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

Mechanisms for initiation of food allergy by skin pre-disposed to atopic dermatitis

Food allergy can be life-threatening and often develops early in life. In infants and children, loss-of-function mutations in skin barrier genes associate with food allergy. In a mouse model with skin barrier mutations (Flakey Tail, FT+/- mice), topical epicutaneous sensitization to a food allergen peanut extract (PNE), an environmental allergen Alternaria alternata (Alt) and a detergent induce food allergy and then an oral PNE-challenge induces anaphylaxis. Exposures to these allergens and detergents can occur for infants and children in a household setting. From the clinical and preclinical studies of neonates and children with skin barrier mutations, early oral exposure to allergenic foods before skin sensitization may induce tolerance to food allergens and thus protect against development of food allergy. In the FT+/- mice, oral food allergen prior to skin sensitization induce tolerance to food allergens. However, when the skin of FT+/- pups are exposed to a ubiquitous environmental allergen at the time of oral consumption of food allergens, this blocks the induction of tolerance to the food allergen and the mice can then be skin sensitized with the food allergen. The development of food allergy in neonatal FT+/- mice is mediated by altered skin responses to allergens with increases in skin expression of interleukin 33, oncostatin M and amphiregulin. The development of neonate food allergy is enhanced when born to an allergic mother, but it is inhibited by maternal supplementation with α-tocopherol. Moreover, preclinical studies suggest that food allergen skin sensitization can occur before manifestation of clinical features of atopic dermatitis. Thus, these parameters may impact design of clinical studies for food allergy, when stratifying individuals by loss of skin barrier function or maternal atopy before offspring development of atopic dermatitis.

Preclinical models of maternal asthma and progeny outcomes: a scoping review

There is an increased risk of adverse perinatal outcomes in the ∼17% of women with asthma during pregnancy. The mechanisms linking maternal asthma and adverse outcomes are largely unknown, but reflect joint effects of genetics and prenatal exposure to maternal asthma. Animal models are essential to understand the underlying mechanisms independent of genetics and comorbidities, and enable safe testing of interventions. This scoping review aimed to explore the methodology, phenotype, characteristics, outcomes and quality of published studies using preclinical maternal asthma models. MEDLINE (PubMed), Embase (Elsevier) and Web of Science were systematically searched using previously validated search strings for maternal asthma and for animal models. Two reviewers independently screened titles and abstracts, full texts, and then extracted and assessed the quality of each study using the Animal Research: Reporting of In Vivo Experiments (ARRIVE) 2.0 guidelines. Out of 3618 studies identified, 39 were eligible for extraction. Most studies were in rodents (86%) and all were models of allergic asthma. Maternal and progeny outcomes included airway hyperresponsiveness, airway resistance, inflammation, lung immune cells, lung structure and serum immunoglobulins and cytokines. Experimental design (100%), procedural details (97%) and rationale (100%) were most often reported. Conversely, data exclusion (21%), blinding (18%) and adverse events (8%) were reported in a minority of studies. Species differences in physiology and timing of development, the use of allergens not relevant to humans and a lack of comparable outcome measures may impede clinical translation. Future studies exploring models of maternal asthma should adhere to the minimum core outcomes set presented in this review.

Vitamin E deficiency in childhood: a narrative review

Vitamin E is an important nutrient from the earliest stages of life. It plays key roles as an antioxidant and in the maintenance of the immune system, among others. Vitamin E deficiency (VED), which occurs more frequently in children, is rarely addressed in the literature. This narrative review aims to summarise the chemistry, biology, serum indicators and clinical trials that have evaluated the impact of fortification and other relevant aspects of vitamin E, in addition to the prevalence of its deficiency, in children worldwide. Vitamin E intake in recommended amounts is essential for this nutrient to perform its functions in the body. Serum α-tocopherol is the most widely used biochemical indicator to assess the prevalence of VED. VED has been associated with symptoms secondary to fat malabsorption and may lead to peripheral neuropathy and increased erythrocyte haemolysis. Reduced concentrations of α-tocopherol may be caused by the combination of diets with low amounts of vitamin E and inadequate consumption of fats, proteins and calories. The lowest prevalence of VED was found in Asia and the highest in North America and Brazil. High proportions of VED provide evidence that this nutritional deficiency is a public health problem in children and still little addressed in the international scientific literature. The planning, evaluation and implementation of health policies aimed at combatting VED in the paediatric population are extremely important.

