Maternal dietary loads of α-tocopherol depress protein kinase C signaling and synaptic plasticity in rat postnatal developing hippocampus and promote permanent deficits in adult offspring

Vitamins, minerals and their maternal levels' role in brain development: An updated literature-review

One's neurobehavioural and mental health are built during the exact and complex process of brain development. It is thought that fetal development is where neuropsychiatric disorders first emerged. Behavioural patterns can change as a result of neuropsychiatric illnesses. The incidence is rising quickly; nevertheless, providing exceptional care remains a significant challenge for families and healthcare systems. It has been demonstrated that one of the main factors causing the transmission of these diseases is maternal exposure. Through physiologic pathways, maternal health and intrauterine exposures can affect brain development. Our attention has been focused on epigenetic factors, particularly in the gestational environment, which may be responsible for human neurodegenerative diseases since our main mental development occurs during the nine months of intrauterine life. After thoroughly searching numerous databases, this study examined the effect of fat-soluble vitamins, water-soluble vitamins, and minerals and their maternal-level effect on brain development.

Asthma, allergy and vitamin E: Current and future perspectives

Asthma and allergic disease result from interactions of environmental exposures and genetics. Vitamin E is one environmental factor that can modify development of allergy early in life and modify responses to allergen after allergen sensitization. Seemingly varied outcomes from vitamin E are consistent with the differential functions of the isoforms of vitamin E. Mechanistic studies demonstrate that the vitamin E isoforms α-tocopherol and γ-tocopherol have opposite functions in regulation of allergic inflammation and development of allergic disease, with α-tocopherol having anti-inflammatory functions and γ-tocopherol having pro-inflammatory functions in allergy and asthma. Moreover, global differences in prevalence of asthma by country may be a result, at least in part, of differences in consumption of these two isoforms of tocopherols. It is critical in clinical and animal studies that measurements of the isoforms of tocopherols be determined in vehicles for the treatments, and in the plasma and/or tissues before and after intervention. As allergic inflammation is modifiable by tocopherol isoforms, differential regulation by tocopherol isoforms provide a foundation for development of interventions to improve lung function in disease and raise the possibility of early life dietary interventions to limit the development of lung disease.

Calsequestrin Deletion Facilitates Hippocampal Synaptic Plasticity and Spatial Learning in Post-Natal Development

Experimental evidence highlights the involvement of the endoplasmic reticulum (ER)-mediated Ca²⁺ signals in modulating synaptic plasticity and spatial memory formation in the hippocampus. Ca²⁺ release from the ER mainly occurs through two classes of Ca²⁺ channels, inositol 1,4,5-trisphosphate receptors (InsP3Rs) and ryanodine receptors (RyRs). Calsequestrin (CASQ) and calreticulin (CR) are the most abundant Ca²⁺-binding proteins allowing ER Ca²⁺ storage. The hippocampus is one of the brain regions expressing CASQ, but its role in neuronal activity, plasticity, and the learning processes is poorly investigated. Here, we used knockout mice lacking both CASQ type-1 and type-2 isoforms (double (d)CASQ-null mice) to: a) evaluate in adulthood the neuronal electrophysiological properties and synaptic plasticity in the hippocampal Cornu Ammonis 1 (CA1) field and b) study the performance of knockout mice in spatial learning tasks. The ablation of CASQ increased the CA1 neuron excitability and improved the long-term potentiation (LTP) maintenance. Consistently, (d)CASQ-null mice performed significantly better than controls in the Morris Water Maze task, needing a shorter time to develop a spatial preference for the goal. The Ca²⁺ handling analysis in CA1 pyramidal cells showed a decrement of Ca²⁺ transient amplitude in (d)CASQ-null mouse neurons, which is consistent with a decrease in afterhyperpolarization improving LTP. Altogether, our findings suggest that CASQ deletion affects activity-dependent ER Ca²⁺ release, thus facilitating synaptic plasticity and spatial learning in post-natal development.

