The influence of selenium on immune responses

Dietary micronutrients in the wake of COVID-19: an appraisal of evidence with a focus on high-risk groups and preventative healthcare

Existing micronutrient deficiencies, even if only a single micronutrient, can impair immune function and increase susceptibility to infectious disease. Certain population groups are more likely to have micronutrient deficiencies, while certain disease pathologies and treatment practices also exacerbate risk, meaning these groups tend to suffer increased morbidity and mortality from infectious diseases. Optimisation of overall nutritional status, including micronutrients, can be effective in reducing incidence of infectious disease. Micronutrient deficiencies are rarely recognised but are prevalent in the UK, as well as much more widely, particularly in high-risk groups susceptible to COVID-19. Practitioners should be aware of this fact and should make it a consideration for the screening process in COVID-19, or when screening may be difficult or impractical, to ensure blanket treatment as per the best practice guidelines. Correction of established micronutrient deficiencies, or in some cases assumed suboptimal status, has the potential to help support immune function and mitigate risk of infection. The effects of and immune response to COVID-19 share common characteristics with more well-characterised severe acute respiratory infections. Correction of micronutrient deficiencies has proven effective in several infectious diseases and has been shown to promote favourable clinical outcomes. Micronutrients appear to play key roles in mediating the inflammatory response and such effects may be enhanced through correction of deficiencies. Many of those at highest risk during the COVID-19 pandemic are also populations at highest risk of micronutrient deficiencies and poorer overall nutrition. Correction of micronutrient deficiencies in established COVID-19 infection may contribute to supporting immune response to infection in those at highest risk. There is a need for further research to establish optimal public health practice and clinical intervention regimens.

Effect of supra-nutritional selenium-enriched probiotics on hematobiochemical, hormonal, and Doppler hemodynamic changes in male goats

In this study, the influence of supra-nutritional organic selenium (Se) supplement on hematology and plasma biochemicals, including antioxidant parameters and plasma reproductive hormones, as well as blood flow characteristics in the supratesticular and common carotid arteries (STA and CCA, respectively) were investigated. For this purpose, 15 male goats were used and classified into three equal groups according to the supplementation of the basal diet (BD): negative control (NC), probiotic (Pro), and Se-probiotic (Se-Pro) groups. Blood perfusion in the STA and CCA was assessed by Doppler ultrasonography at three different time intervals: at the experimental onset (T0), 3 weeks of dietary supplement (T3), and after 6 weeks of observation (T6). Concomitantly, blood samples were withdrawn for hematobiochemical and hormonal changes. Results revealed no evidence of clinical abnormality, with some enhanced hematological parameters and antioxidant (SOD and GPX) levels in goats of the Se-Pro and Pro groups. High concentrations of FSH were found in the Se-Pro at T6 compared to its values in other groups. Similarly, testosterone levels were elevated in the Pro and Se-Pro groups at T3 compared to other time points. There were significant increases in levels of IGF-1 in the Pro and Se-Pro groups compared to the NC group. Significant (P < 0.05) increases in the values of the blood volume within the CCA and the STA were noted in the Se-Pro group, and the highest values were observed at T6 (CCA, 427.4 ± 33 ml/min; STA, 49.9 ± 5.0 ml/min). In conclusion, supra-nutritional organic selenium improves some hematobiochemical parameters, reproductive hormones, and the blood perfusion within the CCA and STA in goats.

