Impact of vitamin E on immune function and its clinical implications

Analysis of blood and nasal epithelial transcriptomes to identify mechanisms associated with control of SARS-CoV-2 viral load in the upper respiratory tract

OBJECTIVES

The amount of SARS-CoV-2 detected in the upper respiratory tract (URT viral load) is a key driver of transmission of infection. Current evidence suggests that mechanisms constraining URT viral load are different from those controlling lower respiratory tract viral load and disease severity. Understanding such mechanisms may help to develop treatments and vaccine strategies to reduce transmission. Combining mathematical modelling of URT viral load dynamics with transcriptome analyses we aimed to identify mechanisms controlling URT viral load.

METHODS

COVID-19 patients were recruited in Spain during the first wave of the pandemic. RNA sequencing of peripheral blood and targeted NanoString nCounter transcriptome analysis of nasal epithelium were performed and gene expression analysed in relation to paired URT viral load samples collected within 15 days of symptom onset. Proportions of major immune cells in blood were estimated from transcriptional data using computational differential estimation. Weighted correlation network analysis (adjusted for cell proportions) and fixed transcriptional repertoire analysis were used to identify associations with URT viral load, quantified as standard deviations (z-scores) from an expected trajectory over time.

RESULTS

Eighty-two subjects (50% female, median age 54 years (range 3-73)) with COVID-19 were recruited. Paired URT viral load samples were available for 16 blood transcriptome samples, and 17 respiratory epithelial transcriptome samples. Natural Killer (NK) cells were the only blood cell type significantly correlated with URT viral load z-scores (r = -0.62, P = 0.010). Twenty-four blood gene expression modules were significantly correlated with URT viral load z-score, the most significant being a module of genes connected around IFNA14 (Interferon Alpha-14) expression (r = -0.60, P = 1e-10). In fixed repertoire analysis, prostanoid-related gene expression was significantly associated with higher viral load. In nasal epithelium, only GNLY (granulysin) gene expression showed significant negative correlation with viral load.

CONCLUSIONS

Correlations between the transcriptional host response and inter-individual variations in SARS-CoV-2 URT viral load, revealed many molecular mechanisms plausibly favouring or constraining viral replication. Existing evidence corroborates many of these mechanisms, including likely roles for NK cells, granulysin, prostanoids and interferon alpha-14. Inhibition of prostanoid production and administration of interferon alpha-14 may be attractive transmission-blocking interventions.

A-910823, a squalene-based emulsion adjuvant, induces T follicular helper cells and humoral immune responses via α-tocopherol component

Background

Adjuvants are chemical or biological materials that enhance the efficacy of vaccines. A-910823 is a squalene-based emulsion adjuvant used for S-268019-b, a novel vaccine against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that is currently in clinical development. Published evidence has demonstrated that A-910823 can enhance the induction of neutralizing antibodies against SARS-CoV-2 in humans and animal models. However, the characteristics and mechanisms of the immune responses induced by A-910823 are not yet known.

Methods and Results

To characterize A-910823, we compared the adaptive immune response profile enhanced by A-910823 with that of other adjuvants (AddaVax, QS21, aluminum salt-based adjuvants, and empty lipid nanoparticle [eLNP]) in a murine model. Compared with other adjuvants, A-910823 enhanced humoral immune responses to an equal or greater extent following potent T follicular helper (Tfh) and germinal center B (GCB) cell induction, without inducing a strong systemic inflammatory cytokine response. Furthermore, S-268019-b containing A-910823 adjuvant produced similar results even when given as a booster dose following primary administration of a lipid nanoparticle-encapsulated messenger RNA (mRNA-LNP) vaccine. Preparation of modified A-910823 adjuvants to identify which components of A-910823 play a role in driving the adjuvant effect and detailed evaluation of the immunological characteristics induced by each adjuvant showed that the induction of humoral immunity and Tfh and GCB cell induction in A-910823 were dependent on α-tocopherol. Finally, we revealed that the recruitment of inflammatory cells to the draining lymph nodes and induction of serum cytokines and chemokines by A-910823 were also dependent on the α-tocopherol component.

Conclusions

This study demonstrates that the novel adjuvant A-910823 is capable of robust Tfh cell induction and humoral immune responses, even when given as a booster dose. The findings also emphasize that α-tocopherol drives the potent Tfh-inducing adjuvant function of A-910823. Overall, our data provide key information that may inform the future production of improved adjuvants.

