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

Vitamin E decreased the activity of acetylcholinesterase and level of lipid peroxidation in brain of rats exposed to aged and diluted sidestream smoke

INTRODUCTION

The biological systems of both smoker and passive smoking suffer changes caused by toxic compounds from cigarette smoke such as inflammation, lipid peroxidation, and deficiency of vitamin E. The aim of the present study was to evaluate the effect of vitamin E on acetylcholinesterase (AChE) activity and the lipid peroxidation level in the brain of rats in the model of exposure to aged and diluted sidestream smoke (ADSS).

METHODS

Adult male Wistar rats (200-300 g) were exposed to ADSS for 4 weeks and treated with vitamin E (50 mg/kg/day) loaded by gavage. In the first, second, third, and fourth weeks, animals were concomitantly exposed to the smoke of 1, 2, 3, and 4 cigarettes/day, respectively. The duration of each exposure was 15 min, daily.

RESULTS

For rats exposed to ADSS, the AChE activity and lipid peroxidation level increased in the striatum, cerebral cortex, and cerebellum. In contrast, the activity of AChE and the level of lipid peroxidation decreased in the smoke group treated with vitamin E.

CONCLUSIONS

The results suggest that the rats exposed to ADSS and treated with vitamin E significantly reduced the raised activity of AChE and level lipid peroxidation from the brain structures studied. The study, therefore, concludes that vitamin E could be considered as a therapeutic agent in this type of exposure.

Bacterial adherence on UHMWPE with vitamin E: an in vitro study

Orthopaedic materials may improve its capacity to resist bacterial adherence, and subsequent infection. Our aim was to test the bacterial adherence to alpha-tocopherol (frequently named vitamin E, VE) doped or blended UHMWPE with S. aureus and S. epidermidis, compared to virgin material. Collection strains and clinical strains isolated from patients with orthopaedic infections were used, with the biofilm-developing ability as a covariable. While collection strains showed significantly less adherence to VE-UHMWPE, some clinical strains failed to confirm this effect, leading to the conclusion that VE doped or blended UHMWPE affects the adherence of some S. epidermidis and S. aureus strains, independently of the concentration in use, but the results showed important intraspecies differences and cannot be generalized.

Moderate Exercise Improves Immunity and Decreases Illness Rates

Moderate exercise training causes favorable perturbations in immunity and a reduction in incidence of upper-respiratory illness (URI). During each bout of moderate exercise, an enhanced recirculation of immunoglobulins, neutrophils, and natural killer cells occurs that persists for up to 3 hours postexercise. This exercise-induced surge in immune cells from the innate immune system is transient but improves overall surveillance against pathogens. As moderate exercise continues on a near-daily basis for 12 to 15 weeks, the number of symptom days with URI is decreased 25% to 50% compared with randomized sedentary controls. Epidemiological and animal studies support this inverse relationship between URI risk and increased physical activity. Recent evidence indicates that maintaining leanness and a physically active lifestyle during adulthood reduces systemic inflammation, an underlying factor in multiple chronic diseases. The anti-inflammatory influence of near-daily physical activity in lowering C-reactive protein, total blood leukocytes, interleukin-6, and other inflammatory cytokines may play a key role in lowering risk of cardiovascular disease, certain types of cancer, type 2 diabetes, sarcopenia, and dementia.

Diet and asthma: nutrition implications from prevention to treatment

Asthma is characterized by lung airway inflammation initiated and perpetuated by an inappropriate immune response, increased airway responsiveness, and variable airflow obstruction. In Western countries there has been a marked increase in asthma prevalence such that it has become a public health concern. It has been hypothesized that the increase may be due to changing antioxidant intake, increasing dietary ratio of n-6:n-3 polyunsaturated fatty acids (PUFA), and vitamin D deficiency (and supplementation). Observational studies have reported associations between asthma and dietary antioxidants (vitamin E, vitamin C, carotenoids, selenium, polyphenols, and fruit), PUFA, and vitamin D. However, supplementing the diets of adults with asthma with antioxidants and n-3 PUFA has minimal, if any, clinical benefit. Currently there is insufficient evidence to support the use of nutrient supplements to complement conventional treatment; however, results of ongoing studies are awaited, and additional research is required, particularly in children. Interest in the potential of dietary intervention during pregnancy to reduce the likelihood of childhood asthma has increased. A small number of cohort studies have highlighted associations between childhood asthma and reduced maternal intake of some nutrients (vitamin E, vitamin D, selenium, zinc, and PUFA) during pregnancy. Although vitamin D intervention studies during pregnancy are ongoing and two intervention studies suggest that dietary PUFA manipulation during pregnancy may be advantageous, further trials are needed to establish if modification of maternal nutrient intake during pregnancy can be used as a healthy, low cost, public health measure to reduce the prevalence of childhood asthma.

Fetal programming: Early-life modulations that affect adult outcomes

Asthma is a common disease, and the number of people diagnosed with it increases every year. Although genetic background and environmental exposures play major roles in the development of asthma, one cannot overlook the developmental origin of adult disease or fetal programming theory. This review examines the social, genetic, and environmental factors that are associated with fetal programming of asthma. We also present recent studies from our laboratory that strengthen these observations. It is our hope that the reader will come away with a current view of fetal programming in asthma.