Strengthening the Immune System and Reducing Inflammation and Oxidative Stress through Diet and Nutrition: Considerations during the COVID-19 Crisis

The coronavirus-disease 2019 (COVID-19) was announced as a global pandemic by the World Health Organization. Challenges arise concerning how to optimally support the immune system in the general population, especially under self-confinement. An optimal immune response depends on an adequate diet and nutrition in order to keep infection at bay. For example, sufficient protein intake is crucial for optimal antibody production. Low micronutrient status, such as of vitamin A or zinc, has been associated with increased infection risk. Frequently, poor nutrient status is associated with inflammation and oxidative stress, which in turn can impact the immune system. Dietary constituents with especially high anti-inflammatory and antioxidant capacity include vitamin C, vitamin E, and phytochemicals such as carotenoids and polyphenols. Several of these can interact with transcription factors such as NF-kB and Nrf-2, related to anti-inflammatory and antioxidant effects, respectively. Vitamin D in particular may perturb viral cellular infection via interacting with cell entry receptors (angiotensin converting enzyme 2), ACE2. Dietary fiber, fermented by the gut microbiota into short-chain fatty acids, has also been shown to produce anti-inflammatory effects. In this review, we highlight the importance of an optimal status of relevant nutrients to effectively reduce inflammation and oxidative stress, thereby strengthening the immune system during the COVID-19 crisis.

Nutrition, immunity and COVID-19

The immune system protects the host from pathogenic organisms (bacteria, viruses, fungi, parasites). To deal with this array of threats, the immune system has evolved to include a myriad of specialised cell types, communicating molecules and functional responses. The immune system is always active, carrying out surveillance, but its activity is enhanced if an individual becomes infected. This heightened activity is accompanied by an increased rate of metabolism, requiring energy sources, substrates for biosynthesis and regulatory molecules, which are all ultimately derived from the diet. A number of vitamins (A, B6, B12, folate, C, D and E) and trace elements (zinc, copper, selenium, iron) have been demonstrated to have key roles in supporting the human immune system and reducing risk of infections. Other essential nutrients including other vitamins and trace elements, amino acids and fatty acids are also important. Each of the nutrients named above has roles in supporting antibacterial and antiviral defence, but zinc and selenium seem to be particularly important for the latter. It would seem prudent for individuals to consume sufficient amounts of essential nutrients to support their immune system to help them deal with pathogens should they become infected. The gut microbiota plays a role in educating and regulating the immune system. Gut dysbiosis is a feature of disease including many infectious diseases and has been described in COVID-19. Dietary approaches to achieve a healthy microbiota can also benefit the immune system. Severe infection of the respiratory epithelium can lead to acute respiratory distress syndrome (ARDS), characterised by excessive and damaging host inflammation, termed a cytokine storm. This is seen in cases of severe COVID-19. There is evidence from ARDS in other settings that the cytokine storm can be controlled by n-3 fatty acids, possibly through their metabolism to specialised pro-resolving mediators.

Selenium and stable mercury isotopes provide new insights into mercury toxicokinetics in pilot whales

High exposures of mammalian species to inorganic mercury (Hg^II) and methylmercury (MeHg) have been associated with adverse effects on behavior and reproduction. Different mammalian species exhibit varying responses to similar external exposure levels, reflecting potential differences in Hg toxicokinetics. Here, we use Hg stable isotopes, total Hg, MeHg and selenium (Se) concentrations measured in multiple tissues of North Atlantic pilot whales (Globicephala melas) to investigate processes affecting the distribution and accumulation of Hg^II and MeHg. We find that simple mixing of two distinct isotopic end-members: MeHg (1.4‰) and Hg^II (-1.6‰) can explain the observed variability of δ²⁰²Hg in brain tissue. A similar isotopic composition for the MeHg end-member in the brain, muscle, heart, and kidney suggests efficient exchange of MeHg in blood throughout the body. By contrast, the Hg isotopic composition of the liver of adult whales is different from younger whales and other tissues that follow the two-end member mixing model. Measured Se:Hg ratios are lowest in adult whales with the highest levels of MeHg exposure. In these individuals, Se availability is likely reduced by complexation with demethylated Hg^II. We speculate that this results in a higher fraction of labile Hg^II eliminated from the liver of adult whales compared to young whales and subsequent redistribution to other tissues, potentially affecting toxicity.

