Vitamin E and immune response in the aged: molecular mechanisms and clinical implications

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.

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.

Vitamin E Status Is Inversely Associated with Risk of Incident Tuberculosis Disease among Household Contacts

Background

Few studies have previously assessed how pre-existing vitamin E status is associated with risk of tuberculosis (TB) disease progression.

Objective

We evaluated the association between baseline plasma concentrations of 3 vitamin E isomers (α-tocopherol, γ-tocopherol, and δ-tocopherol) and TB disease risk.

Methods

We conducted a case-control study nested within a longitudinal cohort of household contacts (HHCs) of pulmonary TB cases in Lima, Peru. We defined cases as HHCs who developed active TB disease ≥15 d after the diagnosis of the index patient, and we matched each case to 4 control cases who did not develop active TB based on age by year and gender. We used univariate and multivariate conditional logistic regression to calculate ORs for incident TB disease by plasma concentrations of α-tocopherol, γ-tocopherol, and δ-tocopherol.

Results

Among 6751 HIV-negative HHCs who provided baseline blood samples, 180 developed secondary TB during follow-up. After controlling for possible confounders, we found that baseline α-tocopherol deficiency conferred increased risk of incident TB disease (adjusted OR: 1.59; 95% CI: 1.02, 2.50; P = 0.04). Household contacts in the lowest tertile of δ-tocopherol were also at increased risk of progression to TB disease compared to those in the highest tertile (tertile 1 compared with tertile 3, adjusted OR: 2.29; 95% CI: 1.29, 4.09; P-trend = 0.005). We found no association between baseline concentration of γ-tocopherol and incident TB disease.

Conclusions

Vitamin E deficiency was associated with an increased risk of progression to TB disease among HHCs of index TB cases. Assessment of vitamin E status among individuals at high risk for TB disease may play a role in TB control efforts.

They Are What You Eat: Can Nutritional Factors during Gestation and Early Infancy Modulate the Neonatal Immune Response?

The ontogeny of the human immune system is sensitive to nutrition even in the very early embryo, with both deficiency and excess of macro- and micronutrients being potentially detrimental. Neonates are particularly vulnerable to infectious disease due to the immaturity of the immune system and modulation of nutritional immunity may play a role in this sensitivity. This review examines whether nutrition around the time of conception, throughout pregnancy, and in early neonatal life may impact on the developing infant immune system.

Impact of Childhood Malnutrition on Host Defense and Infection

The global impact of childhood malnutrition is staggering. The synergism between malnutrition and infection contributes substantially to childhood morbidity and mortality. Anthropometric indicators of malnutrition are associated with the increased risk and severity of infections caused by many pathogens, including viruses, bacteria, protozoa, and helminths. Since childhood malnutrition commonly involves the inadequate intake of protein and calories, with superimposed micronutrient deficiencies, the causal factors involved in impaired host defense are usually not defined. This review focuses on literature related to impaired host defense and the risk of infection in primary childhood malnutrition. Particular attention is given to longitudinal and prospective cohort human studies and studies of experimental animal models that address causal, mechanistic relationships between malnutrition and host defense. Protein and micronutrient deficiencies impact the hematopoietic and lymphoid organs and compromise both innate and adaptive immune functions. Malnutrition-related changes in intestinal microbiota contribute to growth faltering and dysregulated inflammation and immune function. Although substantial progress has been made in understanding the malnutrition-infection synergism, critical gaps in our understanding remain. We highlight the need for mechanistic studies that can lead to targeted interventions to improve host defense and reduce the morbidity and mortality of infectious diseases in this vulnerable population.

Highly stereoselective construction of the C2 stereocentre of α-tocopherol (vitamin E) by asymmetric addition of Grignard reagents to ketones

Tertiary alcohol precursors of both C2 diastereoisomers of α-tocopherol were prepared in three ways by our recently reported asymmetric Grignard synthesis. The versatility of Grignard chemistry inherent in its three-way disconnection was exploited to allow the synthesis of three product grades: 77 : 23 dr (5 steps), 81 : 19 dr (5 steps) and 96 : 4 dr (7 steps, one gram scale) from readily available and abundant starting materials. The products were converted to their respective α-tocopherols in 3 steps, which allowed a definitive re-assignment of their absolute configurations.

The Alpha-Tocopherol Form of Vitamin E Boosts Elastase Activity of Human PMNs and Their Ability to Kill Streptococcus pneumoniae

Despite the availability of vaccines, Streptococcus pneumoniae remains a leading cause of life-threatening infections, such as pneumonia, bacteremia and meningitis. Polymorphonuclear leukocytes (PMNs) are a key determinant of disease course, because optimal host defense requires an initial robust pulmonary PMN response to control bacterial numbers followed by modulation of this response later in infection. The elderly, who manifest a general decline in immune function and higher basal levels of inflammation, are at increased risk of developing pneumococcal pneumonia. Using an aged mouse infection model, we previously showed that oral supplementation with the alpha-tocopherol form of vitamin E (α-Toc) decreases pulmonary inflammation, in part by modulating neutrophil migration across lung epithelium into alveolar spaces, and reverses the age-associated decline in resistance to pneumococcal pneumonia. The objective of this study was to test the effect of α-Toc on the ability of neutrophils isolated from young (22–35 years) or elderly (65–69 years) individuals to migrate across epithelial cell monolayers in response to S. pneumoniae and to kill complement-opsonized pneumococci. We found that basal levels of pneumococcal-induced transepithelial migration by PMNs from young or elderly donors were indistinguishable, suggesting that the age-associated exacerbation of pulmonary inflammation is not due to intrinsic properties of PMNs of elderly individuals but rather may reflect the inflammatory milieu of the aged lung. Consistent with its anti-inflammatory activity, α-Toc treatment diminished PMN migration regardless of donor age. Unexpectedly, unlike previous studies showing poor killing of antibody-opsonized bacteria, we found that PMNs of elderly donors were more efficient at killing complement-opsonized bacteria ex vivo than their younger counterparts. We also found that the heightened antimicrobial activity in PMNs from older donors correlated with increased activity of neutrophil elastase, a serine protease that is required to kill pneumococci. Notably, incubation with α-Toc increased PMN elastase activity from young donors and boosted their ability to kill complement-opsonized pneumococci. These findings demonstrate that α-Toc is a potent modulator of PMN responses and is a potential nutritional intervention to combat pneumococcal infection.