Randomised vitamin E supplementation and risk of chronic lung disease in the Women's Health Study

BACKGROUND

The oxidant/antioxidant balance in lung tissue is hypothesised to contribute to the risk of chronic obstructive pulmonary disease (COPD). Observational studies consistently report higher antioxidant status associated with lower COPD risk, but few randomised studies have been reported.

METHODS

A post hoc analysis of 38,597 women without chronic lung disease at baseline was conducted in the Women's Health Study (WHS) to test the effect of vitamin E on the risk of incident chronic lung disease. The WHS is a randomised double-blind placebo-controlled factorial trial of vitamin E (600 IU every other day) and aspirin (100 mg every other day) in female health professionals aged≥45 years. Using Cox proportional hazards models, the effect of randomised vitamin E assignment on self-reported physician-diagnosed chronic lung disease was evaluated.

RESULTS

During 10 years of follow-up (376,710 person-years), 760 first occurrences of chronic lung disease were reported in the vitamin E arm compared with 846 in the placebo arm (HR 0.90; 95% CI 0.81 to 0.99; p=0.029). This 10% reduction in the risk of incident chronic lung disease was not modified by cigarette smoking, age, randomised aspirin assignment, multivitamin use or dietary vitamin E intake (minimum p for interaction=0.19). Current cigarette smoking was a strong predictor of chronic lung disease risk (HR 4.17; 95% CI 3.70 to 4.70; vs. never smokers).

CONCLUSIONS

In this large randomised trial, assignment to 600 IU vitamin E led to a 10% reduction in the risk of chronic lung disease in women.

Vitamin E and immunity

Vitamin E is the most important chain-breaking, lipid-soluble antioxidant present in body tissues of all cells and is considered the first line of defense against lipid peroxidation and it is important for normal function of the immune cells. However, vitamin E deficiency is rare in well-nourished healthy subjects and is not a problem, even among people living on relatively poor diets, both T- and B-cell functions are impaired by vitamin E deficiency. While immune cells are particularly enriched in vitamin E because of their high polyunsaturated fatty acid content, this point puts them at especially high risk for oxidative damage. Besides its immunomodulatory effects, vitamin E also plays an important role in carcinogenesis with its antioxidant properties against cancer, and ischemic heart disease with limiting the progression of atherosclerosis. Supplementation of vitamin E significantly enhances both cell mediated and humoral immune functions in humans, especially in the elderly and animals.

DietaryRRR-α-tocopherol succinate attenuates lipopolysaccharide-induced inflammatory cytokines secretion in broiler chicks

The anti-inflammatory effects of two esters of α-tocopherol (α-TOH),all-rac-α-TOH acetate (dl-α-TOA) andRRR-α-TOH succinate (d-α-TOS), on broilers repeatedly challenged with lipopolysaccharide (LPS) were investigated. Three hundred and twenty 1-d-old broiler chicks were allotted into four treatment groups and fed on a control diet (30 mg/kgdl-α-TOA) or diets containing 10, 30, 50 mg/kgd-α-TOS. Half of the birds from each treatment group were challenged with 0·9 % NaCl solution or LPS (250 μg/kg body weight) at 16, 18 and 20 d of age. The results indicated that the pretreatment of birds with 50 mg/kgd-α-TOS markedly reduced serum PGE2secretion and increased the concentrations of serum or hepatic α-TOH. When LPS-challenged birds were pretreated with 30 or 50 mg/kgd-α-TOS, the increases of plasma and splenic concentrations of interferon-γ, IL-1β, IL-2, IL-6, IL-4 and IL-10 were dramatically attenuated. Also, a significant decrease of hepatic reactive oxygen species (ROS) and hepatic or splenic phosphokinase C (PKC) activities was found in birds pretreated with 30 or 50 mg/kgd-α-TOS. Furthermore,d-α-TOS inhibited the activation of NF-κB by preventing the degradation of inhibitory-κBα. In conclusion, D-α-TOS is able to prevent LPS-induced inflammation responsein vivo.The beneficial effect may depend on suppressing the secretion of various plasma and splenic inflammatory mediators through inhibiting NF-κB activation and by blocking ROS signalling, in which PKC may play an assistant role.

Dietary supplementation with tocotrienols enhances immune function in C57BL/6 mice

alpha-Tocopherol (alpha-Toc) enhances T cell function, whereas little is known in this regard for tocotrienols (T3), the less-known members of the vitamin E family. We pair-fed young (4 mo) and old (23 mo) C57BL/6 mice 0.1% Tocomin 50%, a mixture of T3 and alpha-Toc or a control diet containing an equal amount of alpha-Toc for 6 wk. As expected, lymphocyte proliferation was lower in the old mice compared with the young mice. Lymphocyte proliferation in the old T3 group was significantly higher than that in the old control group, whereas no significant difference was found in young mice. Splenocytes from old mice produced less interleukin (IL)-2, IL-4, IL-6, and IL-10 compared with young mice, whereas no significant age-related difference was found in IL-1beta, tumor necrosis factor-alpha, and interferon-gamma. T3 feeding was associated with a higher IL-1beta production in old mice but not in young mice. Peritoneal macrophages from old mice produced significantly more IL-1beta, IL-6, IL-10, and prostaglandin E(2) (PGE(2)) compared with those from young mice. Mice of both ages fed T3 had higher production of IL-1beta but not PGE(2) or other cytokines. In the in vitro study, splenocytes isolated from young and old mice were supplemented with the purified form of each individual T3 (0.01-10 mumol/L) and mitogen-stimulated cell proliferation was determined. All T3 enhanced lymphocyte proliferation in old but not young mice with a potency order of alpha- > gamma- > delta-T3. Together, these results suggest a beneficial effect of T3 in improving the age-related decline in T cell function.