A pilot randomized clinical trial of γ-tocopherol supplementation on wood smoke-induced neutrophilic and eosinophilic airway inflammation

Background

Air pollutants, including particulates from wood smoke, are a significant cause of exacerbation of lung disease. γ-Tocopherol is an anti-inflammatory isoform of vitamin E that has been shown to reduce allergen-, ozone-, and endotoxin-induced inflammation.

Objective

The objective of this study was to determine whether γ-tocopherol would prevent experimental wood smoke-induced airway inflammation in humans.

Methods

This was a randomized, placebo-controlled clinical trial testing the effect of a short course of γ-tocopherol-enriched supplementation on airway inflammation following a controlled exposure to wood smoke particulates.

Results

Short-course γ-tocopherol intervention did not reduce wood smoke-induced neutrophilic airway inflammation, but it did prevent wood smoke-induced eosinophilic airway inflammation.

Conclusion

γ-Tocopherol is a potential intervention for exacerbation of allergic airway inflammation, but further study examining longer dosing periods is required.

Catching Our Breath: Updates on the Role of Dendritic Cell Subsets in Asthma

Dendritic cells (DCs), as potent antigen presenting cells, are known to play a central role in the pathophysiology of asthma. The understanding of DC biology has evolved over the years to include multiple subsets of DCs with distinct functions in the initiation and maintenance of asthma. Furthermore, asthma is increasingly recognized as a heterogeneous disease with potentially diverse underlying mechanisms. The goal of this review is to summarize the role of DCs and the various subsets therein in the pathophysiology of asthma and highlight some of the crucial animal models shaping the field today. Potential future avenues of investigation to address existing gaps in knowledge are discussed.

The Role of Vitamins in the Pathogenesis of Asthma

Vitamins play a crucial role in the proper functioning of organisms. Disturbances of their levels, seen as deficiency or excess, enhance the development of various diseases, including those of the cardiovascular, immune, or respiratory systems. The present paper aims to summarize the role of vitamins in one of the most common diseases of the respiratory system, asthma. This narrative review describes the influence of vitamins on asthma and its main symptoms such as bronchial hyperreactivity, airway inflammation, oxidative stress, and airway remodeling, as well as the correlation between vitamin intake and levels and the risk of asthma in both pre- and postnatal life.

Dysbiotic lung microbial communities of neonates from allergic mothers confer neonate responsiveness to suboptimal allergen

In humans and animals, offspring of allergic mothers have increased responsiveness to allergens. This is blocked in mice by maternal supplementation with α-tocopherol (αT). Also, adults and children with allergic asthma have airway microbiome dysbiosis with increased Proteobacteria and may have decreased Bacteroidota. It is not known whether αT alters neonate development of lung microbiome dysbiosis or whether neonate lung dysbiosis modifies development of allergy. To address this, the bronchoalveolar lavage was analyzed by 16S rRNA gene analysis (bacterial microbiome) from pups of allergic and non-allergic mothers with a basal diet or αT-supplemented diet. Before and after allergen challenge, pups of allergic mothers had dysbiosis in lung microbial composition with increased Proteobacteria and decreased Bacteroidota and this was blocked by αT supplementation. We determined whether intratracheal transfer of pup lung dysbiotic microbial communities modifies the development of allergy in recipient pups early in life. Interestingly, transfer of dysbiotic lung microbial communities from neonates of allergic mothers to neonates of non-allergic mothers was sufficient to confer responsiveness to allergen in the recipient pups. In contrast, neonates of allergic mothers were not protected from development of allergy by transfer of donor lung microbial communities from either neonates of non-allergic mothers or neonates of αT-supplemented allergic mothers. These data suggest that the dysbiotic lung microbiota is dominant and sufficient for enhanced neonate responsiveness to allergen. Importantly, infants within the INHANCE cohort with an anti-inflammatory profile of tocopherol isoforms had an altered microbiome composition compared to infants with a pro-inflammatory profile of tocopherol isoforms. These data may inform design of future studies for approaches in the prevention or intervention in asthma and allergic disease early in life.