Significant Effects of Maternal Diet During Pregnancy on the Murine Fetal Brain Transcriptome and Offspring Behavior

BACKGROUND

Maternal over- and undernutrition in pregnancy plays a critical role in fetal brain development and function. The effects of different maternal diet compositions on intrauterine programing of the fetal brain is a lesser-explored area. The goal of this study was to investigate the impact of two chowmaternal diets on fetal brain gene expression signatures, fetal/neonatal growth, and neonatal and adult behavior in a mouse model.

METHODS

Throughout pregnancy and lactation, female C57Bl/6J mice were fed one of two standard, commercially available chow diets (pellet versus powder). The powdered chow diet was relatively deficient in micronutrients and enriched for carbohydrates and n-3 long-chain polyunsaturated fatty acids compared to the pelleted chow. RNA was extracted from embryonic day 15.5 forebrains and hybridized to whole genome expression microarrays (N = 5/maternal diet group). Functional analyses of significantly differentially expressed fetal brain genes were performed using Ingenuity Pathways Analysis and Gene Set Enrichment Analysis. Neonatal behavior was assessed using a validated scale (N = 62 pellet-exposed and 31 powder-exposed). Hippocampal learning, locomotor behavior, and motor coordination were assessed in a subset of adults using fear conditioning, open field testing, and Rotarod tests (N = 16 pellet-exposed, 14 powder-exposed).

RESULTS

Comparing powdered to pelleted chow diets, neither maternal weight trajectory in pregnancy nor embryo size differed. Maternal powdered chow diet was associated with 1647 differentially expressed fetal brain genes. Functional analyses identified significant upregulation of canonical pathways and upstream regulators involved in cell cycle regulation, synaptic plasticity, and sensory nervous system development in the fetal brain, and significant downregulation of pathways related to cell and embryo death. Pathways related to DNA damage response, brain immune response, amino acid and fatty acid transport, and dopaminergic signaling were significantly dysregulated. Powdered chow-exposed neonates were significantly longer but not heavier than pelleted chow-exposed counterparts. On neonatal behavioral testing, powdered chow-exposed neonates achieved coordination- and strength-related milestones significantly earlier, but sensory maturation reflexes significantly later. On adult behavioral testing, powdered chow-exposed offspring exhibited hyperactivity and hippocampal learning deficits.

CONCLUSION

In wild-type offspring, two diets that differed primarily with respect to micronutrient composition had significant effects on the fetal brain transcriptome, neonatal and adult behavior. These effects did not appear to be mediated by alterations in gross maternal nutritional status nor fetal/neonatal weight. Maternal dietary content is an important variable to consider for investigators evaluating fetal brain development and offspring behavior.

Maternal Creatine Supplementation Positively Affects Male Rat Hippocampal Synaptic Plasticity in Adult Offspring

Creatine plays a crucial role in developing the brain, so much that its genetic deficiency results in mental dysfunction and cognitive impairments. Moreover, creatine supplementation is currently under investigation as a preventive measure to protect the fetus against oxidative stress during difficult pregnancies. Although creatine use is considered safe, posing minimal risk to clinical health, we found an alteration in morpho-functional maturation of neurons when male rats were exposed to creatine loads during brain development. In particular, increased excitability and enhanced long-term potentiation (LTP) were observed in the hippocampal pyramidal neurons of weaning pups. Since these effects were observed a long time after creatine treatment had been terminated, long-lasting modifications persisting into adulthood were hypothesized. Such modifications were investigated in the present study using morphological, electrophysiological, and calcium imaging techniques applied to hippocampal Cornu Ammonis 1 (CA1) neurons of adult rats born from dams supplemented with creatine. When compared to age-matched controls, the treated adult offspring were found to retain enhanced neuron excitability and an improved LTP, the best-documented neuronal substrate for memory formation. While translating data from rats to humans does have limitations, our findings suggest that prenatal creatine supplementation could have positive effects on adult cognitive abilities.