Dietary verbascoside supplementation in donkeys: effects on milk fatty acid profile during lactation, and serum biochemical parameters and oxidative markers

Various uses of donkeys' milk have been recently proposed for human consumption on the basis of its nutritional characteristics. Improvements in milk fatty acid profile and animal oxidative status can be induced through dietary supplementation of phenolic compounds. The study aimed to evaluate in donkeys the effects of dietary supplementation with verbascoside (VB) on: (i) the fatty acid profile and vitamins A and E contents of milk during a whole lactation, and (ii) blood biochemical parameters and markers of oxidative status of the animals. At foaling, 12 lactating jennies were subdivided into two groups (n 6): control, without VB supplement; VB, receiving a lipid-encapsulated VB supplement. Gross composition, fatty acid profile and vitamins A and E contents in milk were assessed monthly over the 6 months of lactation. Serum total cholesterol, high-density lipoproteins cholesterol and low-density lipoproteins cholesterol, tryglicerides, non-esterified fatty acid, bilirubin, alanine aminotransferase (ALT), aspartate aminotransferase, reactive oxygen metabolites, thiobarbituric acid reactive substances (TBARs), vitamin A and vitamin E were evaluated at 8 days after foaling (D0) and then at D90, D105 and D120 of lactation. In milk, the VB supplementation decreased the saturated fatty acids (P<0.05) and increased the monounsaturated fatty acids (P<0.05), and vitamins A and E (P<0.01) values. On the serum parameters, the VB supplementation decreased total cholesterol (P<0.01), tryglicerides, bilirubin, ALT and TBARs, and increased (P<0.01) vitamin E. In conclusion, the VB dietary supplementation affects the nutritional quality of donkey's milk with a benefit on the oxidative status and serum lipidic profile of the animals.

Vitamin E for the treatment of children with hepatitis B e antigen-positive chronic hepatitis: A systematic review and meta-analysis

AIM

To assess vitamin E efficacy, defined as its ability to induce hepatitis B e antigen (HBeAg) seroconversion, in children with HBeAg-positive persistent hepatitis.

METHODS

In July 2016, we extracted articles published in MEDLINE and the Cochrane Library using the following search terms: "chronic hepatitis B", "children", "childhood", "therapy", "treatment", "vitamin E", "tocopherols", "tocotrienols". Only randomized controlled trials (RCTs) published in English language were collected.

RESULTS

Three RCTs met inclusion criteria and were considered in the present meta-analysis. Overall, 23/122 children in the treatment group underwent HBeAg seroconversion vs 3/74 in the control group (OR = 3.96, 95%CI: 1.18-13.25, P = 0.025).

CONCLUSION

Although our meta-analysis has several limits, including the very small number of available studies and enrolled children with HBeAg positivity-related hepatitis, it suggests that vitamin E use may enhance the probability to induce HBeAg seroconversion in these patients. Further well designed and adequately sized trials are required to confirm or deny these very preliminary results.

Nutritional modulation of age-related changes in the immune system and risk of infection

The immune system undergoes some adverse alterations during aging, many of which have been implicated in the increased morbidity and mortality associated with infection in the elderly. In addition to intrinsic changes to the immune system with aging, the elderly are more likely to have poor nutritional status, which further impacts the already impaired immune function. Although the elderly often have low zinc serum levels, several manifestations commonly observed during zinc deficiency are similar to the changes in immune function with aging. In the case of vitamin E, although its deficiency is rare, the intake above recommended levels is shown to enhance immune functions in the elderly and to reduce the risk of acquiring upper respiratory infections in nursing home residents. Vitamin D is a critical vitamin in bone metabolism, and its deficiency is far more common, which has been linked to increased risk of infection as demonstrated in a number of observational studies including those in the elderly. In this review, we focus on zinc, vitamin E, and vitamin D, the 3 nutrients which are relatively well documented for their roles in impacting immune function and infection in the elderly, to discuss the findings in this context reported in both the observational studies and interventional clinical trials. A perspective will be provided based on the analysis of information under review.

Nutritional Considerations for Healthy Aging and Reduction in Age-Related Chronic Disease

A projected doubling in the global population of people aged ≥60 y by the year 2050 has major health and economic implications, especially in developing regions. Burdens of unhealthy aging associated with chronic noncommunicable and other age-related diseases may be largely preventable with lifestyle modification, including diet. However, as adults age they become at risk of "nutritional frailty," which can compromise their ability to meet nutritional requirements at a time when specific nutrient needs may be high. This review highlights the role of nutrition science in promoting healthy aging and in improving the prognosis in cases of age-related diseases. It serves to identify key knowledge gaps and implementation challenges to support adequate nutrition for healthy aging, including applicability of metrics used in body-composition and diet adequacy for older adults and mechanisms to reduce nutritional frailty and to promote diet resilience. This review also discusses management recommendations for several leading chronic conditions common in aging populations, including cognitive decline and dementia, sarcopenia, and compromised immunity to infectious disease. The role of health systems in incorporating nutrition care routinely for those aged ≥60 y and living independently and current actions to address nutritional status before hospitalization and the development of disease are discussed.