Maternal diet during pregnancy: an emerging risk factor for childhood asthma

Evaluation of: Willers SM, Wijga AH, Brunekreef B et al. Maternal food consumption during pregnancy and the longitudinal development of childhood asthma. Am. J. Respir. Crit. Care Med. 178, 124-131 (2008). It has been hypothesized that the recent marked increase in the prevalence of asthma may, in part, be a consequence of changing diet. There is increasing interest in the possibility that childhood asthma may be influenced by maternal diet during pregnancy and an increasing number of studies have highlighted associations between childhood asthma and maternal intake of certain foods (e.g., fish, fruits and vegetables) and nutrients (e.g., vitamin E, vitamin D, zinc and polyunsaturated fatty acids) during pregnancy. Maternal diet during pregnancy has the potential to influence fetal immune and airway development during a critical period of life with long-term irreversible consequences, such as childhood asthma. Further research, particularly intervention studies, needs to be carried out to establish whether dietary intervention during pregnancy can be used as a healthy, low-cost, public-health measure to reduce the prevalence of childhood asthma.

Consumption of vegetables, fruit, and antioxidants during pregnancy and wheeze and eczema in infants

BACKGROUND

Two previous cohort studies showed inverse relationships between maternal vitamin E and zinc intake during pregnancy and the risk of wheeze and/or asthma in the offspring. We investigated the association between maternal intake of vegetables, fruit, and selected antioxidants during pregnancy and the risk of wheeze and eczema in the offspring aged 16-24 months.

METHODS

Subjects were 763 Japanese mother-child pairs. Data on maternal intake during pregnancy were assessed with a diet history questionnaire. Data on symptoms of wheeze and eczema were based on criteria of the International Study of Asthma and Allergies in Childhood.

RESULTS

Higher maternal intake of green and yellow vegetables, citrus fruit, and beta-carotene during pregnancy was significantly associated with a reduced risk of eczema, but not wheeze, in the offspring {adjusted odds ratios (ORs) between extreme quartiles [95% confidence intervals (CIs)] = 0.41 (0.24-0.71), 0.53 (0.30-0.93), and 0.52 (0.30-0.89), respectively}. Maternal vitamin E consumption during pregnancy was significantly inversely related to the risk of infantile wheeze, but not eczema [adjusted OR (95% CI) = 0.54 (0.32-0.90)]. No statistically significant exposure-response associations were observed between maternal intake of total vegetables, vegetables other than green and yellow vegetables, total fruit, apples, alpha-carotene, vitamin C, or zinc and the risk of wheeze or eczema in the children.

CONCLUSIONS

Higher maternal consumption of green and yellow vegetables, citrus fruit, and beta-carotene during pregnancy may be protective against the development of eczema in the offspring. Higher maternal vitamin E intake during pregnancy may reduce the risk of infantile wheeze.

The effects of vitamin E on NK cell activity and lymphocyte proliferation in treated mice by 2,3,7,8-tetrachlorodibenzo-p-dioxin

The study was conducted to investigate the effects of vitamin E on NK cell activity and lymphocyte proliferation in tr eated female mice by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). In chronic TCDD trial, 45 mice were divided into 5 groups, and the levels of TCDD and vitamin E were 0 and 0, 100 and 0, 100 and 20, 100 and 100, and 100 ng/kg/d and 500 mg/kg/d, respectively. In acute TCDD trial, 24 mice were divided into three groups, and the levels of TCDD and vitamin E were 0 and 0, 30 and 0, and 30 microg/kg and 100 mg/kg, respectively. The results showed chronic TCDD-treatment caused decrease tendencies of spleen NK cell activity and lymphocyte proliferation, and vitamin E 100mg/kg alleviated the decreases tendencies caused by chronic TCDD-treatment, and the lymphocyte proliferation in the group given vitamin E 100mg/kg was significantly higher than that of the chronic TCDD-treated group. Acute TCDD-treatment suppressed the NK cell activity and lymphocyte proliferation, and vitamin E 100mg/kg significantly alleviated the decrease caused by acute TCDD-treatment. These results suggested that TCDD resulted in immunotoxicity, and the toxicity of acute TCDD-treatment was severe compared with chronic TCDD, while vitamin E alleviated the immunotoxicity from TCDD.