Brain Vitamin E Deficiency During Development Is Associated With Increased Glutamate Levels and Anxiety in Adult Mice

Vitamin E, the most important lipophilic radical scavenging antioxidant in vivo, has a pivotal role in brain. In an earlier study, we observed that adult mice with a defect in the gene encoding plasma phospholipid transfer protein (PLTP) display a moderate reduction in cerebral vitamin E levels, and exacerbated anxiety despite normal locomotion and memory functions. Here we sought to determine whether dietary vitamin E supplementation can modulate neurotransmitter levels and alleviate the increased anxiety phenotype of PLTP-deficient (PLTP^−/−) mice. To address this question, a vitamin E-enriched diet was used, and two complementary approches were implemented: (i) “early supplementation”: neurotransmitter levels and anxiety were assessed in 6 months old PLTP^−/− mice born from vitamin E-supplemented parents; and (ii) “late supplementation”: neurotransmitter levels and anxiety were assessed in 6 months old PLTP^−/− mice fed a vitamin E-enriched diet from weaning. Our results show for the first time that an inadequate supply of vitamin E during development, due to moderate maternal vitamin E deficiency, is associated with reduced brain vitamin E levels at birth and irreversible alterations in brain glutamate levels. They also suggest this deficiency is associated with increased anxiety at adulthood. Thus, the present study leads to conclude on the importance of the micronutrient vitamin E during pregnancy.

α-Tocopherol at Nanomolar Concentration Protects Cortical Neurons against Oxidative Stress

The aim of the present work is to study the mechanism of the α-tocopherol (α-T) protective action at nanomolar and micromolar concentrations against H₂O₂-induced brain cortical neuron death. The mechanism of α-T action on neurons at its nanomolar concentrations characteristic for brain extracellular space has not been practically studied yet. Preincubation with nanomolar and micromolar α-T for 18 h was found to increase the viability of cortical neurons exposed to H₂O₂; α-T effect was concentration-dependent in the nanomolar range. However, preincubation with nanomolar α-T for 30 min was not effective. Nanomolar and micromolar α-T decreased the reactive oxygen species accumulation induced in cortical neurons by the prooxidant. Using immunoblotting it was shown that preincubation with α-T at nanomolar and micromolar concentrations for 18 h prevented Akt inactivation and decreased PKCδ activation induced in cortical neurons by H₂O₂. α-T prevented the ERK1/2 sustained activation during 24 h caused by H₂O₂. α-T at nanomolar and micromolar concentrations prevented a great increase of the proapoptotic to antiapoptotic proteins (Bax/Bcl-2) ratio, elicited by neuron exposure to H₂O₂. The similar neuron protection mechanism by nanomolar and micromolar α-T suggests that a “more is better” approach to patients’ supplementation with vitamin E or α-T is not reasonable.

Vitamin E: Emerging aspects and new directions

The discovery of vitamin E will have its 100th anniversary in 2022, but we still have more questions than answers regarding the biological functions and the essentiality of vitamin E for human health. Discovered as a factor essential for rat fertility and soon after characterized for its properties of fat-soluble antioxidant, vitamin E was identified to have signaling and gene regulation effects in the 1980s. In the same years the cytochrome P-450 dependent metabolism of vitamin E was characterized and a first series of studies on short-chain carboxyethyl metabolites in the 1990s paved the way to the hypothesis of a biological role for this metabolism alternative to vitamin E catabolism. In the last decade other physiological metabolites of vitamin E have been identified, such as α-tocopheryl phosphate and the long-chain metabolites formed by the ω-hydroxylase activity of cytochrome P-450. Recent findings are consistent with gene regulation and homeostatic roles of these metabolites in different experimental models, such as inflammatory, neuronal and hepatic cells, and in vivo in animal models of acute inflammation. Molecular mechanisms underlying these responses are under investigation in several laboratories and side-glances to research on other fat soluble vitamins may help to move faster in this direction. Other emerging aspects presented in this review paper include novel insights on the mechanisms of reduction of the cardiovascular risk, immunomodulation and antiallergic effects, neuroprotection properties in models of glutamate excitotoxicity and spino-cerebellar damage, hepatoprotection and prevention of liver toxicity by different causes and even therapeutic applications in non-alcoholic steatohepatitis. We here discuss these topics with the aim of stimulating the interest of the scientific community and further research activities that may help to celebrate this anniversary of vitamin E with an in-depth knowledge of its action as vitamin.