Vitamin E and the risk of pneumonia: using the I 2 statistic to quantify heterogeneity within a controlled trial

Analyses in nutritional epidemiology usually assume a uniform effect of a nutrient. Previously, four subgroups of the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study of Finnish male smokers aged 50-69 years were identified in which vitamin E supplementation either significantly increased or decreased the risk of pneumonia. The purpose of this present study was to quantify the level of true heterogeneity in the effect of vitamin E on pneumonia incidence using the I 2 statistic. The I 2 value estimates the percentage of total variation across studies that is explained by true differences in the treatment effect rather than by chance, with a range from 0 to 100 %. The I 2 statistic for the effect of vitamin E supplementation on pneumonia risk for five subgroups of the ATBC population was 89 % (95 % CI 78, 95 %), indicating that essentially all heterogeneity was true variation in vitamin E effect instead of chance variation. The I 2 statistic for heterogeneity in vitamin E effects on pneumonia risk was 92 % (95 % CI 80, 97 %) for three other ATBC subgroups defined by smoking level and leisure-time exercise level. Vitamin E decreased pneumonia risk by 69 % among participants who had the least exposure to smoking and exercised during leisure time (7·6 % of the ATBC participants), and vitamin E increased pneumonia risk by 68 % among those who had the highest exposure to smoking and did not exercise (22 % of the ATBC participants). These findings refute there being a uniform effect of vitamin E supplementation on the risk of pneumonia.

Studies on oxidants and antioxidants with a brief glance at their relevance to the immune system

Free radical generation occurs continuously within cells as a consequence of common metabolic processes. However, in high concentrations, whether from endogenous or exogenous sources, free radicals can lead to oxidative stress; a harmful process that cause serious damages to all biomolecules in our body hence impairs cell functions and even results in cell death and diseased states. Oxidative injuries accumulate over time and participate in cancer development, cardiovascular and neurodegenerative disorders as well as aging. Nature has bestowed the human body with a complex web of antioxidant defense system including enzymatic antioxidants like glutathione peroxidase and glutathione reductase, catalase and superoxide dismutase as well as non-enzymatic antioxidants such as thiol antioxidants, melatonin, coenzyme Q, and metal chelating proteins, which are efficient enough to fight against excessive free radicals. Also, nutrient antioxidants such as vitamin C, vitamin E, carotenoids, polyphenols, and trace elements are known to have high antioxidant potency to assist in minimizing harmful effects of reactive species. The immune system is also extremely vulnerable to oxidant and antioxidant balance as uncontrolled free radical production can impair its function and defense mechanism. The present paper reviews the ways by which free radicals form in the body and promote tissue damage, as well as the role of the antioxidants defense mechanisms. Finally, we will have a brief glance at oxidants and antioxidants relevance to the immune system.

Plasma phospholipid transfer protein (PLTP) modulates adaptive immune functions through alternation of T helper cell polarization

OBJECTIVE

Plasma phospholipid transfer protein (PLTP) is a key determinant of lipoprotein metabolism, and both animal and human studies converge to indicate that PLTP promotes atherogenesis and its thromboembolic complications. Moreover, it has recently been reported that PLTP modulates inflammation and immune responses. Although earlier studies from our group demonstrated that PLTP can modify macrophage activation, the implication of PLTP in the modulation of T-cell-mediated immune responses has never been investigated and was therefore addressed in the present study. Approach and results: In the present study, we demonstrated that PLTP deficiency in mice has a profound effect on CD4⁺ Th0 cell polarization, with a shift towards the anti-inflammatory Th2 phenotype under both normal and pathological conditions. In a model of contact hypersensitivity, a significantly impaired response to skin sensitization with the hapten-2,4-dinitrofluorobenzene (DNFB) was observed in PLTP-deficient mice compared to wild-type (WT) mice. Interestingly, PLTP deficiency in mice exerted no effect on the counts of total white blood cells, lymphocytes, granulocytes, or monocytes in the peripheral blood. Moreover, PLTP deficiency did not modify the amounts of CD4⁺ and CD8⁺ T lymphocyte subsets. However, PLTP-deficiency, associated with upregulation of the Th2 phenotype, was accompanied by a significant decrease in the production of the pro-Th1 cytokine interleukin 18 by accessory cells.

CONCLUSIONS

For the first time, this work reports a physiological role for PLTP in the polarization of CD4⁺ T cells toward the pro-inflammatory Th1 phenotype.

Old and new adjuvants for hepatitis B vaccines

The safety and immunogenicity profiles of currently available recombinant hepatitis B vaccines are excellent. However, it remains a real challenge to induce protective immunity in the target groups that respond poorly or not at all to conventional vaccines. Ideally, a hepatitis B vaccine can be developed that conveys lifelong protection against infection rapidly after the injection of a single dose. Although this goal is far from being reached, important improvements have been made. Novel vaccine adjuvants have been developed that enhance the immunogenicity of recombinant hepatitis B vaccines while maintaining a good safety profile. The different adjuvants and adjuvant systems that are discussed herein have all been thoroughly evaluated in clinical trials and some have reached or are close to reach the market.