Session 1: Allergic disease: Nutrition as a potential determinant of asthma

Asthma is characterised by chronic lung airway inflammation, increased airway responsiveness and variable airflow obstruction. In Westernised countries asthma is a public health concern because of its prevalence, associated ill health and high societal and healthcare costs. In recent decades there has been a marked increase in asthma prevalence, particularly in Westernised countries. It has been proposed that changing diet has contributed to the increase in asthma. Several dietary hypotheses exist; the first relates the increase in asthma to declining dietary antioxidant intake, the second to decreased intake of long-chain n-3 PUFA and increasing intake of n-6 PUFA. Vitamin D supplementation and deficiency have also been hypothesised to have contributed to the increase in asthma. Observational studies have reported associations between asthma and dietary antioxidants (vitamin E, vitamin C, carotenoids, Se, flavonoids, fruit), lipids (PUFA, butter, margarine, fish) and vitamin D. However, supplementing the diets of adults with asthma with antioxidants and lipids has minimal, if any, clinical benefit. There is growing interest in the possibility that childhood asthma is influenced by maternal diet during pregnancy, with studies highlighting associations between childhood asthma and maternal intake of some nutrients (vitamin E, vitamin D, Se, PUFA) during pregnancy. It has been suggested that maternal diet during pregnancy influences fetal airway and/or immune development. Further intervention studies are needed to establish whether modification of maternal nutrient intake during pregnancy can be used as a healthy low-cost public health measure to reduce the prevalence of childhood asthma.

Antioxidants and allergic disease: a case of too little or too much?

Speculation persists as to the possible role, if any, of dietary antioxidants in allergic disease. While it has been hypothesized that the recent increase in allergic disease is a consequence of declining dietary antioxidant intake, an alternative hypothesis proposes that the increase in allergic disease is due to increasing antioxidant intake. Dietary trends are conflicting; the intake of some antioxidants has declined, for others intakes are likely to have increased. Animal model studies demonstrate that antioxidant supplementation at the time of primary and subsequent allergen exposure attenuates allergic inflammatory responses. The data from human studies are less clear. Observational epidemiological studies of humans are beset by several methodological limitations associated with the assessment of diet and predominantly focus on asthma. Most observational studies report potentially beneficial associations between dietary antioxidants and allergic outcomes, but a small minority report potentially adverse associations. Human intervention studies suggest that single antioxidant supplements confer minimal, if any clinical benefit in adults with asthma, however, there is still scope for studies in children, atopic dermatitis, allergic rhinitis (AR) and of antioxidant combinations. More recently, it has been suggested that dietary antioxidants in the developmental context of fetal and infant development influence the development childhood asthma and atopic sensitization possibly by affecting the first interactions between the neonatal immune system and allergens. While a small number of birth cohort studies have reported potentially beneficial associations between maternal intake of some antioxidants during pregnancy and childhood asthma, there is very limited data suggesting associations between maternal antioxidant intake and childhood atopic dermatitis and AR. The available epidemiological, animal, molecular and immunological data suggest that there are associations between antioxidants and asthma and to a much lesser extent, atopic dermatitis and AR. However, the exact nature of the relationships and the potential for therapeutic intervention remain unclear.

Nutrition and age-associated inflammation: implications for disease prevention

Accumulating evidence suggests that aging is associated with dysregulated immune and inflammatory responses. Investigation into the cellular and molecular mechanisms underlying this phenomenon suggests that an up-regulated cyclooxygenase (COX)-2 expression, and resulting increase in production of prostaglandin E(2) (PGE(2)), is a critical factor. Macrophages from old mice have significantly higher levels of PGE(2) production compared with those from young mice, a result of increased COX-2 expression and protein levels leading to increased COX enzyme activity. Furthermore, studies suggest that the age-associated increase in macrophage PGE(2) production is due to ceramide-induced up-regulation of nuclear factor-kappa B activation. Such processes may also occur in cell types other than macrophages, lending further insight into potential mechanisms of age-related diseases. Moreover, the excess PGE(2) induces harmful effects in other cell types such as T cells and adipocytes through the negative crosstalk between macrophages with other cells, resulting in further increased susceptibility to diseases. Nutrient/dietary medications, such as antioxidants and certain lipids have suggested a promising route to reduce the age-related increase in COX activity and PGE(2) production that is associated with several disease states.

Severe vitamin E deficiency modulates airway allergic inflammatory responses in the murine asthma model

Allergic asthma is a complex immunologically mediated disease associated with increased oxidative stress and altered antioxidant defenses. It was hypothesized that alpha-tocopherol (alpha-T) decreases oxidative stress and therefore its absence may influence allergic inflammatory process, a pathobiology known to be accompanied by oxidative stress. Therefore, selected parameters of allergic asthma sensitization and inflammation were evaluated following ovalbumin sensitization and re-challenge of alpha-T transfer protein (TTP) knock-out mice (TTP(-/-)) that have greatly reduced lung alpha-T levels (e.g.<5%) compared to their litter mate controls (TTP(+/+)). Results showed that severe alpha-T deficiency result in a blunted lung expression of IL-5 mRNA and IL-5 protein and plasma IgE levels compared with TTP(+/+) mice following immune sensitization and rechallenge, although lung lavage eosinophil levels were comparable in both genomic strains. It is concluded that the initial stimulation of immune responses by the TTP(-/-) mice were generally blunted compared to the TTP(+/+) mice, thus diminishing some aspects of subsequent allergic inflammatory processes.