Development of Polylactic Acid Films with Selenium Microparticles and Its Application for Food Packaging

Selenium is a natural element which exists in the human body and plays an important role in metabolism. Along with this, selenium also possesses antibacterial and antioxidant properties. Using selenium microparticles (SeMPs) in food packaging films is exceptional. In this experiment, a solution casting method was used to make film. For this purpose, we used polylactic acid (PLA) as a substrate for the formation of a film membrane while SeMPs were added with certain ratios to attain antibacterial and antioxidant properties. The effects of SeMPs on the PLA film and the value of SeMPs in food packaging film production were investigated. The effects of the SeMPs contents on the features of the film, such as its mechanical property, solubility, swelling capacity, water vapor permeability, antioxidant activity, and the antibacterial activity of the composite membrane against Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative) strains, were studied. The results manifest that the PLA/SeMPs films showed higher water resistance, UV resistance, antioxidant activity, and antibacterial activity than pure PLA film. When the concentration of SeMPs was 1.5 wt%, the composite membrane showed the best comprehensive performance. Although the tensile strength and elongation at break of the membrane were slightly reduced by the addition of SeMPs, the results show that PLA/SeMPs films are still suitable for food packaging and would be a very promising material for food packaging.

The effect of selenium on the autophagy of macrophage infected by Staphylococcus aureus

Selenium can alleviate the inflammatory reaction infected by Staphylococcus aureus (S. aureus). However, the role of selenium on the autophagy in RAW264.7 macrophages infected by S. aureus has not been reported. The goal of this study was to clarify the effect of selenium on the autophagy and related inflammatory pathways (MAPK and NF-κB) in RAW264.7 macrophages infected by S. aureus. RAW264.7 macrophages were co-treated with Na₂SeO₃ and S. aureus. The expression of related inflammatory pathways (MAPK and NF-κB) and autophagy-related proteins were detected by Western blotting. The microtubule-binding protein light chain 3 (LC3) puncta were measured with immunofluorescence staining. The ultrastructure of RAW264.7 macrophages infected by S. aureus was detected by transmission electron microscope (TEM). And plate counting method was used to detect the proliferation of S. aureus in RAW264.7 macrophages. The results showed that the expression levels of LC3 II increased and the expression levels of p62 decreased after adding selenium, compared with S. aureus infection group. Compared with S. aureus infection group, the intracellular LC3 puncta and autophagic vesicles, autophagosomes, and autolysosomes increased with selenium supplementation. The number of S. aureus proliferation decreased with addition of selenium, compared with S. aureus infection group. Selenium could significantly inhibit the phosphorylation of MAPK and NF-κB signaling pathway key proteins, compared with S. aureus infection group. In summary, selenium could promote the autophagy in macrophages infected by S. aureus, alleviate the blockade of autophagic flow, depress the transcription of MAPK and NF-κB signaling pathways, and inhibit the proliferation of S. aureus in RAW264.7 macrophages.

Selenium Status in Elderly People: Longevity and Age-Related Diseases

BACKGROUND

Selenium (Se) is a trace element active in selenoproteins, which can regulate oxidative stress. It is generally perceived as an import factor for maintaining health in the elderly.

METHODS

The goal of this review is to discuss selenium concentration in biological samples, primarily serum or plasma, as a function of age and its relation with longevity. The elemental level in various age-related diseases is reviewed.

CONCLUSION

Highest selenium values were observed in healthy adults, while in an elderly population significantly lower concentrations were reported. Variables responsible for contradictory findings are mentioned. Risk and benefits of Se-supplementation still remain under debate.