α-Tocopherol and Hippocampal Neural Plasticity in Physiological and Pathological Conditions

Neuroplasticity is an "umbrella term" referring to the complex, multifaceted physiological processes that mediate the ongoing structural and functional modifications occurring, at various time- and size-scales, in the ever-changing immature and adult brain, and that represent the basis for fundamental neurocognitive behavioral functions; in addition, maladaptive neuroplasticity plays a role in the pathophysiology of neuropsychiatric dysfunctions. Experiential cues and several endogenous and exogenous factors can regulate neuroplasticity; among these, vitamin E, and in particular α-tocopherol (α-T), the isoform with highest bioactivity, exerts potent effects on many plasticity-related events in both the physiological and pathological brain. In this review, the role of vitamin E/α-T in regulating diverse aspects of neuroplasticity is analyzed and discussed, focusing on the hippocampus, a brain structure that remains highly plastic throughout the lifespan and is involved in cognitive functions. Vitamin E-mediated influences on hippocampal synaptic plasticity and related cognitive behavior, on post-natal development and adult hippocampal neurogenesis, as well as on cellular and molecular disruptions in kainate-induced temporal seizures are described. Besides underscoring the relevance of its antioxidant properties, non-antioxidant functions of vitamin E/α-T, mainly involving regulation of cell signaling molecules and their target proteins, have been highlighted to help interpret the possible mechanisms underlying the effects on neuroplasticity.

γ-Tocopherol supplementation of allergic female mice augments development of CD11c+CD11b+ dendritic cells in utero and allergic inflammation in neonates

γ-Tocopherol increases responses to allergen challenge in allergic adult mice, but it is not known whether γ-tocopherol regulates the development of allergic disease. Development of allergic disease often occurs early in life. In clinical studies and animal models, offspring of allergic mothers have increased responsiveness to allergen challenge. Therefore, we determined whether γ-tocopherol augments development of allergic responses in offspring of allergic female mice. Allergic female mice were supplemented with γ-tocopherol starting at mating. The pups from allergic mothers developed allergic lung responses, whereas pups from saline-treated mothers did not respond to allergen challenge. The γ-tocopherol supplementation of allergic female mice increased the numbers of eosinophils twofold in the pup bronchoalveolar lavage and lungs after allergen challenge. There was also about a twofold increase in pup lung CD11b(+) subsets of CD11c(+) dendritic cells and in numbers of these dendritic cells expressing the transcription factor IRF4. There was no change in several CD11b(-) dendritic cell subsets. Furthermore, maternal supplementation with γ-tocopherol increased the number of fetal liver CD11b(+)CD11c(+) dendritic cells twofold in utero. In the pups, γ-tocopherol increased lung expression of the inflammatory mediators CCL11, amphiregulin, activin A, and IL-5. In conclusion, maternal supplementation with γ-tocopherol increased fetal development of subsets of dendritic cells that are critical for allergic responses and increased development of allergic responses in pups from allergic mothers. These results have implications for supplementation of allergic mothers with γ-tocopherol in prenatal vitamins.

Maternal creatine supplementation affects the morpho-functional development of hippocampal neurons in rat offspring

Creatine supplementation has been shown to protect neurons from oxidative damage due to its antioxidant and ergogenic functions. These features have led to the hypothesis of creatine supplementation use during pregnancy as prophylactic treatment to prevent CNS damage, such as hypoxic-ischemic encephalopathy. Unfortunately, very little is known on the effects of creatine supplementation during neuron differentiation, while in vitro studies revealed an influence on neuron excitability, leaving the possibility of creatine supplementation during the CNS development an open question. Using a multiple approach, we studied the hippocampal neuron morphological and functional development in neonatal rats born by dams supplemented with 1% creatine in drinking water during pregnancy. CA1 pyramidal neurons of supplemented newborn rats showed enhanced dendritic tree development, increased LTP maintenance, larger evoked-synaptic responses, and higher intrinsic excitability in comparison to controls. Moreover, a faster repolarizing phase of action potential with the appearance of a hyperpolarization were recorded in neurons of the creatine-treated group. Consistently, CA1 neurons of creatine exposed pups exhibited a higher maximum firing frequency than controls. In summary, we found that creatine supplementation during pregnancy positively affects morphological and electrophysiological development of CA1 neurons in offspring rats, increasing neuronal excitability. Altogether, these findings emphasize the need to evaluate the benefits and the safety of maternal intake of creatine in humans.