Vitamin E ingestion improves several immune functions in elderly men and women

The effects of diet supplementation with the antioxidant vitamin E (200 mg daily) on several blood neutrophil, lymphocyte and natural killer cell functions have been investigated in healthy elderly men and women before supplementation, after 3 months of supplementation and 6 months after the end of supplementation (post-supplementation). In parallel, samples of healthy adult men and women were used as age controls. In elderly men and women, an impairment of immune functions was observed in comparison with the respective adult controls and the intake of vitamin E resulted in a significant enhancement of immune parameters in both elderly men and women, bringing their values close to those in the adults. These effects were not found in post-supplementation samples in several but not in all functions. The present findings suggest that supplementation with vitamin E can produce an improvement of immune functions and therefore of health in aged people.

Age-associated changes in immune and inflammatory responses: impact of vitamin E intervention

Aging is associated with dysregulated immune and inflammatory responses. Declining T cell function is the most significant and best-characterized feature of immunosenescence. Intrinsic changes within T cells and extrinsic factors contribute to the age-associated decline in T cell function. T cell defect seen in aging involves multiple stages from early receptor activation events to clonal expansion. Among extrinsic factors, increased production of T cell-suppressive factor PGE(2) by macrophages (Mphi) is most recognized. Vitamin E reverses an age-associated defect in T cells, particularly naïve T cells. This effect of vitamin E is also reflected in a reduced rate of upper respiratory tract infection in the elderly and enhanced clearance of influenza infection in a rodent model. The T cell-enhancing effect of vitamin E is accomplished via its direct effect on T cells and indirectly by inhibiting PGE(2) production in Mphi. Up-regulated inflammation with aging has attracted increasing attention as a result of its implications in the pathogenesis of diseases. Increased PGE(2) production in old Mphi is a result of increased cyclooxygenase 2 (COX-2) expression, leading to higher COX enzyme activity, which in turn, is associated with the ceramide-induced up-regulation of NF-kappaB. Similar to Mphi, adipocytes from old mice have a higher expression of COX-2 as well as inflammatory cytokines IL-1beta, IL-6, and TNF-alpha, which might also be related to elevated levels of ceramide and NF-kappaB activation. This review will discuss the above age-related immune and inflammatory changes and the effect of vitamin E as nutritional intervention with a focus on the work conducted in our laboratory.

The interaction between nutrition and infection

Infection and malnutrition have always been intricately linked. Malnutrition is the primary cause of immunodeficiency worldwide, and we are learning more and more about the pathogenesis of this interaction. Five infectious diseases account for more than one-half of all deaths in children aged <5 years, most of whom are undernourished. Micronutrient deficiencies have effects such as poor growth, impaired intellect, and increased mortality and susceptibility to infection. The worldwide magnitude of parasite infection is enormous. It is understood that parasites may lead to malnutrition, but the extent to which malnutrition causes increased parasite infestation is not known; thus, the conditions need to be addressed together. Nutritional deficiencies associated with pregnancy are associated with poor immune response to infection. Because this immune deficiency is partially compensated by breast-feeding, this is the single best way to protect infants from infection. Malnutrition and nutritional alterations, common complications of human immunodeficiency virus infection, include disorders of food intake, nutrient absorption, and intermediary metabolism and play a significant and independent role in morbidity and mortality. The 21st century provides new information and new challenges. With new technologies and political changes, it is hoped that a healthier, more disease-free, and better-nourished population will emerge.

Effect of exogenous vitamin E on proliferation and cytokine production in peripheral blood mononuclear cells from patients with tuberculosis

Micronutrient deficiencies are frequently associated with tuberculosis (TB) worldwide. We tested the effect of exogenous vitamin E on proliferation and cytokine production of peripheral blood mononuclear cells (PBMC) from TB patients and healthy purified protein derivative (PPD)+ volunteers. Proliferation was stimulated with mycobacterial antigen (PPD) and evaluated by the incorporation of tritiated thymidine in PBMC cultured with or without 50 microm-vitamin E for 6 d. Cytokine production (IL-2 and interferon (IFN)-gamma) was determined by intracellular cytokine staining and by ELISA in the supernatant of PBMC stimulated for 24 h with phytohaemagglutinin or PPD. Our results show that culture with vitamin E increased (P < or = 0.05 ) the antigen-induced proliferation of PBMC in TB patients but not in healthy PPD+ volunteers. No significant changes in the number of cytokine-producing cells or in the production of IFN-gamma were observed with vitamin E treatment. These results indicate that vitamin E may enhance the antigen-specific in vitro response of PBMC from TB patients.

Age-associated inflammatory changes: role of nutritional intervention

Accumulating evidence suggests that aging is associated with dysregulated immune and inflammatory responses. Investigation into the cellular and molecular mechanisms underlying this phenomenon suggests that an up-regulated cyclooxygenase (COX)-2 expression, and resulting increase in production of prostaglandin E2 (PGE2), is a critical factor. Macrophages from old mice have significantly higher levels of PGE2 production compared with those from young mice, a result of increased COX-2 expression and protein levels leading to increased COX enzyme activity. Further, it is possible that the age-associated increase in macrophage PGE2 production is due to ceramide-induced up-regulation of nuclear factor-kappa B activation. Such processes may also occur in cell types other than macrophages, lending further insight into potential mechanisms of age-related disease. More research is necessary to determine the efficacy of nutrient/dietary modifications, such as antioxidants and lipids, for reducing the age-related increase in COX activity and PGE2 production that are associated with several disease states.