Selenium level does not differ in blood but increased in cerebrospinal fluid in Parkinson's disease: a meta-analysis

Objective: Recent studies have found that selenium (Se) levels were associated with the risk of Parkinson's disease (PD), but the results were contradictory. Therefore, this meta-analysis was conducted to investigate the correlation between Se levels and PD.Methods: PubMed, Embase and Web of Science were searched published up to 28 October 2019. The differences between groups were analyzed by forest plots and results were pooled and assessed using a random-effect model. Standardized mean difference (SMD) and 95% confidence interval (CI) were used to assess the association between Se levels and the risk of PD. Subgroup analysis, meta-regression, and sensitivity analysis were also conducted. Publication bias was estimated using Begg's regression asymmetry test.Results: Finally, 12 articles involving 601 PD patients and 749 controls were included in this meta-analysis. The meta-analysis revealed a significantly higher cerebrospinal fluid (CSF) Se level in PD patients than those in controls (SMD = 1.22; 95%CI [0.05, 2.39]; p = 0.000). No publication bias was found.Conclusion: The meta-analysis indicated that CSF Se levels in PD patients were significantly higher than those in controls.

Selenium and Zinc Biofortification of Pleurotus eryngii Mycelium and Fruiting Bodies as a Tool for Controlling Their Biological Activity

Pleurotus eryngii (DC:Fr.) Quel. is a cultivated mushroom of high culinary value and medicinal properties. Mycelium of P. eryngii is characterized by the ability of effective bio-elements absorption from growth media so it could be biofortified with trace elements with a functional activity in the human body. In this study, the ability of P. eryngii mycelia from in vitro cultures as well as fruiting bodies were investigated in terms of their effectiveness in zinc and selenium accumulation. The effect of Se and Zn biofortification on productivity, chemical compounds, and bio-elements content of P. eryngii was determined as well. To enhance Se and Zn content in P. eryngii fruiting bodies and mycelia, substrates were supplemented with sodium selenite, at a concentration of 50 mg L^-1, zinc sulfate, and zinc hydro-aspartate at a concentration of 87.2 and 100.0 mg L^-1, respectively. Mentioned Zn concentrations contained the same amount of zinc(II) ions, namely 20 mg L^-1. The content of organic compounds include phenolic compounds and lovastatin, which were determined by a high-performance liquid chromatography with diode-array detector (HPLC-DAD) and reverse phase high-performance liquid chromatography (RP-HPLC) method with UV detection. The ability of P. eryngii to accumulate zinc and selenium from the culture medium was demonstrated. The degree of accumulation of zinc turned out to be different depending on the type of salt used. The present study also showed that conducting mycelium of P. eryngii in in vitro culture, with a higher content of zinc ions, can result in obtaining the materials with better antioxidant ability. The results of this study can be used to develop the composition of growing media, which ensures the production of biomass with the desired composition of elements.

Biogenic selenium nanoparticles target chronic toxoplasmosis with minimal cytotoxicity in a mouse model

Introduction. Nanoparticles (NPs) have numerous biological benefits due to their large surface-volume ratio and convenient entry into cells compared to other particles. Previous research has shown the antimicrobial properties of biogenic selenium NPs (SeNps) and their effects on cellular immunomodulatory cytokines that play a key role in controlling infections.Aim. This study aimed to evaluate the therapeutic effects of SeNPs against chronic toxoplasmosis in mice.Methodology. Infected mice with Toxoplasma gondii (Tehran strain) were orally treated with SeNPs at doses of 2.5, 5 and 10 mg kg^-1 once a day for 14 days. On the fifthteenth day, the mean number of brain-tissue cysts and the mRNA levels of TNF-α, IL-12, IL-10, IFN-γ and inducible nitric oxide synthase (iNOS) in the mice of each group were recorded. Moreover, serum clinical chemistry factors in the treated mice were examined to determine the safety of SeNPs.Results. The mean number of tissue cysts was significantly (P<0.001) decreased in mice treated with SeNPs in a dose-dependent manner compared with the control group. The mRNA levels of inflammatory cytokines were significantly increased in mice treated with SeNPs at a dose of 10 mg kg^-1 compared with the control subgroup (P<0.05). No significant variation (P>0.05) observed in clinical chemistry parameters among the mice in the control subgroup compared with those treated with SeNPs.Conclusion. The findings demonstrated the therapeutic effects of SeNPs with no considerable toxicity against latent toxoplasmosis in the mouse model. Nevertheless, further studies are obligatory to reveal the exact anti-Toxoplasma mechanisms of SeNPs.