α-Tocopherol supplementation of allergic female mice inhibits development of CD11c+CD11b+ dendritic cells in utero and allergic inflammation in neonates

α-Tocopherol blocks responses to allergen challenge in allergic adult mice, but it is not known whether α-tocopherol regulates the development of allergic disease. Development of allergic disease often occurs early in life. In clinical studies and animal models, offspring of allergic mothers have increased responsiveness to allergen challenge. Therefore, we determined whether α-tocopherol blocked development of allergic responses in offspring of allergic female mice. Allergic female mice were supplemented with α-tocopherol starting at mating. The pups from allergic mothers developed allergic lung responses, whereas pups from saline-treated mothers did not respond to the allergen challenge, and α-tocopherol supplementation of allergic female mice resulted in a dose-dependent reduction in eosinophils in the pup bronchoalveolar lavage and lungs after allergen challenge. There was also a reduction in pup lung CD11b(+) dendritic cell subsets that are critical to development of allergic responses, but there was no change in several CD11b(-) dendritic cell subsets. Furthermore, maternal supplementation with α-tocopherol reduced the number of fetal liver CD11b(+) dendritic cells in utero. In the pups, there was reduced allergen-induced lung mRNA expression of IL-4, IL-33, TSLP, CCL11, and CCL24. Cross-fostering pups at the time of birth demonstrated that α-tocopherol had a regulatory function in utero. In conclusion, maternal supplementation with α-tocopherol reduced fetal development of subsets of dendritic cells that are critical for allergic responses and reduced development of allergic responses in pups from allergic mothers. These results have implications for supplementation of allergic mothers with α-tocopherol.

Maternal dietary loads of alpha-tocopherol increase synapse density and glial synaptic coverage in the hippocampus of adult offspring

An increased intake of the antioxidant α-Tocopherol (vitamin E) is recommended in complicated pregnancies, to prevent free radical damage to mother and fetus. However, the anti-PKC and antimitotic activity of α-Tocopherol raises concerns about its potential effects on brain development. Recently, we found that maternal dietary loads of α-Tocopherol through pregnancy and lactation cause developmental deficit in hippocampal synaptic plasticity in rat offspring. The defect persisted into adulthood, with behavioral alterations in hippocampus-dependent learning. Here, using the same rat model of maternal supplementation, ultrastructural morphometric studies were carried out to provide mechanistic interpretation to such a functional impairment in adult offspring by the occurrence of long-term changes in density and morphological features of hippocampal synapses. Higher density of axo-spinous synapses was found in CA1 stratum radiatum of α-Tocopherol-exposed rats compared to controls, pointing to a reduced synapse pruning. No morphometric changes were found in synaptic ultrastructural features, i.e., perimeter of axon terminals, length of synaptic specializations, extension of bouton-spine contact. Glia-synapse anatomical relationship was also affected. Heavier astrocytic coverage of synapses was observed in Tocopherol-treated offspring, notably surrounding axon terminals; moreover, the percentage of synapses contacted by astrocytic endfeet at bouton-spine interface (tripartite synapses) was increased. These findings indicate that gestational and neonatal exposure to supranutritional tocopherol intake can result in anatomical changes of offspring hippocampus that last through adulthood. These include a surplus of axo-spinous synapses and an aberrant glia-synapse relationship, which may represent the morphological signature of previously described alterations in synaptic plasticity and hippocampus-dependent learning.