Nutritional approach for increasing public health during pandemic of COVID-19: A comprehensive review of antiviral nutrients and nutraceuticals

Background: The novel coronavirus (COVID-19) is considered as the most life-threatening pandemic disease during the last decade. The individual nutritional status, though usually ignored in the management of COVID-19, plays a critical role in the immune function and pathogenesis of infection. Accordingly, the present review article aimed to report the effects of nutrients and nutraceuticals on respiratory viral infections including COVID-19, with a focus on their mechanisms of action. Methods: Studies were identified via systematic searches of the databases including PubMed/ MEDLINE, ScienceDirect, Scopus, and Google Scholar from 2000 until April 2020, using keywords. All relevant clinical and experimental studies published in English were included. Results: Protein-energy malnutrition (PEM) is common in severe respiratory infections and should be considered in the management of COVID-19 patients. On the other hand, obesity can be accompanied by decreasing the host immunity. Therefore, increasing physical activity at home and a slight caloric restriction with adequate intake of micronutrients and nutraceuticals are simple aids to boost host immunity and decrease the clinical manifestations of COVID-19. Conclusion: The most important nutrients which can be considered for COVID-19 management are vitamin D, vitamin C, vitamin A, folate, zinc, and probiotics. Their adequacy should be provided through dietary intake or appropriate supplementation. Moreover, adequate intake of some other dietary agents including vitamin E, magnesium, selenium, alpha linolenic acid and phytochemicals are required to maintain the host immunity.

Effects of select dietary supplements on the prevention and treatment of viral respiratory tract infections: a systematic review of randomized controlled trials

Introduction: Viral respiratory tract infections (RTIs) have been recognized as a global public health burden. Despite current theories about their effectiveness, the true benefits of dietary supplements on the prevention and treatment of viral RTIs remain elusive, due to contradictory reports. Hence, we aimed to evaluate the effectiveness of dietary supplements on the prevention and treatment of viral RTIs.Areas covered: We systematically searched databases of PubMed, Web of Science, Scopus, and Google Scholar through 4 March 2020, to identify randomized controlled trials that evaluated the effects of consuming selected dietary supplements on the prevention or treatment of viral RTIs.Expert opinion: Thirty-nine randomized controlled trials (n = 16,797 participants) were eligible and included. Namely, vitamin D supplementation appeared to improve viral RTIs across cohorts particulate in those with vitamin D deficiency. Among the evaluated dietary supplements, specific lactobacillus strains were used most commonly with selected prebiotics that showed potentially positive effects on the prevention and treatment of viral RTIs. Further, ginseng extract supplementation may effectively prevent viral RTIs as adjuvant therapy. However, longitudinal research is required to confirm these observations and address the optimal dose, duration, and safety of dietary supplements being publicly recommended.

Immunoinflammatory effects of dietary bioactive compounds

Inflammation is a key mechanism of the immune system that can be elicited by several factors, among them several chemical, physical and biological agents. Once stimulated, the inflammatory response activates a series of signaling pathways and a number of immune cells which promote, in a very coordinated manner, the neutralization of the infectious agent. However, if uncontrolled, the inflammatory status may become chronic leading, potentially, to tissue damage and disease onset. Several risk factors are associated with the development of chronic inflammation and, among these factors, diet plays an essential role. In this chapter the effects of some dietary bioactive compounds, including micronutrients, omega-3 fatty acids, nucleotides and polyphenols, on the immunoinflammatory responses in different cellular, animal and human studies have been summarized.

Natural Products: Evidence for Neuroprotection to Be Exploited in Glaucoma

Glaucoma, a leading cause of irreversible blindness worldwide, is an optic neuropathy characterized by the progressive death of retinal ganglion cells (RGCs). Elevated intraocular pressure (IOP) is recognized as the main risk factor. Despite effective IOP-lowering therapies, the disease progresses in a significant number of patients. Therefore, alternative IOP-independent strategies aiming at halting or delaying RGC degeneration is the current therapeutic challenge for glaucoma management. Here, we review the literature on the neuroprotective activities, and the underlying mechanisms, of natural compounds and dietary supplements in experimental and clinical glaucoma.