Moderate dietary supplementation with vitamin E enhances lymphocyte functionality in the adult cat

This study aimed to determine the effects of supplemental Vit E and/or Se on selected parameters of the immune system of the cat. Nine diets were fed in a 3 × 3 factorial design with no supplementation (control (C)); and either moderate (M); or high (H) levels of Vit E (0, 225 or 450 mg/kg DM diet) and/or Se (0, 2 or 10 mg/kg DM diet) added to a complete and balanced basal diet. After 28 days of feeding, enhanced lymphocyte proliferative responses to Concanavalin A and phytohaemagglutinin were observed (P < 0.05) in cats fed diets containing supplemental Vit E, irrespective of whether they also contained Se. Cats in the MVitE, HVitE, MVitE + MSe, HVitE + MSe, and HVitE + HSe groups all showed enhancement of phagocytic activity compared to control animals (P < 0.001). Our results indicate that a supplemental level of 225 mg/kg DM diet Vit E appears to have beneficial effects on immune function in the cat.

The α-tocopherol form of vitamin E reverses age-associated susceptibility to streptococcus pneumoniae lung infection by modulating pulmonary neutrophil recruitment

Streptococcus pneumoniae infections are an important cause of morbidity and mortality in older patients. Uncontrolled neutrophil-driven pulmonary inflammation exacerbates this disease. To test whether the α-tocopherol (α-Toc) form of vitamin E, a regulator of immunity, can modulate neutrophil responses as a preventive strategy to mitigate the age-associated decline in resistance to S. pneumoniae, young (4 mo) and old (22-24 mo) C57BL/6 mice were fed a diet containing 30-PPM (control) or 500-PPM (supplemented) α-Toc for 4 wk and intratracheally infected with S. pneumoniae. Aged mice fed a control diet were exquisitely more susceptible to S. pneumoniae than young mice. At 2 d postinfection, aged mice suffered 1000-fold higher pulmonary bacterial burden, 2.2-fold higher levels of neutrophil recruitment to the lung, and a 2.25-fold higher rate of lethal septicemia. Strikingly, α-Toc supplementation of aged mice resulted in a 1000-fold lower bacterial lung burden and full control of infection. This α-Toc-induced resistance to pneumococcal challenge was associated with a 2-fold fewer pulmonary neutrophils, a level comparable to S. pneumoniae-challenged, conventionally fed young mice. α-Toc directly inhibited neutrophil egress across epithelial cell monolayers in vitro in response to pneumococci or hepoxilin-A3, an eicosanoid required for pneumococcus-elicited neutrophil trans-epithelial migration. α-Toc altered expression of multiple epithelial and neutrophil adhesion molecules involved in migration, including CD55, CD47, CD18/CD11b, and ICAM-1. These findings suggest that α-Toc enhances resistance of aged mice to bacterial pneumonia by modulating the innate immune response, a finding that has potential clinical significance in combating infection in aged individuals through nutritional intervention.

Possible role of tocopherols in the modulation of host microRNA with potential antiviral activity in patients with hepatitis B virus-related persistent infection: a systematic review

Hepatitis B virus (HBV) infection represents a serious global health problem and persistent HBV infection is associated with an increased risk of cirrhosis, hepatocellular carcinoma and liver failure. Recently, the study of the role of microRNA (miRNA) in the pathogenesis of HBV has gained considerable interest as well as new treatments against this pathogen have been approved. A few studies have investigated the antiviral activity of vitamin E (VE) in chronic HBV carriers. Herein, we review the possible role of tocopherols in the modulation of host miRNA with potential anti-HBV activity. A systematic research of the scientific literature was performed by searching the MEDLINE, Cochrane Library and EMBASE databases. The keywords used were 'HBV therapy', 'HBV treatment', 'VE antiviral effects', 'tocopherol antiviral activity', 'miRNA antiviral activity' and 'VE microRNA'. Reports describing the role of miRNA in the regulation of HBV life cycle, in vitro and in vivo available studies reporting the effects of VE on miRNA expression profiles and epigenetic networks, and clinical trials reporting the use of VE in patients with HBV-related chronic hepatitis were identified and examined. Based on the clinical results obtained in VE-treated chronic HBV carriers, we provide a reliable hypothesis for the possible role of this vitamin in the modulation of host miRNA profiles perturbed by this viral pathogen and in the regulation of some cellular miRNA with a suggested potential anti-HBV activity. This approach may contribute to the improvement of our understanding of pathogenetic mechanisms involved in HBV infection and increase the possibility of its management and treatment.

Relationships between immunoglobulin and fat-soluble vitamins in colostrum of Japanese Black multiparous cows

Data from 19 Japanese Black multiparous cows were collected to clarify the relationships among immunoglobulin (Ig) G, IgA, β-carotene, vitamin A and α-tocopherol contents in colostrum of cows in order to evaluate the role of fat-soluble vitamins on colostral IgG and IgA production. Mean colostral IgG was 141 mg/mL, ranging from 65 to 208 mg/mL, whereas mean colostral IgA was 8.7 mg/mL, ranging from 1.0 to 34.6 mg/mL. Colostral IgG increased with aging in multiparous cows. There were positive correlations between colostral IgG and colostral vitamin A or colostral α-tocopherol in cows, and the higher adjusted R(2) was obtained in the prediction model of colostral IgG from age and colostral vitamin A. Colostral vitamin A was positively correlated with colostral β-carotene or colostral α-tocopherol in cows, but there were no relationships between colostral IgA and colostral IgG or colostral fat-soluble vitamins. These results indicate that fat-soluble vitamin contents in colostrum of cows may change in similar patterns and high colostral vitamin A is related with high colostral IgG.