Post-seizure α-tocopherol treatment decreases neuroinflammation and neuronal degeneration induced by status epilepticus in rat hippocampus

Vitamin E (as α-tocopherol, α-T) was shown to have beneficial effects in epilepsy, mainly ascribed to its antioxidant properties. Besides radical-induced neurotoxicity, neuroinflammation is also involved in the pathophysiology of epilepsy, since neuroglial activation and cytokine production exacerbate seizure-induced neurotoxicity and contribute to epileptogenesis. We previously showed that α-T oral supplementation before inducing status epilepticus, markedly reduces astrocytic and microglial activation, neuronal cell death and oxidative stress in the hippocampus, as observed 4 days after seizure. In order to evaluate the possibility that such a neuroprotective and anti-inflammatory effect may also provide a strategy for an acute intervention in epilepsy, in this study, seizures were induced by single intaperitoneal injection of kainic acid and, starting from 3 h after status epilepticus, rats were treated with an intraperitoneal bolus of α-T (250 mg/kg b.w.; once a day) for 4 days, that was the time after which morphological and biochemical analyses were performed on hippocampus. Post-seizure α-T administration significantly reduced astrocytosis and microglia activation, and decreased neuron degeneration and spine loss; these effects were associated with the presence of a lowered lipid peroxidation in hippocampus. These results confirm and further emphasize the anti-inflammatory and neuroprotective role of α-T in kainic acid-induced epilepsy. Moreover, the findings show that post-seizure treatment with α-T provides an effective secondary prevention against post-seizure inflammation-induced brain damages and possibly against their epileptogenic effects.

Physical exercise and environment exploration affect synaptogenesis in adult-generated neurons in the rat dentate gyrus: possible role of BDNF

A brief training in a pool maze, with or without cognitive tasks, modifies the synaptogenesis and maturation of newborn neurons in adult rat dentate gyrus. These types of trainings have many aspects, including physical activity and exploration. Therefore, to evaluate whether physical exercise and environment exploration are able to affect synapse formation and the maturation of adult-generated neurons, GFP-retrovirus infusion was performed on rats which, on the fourth day after injection, were housed under running conditions or allowed to explore an enriched environment briefly in the absence of exercise for the following three days. Afterward, at the end of the trainings, electrophysiological and morphological studies were conducted. Considering that neurotrophic factors increase after exercise or environment exploration, hippocampal BDNF levels and TrkB receptor activation were evaluated. In this study, we show that both spontaneous physical activity and enriched environment exploration induced synaptogenesis and T-type voltage-dependent Ca(2+) currents in very immature neurons. Hippocampal BDNF levels and TrkB receptor activation were determined to be increasing following physical activity and exploration. A possible contribution of BDNF signaling in mediating the observed effects was supported by the use of 7-8-dihydroxyflavone, a selective TrkB agonist, and of ANA-12, an inhibitor of TrkB receptors.

The α-tocopherol transfer protein is essential for vertebrate embryogenesis

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’s significance during fetal development. TTP and vitamin E are essential for productive pregnancy in rodents, but their precise physiological role in embryogenesis is unknown. We hypothesize that TTP is required to regulate delivery of α-tocopherol to critical target sites in the developing embryo. We tested to find if TTP is essential for proper vertebrate development, utilizing the zebrafish as a non-placental model. We verify that TTP is expressed in the adult zebrafish and its amino acid sequence is homologous to the human ortholog. We show that embryonic transcription of TTP mRNA increases >7-fold during the first 24 hours following fertilization. In situ hybridization demonstrates that Ttpa transcripts are localized in the developing brain, eyes and tail bud at 1-day post fertilization. Inhibiting TTP expression using oligonucleotide morpholinos results in severe malformations of the head and eyes in nearly all morpholino-injected embryos (88% compared with 5.6% in those injected with control morpholinos or 1.7% in non-injected embryos). We conclude that TTP is essential for early development of the vertebrate central nervous system.