Immunonutrition in surgical and critically ill patients

Surgery, trauma, burns and injury induce an inflammatory response that can become excessive and damaging in some patients. This hyperinflammation can be followed by an immunosuppressed state which increases susceptibility to infection. The resulting septic syndromes are associated with significant morbidity and mortality. A range of nutrients are able to modulate inflammation (and the associated oxidative stress) and to maintain or improve immune function. These include several amino acids, antioxidant vitamins and minerals, long-chain n-3 fatty acids and nucleotides. Experimental studies support a role for each of these nutrients in surgical, injured or critically ill patients. There is good evidence that glutamine influences immune function in such patients and that this is associated with clinical improvement. Evidence is also mounting for the use of long-chain n-3 fatty acids in surgical and septic patients, but more evidence of clinical efficacy is required. Mixtures of antioxidant vitamins and minerals are also clinically effective, especially if they include selenium. Their action appears not to involve improved immune function, although an anti-inflammatory mode of action has not been ruled out. Enteral immunonutrient mixtures, usually including arginine, nucleotides and long-chain n-3 fatty acids, have been used widely in surgical and critically ill patients. Evidence of efficacy is good in surgical patients. However whether these same mixtures are beneficial, or should even be used, in critically ill patients remains controversial, since some studies show increased mortality with such mixtures. There is a view that this is due to a high arginine content driving nitric oxide production.

Selected vitamins and trace elements support immune function by strengthening epithelial barriers and cellular and humoral immune responses

Adequate intakes of micronutrients are required for the immune system to function efficiently. Micronutrient deficiency suppresses immunity by affecting innate, T cell mediated and adaptive antibody responses, leading to dysregulation of the balanced host response. This situation increases susceptibility to infections, with increased morbidity and mortality. In turn, infections aggravate micronutrient deficiencies by reducing nutrient intake, increasing losses, and interfering with utilization by altering metabolic pathways. Insufficient intake of micronutrients occurs in people with eating disorders, in smokers (active and passive), in individuals with chronic alcohol abuse, in certain diseases, during pregnancy and lactation, and in the elderly. This paper summarises the roles of selected vitamins and trace elements in immune function. Micronutrients contribute to the body's natural defences on three levels by supporting physical barriers (skin/mucosa), cellular immunity and antibody production. Vitamins A, C, E and the trace element zinc assist in enhancing the skin barrier function. The vitamins A, B6, B12, C, D, E and folic acid and the trace elements iron, zinc, copper and selenium work in synergy to support the protective activities of the immune cells. Finally, all these micronutrients, with the exception of vitamin C and iron, are essential for antibody production. Overall, inadequate intake and status of these vitamins and trace elements may lead to suppressed immunity, which predisposes to infections and aggravates malnutrition. Therefore, supplementation with these selected micronutrients can support the body's natural defence system by enhancing all three levels of immunity.

Immunosupportive therapies in aging

The primary role of the immune system is to protect the organism against pathogens, but age-associated alterations to immunity increase the susceptibility of the elderly to infectious disease. The exact nature of these changes is still controversial, but the use of screening procedures, such as the SENIEUR protocol to exclude underlying illness, helped to better characterize the changes actually related to physiological aging rather than pathology. It is generally agreed that the most marked changes occur in the cellular immune response reflecting profound alterations in T cells. Much of this is due to thymic involution as well as changes in the proportions of T cell subpopulations resulting from antigen exposure, and altered T cell activation pathways. However, a body of data indicates that innate immune responses, including the critical bridge between innate and adaptive immunity, and antigen presenting capacity are not completely resistant to senescence processes. The consequences of all these alterations are an increased incidence of infections, as well as possibly cancers, autoimmune disorders, and chronic inflammatory diseases. The leading question is what, if anything, can we do to prevent these deleterious changes without dangerously dysregulating the precarious balance of productive immunity versus immunopathology? There are many potential new therapeutic means now available to modulate immunosenescence and many others are expected to be available shortly. One main problem in applying these experimental therapies is ethical: there is a common feeling that as ageing is not a disease; the elderly are not sick and therefore do not require adventurous therapies with unpredictable side-effects in mostly frail individuals. Animal models are not helpful in this context. In this chapter we will first briefly review what we think we know about human immunosenescence and its consequences for the health status of elderly individuals. We will then discuss possible interventions that might one day become applicable in an appropriate ethical environment.

Total alpha-tocopherol intakes are associated with serum alpha-tocopherol concentrations in African American adults

African Americans in the southern United States have a high prevalence of chronic disease. Tocopherol intake and status have been associated with protection against several chronic diseases. Our objectives were, therefore, to examine the association between tocopherol intakes as measured by 2 regional FFQ and their corresponding concentrations in serum and to report on dietary sources of tocopherols in 404 men and women participating in the cross-sectional Diet and Physical Activity Sub-Study of the Jackson Heart Study. A large proportion (49% of men and 66% of women) reported dietary supplement use. Only 5.8% of men and 4.5% of women met the estimated average requirement (EAR) for vitamin E from foods alone, whereas 44.2% men and 49.2% women met it from foods and supplements. Total (diet + supplement) intake of alpha-tocopherol was associated with its corresponding measure in serum. Vitamin E supplement use, sex, serum cholesterol, education, and BMI, but not gamma-tocopherol intakes, were associated with serum gamma-tocopherol. For delta-tocopherol, associated variables included sex and serum cholesterol. The top food sources of alpha- and gamma-tocopherol were snack chips and the top food source of delta-tocopherol was margarine. Despite prevalent vitamin E supplement use, more than one-half of this population did not meet the EAR for alpha-tocopherol intake and very few met it from food alone. Supplement use was associated with higher alpha- but lower gamma-tocopherol concentration in serum. The possible health implications of this difference in relative tocopherol subtypes require further study.