β-Glucosylceramides and Tocopherols Regulate Development and Function of Dendritic Cells

In humans and mice, offspring of allergic mothers are predisposed to development of allergy. In mice, allergic mothers have elevated β-glucosylceramides (βGlcCers) that are transported to the fetus via the placenta and to offspring via milk. The elevated βGlcCers increase the number of fetal liver CD11c+CD11b+ dendritic cells (DCs) and offspring allergen-induced lung eosinophilia. These effects are modifiable by maternal dietary supplementation with the plant-derived lipids α-tocopherol and γ-tocopherol. It is not known whether βGlcCers and tocopherols directly regulate development of DCs. In this study, we demonstrated that βGlcCers increased development of GM-CSF-stimulated mouse bone marrow-derived DCs (BMDCs) in vitro without altering expression of costimulatory molecules. This increase in BMDC numbers was blocked by α-tocopherol and potentiated by γ-tocopherol. Furthermore, βGlcCers increased protein kinase Cα (PKCα) and PKCδ activation in BMDCs that was blocked by α-tocopherol. In contrast, γ-tocopherol increased BMDC PKCα and PKCδ activation and enhanced the βGlcCer-induced increase in PKCδ activation in a DC subset. Ag processing per DC was minimally enhanced in βGlcCer-treated BMDCs and not altered ex vivo in lung DCs from pups of allergic mothers. Pups of allergic mothers had an increased proportion of CD11b+CD11c+ subsets of DCs, contributing to enhanced stimulation of T cell proliferation ex vivo. Thus, βGlcCer, which is both necessary and sufficient for development of allergic predisposition in offspring of allergic mothers, directly increased development and PKC activation in BMDCs. Furthermore, this was modifiable by dietary tocopherols. This may inform design of future studies for the prevention or intervention in asthma and allergic disease.

Microbiome-Immune Interactions in Allergy and Asthma

The human microbiota has been established as a key regulator of host health, in large part owing to its constant interaction with and impact on host immunity. A range of environmental exposures spanning from the prenatal period through adulthood are known to affect the composition and molecular productivity of microbiomes across mucosal and dermal tissues with short- and long-term consequences for host immune function. Here we review recent findings in the field that provide insights into how microbial-immune interactions promote and sustain immune dysfunction associated with allergy and asthma. We consider both early life microbiome perturbation and the molecular underpinnings of immune dysfunction associated with subsequent allergy and asthma development in childhood, as well as microbiome features that relate to phenotypic attributes of allergy and asthma in older patients with established disease.

Cord blood sphingolipids are associated with atopic dermatitis and wheeze in the first year of life

Background

Allergen-sensitized pregnant mice have increased plasma levels of the lipids β-glucosylceramides (βGlcCers) that are transplacentally transferred to the fetus, increased subsets of proinflammatory dendritic cells in the fetal liver and pup lung, and increased allergen-induced offspring lung inflammation.

Objective

Our aim was to determine whether these preclinical observations extend to a human association of βGlcCers with wheeze and allergic disease in the prospective Wisconsin Infant Study Cohort.

Methods

We measured 74 lipids in cord blood plasma by using mass spectrometry detection of sphingolipids, eicosanoids, and docosinoids, as well as an ELISA for 13-hydroxyoctadecadienoic acid. Lipid profiles were determined by unbiased Uniform Manifold Approximation and Projection dimensional reduction machine learning. Lipid profiles and a proinflammatory lipid index were analyzed for association with maternal allergy and childhood outcomes of wheeze, atopic dermatitis, cord blood leukocytes, and total IgE level at age 1 year.

Results

Uniform Manifold Approximation and Projection analysis of lipids defined 8 cluster-specific plasma lipid profiles. Cluster 6 had significantly lower levels of plasma βGlcCers and a higher frequency of cord blood plasmacytoid dendritic cells that mediate anti-inflammatory responses, which is consistent with an anti-inflammatory profile. For clusters and for each infant, a proinflammatory lipid index was calculated to reflect the sum of the proinflammatory lipids minus the anti-inflammatory lipids that were significantly different than in cluster 6. The cluster proinflammatory lipid index was associated with cord blood basophil frequency and with wheeze and atopic dermatitis in the first year of life. The infant inflammatory lipid index was associated with increased risk of wheeze in the first year of life.

Conclusion

The cord blood proinflammatory lipid index is associated with early-life atopic dermatitis and wheezing.

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.

