alone did not. This effect may be attributed to the tocotrienol content of palm vitamin E. Therefore, tocotrienols play an important role in bone calcification.

[The dependence of lipid peroxidation and blood hemostasis from antioxidant activity of different tissues]

The experiments with rabbits show that animal maintenance on the antioxidant-free diet leads to the peroxidative lipid oxidation (PLO), hemostasis activation and to the superoxidedismutase (SOD) level reducing in a blood and tissues (of cerebrum, heart, kidney, stomach). The greatest SOD activity decreasing is observed in the cerebrum and heart tissues. Probably, these organs make the most considerable contribution in PLO and hemostasis course in the antioxidative reducing conditions.

Folate and Vitamin E Deficiency Impair Cognitive Performance in Mice Subjected to Oxidative Stress: Differential Impact on Normal Mice and Mice Lacking Apolipoprotein E

One factor contributing to the age-related decline in cognitive performance is increased oxidative stress, that can arise from environmental, nutritional, and/or genetic compromise. Folate deficiency has been linked to several age-related neurodegenerative conditions, including Alzheimer's disease (AD), at least in part by increasing oxidative stress. Folate deficiency also potentiates the impact of other known risk factors for AD. Adecrease in function of apolipoprotein E (ApoE), is associated with increased oxidative stress and is a risk factor for AD. We tested the combined impact of dietary deficiencies in folate and vitamin E, coupled with exposure to high dietary iron as a pro-oxidant, on cognitive performance in normal and ApoE-/- mice by monitoring the percent alternation in passive Y and T maze tests. Both normal and ApoE-/- mice displayed some cognitive impairment when deprived of folate and vitamin E and exposed to iron, but ApoE-/- mice were more severely affected. These findings highlight the potential combined impact of dietary deficiencies and genetic predisposition to neurodegeneration. They further leave open the possibility that one or more risk factors may remain latent, and neurodegeneration may ensue only following augmentation by one or more additional traumatic events or conditions.

Neural precursor proliferation and newborn cell survival in the adult rat dentate gyrus are affected by vitamin E deficiency

The adult hippocampal neurogenesis is affected by vitamin E deficiency. In the present investigation we examined if neural precursor proliferation, newborn cell survival or both are altered by vitamin E deficiency. 5-Bromo-2'-deoxyuridine (BrdU) was employed as a marker of proliferating cells. BrdU-labelled cells were revealed 1 and 30 days after BrdU administration in order to evaluate proliferation and newborn cell survival, respectively. Cell proliferation decreased in controls from juvenile to adult age, and the decrease was lesser in vitamin E deficiency. Thus we found a higher number of proliferating cells in vitamin E-deficient rats than in age-matched controls at 5 months of age. Comparing the number of BrdU-positive cells between 1 and 30 days after the last BrdU injection revealed a remarkable decrease in all groups; this is the greatest in vitamin E-deficient rats and the lowest in control rats. Consistently cell death in the dentate gyrus, assessed by TUNEL technique, was found to decrease from 1 to 5 months of age, but at 5 months it was significantly higher in vitamin E-deficient rats than in age-matched controls. These data show that vitamin E deficiency enhances neural precursor proliferation and cell death during adult neurogenesis.

Metal working fluids: sub-chronic effects on pulmonary functions in B6C3F1 mice given vitamin E deficient and sufficient diets