Interplay between surface properties of standard, vitamin E blended and oxidised ultra high molecular weight polyethylene used in total joint replacement and adhesion of Staphylococcus aureus and Escherichia coli

We have assessed the different adhesive properties of some of the most common bacteria associated with periprosthetic joint infection on various types of ultra high molecular Weight Polyethylene (UHMWPE). Quantitative in vitro analysis of the adhesion of biofilm producing strains of Staphylococcus aureus and Escherichia coli to physically and chemically characterised standard UHMWPE (PE), vitamin E blended UHMWPE (VE-PE) and oxidised UHMWPE (OX-PE) was performed using a sonication protocol. A significant decreased bacterial adhesion was registered for both strains on VE-PE, in comparison with that observed on PE, within 48 hours of observation (S. aureus p = 0.024 and E. coli p = 0.008). Since Vitamin E reduces bacterial adhesive ability, VE-stabilised UHMWPE could be valuable in joint replacement by presenting excellent mechanical properties, while reducing bacterial adhesiveness.

Vitamin E-gene interactions in aging and inflammatory age-related diseases: implications for treatment. A systematic review

Aging is a complex biological phenomenon in which the deficiency of the nutritional state combined with the presence of chronic inflammation and oxidative stress contribute to the development of many age-related diseases. Under this profile, the free radicals produced by the oxidative stress lead to a damage of DNA, lipids and proteins with subsequent altered cellular homeostasis and integrity. In young-adult age, the cell has a complex efficient system to maintain a proper balance between the levels of free radicals and antioxidants ensuring the integrity of cellular components. In contrast, in old age this balance is poorly efficient compromising cellular homeostasis. Supplementation with Vitamin E can restore the balance and protect against the deteriorating effects of oxidative stress, progression of degenerative diseases, and aging. Experiments in cell cultures and in animals have clearly shown that Vitamin E has a pivotal role as antioxidant agent against the lipid peroxidation on cell membranes preserving the tissue cells from the oxidative damage. Such a role has been well documented in immune, endothelial, and brain cells from old animals describing how the Vitamin E works both at cytoplasmatic and nuclear levels with an influence on many genes related to the inflammatory/immune response. All these findings have supported a lot of clinical trials in old humans and in inflammatory age-related diseases with however contradictory and inconsistent results and even indicating a dangerous role of Vitamin E able to affect mortality. Various factors can contribute to all the discrepancies. Among them, the doses and the various isoforms of Vitamin E family (α,β,γ,δ tocopherols and the corresponding tocotrienols) used in different trials. However, the more plausible gap is the poor consideration of the Vitamin E-gene interactions that may open new roadmaps for a correct and personalized Vitamin E supplementation in aging and age-related diseases with satisfactory results in order to reach healthy aging and longevity. In this review, this peculiar nutrigenomic and/or nutrigenetic aspect is reported and discussed at the light of specific polymorphisms affecting the Vitamin E bioactivity.

Extracts of Cistanche deserticola Can Antagonize Immunosenescence and Extend Life Span in Senescence-Accelerated Mouse Prone 8 (SAM-P8) Mice

The senescence accelerated mouse prone 8 substrain (SAM-P8), widely accepted as an animal model for studying aging and antiaging drugs, was used to examine the effects of dietary supplementation with extracts of Cistanche deserticola (ECD) which has been used extensively in traditional Chinese medicine because of its perceived ability to promote immune function in the elderly. Eight-month-old male SAM-P8 mice were treated with ECD by daily oral administrations for 4 weeks. The results showed that dietary supplementation of 150 mg/kg and 450 mg/kg of ECD could extend the life span measured by Kaplan-Meier survival analysis in dose-dependent manner. Dietary supplementation of SAM-P8 mice for 4 weeks with 100, 500, and 2500 mg/kg of ECD was shown to result in significant increases in both naive T and natural killer cells in blood and spleen cell populations. In contrast, peripheral memory T cells and proinflammatory cytokine, IL-6 in serum, were substantially decreased in the mice that ingested 100 and 500 mg/kg of ECD daily. Additionally, Sca-1 positive cells, the recognized progenitors of peripheral naive T cells, were restored in parallel. Our results provide clear experimental support for long standing clinical observational studies showing that Cistanche deserticola possesses significant effects in extending life span and suggest this is achieved by antagonizing immunosenescence.

Nutrition, diet and immunosenescence

Ageing is characterized by immunosenescence and the progressive decline in immunity in association with an increased frequency of infections and chronic disease. This complex process affects both the innate and adaptive immune systems with a progressive decline in most immune cell populations and defects in activation resulting in loss of function. Although host genetics and environmental factors, such as stress, exercise and diet can impact on the onset or course of immunosenescence, the mechanisms involved are largely unknown. This review focusses on identifying the most significant aspects of immunosenescence and on the evidence that nutritional intervention might delay this process, and consequently improve the quality of life of the elderly.

Complex effects of vitamin E and vitamin C supplementation on in vitro neonatal mononuclear cell responses to allergens

Low maternal dietary vitamin E (but not vitamin C) intake during pregnancy has been associated with increased in vitro cord blood mononuclear cell (CBMC) proliferative responses, childhood wheezing and asthma. We investigated whether these associations reflect direct effects of vitamin E by investigating the effects of supplementing CBMC cultures with physiological concentrations of vitamin E. CBMC from seventy neonates were cultured supplemented with either nothing, α-tocopherol or ascorbic acid. Proliferative, IFN-γ, IL-4, IL-10 and TGF-β responses were measured. In general, vitamin E supplementation was associated with a trend for reduced proliferative responses after stimulation with antigens and house dust mite, and with increased proliferation after stimulation with timothy grass allergen. There was a trend for CBMC cultures to exhibit decreased secretion of IFN-γ, IL-10 and IL-4. Supplementation with vitamin C had no effect on CBMC proliferation, but increased IFN-γ and IL-4 production, and decreased IL-10 production. In conclusion, in vitro vitamin E and C supplementation of CBMC modifies neonatal immune function, but not in a manner predicted by observational epidemiological studies. The observed associations between vitamin E and childhood respiratory disease are complex, and the nature and form of nutritional intervention need to be carefully considered before inclusion in trials.