Gamma-tocopherol, a major form of vitamin E in diets: Insights into antioxidant and anti-inflammatory effects, mechanisms, and roles in disease management

γ-Tocopherol (γT) is a major form of vitamin E in the US diet and the second most abundant vitamin E in the blood and tissues, while α-tocopherol (αT) is the predominant vitamin E in tissues. During the last >25 years, research has revealed that γT has unique antioxidant and anti-inflammatory activities relevant to disease prevention compared to αT. While both compounds are potent lipophilic antioxidants, γT but not αT can trap reactive nitrogen species by forming 5-nitro-γT, and appears to show superior protection of mitochondrial function. γT inhibits ionophore-stimulated leukotrienes by blocking 5-lipoxygenase (5-LOX) translocation in leukocytes, decreases cyclooxygenase-2 (COX-2)-catalyzed prostaglandins in macrophages and blocks the growth of cancer cells but not healthy cells. For these activities, γT is stronger than αT. Moreover, γT is more extensively metabolized than αT via cytochrome P-450 (CYP4F2)-initiated side-chain oxidation, which leads to formation of metabolites including 13'-carboxychromanol (13'-COOH) and carboxyethyl-hydroxychroman (γ-CEHC). 13'-COOH and γ-CEHC are shown to be the predominant metabolites found in feces and urine, respectively. Interestingly, γ-CEHC has natriuretic activity and 13'-COOH inhibits both COX-1/-2 and 5-LOX activity. Consistent with these mechanistic findings of γT and metabolites, studies show that supplementation of γT mitigates inflammation and disease symptoms in animal models with induced inflammation, asthma and cancer. In addition, supplementation of γT decreased inflammation markers in patients with kidney diseases and mild asthma. These observations support that γT may be useful against inflammation-associated diseases.

Mechanisms for Alternaria alternata Function in the Skin During Induction of Peanut Allergy in Neonatal Mice With Skin Barrier Mutations

Neonatal mice with heterozygous mutations in genes encoding the skin barrier proteins filaggrin and mattrin (flaky tail mice [FT^+/-]) exhibit oral peanut-induced anaphylaxis after skin sensitization. As we have previously reported, sensitization in this model is achieved via skin co- exposure to the environmental allergen Alternaria alternata (Alt), peanut extract (PNE), and detergent. However, the function of Alt in initiation of peanut allergy in this model is little understood. The purpose of this study was to investigate candidate cytokines induced by Alt in the skin and determine the role of these cytokines in the development of food allergy, namely oncostatin M (Osm), amphiregulin (Areg), and IL-33. RT-qPCR analyses demonstrated that skin of FT^+/- neonates expressed Il33 and Osm following Alt or Alt/PNE but not PNE exposure. By contrast, expression of Areg was induced by either Alt, PNE, or Alt/PNE sensitization in FT^+/- neonates. In scRNAseq analyses, Osm, Areg, and Il33 were expressed by several cell types, including a keratinocyte cluster that was expanded in the skin of Alt/PNE-exposed FT^+/- pups as compared to Alt/PNE-exposed WT pups. Areg and OSM were required for oral PNE-induced anaphylaxis since anaphylaxis was inhibited by administration of neutralizing anti-Areg or anti-OSM antibodies prior to each skin sensitization with Alt/PNE. It was then determined if intradermal injection of recombinant IL33 (rIL33), rAreg, or rOSM in the skin could substitute for Alt during skin sensitization to PNE. PNE skin sensitization with intradermal rIL33 was sufficient for oral PNE-induced anaphylaxis, whereas skin sensitization with intradermal rAreg or rOSM during skin exposure to PNE was not sufficient for anaphylaxis to oral PNE challenge. Based on these studies a pathway for IL33, Areg and OSM in Alt/PNE sensitized FT^+/- skin was defined for IgE induction and anaphylaxis. Alt stimulated two pathways, an IL33 pathway and a pathway involving OSM and Areg. These two pathways acted in concert with PNE to induce food allergy in pups with skin barrier mutations.

β-Glucosylceramide From Allergic Mothers Enhances Offspring Responsiveness to Allergen