Metal working fluids (MWFs) have been widely known to cause asthma and neoplasia of the larynx, pancreas, rectum, skin and urinary bladder (Textbook of Clinical Occupational and Environmental Medicine (1994) 814; Am. J. Ind. Med. 32 (1997) 240; Am. J. Ind. Med. 33 (1997) 282; Am. J. Ind. Med. 22 (1994) 185). Other non-neoplastic respiratory effects in industrial workers attributed to MWFs include increased rates of cough, phlegm production, wheeze, chronic bronchitis and chest tightness (Eur. J. Resir. Dis. 63(118) (1982), 79; J. Occup. Med. 24 (1982) 473; Am. J. Ind. Med. 32 (1997) 450). The epidemic and endemic nature of immune mediated lung morbidity commonly known as hypersensitivity pneumonitis in workers from several different industries using MWFs has been well documented (J. Allergy clin. Immunol. 91 (1993) 311; Chest 108 (1995) 636; MMWR45 (1996) 606; Am. J. Ind. Med. 32 (1997) 423). We studied morphological/functional and antioxidant outcomes in lungs after inhalation exposure of vitamin E deficient mice to MWF (27 mg m(-3) 17 weeks, 5 days a week, 6 h a day). Mice were given vitamin E deficient (<10 IU kg(-1) vitamin E) or basal diets (50 IU kg(-1) vitamin E) for 35 weeks. Inhalation exposure to MWF started after 18 weeks on diet. Microscopic observation of lungs from mice given vitamin E deficient or sufficient diets revealed no inflammation or morphological alteration after exposure to MWF. Mice given vitamin E deficient diet exhibited a significant decrease (P<0.05) in breathing rate, peak inspiratory/expiratory flow, minute ventilation, and tidal volume compared with sufficient controls. However, no differences were found after exposure to MWF in pulmonary function, with the exception of tidal volume which also significantly decreased (P<0.05). Exposure to MWF reduced vitamin E, protein thiol and ascorbate level in lungs. Exposure to MWF in combination with a vitamin E deficient diet resulted in significantly enhanced accumulation of peroxidative products compared with vitamin E deficient controls. This is the first report that describes the increase of oxidative stress in the lungs after MWF exposure.

Effects of vitamin E deficiency on fatigue and muscle contractile properties

Radical-mediated oxidative damage of skeletal muscle membranes has been implicated in the fatigue process. Vitamin E (VE) is a major chain breaking antioxidant that has been shown to reduce contraction-mediated oxidative damage. We hypothesized that VE deficiency would adversely affect muscle contractile function, resulting in a more rapid development of muscular fatigue during exercise. To test this postulate, rats were fed either a VE-deficient (EDEF) diet or a control (CON) diet containing VE. Following a 12-week feeding period, animals were anesthetized and mechanically ventilated. Muscle endurance (fatigue) and contractile properties were evaluated using an in situ preparation of the tibialis anterior (TA) muscle. Contractile properties of the TA muscle were determined before and after a fatigue protocol. The muscle fatigue protocol consisted of 60 min of repetitive contractions (250 ms trains at 15 Hz; duty cycle=11%) of the TA muscle. Prior to the fatigue protocol, no significant differences existed in the force-frequency curves between EDEF and CON animals. At the completion of the fatigue protocol, muscular force production was significantly ( P<0.05) lower in the EDEF group (reduced by 69%) compared to CON group (reduced by 38%). Following the fatigue protocol, a right shift existed in the force-frequency curve at low stimulation frequencies (</=40 Hz) in the EDEF animals compared to the CON animals ( P<0.05). The stimulated and the contralateral TA muscle from the EDEF animals had significantly higher markers of lipid peroxidation compared to the same muscles in the CON animals ( P<0.05). These data support the hypothesis that VE deficiency impairs muscular endurance and alters muscle contractile properties following a prolonged series of contractions.

d-MDMA during vitamin E deficiency: effects on dopaminergic neurotoxicity and hepatotoxicity