Effect of multivitamin supplementation on measles vaccine response among HIV-exposed uninfected Tanzanian infants

Immunization and nutritional interventions are mainstays of child health programs in sub-Saharan Africa, yet few published data exist on their interactions. HIV-exposed (but uninfected) infants enrolled in a randomized placebo-controlled trial of multivitamin supplements (vitamins B complex, C, and E) conducted in Tanzania were sampled for an assessment of measles IgG quantity and avidity at 15 to 18 months. Infants were vaccinated between 8.5 and 12 months of age, and all mothers received high-dose multivitamins as the standard of care. Of 201 HIV-exposed infants who were enrolled, 138 (68.7%) were seropositive for measles. There were no effects of infant multivitamin supplementation on measles seroconversion proportions, IgG concentrations, or IgG avidity (P > 0.05). The measles seroconversion proportion was greater for HIV-exposed infants vaccinated at 10 to 11 months of age than for those vaccinated at 8.5 to 10 months (P = 0.032) and greater for infants whose mothers had a CD4 T-cell count of <200 cells/μl than for infants whose mothers had a CD4 T-cell count of >350 cells/μl (P = 0.039). Stunted infants had a significantly decreased IgG quantity compared to nonstunted infants (P = 0.012). As for measles avidity, HIV-exposed infants vaccinated at 10 to 11 months had increased antibody avidity compared to those vaccinated at 8.5 to 10 months (P = 0.031). Maternal CD4 T-cell counts of <200 cells/μl were associated with decreased avidity compared to counts of >350 cells/μl (P = 0.047), as were lower infant height-for-age z-scores (P = 0.016). Supplementation with multivitamins containing B complex, C, and E does not appear to improve measles vaccine responses for HIV-exposed infants. Studies are needed to better characterize the impact of maternal HIV disease severity on the immune system development of HIV-exposed infants and the effect of malnutrition interventions on vaccine responses. (This study has been registered at ClinicalTrials.gov under registration no. NCT00197730.).

Feeding the immune system

A well-functioning immune system is key to providing good defence against pathogenic organisms and to providing tolerance to non-threatening organisms, to food components and to self. The immune system works by providing an exclusion barrier, by identifying and eliminating pathogens and by identifying and tolerating non-threatening sources of antigens, and by maintaining a memory of immunological encounters. The immune system is complex involving many different cell types distributed throughout the body and many different chemical mediators some of which are involved directly in defence while others have a regulatory role. Babies are born with an immature immune system that fully develops in the first few years of life. Immune competence can decline with ageing. The sub-optimal immune competence that occurs early and late in life increases susceptibility to infection. Undernutrition decreases immune defences, making an individual more susceptible to infection. However, the immune response to an infection can itself impair nutritional status and alter body composition. Practically all forms of immunity are affected by protein-energy malnutrition, but non-specific defences and cell-mediated immunity are most severely affected. Micronutrient deficiencies impair immune function. Here, vitamins A, D and E, and Zn, Fe and Se are discussed. The gut-associated lymphoid tissue is especially important in health and well-being because of its close proximity to a large and diverse population of organisms in the gastrointestinal tract and its exposure to food constituents. Certain probiotic bacteria which modify the gut microbiota enhance immune function in laboratory animals and may do so in human subjects.

The effects of natural and modified clinoptilolite on intestinal barrier function and immune response to LPS in broiler chickens

The protection of intestinal barrier function and the anti-inflammatory effects of natural clinoptilolite (NCLI) and modified clinoptilolite (MCLI) were investigated in broilers that were repeatedly challenged with lipopolysaccharide (LPS). A total of 288 1-d-old broiler chicks were divided equally into three treatment groups: control, NCLI-treated (2%) and MCLI-treated (2%). Half of the birds from each treatment group were challenged with 0.9% NaCl solution or LPS (250μg/kg body weight, administered orally) at 16, 18 and 21d of age. The results indicated that, prior to LPS challenge, the diet had no effect on bird growth performance (P>0.05). The oral administration of LPS was also not associated with any significant changes in poultry performance (P>0.05). In LPS-challenged birds that were pretreated with NCLI (2%) or MCLI (2%), the LPS-induced increases in the plasma and intestinal mucosa concentrations of TNF-α, IL-1β, IL-2, IL-6, IL-4 and IL-10 were dramatically attenuated. Additionally, significant decreases in the plasma d-lactic acid and diamine oxidase (DAO) levels were found in birds that were pretreated with NCLI or MCLI. Furthermore, both NCLI and MCLI reduced the sICAM-1 concentration in the intestinal mucosa. In conclusion, NCLI and MCLI are able to prevent the LPS-induced intestinal mucosa damage and inflammatory response in vivo. These beneficial effects suggest that NCLI and MCLI act as anti-inflammatory agents in part by inhibiting neutrophil infiltration and hyperactivation and by suppressing the secretion of various plasma and intestinal mucosa inflammatory mediators.