In animals and humans, offspring of allergic mothers have increased responsiveness to allergen and the allergen-specificity of the offspring can be different than that of the mother. In our preclinical models, the mother's allergic responses influence development of the fetus and offspring by elevating numbers of cells in dendritic cell subsets. A major question is the identity of maternal factors of allergic mothers that alter offspring development of responsiveness to allergen. Lipids are altered during allergic responses and lipids are transported to the fetus for growth and formation of fetal membranes. We hypothesized that pro-inflammatory lipids, that are elevated in allergic mothers, are transported to the fetus and regulate fetal immune development. We demonstrate in this report that there was a significant 2-fold increase in β-glucosylceramides (βGlcCer) in allergic mothers, the fetal liver and her offspring. The βGlcCer were transported from mother's plasma, across the placenta, to the fetus and in breastmilk to the offspring. Administration of βGlcCer to non-allergic mothers was sufficient for offspring responses to allergen. Importantly, maternal administration of a clinically relevant pharmacological inhibitor of βGlcCer synthase returned βGlcCer to normal levels in the allergic mothers and her offspring and blocked the offspring increase in dendritic cell subsets and offspring allergen responsiveness. In summary, allergic mothers had increased βGlcCer that was transported to offspring and mediated increases in offspring DCs and responsiveness to allergen. These data have a significant impact on our understanding of mechanisms for development of allergies in offspring of allergic mothers and have the potential to lead to novel interventions that significantly impact risk for allergic disease early in life.

Anti-allergic effects of vitamin E in allergic diseases: An updated review

Allergic diseases are caused by the immune system's response to innocent antigens called allergens. Recent decades have seen a significant increase in the prevalence of allergic diseases worldwide, which has imposed various socio-economic effects in different countries. Various factors, including genetic factors, industrialization, improved hygiene, and climate change contribute to the development of allergic diseases in many parts of the world. Moreover, changes in lifestyle and diet habits play pivotal roles in the prevalence of allergic diseases. Dietary changes caused by decreased intake of antioxidants such as vitamin E lead to the generation of oxidative stress, which is central to the development of allergic diseases. It has been reported in many articles that oxidative stress diverts immune responses to the cells associated with the pathogenesis of allergic diseases. The aim of this short review was to summarize current knowledge about the anti-allergic properties of vitamin E.

Allergy Modulation by N-3 Long Chain Polyunsaturated Fatty Acids and Fat Soluble Nutrients of the Mediterranean Diet

The Mediterranean diet, containing valuable nutrients such as n-3 long chain poly-unsaturated fatty acids (LCPUFAs) and other fat-soluble micronutrients, is known for its health promoting and anti-inflammatory effects. Its valuable elements might help in the battle against the rising prevalence of non-communicable diseases (NCD), including the development of allergic diseases and other (chronic) inflammatory diseases. The fat fraction of the Mediterranean diet contains bioactive fatty acids but can also serve as a matrix to dissolve and increase the uptake of fat-soluble vitamins and phytochemicals, such as luteolin, quercetin, resveratrol and lycopene with known immunomodulatory and anti-inflammatory capacities. Especially n-3 LCPUFAs such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) derived from marine oils can target specific receptors or signaling cascades, act as eicosanoid precursors and/or alter membrane fluidity and lipid raft formation, hereby exhibiting anti-inflammatory properties. Beyond n-3 LCPUFAs, fat-soluble vitamins A, D, E, and K1/2 have the potential to affect pro-inflammatory signaling cascades by interacting with receptors or activating/inhibiting signaling proteins or phosphorylation in immune cells (DCs, T-cells, mast cells) involved in allergic sensitization or the elicitation/effector phase of allergic reactions. Moreover, fat-soluble plant-derived phytochemicals can manipulate signaling cascades, mostly by interacting with other receptors or signaling proteins compared to those modified by fat-soluble vitamins, suggesting potential additive or synergistic actions by applying a combination of these nutrients which are all part of the regular Mediterranean diet. Research concerning the effects of phytochemicals such as polyphenols has been hampered due to their poor bio-availability. However, their solubility and uptake are improved by applying them within the dietary fat matrix. Alternatively, they can be prepared for targeted delivery by means of pharmaceutical approaches such as encapsulation within liposomes or even unique nanoparticles. This review illuminates the molecular mechanisms of action and possible immunomodulatory effects of n-3 LCPUFAs and fat-soluble micronutrients from the Mediterranean diet in allergic disease development and allergic inflammation. This will enable us to further appreciate how to make use of the beneficial effects of n-3 LCPUFAs, fat-soluble vitamins and a selection of phytochemicals as active biological components in allergy prevention and/or symptom reduction.

Associations of α- and γ-tocopherol during early life with lung function in childhood

BACKGROUND

Tocopherol isoforms may regulate child lung growth and spirometric measures.

OBJECTIVE

Our aim was to determine the extent to which plasma α-tocopherol (α-T) or γ-tocopherol (γ-T) isoform levels in early childhood or in utero are associated with childhood lung function.