Contribution of selected vitamins and trace elements to immune function

Adequate intakes of vitamins and trace elements are required for the immune system to function efficiently. Micronutrient deficiency suppresses immune functions by affecting the innate T-cell-mediated immune response and adaptive antibody response, and leads to dysregulation of the balanced host response. This increases the susceptibility to infections, with increased morbidity and mortality. In turn, infections aggravate micronutrient deficiencies by reducing nutrient intake, increasing losses, and interfering with utilization by altering metabolic pathways. Insufficient intake of micronutrients occurs in people with eating disorders, in smokers (both active and passive), in individuals with chronic alcohol abuse, in patients with certain diseases, during pregnancy and lactation, and in the elderly. With aging a variety of changes are observed in the immune system, which translate into less effective innate and adaptive immune responses and increased susceptibility to infections. Antioxidant vitamins and trace elements (vitamins C, E, selenium, copper, and zinc) counteract potential damage caused by reactive oxygen species to cellular tissues and modulate immune cell function through regulation of redox-sensitive transcription factors and affect production of cytokines and prostaglandins. Adequate intake of vitamins B(6), folate, B(12), C, E, and of selenium, zinc, copper, and iron supports a Th1 cytokine-mediated immune response with sufficient production of proinflammatory cytokines, which maintains an effective immune response and avoids a shift to an anti-inflammatory Th2 cell-mediated immune response and an increased risk of extracellular infections. Supplementation with these micronutrients reverses the Th2 cell-mediated immune response to a proinflammatory Th1 cytokine-regulated response with enhanced innate immunity. Vitamins A and D play important roles in both cell-mediated and humoral antibody response and support a Th2-mediated anti-inflammatory cytokine profile. Vitamin A deficiency impairs both innate immunity (mucosal epithelial regeneration) and adaptive immune response to infection resulting in an impaired ability to counteract extracellular pathogens. Vitamin D deficiency is correlated with a higher susceptibility to infections due to impaired localized innate immunity and defects in antigen-specific cellular immune response. Overall, inadequate intake and status of these vitamins and minerals may lead to suppressed immunity, which predisposes to infections and aggravates malnutrition.

Cellular, molecular and clinical aspects of vitamin E on atherosclerosis prevention

Randomised clinical trials and epidemiologic studies addressing the preventive effects of vitamin E supplementation against cardiovascular disease reported both positive and negative effects, and recent meta-analyses of the clinical studies were rather disappointing. In contrast to that, many animal studies clearly show a preventive action of vitamin E in several experimental settings, which can be explained by the molecular and cellular effects of vitamin E observed in cell cultures. This review is focusing on the molecular effects of vitamin E on the cells playing a role during atherosclerosis, in particular on the endothelial cells, vascular smooth muscle cells, monocytes/macrophages, T cells, and mast cells. Vitamin E may act by normalizing aberrant signal transduction and gene expression in antioxidant and non-antioxidant manners; in particular, over-expression of scavenger receptors and consequent foam cell formation can be prevented by vitamin E. In addition to that, the cellular effects of alpha-tocopheryl phosphate and of EPC-K1, a composite molecule between alpha-tocopheryl phosphate and l-ascorbic acid, are summarized.

Early life events in asthma--diet

It has been hypothesized that the recent increase in the prevalence of asthma may, in part, be a consequence of changing diet. There is now increasing interest in the possibility that childhood asthma may be influenced by maternal diet during pregnancy and/or diet during early childhood. A number of observational studies and a childhood fish oil supplementation study provide little support for the notion that early childhood intake of polyunsaturated fatty acids (PUFAs) influence the development of childhood asthma. Recent work however, suggests that supplementation of maternal diet with fish oil is associated with altered neonatal immune responses to allergens. Further work is required to establish whether this immunological observation is translated into clinical outcomes. Two birth cohorts have now reported reduced maternal intake of vitamin E, zinc and vitamin D during pregnancy to be associated with increased asthma and wheezing outcomes in children up to the age of 5 years. Early life diet could modulate the likelihood of childhood asthma by affecting fetal airway development and/or influencing the initial early life interactions between allergens and the immune system. In animal models, vitamin E, zinc and vitamin D have been shown to modify fetal lung development and vitamin E, zinc, vitamin D and PUFA can modulate T-cell responses. Further research, particularly, early life intervention studies need to be carried out to establish whether early life dietary intervention can be used as a public health measure to reduce the prevalence of childhood asthma.