The mechanism of 3,4-methylenedioxymethamphetamine (d-MDMA)-induced neurotoxicity may involve formation of toxic radical species. Endogenous defenses against toxic radical species include tissue stores of vitamin E, and thiols. We examined whether vitamin E deficiency could alter d-MDMA-induced neurotoxicity by administration of the drug to animals with diet induced vitamin E deficiency. Brain vitamin E levels in deficient mice were reduced 75% compared to sufficient animals. Animals received d-MDMA 5 or 10 mg/kg or saline (delivered every 2 hx4, s.c.). Diet slightly altered d-MDMA-induced temperature modulation. In brain, MDMA treatment reduced vitamin E, total antioxidant reserve and protein thiols 72 h after the first dose. In liver, MDMA treatment reduced glutathione and total antioxidant reserve at the same time point. The vitamin E-deficient group, treated with the low dose of d-MDMA, exhibited neurotoxic responses, including reduced striatal dopamine (47%) and elevated GFAP protein (3-fold): while the sufficient diet group was not altered. The higher d-MDMA dose caused neurotoxic responses in both diet groups. Liver toxicity was determined by histopathologic examination. d-MDMA caused hepatic necrosis that was more severe in vitamin E deficient than sufficient mice. These data indicate that (1) d-MDMA administration reduces antioxidant measures at a time coincident with d-MDMA-induced neuronal damage and (2) vitamin E deficiency increases susceptibility to d-MDMA-induced neurotoxicity and hepatic necrosis.

Effect of deficiency of vitamins C and/or E on lipoprotein metabolism in osteogenic disorder Shionogi rat, a strain unable to synthesize ascorbic acid

The effects of vitamin C and/or E deficiency on lipoprotein metabolism were investigated in the inherently scorbutic Osteogenic Disorder Shionogi (ODS) rat. In the vitamin C-deficient (C-def) group, marked increases in plasma VLDL and LDL cholesterol were observed (by comparison with the vitamins C- and E-sufficient control group). In rats kept deficient in both vitamin C and vitamin E (C,E-def), LDL cholesterol was significantly higher than in the C-def group even though the levels of VLDL and HDL cholesterol were similar between the two groups. TBARS values for the LDL fraction in the C-def group were of the same magnitude as in the E-def group, and these values were significantly higher than those obtained for the control group. In the C,E-def group, the values were even higher than in the E-def and C-def groups. The nondenatured PAGE of the LDL fraction indicated the appearance of HDLc in the C-def and C,E-def groups. The SDS-PAGE of the LDL fraction showed increased apo B-48 in the C-def and C,E-def groups and increased apo E in the C,E-def group. Decreased plasma LCAT activity in the E-def, C-def, and C,E-def groups indicated an alteration in HDL metabolism as a result of oxidation. These results suggest that lipid peroxidation and some distinct features of lipoprotein metabolism resulting from vitamin C deficiency become more significant when vitamin E is also deficient along with vitamin C deficiency.

The 80th anniversary of vitamin E: beyond its antioxidant properties

Molecules provided with an antioxidant function may have additional properties, the latter being sometimes of greater importance than the former. In the last ten years, alpha-tocopherol has revealed precise cellular functions, some of which are independent of its antioxidant/radical scavenging ability. At the posttranslational level, alpha-tocopherol inhibits protein kinase C and 5-lipoxygenase and activates protein phosphatase 2A and diacylglycerol kinase. Some genes (CD36, alpha-TTP, alpha-tropomyosin, and collagenase) are affected by alpha-tocopherol at the transcriptional level. alpha-Tocopherol also induces inhibition of cell proliferation, platelet aggregation and monocyte adhesion. These effects are unrelated to the antioxidant activity of vitamin E, but rather are believed to be a result of specific interactions of vitamin E with components of the cell, e. g. proteins, enzymes and membranes. This review focuses on novel non-antioxidant functions of alpha-tocopherol and discusses the possibility that many of the effects previously attributed to the antioxidant functions can also be explained by non-antioxidant mechanisms.