METHODS

We included 622 participants in the Project Viva cohort who had lung function at a mid-childhood visit (age 6-10 years). Maternal and child tocopherol isoform levels were measured by HPLC at the second trimester and 3 years of age, respectively. Multivariable linear regression models (adjusted for mid-childhood body mass index z scores, maternal education, smoking in pregnancy, and prenatal particulate matter with diameter of <2.5 micrometers (PM_2.5) particulate exposure) stratified by tertiles of child γ-T level were used to assess the association of α-T levels with FEV₁ and forced vital capacity (FVC) percent predicted. Similarly, models stratified by child α-T tertile evaluated associations of γ-T levels with lung function. We performed similar analyses with maternal second trimester tocopherol isoform levels.

RESULTS

The median maternal second trimester α-T level was 63 μM (interquartile range = 47-82). The median early-childhood level was 25 μM (interquartile range = 20-33 μM). In the lowest tertile of early-childhood γ-T, children with a higher α-T level (per 10 μM) had a higher mid-childhood FEV₁ percent predicted (β = 3.09; 95% CI = 0.58-5.59 and a higher FVC percent predicted (β = 2.77; 95% CI = 0.47-5.06). This protective association of α-T was lost at higher γ-T levels. We did not see any consistent associations of second trimester levels of either α-T or γ-T with mid-childhood FEV₁ or FVC.

CONCLUSION

When γ-T levels were in the lowest tertile, a higher early-childhood α-T level was associated with better lung function at mid-childhood. Second trimester maternal plasma α-T concentration was 3-fold higher than in the adult nonpregnant female population.

Activin-A in the regulation of immunity in health and disease

The TGF-β superfamily of cytokines plays pivotal roles in the regulation of immune responses protecting against or contributing to diseases, such as, allergy, autoimmunity and cancer. Activin-A, a member of the TGF-β superfamily, was initially identified as an inducer of follicle-stimulating hormone secretion. Extensive research over the past decades illuminated fundamental roles for activin-A in essential biologic processes, including embryonic development, stem cell maintenance and differentiation, haematopoiesis, cell proliferation and tissue fibrosis. Activin-A signals through two type I and two type II receptors which, upon ligand binding, activate their kinase activity, phosphorylate the SMAD2 and 3 intracellular signaling mediators that form a complex with SMAD4, translocate to the nucleus and activate or silence gene expression. Most immune cell types, including macrophages, dendritic cells (DCs), T and B lymphocytes and natural killer cells have the capacity to produce and respond to activin-A, although not in a similar manner. In innate immune cells, including macrophages, DCs and neutrophils, activin-A exerts a broad range of pro- or anti-inflammatory functions depending on the cell maturation and activation status and the spatiotemporal context. Activin-A also controls the differentiation and effector functions of Th cell subsets, including Th9 cells, T_FH cells, Tr1 Treg cells and Foxp3⁺ Treg cells. Moreover, activin-A affects B cell responses, enhancing mucosal IgA secretion and inhibiting pathogenic autoantibody production. Interestingly, an array of preclinical and clinical studies has highlighted crucial functions of activin-A in the initiation, propagation and resolution of human diseases, including autoimmune diseases, such as, systemic lupus erythematosus, rheumatoid arthritis and pulmonary alveolar proteinosis, in allergic disorders, including allergic asthma and atopic dermatitis, in cancer and in microbial infections. Here, we provide an overview of the biology of activin-A and its signaling pathways, summarize recent studies pertinent to the role of activin-A in the modulation of inflammation and immunity, and discuss the potential of targeting activin-A as a novel therapeutic approach for the control of inflammatory diseases.

Delineation of the Individual Effects of Vitamin E Isoforms on Early Life Incident Wheezing

OBJECTIVES

To test the hypothesis that maternal plasma alpha-tocopherol levels are associated with protection from childhood wheeze and that this protection is modified by gamma-tocopherol.

STUDY DESIGN

We conducted a prospective nested study in the Infant Susceptibility to Pulmonary Infections and Asthma Following Respiratory Syncytial Virus Exposure birth cohort of 652 children with postpartum maternal plasma vitamin E isoforms used as a surrogate for pregnancy concentrations. Our outcomes were wheezing and recurrent wheezing over a 2-year period, ascertained using validated questionnaires. We assessed the association of alpha- and gamma-tocopherol with wheezing outcomes using multivariable adjusted logistic regression, and tested for interaction between the isoforms with respect to the risk for wheezing outcomes.