α-Tocopherol at nanomolar concentration protects PC12 cells from hydrogen peroxide-induced death and modulates protein kinase activities

The aim of this work was to compare protective and anti-apoptotic effects of α-tocopherol at nanomolar and micromolar concentrations against 0.2 mM H(2)O(2)-induced toxicity in the PC12 neuronal cell line and to reveal protein kinases that contribute to α-tocopherol protective action. The protection by 100 nM α-tocopherol against H(2)O(2)-induced PC12 cell death was pronounced if the time of pre-incubation with α-tocopherol was 3-18 h. For the first time, the protective effect of α-tocopherol was shown to depend on its concentration in the nanomolar range (1 nM < 10 nM < 100 nM), if the pre-incubation time was 18 h. Nanomolar and micromolar α-tocopherol decreased the number of PC12 cells in late apoptosis induced by H(2)O(2) to the same extent if pre-incubation time was 18 h. Immunoblotting data showed that α-tocopherol markedly diminished the time of maximal activation of extracellular signal-regulated kinase 1/2 (ERK 1/2) and protein kinase B (Akt)-induced in PC12 cells by H(2)O(2). Inhibitors of MEK 1/2, PI 3-kinase and protein kinase C (PKC) diminished the protective effect of α-tocopherol against H(2)O(2)-initiated toxicity if the pre-incubation time was long. The modulation of ERK 1/2, Akt and PKC activities appears to participate in the protection by α-tocopherol against H(2)O(2)-induced death of PC12 cells. The data obtained suggest that inhibition by α-tocopherol in late stage ERK 1/2 and Akt activation induced by H(2)O(2) in PC12 cells makes contribution to its protective effect, while total inhibition of these enzymes is not protective.

Circulating antioxidant profile of pregnant women with asthma

BACKGROUND & AIMS

One of the most prevalent complications of pregnancy is asthma which is associated with an increased incidence of intrauterine growth restriction. The mechanisms that affect fetal development in pregnancies complicated by asthma are not clearly defined. Antioxidants are particularly important during pregnancy due to their protective role against a state of high oxidative stress as gestation progresses. The current study was designed to characterise the circulating profile of tocopherols and carotenoids in pregnant women with asthma to determine whether asthma severity and dietary intake were associated with an altered antioxidant profile.

METHODS

Maternal dietary intake and plasma and erythrocyte concentrations of tocopherols and carotenoids were examined in women with (n = 84) and without asthma (n = 47) at 18, 30 and 36 weeks gestation. Tocopherol and carotenoid levels were related to fetal and birth outcomes.

RESULTS

Pregnant women with moderate/severe asthma were found to have increased plasma concentrations of total carotenoids (P < 0.05), lutein (P < 0.05 and α-tocopherol (P < 0.02) late in gestation compared to those women with mild asthma and healthy pregnant controls. Moderate/severe asthmatics had higher erythrocyte α-tocopherol quinone levels early in gestation relative to the controls (P < 0.02) but this marker of oxidative stress decreased as gestation progressed. Tocopherols and carotenoids were positively associated with birth weight centile (P < 0.05).

CONCLUSION

These findings suggest that the maternal system adjusts antioxidant pathways in response to the presence of a high oxidative load induced by asthma during pregnancy in an attempt to ensure continued fetal growth in an adverse environment.

Maternal dietary loads of α-tocopherol differentially influence fear conditioning and spatial learning in adult offspring

α-Tocopherol, the main component of vitamin E, is well known to be a radical scavenger, so an increased intake of vitamin E is recommended in complicated pregnancy, to prevent possible fetus damage by free radical. In a previous work, we found that maternal α-tocopherol supplementation affects PKC-mediated cellular signaling and hippocampal synaptic plasticity in developing brain; the latter effect persists in adulthood. Here, adult rats maternally exposed to supranutritional doses of α-tocopherol were evaluated for Contextual Fear Conditioning and spatial learning in Morris Water Maze, two different hippocampus-dependent learning tasks. Moreover, anxiety, spontaneous activity, and explorative drive were also evaluated as factors potentially affecting learning performance. Treated rats showed a different behavior with respect to controls: performance in Contextual Fear Conditioning was improved, while spatial learning tested in Morris Water Maze, was impaired. The improvement of fear response was not ascribable to differences in anxiety level and/or spontaneous activity; thus it appears to be a specific effect of α-tocopherol overloading during brain development. On the contrary, the impaired performance in Morris Water Maze exhibited by treated rats can be in part explained by their enhanced explorative drive. Although extrapolation from rats to humans is difficult, a caveat in assuming supranutritional doses of vitamin E in pregnancy arises from this study.