Update: effects of antioxidant and non-antioxidant vitamin supplementation on immune function

The purpose of this manuscript is to review the impact of supplementation with vitamins E and C, carotenoids, and the B vitamins on parameters of innate and adaptive immune function as reported from clinical trials in humans. There is evidence to support causal effects of supplementation with vitamins E and C and the carotenoids singly and in combination on selected aspects of immunity, including the functional capacity of innate immune cells, lymphocyte proliferation, and the delayed-type hypersensitivity (DTH) response. Controlled intervention trials of B vitamin-containing multivitamin supplements suggest beneficial effects on immune parameters and clinical outcomes in HIV-positive individuals.

Glutathione depletion inhibits dendritic cell maturation and delayed-type hypersensitivity: Implications for systemic disease and immunosenescence

BACKGROUND

Dendritic cells (DCs) play a key role as antigen-presenting cells in the immune system. There is growing evidence that the redox equilibrium of these cells influences their ability to induce T-cell activation and to regulate the polarity of the immune response. This could affect the outcome of the immune response during systemic diseases and aging.

OBJECTIVE

Our aim was to elucidate the mechanism by which the redox equilibrium of antigen-presenting DCs affects the delayed-type hypersensitivity (DTH) response during experimental modification of glutathione levels, as well as during aging.

METHODS

We looked at the effect of glutathione depletion by diethyl maleate in DCs as well as during systemic administration on the DTH response to the contact-sensitizing antigens, oxazolone, and 2,4-dinitro-1-fluorobenzene. We also determined whether glutathione repletion with N-acetyl cysteine could influence the decline of the DTH response in aged mice.

RESULTS

Glutathione depletion in bone marrow-derived DCs interfered in their ability to mount a DTH response on adoptive transfer into recipient mice. Glutathione depletion interfered in IL-12 production and costimulatory receptor expression in DCs, leading to decreased IFN-gamma production in the skin of recipient mice. Systemic diethyl maleate treatment exerted similar effects on the DTH response and IFN-gamma production, whereas N-acetyl cysteine administration reversed the decline of the DTH response in aged animals.

CONCLUSION

Glutathione depletion downregulates T(H)1 immunity through a perturbation of DC maturation and IL-12 production.

CLINICAL IMPLICATIONS

These data show that the induction of oxidative stress in the immune system, under disease conditions and aging, interferes in T(H)1 immunity.

Anti-inflammatory properties of alpha- and gamma-tocopherol

Natural vitamin E consists of four different tocopherol and four different tocotrienol homologues (alpha,beta, gamma, delta) that all have antioxidant activity. However, recent data indicate that the different vitamin E homologues also have biological activity unrelated to their antioxidant activity. In this review, we discuss the anti-inflammatory properties of the two major forms of vitamin E, alpha-tocopherol (alphaT) and gamma-tocopherol (gammaT), and discuss the potential molecular mechanisms involved in these effects. While both tocopherols exhibit anti-inflammatory activity in vitro and in vivo, supplementation with mixed (gammaT-enriched) tocopherols seems to be more potent than supplementation with alphaT alone. This may explain the mostly negative outcomes of the recent large-scale interventional chronic disease prevention trials with alphaT only and thus warrants further investigation.

Changes in plasma alpha and gamma tocopherol levels before and after long-term local hyperthermia in cancer patients

Local hyperthermia is one of the heat therapies for cancer patients. The effect of this therapy is recognized to affect the immune function. On the other hand, researchers have recently suggested that vitamin E has not only antioxidant but also other functions including the immune function. However, the association between local hyperthermia therapy and vitamin E level is not yet well understood. Comparing plasma alpha and gamma tocopherol levels before and after the therapy, the basal levels of both tocopherols in the cancer patients did not significantly differ from those in healthy subjects. However, the interindividual difference in the basal levels was very wide in the cancer patients. After long-term local hyperthermia (more than 70 days), the levels of both tocopherols were significantly higher than the basal levels. This result suggests that long-term local hyperthermia therapy influences plasma tocopherol level in cancer patients; thus, an increase in vitamin E level may play an important role in the therapy of cancer patients.

Oxidative stress in leukocytes from young prematurely aging mice is reversed by supplementation with biscuits rich in antioxidants

Aging is associated with a progressive dysregulation of immune responses as a result of increased oxidative stress. Therefore, we have assessed the oxidative stress status of peritoneal leukocytes from young prematurely aging mice (PAM) as compared with non-prematurely aging mice (NPAM), as well as the effects on this oxidative stress of a dietary supplementation with biscuits rich in antioxidants (vitamin C, vitamin E, beta-carotenes, zinc and selenium). We found that, in the peritoneal leukocytes, the levels of several parameters of oxidation such as extracellular superoxide anion (O(2)(-)), Prostaglandin E(2) (PGE(2)), nitric oxide, oxidized glutathione (GSSG) and lipid peroxidation (malondialdehyde, MDA) were higher in PAM as compared with NPAM, whereas the antioxidant defences such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione reductase (GR) activities, as well as reduced glutathione (GSH) levels, were decreased. Consequently, young PAM showed an oxidative stress in their leukocytes, which is characteristic of mice of an older chronological age. Antioxidant diet supplementation was able to restore redox homeostasis, increasing the antioxidant and decreasing the oxidant levels. Accordingly, supplementation with adequate levels of antioxidants, from an early age, could be useful to preserve health, especially in prematurely aging populations.