Regulatory role of vitamin E in the immune system and inflammation

Vitamin E, a potent lipid-soluble antioxidant, found in higher concentration in immune cells compared to other cells in blood, is one of the most effective nutrients known to modulate immune function. Vitamin E deficiency has been demonstrated to impair normal functions of the immune system in animals and humans, which can be corrected by vitamin E repletion. Although deficiency is rare, vitamin E supplementation above current dietary recommendations has been shown to enhance the function of the immune system and reduce risk of infection, particularly in older individuals. The mechanisms responsible for the effect of vitamin E on the immune system and inflammation have been explored in cell-based, pre-clinical and clinical intervention studies. Vitamin E modulates T cell function through directly impacting T cell membrane integrity, signal transduction, and cell division, and also indirectly by affecting inflammatory mediators generated from other immune cells. Modulation of immune function by vitamin E has clinical relevance as it affects host susceptibility to infectious diseases such as respiratory infections, in addition to allergic diseases such as asthma. Studies examining the role of vitamin E in the immune system have typically focused on α-tocopherol; however, emerging evidence suggests that other forms of vitamin E, including other tocopherols as well as tocotrienols, may also have potent immunomodulatory functions. Future research should continue to identify and confirm the optimal doses for individuals at different life stage, health condition, nutritional status, and genetic heterogeneity. Future research should also characterize the effects of non-α-alpha-tocopherol vitamin E on immune cell function as well as their potential clinical application. © 2018 IUBMB Life, 71(4):487-494, 2019.

Perspective: Should Vitamin E Recommendations for Older Adults Be Increased?

Current vitamin E requirements are uniformly applied across the population for those >14 y of age. However, aging is associated with alterations in cellular and physiologic functions, which are affected by vitamin E. Therefore, it is questionable whether vitamin E requirements can be uniformly applied to all adult age categories. With aging, there is dysregulation of the immune system in which there are decreased cell-mediated and pathogen defense responses coupled with an overactive, prolonged inflammatory state. Both animal and human studies in the aged suggest that intake above currently recommended levels of vitamin E may improve immune and inflammatory responses and be associated with a reduced risk of infectious disease. We review the evidence that was considered in establishing the current requirements for vitamin E and highlight data that should be considered in determining the vitamin E requirements in older adults, particularly focusing on the evidence suggesting a benefit of increased vitamin E intake on immune function and inflammatory processes and resistance to infection. The main objective of this Perspective is to initiate the discussion of whether the current Dietary Reference Intake for vitamin E should be increased for the older population. We make this suggestion on the basis of mechanistic studies showing biological plausibility, correction of a major cellular dysfunction in older adults, and strong evidence from several animal and a few human studies indicating a reduction in risk and morbidity from infections.

Bilayer polymeric nanocapsules: A formulation approach for a thermostable and adjuvanted E. coli antigen vaccine

One of the strategies used to improve the immunogenicity of purified protein antigens has relied on their association with synthetic nanocarriers, which, in general, have functioned as simple antigen containers. Here, we present a more advanced strategy based on the design of an antigen nanocarrier at the molecular level. The nanocarrier is composed of a vitamin E oily core, surrounded by two layers: a first layer of chitosan and a second of dextran sulphate. The selected antigen, IutA protein from Escherichia coli, was harboured between the two polymeric layers. The final bilayer nanocapsules had a nanometric size (≈ 200 nm), a negative zeta potential (< -40 mV) and a good antigen association efficiency (≈ 70%). The bilayer architecture led to an improvement on the formulation stability and the controlled release of the associated antigen. Remarkably, after being administered to mice, bilayer nanocapsules elicited higher IgG levels than those obtained with antigen precipitated with Alum. Moreover, freeze-dried nanocapsules were stable at room temperature for, at least, 3 months. These promising data, in addition to their contribution to the development of an uropathogenic E. coli vaccine, has allowed us to validate these novel bilayer nanocapsules as adequate platforms for the delivery of protein antigens.