Dietary supplementation with α-tocopherol reduces neuroinflammation and neuronal degeneration in the rat brain after kainic acid-induced status epilepticus

Vitamin E (as α-tocopherol, α-T) is proposed to alleviate glia-mediated inflammation in neurological diseases, but such a role in epilepsy is still elusive. This study investigated the effect of α-T supplementation on glial activation, neuronal cell death and oxidative stress of rat brain exposed to kainate-induced seizures. Animals were fed for 2 weeks with a α-T-enriched diet (estimated intake of 750 mg/kg/day) before undergoing status epilepticus. Compliance to supplementation was demonstrated by the remarkable increase in brain α-T. Four days after seizure, brain α-T returned to baseline and lipid peroxidation markers decreased as compared to non-supplemented rats. Status epilepticus induced a lower up-regulation of astrocytic and microglial antigens (GFAP and MHC II, respectively) and production of pro-inflammatory cytokines (IL-1β and TNF-α) in supplemented than in non-supplemented animals. This anti-inflammatory effect was associated with a lower neuronal cell death. In conclusion, α-T dietary supplementation prevents oxidative stress, neuroglial over-activation and cell death occurring after kainate-induced seizures. This evidence paves the way to an anti-inflammatory and neuroprotective role of α-T interventions in epilepsy.

Alpha-tocopherol protects against memory impairment caused by L-NAME and modulates the injury marker and blood coagulant parameters

Cerebrovascular disease studies have shown similarity between humans and spontaneously hypertensive rats stroke-prone rats in the development of spontaneous stroke and transitory ischemic attacks (TIA). In addition, nitric oxide (NO) suppression by L-arginine methyl ester (L-NAME) can precipitate several vascular diseases including TIA and strokes. On the other hand, alpha-tocopherol (AT) has been associated with beneficial effects on vascular disorders. Four groups were tested to evaluate AT effects on NO inhibition: AT, control (C), AT + L-NAME, and L-NAME. During 4 weeks, all groups had their physiologic parameters evaluated and were submitted to neurological tests. After the sacrifice of the animals, total L-lactate dehydrogenase, fibrinogen levels, and platelet counts were measured. Our results demonstrated improvement in memory function and sensory-motor function of the rats treated with AT. The AT treatment also demonstrated a significant difference on the injury identifier, fibrinogen levels, and platelet count between the treated groups and the L-NAME group. In conclusion, AT reversed damaging L-NAME neurological effects and could be considered as a possible protective agent in neurological diseases.

α-Tocopherol suppresses lipid peroxidation and behavioral and cognitive impairments in the Ts65Dn mouse model of Down syndrome

It is widely accepted that oxidative stress is involved in the pathogenesis of Down syndrome, but the effectiveness of antioxidant treatment remains inconclusive. We tested whether chronic administration of α-tocopherol ameliorates the cognitive deficits exhibited by Ts65Dn mice, a mouse model of Down syndrome. α-Tocopherol was administered to pregnant Ts65Dn females, from the day of conception throughout the pregnancy, and to pups over their entire lifetime, from birth to the end of the behavioral testing period. Cognitive deficits were confirmed for Ts65Dn mice fed a control diet, revealing reduced anxiety or regardlessness in the elevated-plus maze task test and spatial learning deficits in the Morris water maze test. However, supplementation with α-tocopherol attenuated both cognitive impairments. In addition, we found that levels of 8-iso-prostaglandin F(2α) in brain tissue and hydroxyoctadecadienoic acid and 7-hydroxycholesterol in the plasma of Ts65Dn mice were higher than those of control mice. Supplementation with α-tocopherol decreased levels of lipid peroxidation products in Ts65Dn mice. Furthermore, we found out that α-tocopherol improved hypocellularity in the hippocampal dentate gyrus of Ts65Dn mice. These results imply that α-tocopherol supplementation from an early stage may be an effective treatment for the cognitive deficits associated with Down syndrome.