Novel and emerging therapies safeguarding health of humans and their companion animals: a review

Modern medicine has helped to a great extent to eradicate and cure several diseases of mankind and animals. But the existence of incurable diseases like cancer, Acquired Immunodeficiency Syndrome (AIDS), diabetes or rheumatoid arthritis, side effects of allopathic medicine, increasing trend of antibiotic resistance and chemicals and biopesticides causing dietary risk have made the situation more critical than ever before. Thus, it has become a matter of concern for the scientists and researchers to develop novel therapies. Bacteriophage therapy to treat pathogenic bacterial infections, virophage therapy for conservation of global system and avian egg yolk antibody therapy for designing prophylactic strategies against Gastrointestinal (GI) diseases are interesting approaches. Others include the use of cytokines as adjunctive immunomodulators, gene therapy focusing on diseases caused by single gene defects, RNAi technology to suppress specific gene of interest and apoptins for cancer treatment. Stem cell therapy against several diseases and ailments has also been discussed. The use of nanoparticles for better drug delivery, even though costly, has been given equal importance. Nevertheless, immunomodulation, be it through physiological, chemical or microbial products, or through essential micronutrients, probiotics, herbs or cow therapy prove to be cost-effective, causing minimum adverse reactions when compared to allopathy. Development in the field of molecular biology has created an enormous impact on vaccine development. The present review deals with all these novel and emerging therapies essential to safeguard the health of humans and companion animals.

Serum immunoglobulin E (IgE) levels and dietary intake of Korean infants and young children with atopic dermatitis

Atopic dermatitis (AD) has become a serious epidemic in Korean children. We aimed to investigate the association between vitamin C, E and other nutrients, and serum total IgE/specific IgE levels in children with AD. A total of 119 children (0-24 mo) diagnosed with AD were recruited for this cross-sectional study from a medical center in Seoul. A 24 h recall was used to assess dietary intakes. Serum total and six food-allergen specific IgE levels were measured by CAP-FEIA. Serum vitamin E was also measured but only in 25 out of the total 119 participants. Multiple linear regression analysis was performed to estimate the coefficients between serum IgE levels and dietary intake as well as serum vitamin E. Serum vitamin E levels showed a significantly inverse association with serum total IgE and all specific IgE levels (P < 0.05). Fat intake was inversely related with specific-IgEs for egg whites, milk, buck wheat, soy, and peanuts (P < 0.05). Positive associations were found between carbohydrate (CHO) intake and total IgE and specific IgEs to egg whites, milk, soy, and peanuts (P < 0.05). Vitamin C, E and n-3/n-6 fatty acids were not related with serum total IgE and specific IgE levels except for the association between buck wheat and vitamin E. In addition, there were no significant differences between males and females in dietary intake and serum IgE levels by student's t-test. Although dietary vitamin E showed no association with serum IgE levels, serum vitamin E drew a significant inverse relationship with serum IgE levels. The evidence seems to suggest that vitamin E may possibly lower total and specific-IgEs in children with AD, and that it is important to maintain a relatively high serum vitamin E level in children with AD.

Hepatitis B and C virus infections as possible risk factor for pancreatic adenocarcinoma

Pancreatic adenocarcinoma (PAC) is a very aggressive and lethal cancer, with a very poor prognosis, because of absence of early symptoms, advanced stage at presentation, early metastatic dissemination and lack of both specific tests to detect its growth in the initial phases and effective systemic therapies. To date, the causes of PAC still remain largely unknown, but multiple lines of evidence from epidemiological and laboratory researches suggest that about 15-20% of all cancers are linked in some way to chronic infection, in particular it has been shown that several viruses have a role in human carcinogenesis. The purpose of this report is to discuss the hypothesis that two well-known oncogenic viruses, Human B hepatitis (HBV) and Human C hepatitis (HCV) are a possible risk factor for this cancer. Therefore, with the aim to examine the potential link between these viruses and PAC, we performed a selection of observational studies evaluating this association and we hypothesized that some pathogenetic mechanisms involved in liver carcinogenesis might be in common with pancreatic cancer development in patients with serum markers of present or past HBV and HCV infections. To date the available observational studies performed are few, heterogeneous in design as well as in end-points and with not univocal results, nevertheless they might represent the starting-point for future larger and better designed clinical trials to define this hypothesized relationship. Should these further studies confirm an association between HBV/HCV infection and PAC, screening programs might be justified in patients with active or previous hepatitis B and C viral infection.

Decreasing pro-inflammatory cytokine and reversing the immunosenescence with extracts of Pu-erh tea in senescence accelerated mouse (SAM)

Immunosenescence, the progressive decline of adaptive immunity and chronic inflammation with ageing has been demonstrated to be the main factor responsible for infections, cancer and autoimmune conditions in the elderly. Senescence-accelerated mouse (SAM) was used to study the protective effects of Pu-erh tea in the elderly. The senile-prone sub-strain, SAM-P8 mice were administered individually with ripened or crude Pu-erh tea at 125, 250 or 500mg/kg. The results showed that Pu-erh tea significantly increased the fractions of naïve T lymphocytes, CD8(+)CD28(+) T lymphocytes and NK cells in the peripheral blood, but decreased the levels of IL-6 in aged mice. These data suggested that the Pu-erh tea reversed the immunosenescence by restoring the immune deficiency and decreasing pro-inflammatory cytokine. Thus, long term drinking of Pu-erh tea may be beneficial for the aged population in terms of increasing the body's resistance to infection and cancer.