Vitamin E kinetics and the function of tocopherol regulatory proteins

Plasma and tissue alpha-tocopherol concentrations are remarkably stable, which suggests that they are regulated. alpha-Tocopherol transfer protein, tocopherol-associated protein, and tocopherol-binding protein bind alpha-tocopherol. These proteins might function as tocopherol regulatory proteins, although only tocopherol transfer protein has been shown to influence plasma and tissue alpha-tocopherol concentrations. Tissue alpha-tocopherol concentrations likely depend on tocopherol regulatory protein function and tissue lipid content, vitamin E uptake and efflux, oxidative stress, and interactions between vitamin E and other antioxidants. Pharmacokinetic models often divide tissues into rapidly perfused, slowly perfused, and very slowly perfused compartments. Tissue vitamin E concentrations might equilibrate more rapidly in tissues with greater perfusion, greater vitamin E uptake, increased amounts or activities of tocopherol regulatory protein, and lower lipid contents. The rate at which tissue concentrations approach equilibrium, however, does not predict the final equilibrium concentrations because of redistribution among tissues. Redistribution of vitamin E to adipose tissue from other tissues may be significant. Intracellular trafficking of vitamin E might occur in conjunction with membrane recycling because membrane constituents rapidly recycle between the plasma membrane and intracellular endocytic compartments. Thus, tocopherol regulatory proteins may modulate rather than directly regulate vitamin E tissue distribution and intracellular trafficking.

[Vitamin E deficiency. Etiopathogenesis, clinical, histopathologic, and electrical features, and main etiologies]

Vitamin E deficiency is frequently observed in human pathology. In most cases, deficiency is moderate and asymptomatic. Severe deficiency is rare and presents as a progressive neurological syndrome including cerebellar ataxia and posterior cord injury. Neuropathological and electrophysiological features confirm spinocerebellar degeneration. The pathophysiology of vitamin E deficiency nervous dysfunction is still unknown. Oxidative alterations due to the lack of the main lipid-soluble antioxidant could be involved. A few causes of vitamin E deficiency are recognized (malnutrition, impaired lipid absorption, specific anomaly of hepatic or intestinal secretion of vitamin E, excessive endogenous consumption), but diseases associated with vitamin E deficiency are numerous and divers. Symptomatic severe deficiency is constantly observed in ataxia with vitamin E deficiency and abetalipoproteinemia. Intestinal, hepatobiliary, and pancreatic diseases are often associated with more or less marked deficiency. Other pathological circumstances such as malnutrition, alcoholism, hemolytic anemia, renal failure and hemodialysis could be associated with moderated and asymptomatic vitamin E deficiency. Oral or regular administration of high-dose vitamin E is required for patients with symptomatic severe deficiency. An adapted supplementation is recommended for patients with a marginal vitamin E status.

[Electro-oculographic features of persons with vitamin E deficiency]

INTRODUCTION

Vitamin E (VE) deficiency is a very rare condition which may be due to an isolated deficit or be in the context of a malabsorption disorder.

OBJECTIVE

To evaluate the findings from an electrooculographic (EOG) point of view of patients with VE deficiency.

PATIENTS AND METHODS

We made a retrospective evaluation of all persons with a neurological diagnosis of VE seen in the otoneurological department of our hospital. In all patients an EOG recording was made of the saccadic jerks, and the spontaneous, provoked, positional and opticokinetic (NOC) mystagmus, visual suppression of the vestibulo ocular reflex (VOR) and follow up.

RESULTS

We found four cases, with an average age of 9.2 years (range 6 14 years). All the patients but one were male (75%). The EOG findings were related to cerebellar dysfunction (saccadic following) and central nervous system alterations of no value for localization (ataxic following and visual suppression of the VOR). In two patients no anomalies were seen on the EOG recording.

CONCLUSIONS

In persons with VE deficiency EOG alterations are not often seen. However, it may be useful to make the recording when it is thought necessary to detect subclinical cerebellar disorders.

Selenium and vitamin E

Deficiency of selenium and vitamin E has recently been identified as a major health concern of sheep producers in certain regions of the United States, and familiarity with published data on these nutrients seems to be of value to small ruminant practitioners. This article begins with a description of the biochemical roles and metabolism of selenium and vitamin E. A literature review follows in which the influence of these nutrients on the musculoskeletal, reproductive, and immune systems, as well as on flock productivity, is discussed. Methods for detection of deficiency and supplementation strategies are also described.