RESULTS

Children with wheezing (n = 547, n = 167; 31%) and recurrent wheezing (n = 545, n = 55; 10.1%) over a 2-year period were born to mothers with significantly lower postpartum maternal plasma concentrations of alpha-tocopherol, P = .016 and P = .007, respectively. In analyses of IQR increases, alpha-tocopherol was associated with decreased risk of wheezing (aOR 0.70 [95% CI 0.53,0.92]) and recurrent wheezing (aOR 0.63 [95% CI 0.42,0.95]). For gamma-tocopherol, the aOR for wheezing was 0.79 (95% CI 0.56-1.10) and the aOR for recurrent wheezing was 0.56 (95% CI 0.33-0.94, with nonmonotonic association). The association of alpha-tocopherol with wheezing was modified by gamma-tocopherol (P interaction = .05).

CONCLUSIONS

Increases in postpartum maternal plasma alpha-tocopherol isoform concentrations were associated with decreased likelihood of wheezing over a 2-year period. Gamma-tocopherol modified this association.

Environmental cues received during development shape dendritic cell responses later in life

Environmental signals mediated via the aryl hydrocarbon receptor (AHR) shape the developing immune system and influence immune function. Developmental exposure to AHR binding chemicals causes persistent changes in CD4+ and CD8+ T cell responses later in life, including dampened clonal expansion and differentiation during influenza A virus (IAV) infection. Naïve T cells require activation by dendritic cells (DCs), and AHR ligands modulate the function of DCs from adult organisms. Yet, the consequences of developmental AHR activation by exogenous ligands on DCs later in life has not been examined. We report here that early life activation of AHR durably reduces the ability of DC to activate naïve IAV-specific CD8+ T cells; however, activation of naïve CD4+ T cells was not impaired. Also, DCs from developmentally exposed offspring migrated more poorly than DCs from control dams in both in vivo and ex vivo assessments of DC migration. Conditional knockout mice, which lack Ahr in CD11c lineage cells, suggest that dampened DC emigration is intrinsic to DCs. Yet, levels of chemokine receptor 7 (CCR7), a key regulator of DC trafficking, were generally unaffected. Gene expression analyses reveal changes in Lrp1, Itgam, and Fcgr1 expression, and point to alterations in genes that regulate DC migration and antigen processing and presentation as being among pathways disrupted by inappropriate AHR signaling during development. These studies establish that AHR activation during development causes long-lasting changes to DCs, and provide new information regarding how early life environmental cues shape immune function later in life.

The Role of Vitamin E in Immunity

Vitamin E is a fat-soluble antioxidant that can protect the polyunsaturated fatty acids (PUFAs) in the membrane from oxidation, regulate the production of reactive oxygen species (ROS) and reactive nitrogen species (RNS), and modulate signal transduction. Immunomodulatory effects of vitamin E have been observed in animal and human models under normal and disease conditions. With advances in understating of the development, function, and regulation of dendritic cells (DCs), macrophages, natural killer (NK) cells, T cells, and B cells, recent studies have focused on vitamin E’s effects on specific immune cells. This review will summarize the immunological changes observed with vitamin E intervention in animals and humans, and then describe the cell-specific effects of vitamin E in order to understand the mechanisms of immunomodulation and implications of vitamin E for immunological diseases.

Mechanism for initiation of food allergy: Dependence on skin barrier mutations and environmental allergen costimulation

BACKGROUND

Mechanisms for the development of food allergy in neonates are unknown but clearly linked in patient populations to a genetic predisposition to skin barrier defects. Whether skin barrier defects contribute functionally to development of food allergy is unknown.

OBJECTIVE

The purpose of the study was to determine whether skin barrier mutations, which are primarily heterozygous in patient populations, contribute to the development of food allergy.

METHODS

Mice heterozygous for the filaggrin (Flg)ft and Tmem79ma mutations were skin sensitized with environmental and food allergens. After sensitization, mice received oral challenge with food allergen, and then inflammation, inflammatory mediators, and anaphylaxis were measured.

RESULTS

We define development of inflammation, inflammatory mediators, and food allergen-induced anaphylaxis in neonatal mice with skin barrier mutations after brief concurrent cutaneous exposure to food and environmental allergens. Moreover, neonates of allergic mothers have increased responses to suboptimal sensitization with food allergens. Importantly, responses to food allergens by these neonatal mice were dependent on genetic defects in skin barrier function and on exposure to environmental allergens. ST2 blockade during skin sensitization inhibited the development of anaphylaxis, antigen-specific IgE, and inflammatory mediators. Neonatal anaphylactic responses and antigen-specific IgE were also inhibited by oral pre-exposure to food allergen, but interestingly, this was blunted by concurrent pre-exposure of the skin to environmental allergen.