A combination of high-dose vitamin C plus zinc for the common cold

Vitamin C and zinc play important roles in nutrition, immune defence and maintenance of health. Intake of both is often inadequate, even in affluent populations. The common cold continues to place a great burden on society in terms of suffering and economic loss. After an overview of the literature on the effects of the separate administration of either vitamin C or zinc against the common cold, this article presents data from two preliminary, double-blind, randomized, placebo-controlled trials, conducted with a combination of 1000 mg vitamin C plus 10 mg zinc in patients with the common cold. In both studies, a nonsignificant reduction of rhinorrhoea duration (range 9-27%) was seen. In pooled analyses of both studies (n=94), vitamin C plus zinc was significantly more efficient than placebo at reducing rhinorrhoea over 5 days of treatment. Furthermore, symptom relief was quicker and the product was well tolerated. In view of the burden associated with the common cold, supplementation with vitamin C plus zinc may represent an efficacious measure, with a good safety profile, against this infectious viral disease.

Prediagnostic circulating carotenoid levels and the risk of non-Hodgkin lymphoma: the Multiethnic Cohort

This analysis examined the association of non-Hodgkin lymphoma (NHL) with prediagnostic carotenoid levels, a marker for a diet rich in fruits and vegetables. We conducted a nested case-control study within the Multiethnic Cohort with 271 NHL cases and 538 controls matched on sex, ethnicity, location (Hawaii or Los Angeles), birth year, date and time of blood draw, and hours fasting before blood draw. Serum carotenoid levels were obtained by high-pressure liquid chromatography with photodiode array detection. Conditional logistic regression was used to calculate odds ratios (ORs) according to tertiles of serum carotenoids and trend tests using continuous variables. Higher total serum carotenoids (OR(T3 vs T1) = 0.66 [0.46-0.96]; P(trend) = .02), lycopene (OR = 0.54 [0.38-0.78]; P(trend) = .003), and α-cryptoxanthin (OR = 0.53 [0.36-0.78]; P(trend) = .003) were associated with a lower risk of NHL. For retinol (OR = 0.90 [0.61-1.33]; P(trend) = .04), a statistically significant inverse linear trend was detected. Risk estimates remained unchanged with adjustment for NHL risk factors and were similar in analyses stratified by sex and ethnicity; heterogeneity with NHL subtype was detected only for β-carotene. Other carotenoids, including α-carotene, β-carotene, lutein, β-cryptoxanthin, and zeaxanthin, showed no association with risk. These data provide support for a protective role of carotenoid-rich fruits and vegetables in the etiology of NHL.

Concentrations of alpha- and gamma-tocopherols in human breast milk during the first months of lactation and in infant formulas

The aim of this study was to determine the concentrations of alpha- and gamma-tocopherols in human breast milk samples from different periods of lactation and to compare them with tocopherol content in commercially available formulas for infants at corresponding ages. The study included 93 breast milk samples obtained on the 2nd (colostrum, n = 17), 14th (n = 30), 30th (n = 27) and 90th day of lactation (n = 19), along with 90 samples of commercially available initial and follow-on infant formulas. Concentrations of tocopherols were determined using normal-phase high-performance liquid chromatography. Depending on the stage of lactation, human breast milk contained 2.07-9.99 mg L⁻¹ of alpha-tocopherol and 0.22-0.60 mg L⁻¹ of gamma-tocopherol. Breast milk concentrations of alpha-tocopherol decreased with the time of lactation, while significant differences in gamma-tocopherol concentration were observed only between the 14th and 30th day of lactation. There was no significant correlation between the dietary intake of vitamin E and its estimated breast milk concentration, also in women who declared vitamin supplementation. Compared with colostrum, infant formulas were characterised by significantly lower concentrations of alpha-tocopherol and vitamin E. This finding indicates the need of additional vitamin E supplementation of bottle-fed infants during the initial 2-3 days of life.

The role of nutrition in enhancing immunity in aging

Aging is associated with declined immune function, particularly T cell-mediated activity, which contributes to increased morbidity and mortality from infectious disease and cancer in the elderly. Studies have shown that nutritional intervention may be a promising approach to reversing impaired immune function and diminished resistance to infection with aging. However, controversy exists concerning every nutritional regimen tested to date. In this article, we will review the progress of research in this field with a focus on nutrition factor information that is relatively abundant in the literature. While vitamin E deficiency is rare, intake above recommended levels can enhance T cell function in aged animals and humans. This effect is believed to contribute toward increased resistance to influenza infection in animals and reduced incidence of upper respiratory infection in the elderly. Zinc deficiency, common in the elderly, is linked to impaired immune function and increased risk for acquiring infection, which can be rectified by zinc supplementation. However, higher than recommended upper limits of zinc may adversely affect immune function. Probiotics are increasingly being recognized as an effective, immune-modulating nutritional factor. However, to be effective, they require an adequate supplementation period; additionally, their effects are strain-specific and among certain strains, a synergistic effect is observed. Increased intake of fish or n-3 PUFA may be beneficial to inflammatory and autoimmune disorders as well as to several age-related diseases. Conversely, the immunosuppressive effect of fish oils on T cell-mediated function has raised concerns regarding their impact on resistance to infection. Caloric restriction (CR) is shown to delay immunosenescence in animals, but this effect needs to be verified in humans. Timing for CR initiation may be important to determine whether CR is effective or even beneficial at all. Recent studies have suggested that CR, which is effective at improving the immune response of unchallenged animals, might compromise the host's defense against pathogenic infection and result in higher morbidity and mortality. The studies published thus far describe a critical role for nutrition in maintaining the immune response of the aged, but they also indicate the need for a more in-depth, wholestic approach to determining the optimal nutritional strategies that would maintain a healthy immune system in the elderly and promote their resistance to infection and other immune-related diseases.