Suboptimal Serum α-Tocopherol Concentrations Observed among Younger Adults and Those Depending Exclusively upon Food Sources, NHANES 2003-20061-3

Vitamin E is an essential nutrient for human health, with an established function as a lipid-soluble antioxidant that protects cell membranes from free radical damage. Low vitamin E status has been linked to multiple health outcomes, including total mortality. With vitamin E being identified as a ‘shortfall nutrient’ because >90% of American adults are not consuming recommended amounts of vitamin E, we aimed to determine the prevalence of both clinical vitamin E deficiency (serum α-tocopherol concentration < 12 μmol/L) and failure to meet a criterion of vitamin E adequacy, serum α-tocopherol concentration of 30 μmol/L, based on the Estimated Average Requirement (EAR) and lowest mortality rate in the Alpha-Tocopherol Beta-Carotene (ATBC) study. The most recent nationally-representative cross-sectional data (2003–2006) among non-institutionalized US citizens with available serum concentrations of α-tocopherol from the National Health and Nutrition Examination Survey (NHANES); Centers for Disease Control and Prevention were analyzed. Serum α-tocopherol distributions were compared between those reporting consumption of food without supplement use (FOOD) and food and supplement use (FOOD+DS) by sex, age, and race/ethnicity. Only 1% of the US population is clinically deficient. FOOD consumers have lower average α-tocopherol levels (24.9± 0.2 μmol/L) than FOOD+DS users (33.7 ± 0.3 μmol/L), even when adjusted for total cholesterol. Using a criterion of adequacy of 30 μmol/L, 87% of persons 20-30y and 43% of those 51+y had inadequate vitamin E status (p<0.01). A significant greater prevalence of FOOD compared to FOOD+DS users did not meet the criterion of adequacy which was based on the EAR and low ATBC mortality rate consistently across age, sex, and race/ethnic groups. The prevalence of inadequate vitamin E levels is significantly higher among non-users of dietary supplements. With declining usage of vitamin E supplements, the population should be monitored for changes in vitamin E status and related health outcomes.

Aflatoxin levels, plasma vitamins A and E concentrations, and their association with HIV and hepatitis B virus infections in Ghanaians: a cross-sectional study

BACKGROUND

Micronutrient deficiencies occur commonly in people infected with the human immunodeficiency virus. Since aflatoxin exposure also results in reduced levels of several micronutrients, HIV and aflatoxin may work synergistically to increase micronutrient deficiencies. However, there has been no report on the association between aflatoxin exposure and micronutrient deficiencies in HIV-infected people. We measured aflatoxin B1 albumin (AF-ALB) adduct levels and vitamins A and E concentrations in the plasma of HIV-positive and HIV-negative Ghanaians and examined the association of vitamins A and E with HIV status, aflatoxin levels and hepatitis B virus (HBV) infection.

METHODS

A cross-sectional study was conducted in which participants completed a demographic survey and gave a 20 mL blood sample for analysis of AF-ALB levels, vitamins A and E concentrations, CD4 counts, HIV viral load and HBV infection.

RESULTS

HIV-infected participants had significantly higher AF-ALB levels (median for HIV-positive and HIV-negative participants was 0.93 and 0.80 pmol/mg albumin, respectively; p <0.01) and significantly lower levels of vitamin A (-16.94 μg/dL; p <0.0001) and vitamin E (-0.22 mg/dL; p <0.001). For the total study group, higher AF-ALB was associated with significantly lower vitamin A (-4.83 μg/dL for every 0.1 pmol/mg increase in AF-ALB). HBV-infected people had significantly lower vitamin A (-5.66 μg/dL; p = 0.01). Vitamins A and E levels were inversely associated with HIV viral load (p = 0.02 for each), and low vitamin E was associated with lower CD4 counts (p = 0.004).

CONCLUSIONS

Our finding of the significant decrease in vitamin A associated with AF-ALB suggests that aflatoxin exposure significantly compromises the micronutrient status of people who are already facing overwhelming health problems, including HIV infection.

Immunogenetics of drug-induced skin blistering disorders. Part II: Synthesis

The overall immunopathogenesis relevant to a large series of disorders caused by a drug or its associated hyperimmune condition is discussed based upon examining the genetics of severe drug-induced bullous skin problems (sporadic idiosyncratic adverse events including Stevens–Johnson syndrome and Toxic epidermal necrolysis). New results from an exemplar study on shared precipitating and perpetuating inner causes with other related disease phenotypes including aphtous stomatitis, Behçets, erythema multiforme, Hashimoto’s thyroiditis, pemphigus, periodic fevers, Sweet’s syndrome and drug-induced multisystem hypersensitivity are presented. A call for a collaborative, wider demographic profiling and deeper immunotyping in suggested future work is made.