The potential markers involved in newly diagnosed graves' disease and the development of active graves' orbitopathy

BACKGROUND

Graves' disease (GD) patients experience two major issues: one is the severe hyperthyroidism associated with newly diagnosed GD, and the other involves the disfiguring and dysfunctional features of active Graves' orbitopathy (GO). Therefore, the aim of our study was to identify potential markers involved in the initial phase of GD dysfunction and the development of active GO.

METHODS

Seventy-eight subjects were recruited: 40 with newly diagnosed GD, 20 with inactive GO and 18 with active GO. GO activity was evaluated by the clinical activity score (CAS, active GO = CAS ≥ 3), and severity was assessed according to the NOSPECS classification. Plasma selenium concentrations were determined by dual channel hydride generation atomic fluorescence photometry. A liquid chip assay was used to measure plasma Th1 cytokines IFN-γ and TNF-α; Th2 cytokines IL4, IL5 and IL6; Th17 cytokine IL23; Treg cytokines IL10 and TGF-β; and two chemokines, CCL2 (Th2 chemokine) and CXCL10 (Th1 chemokine).

RESULTS

Among the three groups, newly diagnosed GD patients showed significantly elevated plasma levels of CXCL10 and IL-23 (all p < 0.05). Both CXCL10 and IL23 were significantly correlated with hyperthyroidism severity, specifically, increasing FT3 and FT4 and decreasing TSH. Notably, a very strong positive relationship between IL23 and CXCL10 was revealed (adjusted R square = 0.795; p < 0.001). Moreover, the selenium level was lower, while that of CCL2 was higher, in active GO than in inactive GO (p = 0.007, p < 0.001, respectively). Likewise, we also discovered that increasing CCL2 levels and decreasing selenium levels were associated with high CAS. Remarkably, after adjusting for potential confounding factors, selenium (OR, 0.919) and CCL2 (OR, 1.042) were still independent predictors for the diagnosis of active GO, and similar conclusions were drawn by receiver operating characteristic (ROC) curve analysis.

CONCLUSION

Pro-inflammatory cytokines, especially Th17-associated cytokines (e.g., IL23) and Th1 chemokines (e.g., CXCL10), appear to be involved in the initial phase of GD dysfunction. Moreover, we revealed for the first time that decreased plasma selenium levels and increased concentrations of Th2 chemokines (e.g., CCL2) may reflect GO disease activity, shedding light on the diagnosis and evaluation of active GO.

Comparison of selenium bioavailability in milk and serum in dairy cows fed different sources of organic selenium

Context Selenium (Se) bioavailability is an important parameter to consider when supplementing trace minerals to optimise animal health and performance. Aims To assess the biological transfer of Se in milk and serum of three sources of organic Se in dairy cattle: two different pure selenomethionines (SM1, SM2) and Se-yeast (SY) containing selenomethionine, selenocysteine and other forms of organic Se. Methods Forty-five lactating Holstein dairy cows were randomly distributed in nine groups (three sources of organic Se supplemented at three doses: 0.1, 0.2 and 0.3 ppm organic Se in addition to 0.3 ppm of inorganic Se) and the Se concentrations in milk and serum were analysed at different times over 34 days of supplementation. Dry matter intake, milk yield, as well as milk fat and protein contents were recorded daily for each cow. Selenium bioavailability in milk was assessed as the ratio between amount of Se secreted in milk and amount of Se consumed. Key results The lowest Se dose (0.1 ppm), independent of source, did not allow detection a different pattern of transfer into milk and serum, suggesting that at this level, the Se supplied was mainly used to cover the animal needs. Supplementing SY at 0.2 and 0.3 ppm resulted in the most consistent secretion of Se into milk, whereas SM2 was most effective at increasing serum Se concentrations. Conclusions At the supplementing doses of 0.2 and 0.3 ppm, SY elicits an increased transfer of Se into milk concentrations compared with SM1 and SM2, whereas SM2 induces the greatest increase in Se serum concentrations. Implications SY is more effective than SM1 and SM2 at increasing Se transfer into milk. Supplementation of SM2 induces a pattern of Se transfer into milk and serum that differs from the other Se sources suggesting a different metabolism of this particular Se source.