CONCLUSION

These studies uncover mechanisms for food allergy sensitization and anaphylaxis in neonatal mice that are consistent with features of human early-life exposures and genetics in patients with clinical food allergy and demonstrate that changes in barrier function drive development of anaphylaxis to food allergen.

Update on Vitamin E and Its Potential Role in Preventing or Treating Bronchopulmonary Dysplasia

Vitamin E is obtained only through the diet and has a number of important biological activities, including functioning as an antioxidant. Evidence that free radicals may contribute to pathological processes such as bronchopulmonary dysplasia (BPD), a disease of prematurity associated with increased lung injury, inflammation and oxidative stress, led to trials of the antioxidant vitamin E (α-tocopherol) to prevent BPD with variable results. These trials were all conducted at supraphysiologic doses and 2 of these trials utilized a formulation containing a potentially harmful excipient. Since 1991, when the last of these trials was conducted, both neonatal management strategies for minimizing oxygen and ventilator-related lung injury and our understanding of vitamin E isoforms in respiratory health have advanced substantially. It is now known that there are differences between the effects of vitamin E isoforms α-tocopherol and γ-tocopherol on the development of respiratory morbidity and inflammation. What is not known is whether improvements in physiologic concentrations of individual or combinations of vitamin E isoforms during pregnancy or following preterm birth might prevent or reduce BPD development. The answers to these questions require adequately powered studies targeting pregnant women at risk of preterm birth or their premature infants immediately following birth, especially in certain subgroups that are at increased risk of vitamin E deficiency (e.g., smokers). The objective of this review is to compile, update, and interpret what is known about vitamin E isoforms and BPD since these first studies were conducted, and suggest future research directions.

Recent advances in our understanding of the mechanisms of late lung development and bronchopulmonary dysplasia

The objective of lung development is to generate an organ of gas exchange that provides both a thin gas diffusion barrier and a large gas diffusion surface area, which concomitantly generates a steep gas diffusion concentration gradient. As such, the lung is perfectly structured to undertake the function of gas exchange: a large number of small alveoli provide extensive surface area within the limited volume of the lung, and a delicate alveolo-capillary barrier brings circulating blood into close proximity to the inspired air. Efficient movement of inspired air and circulating blood through the conducting airways and conducting vessels, respectively, generates steep oxygen and carbon dioxide concentration gradients across the alveolo-capillary barrier, providing ideal conditions for effective diffusion of both gases during breathing. The development of the gas exchange apparatus of the lung occurs during the second phase of lung development-namely, late lung development-which includes the canalicular, saccular, and alveolar stages of lung development. It is during these stages of lung development that preterm-born infants are delivered, when the lung is not yet competent for effective gas exchange. These infants may develop bronchopulmonary dysplasia (BPD), a syndrome complicated by disturbances to the development of the alveoli and the pulmonary vasculature. It is the objective of this review to update the reader about recent developments that further our understanding of the mechanisms of lung alveolarization and vascularization and the pathogenesis of BPD and other neonatal lung diseases that feature lung hypoplasia.

Oxidative Stress: Harms and Benefits for Human Health

Oxidative stress is a phenomenon caused by an imbalance between production and accumulation of oxygen reactive species (ROS) in cells and tissues and the ability of a biological system to detoxify these reactive products. ROS can play, and in fact they do it, several physiological roles (i.e., cell signaling), and they are normally generated as by-products of oxygen metabolism; despite this, environmental stressors (i.e., UV, ionizing radiations, pollutants, and heavy metals) and xenobiotics (i.e., antiblastic drugs) contribute to greatly increase ROS production, therefore causing the imbalance that leads to cell and tissue damage (oxidative stress). Several antioxidants have been exploited in recent years for their actual or supposed beneficial effect against oxidative stress, such as vitamin E, flavonoids, and polyphenols. While we tend to describe oxidative stress just as harmful for human body, it is true as well that it is exploited as a therapeutic approach to treat clinical conditions such as cancer, with a certain degree of clinical success. In this review, we will describe the most recent findings in the oxidative stress field, highlighting both its bad and good sides for human health.

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.