The Strategy of Boosting the Immune System Under the COVID-19 Pandemic

The novel coronavirus (SARS-CoV-2) infection (COVID-19) has raised considerable concern on the entire planet. On March 11, 2020, COVID-19 was categorized by the World Health Organization (WHO) as a pandemic infection, and by March 18, 2020, it has spread to 146 countries. The first internal defense line against numerous diseases is personalized immunity. Although it cannot be claimed that personalized nutrition will have an immediate impact on a global pandemic, as the nutritional interventions required a long time to induce beneficial outcomes on immunity development, nutritional strategies are still able to clarify and have a beneficial influence on the interplay between physiology and diet, which could make a positive contribution to the condition in the next period. As such, a specific goal for every practitioner is to evaluate different tests to perceive the status of the patient, such as markers of inflammation, insulin regulation, and nutrient status, and to detect possible imbalances or deficiencies. During the process of disease development, the supplementation and addition of different nutrients and nutraceuticals can influence not only the viral replication but also the cellular mechanisms. It is essential to understand that every patient has its individual needs. Even though many nutrients, nutraceuticals, and drugs have beneficial effects on the immune response and can prevent or ameliorate viral infections, it is essential to detect at what stage in COVID-19 progression the patient is at the moment and decide what kind of nutrition intervention is necessary. Furthermore, understanding the pathogenesis of coronavirus infection is critical to make proper recommendations.

Effects of Gene-Eden-VIR and Novirin on SARS-CoV: Implications for COVID-19

The coronavirus (SARS-CoV-2), which causes COVID-19, is a betacoronavirus closely related to the human severe acute respiratory syndrome (SARS)-coronavirus (SARS-CoV). The recent COVID-19 outbreak created an urgent need for treatment. To expedite the development of such treatment, pharmaceutical companies and government agencies are currently testing several existing drugs for their effect on the virus. Gene-Eden-VIR and Novirin are natural, broad-spectrum, antiviral treatments proven to be safe and effective in several clinical studies. In this article, we present evidence indicating that the 5 Gene-Eden-VIR/Novirin ingredients have anti-betacoronavirus, and specifically, anti-SARS-CoV effects. We consider this evidence as a first indication of the anti-coronavirus effects of Gene-Eden-VIR/Novirin. Next, we are planning to conduct a clinical study with users of the treatments to test the effects of Gene-Eden-VIR/Novirin on individuals at risk and those infected with the virus.

Epidemiological study of kidney health in an area with high levels of soil cadmium and selenium: Does selenium protect against cadmium-induced kidney injury?

Chronic exposure to cadmium (Cd) can cause renal dysfunction. Studies of animals, cell cultures, and plants have found that selenium (Se) can effectively alleviate the hazard generated by Cd, but there has been little study of this in general human populations. This study recruited 313 subjects from China's Hubei Province, including 160 living in areas with high soil Cd and Se (exposure group) and 153 living in clean areas (control group). The levels of the following were detected: Cd and Se in blood (B-Cd and B-Se), urine (U-Cd and U-Se), and hair (H-Cd and H-Se); N-acetyl-β-D-glucosaminidase (U-NAG), β₂-microglobulin (U-β₂-MG), and albumin (U-ALB) in urine; and malondialdehyde (S-MDA), superoxide dismutase (S-SOD), and glutathione peroxidase (S-GSH-Px) in serum. In addition, the interactions between Cd and Se were assessed. The median levels of B-Cd, B-Se, U-Cd, U-Se, H-Cd, H-Se, S-MDA, and S-GSH-Px of exposure group (2.60 ng/mL, 238.90 ng/mL, 3.13 μg/g Cr, 45.43 μg/g Cr, 0.06 μg/g, 0.70 μg/g, 5.22 nmol/mL, and 308.89 U, respectively) were significantly higher than of controls (0.95 ng/mL, 130.50 ng/mL, 1.08 μg/g Cr, 30.51 μg/g Cr, 0.04 μg/g, 0.49 μg/g, 4.71 nmol/mL, and 267.54 U, respectively), but there were no significant differences in U-NAG, U-β₂-MG, U-ALB, or S-SOD between the two groups. U-NAG levels were significantly negatively associated with the interaction between Cd and Se (B: -0.511, 95% CI: -0.886, -0.136). Additionally, changes in the direction of the estimated regression coefficient in the low and high H-Se groups were observed for U-Cd and S-MDA (from 0.018 to -0.090), U-Cd and S-GSH-Px (from -0.039 to 0.101). This study found that populations living in areas with high levels of soil Cd and Se did not show greater Cd-induced renal tubular and glomerular injuries than the control population, which could attribute to the protective effects of Se. The protective effects may be related to the peculiar function of Se that Se can combine with free Cd to activate the antioxidant enzyme system.

Effects of Dietary Selenium Deficiency or Excess on Selenoprotein Gene Expression in the Spleen Tissue of Pigs

To evaluate the effects of dietary Se deficiency and excess on the mRNA levels of selenoproteins in pig spleen tissues, 20 healthy uncastrated boars (Duroc × Landrace × Yorkshire, 10 ± 0.72 kg) were randomly divided into four groups (5 pigs per group). The pigs were fed a Se deficient corn-soybean basal feed (Se content <0.03 mg/kg) or basal feed with added sodium selenite at 0.3, 1.0, or 3.0 mg Se/kg diet, respectively. The experiment lasted 16 weeks. The spleen tissue was collected to examine the mRNA expression levels of 24 selenoprotein genes at the end of the study. Compared with pigs in other groups, those fed with the 1.0 mg Se/kg diet had higher mRNA levels of glutathione peroxidase 1 (Gpx1), glutathione peroxidase 2 (Gpx2), deiodinase type II (Dio2), thioredoxin reductase 3 (Txnrd3), selenoprotein H (Selh), selenoprotein N, 1 (Sepn1), selenoprotein P1 (Sepp1), and selenoprotein V (Selv) in the spleen (p < 0.05). Dietary Se deficiency resulted in lower mRNA levels of Gpx1, Gpx2, glutathione peroxidase 3 (Gpx3), Dio2, thioredoxin reductase 2 (Txnrd2), Txnrd3, Selh, selenoprotein I (Seli), selenoprotein K (Selk), selenoprotein M (Selm), Sepn1, Sepp1, and Selv in the spleen than the other three groups. Dietary Se levels did not affect the mRNA levels of glutathione peroxidase 4 (Gpx4), deiodinase type I (Dio1), deiodinase type III (Dio3), selenophosphate synthetase 2 (Sephs2), thioredoxin reductase 1 (Txnrd1), selenoprotein O (Selo), selenoprotein S (Sels), selenoprotein W (Selw), selenoprotein X (Selx), and selenoprotein 15 (Sel15) in the spleen (p > 0.05). Dietary Se levels can affect the transcription levels of 14 selenoprotein genes in the spleen of pigs.

Phenotypic and genetic analysis of milk and serum element concentrations in dairy cows

Enhancing micronutrient (i.e., mineral and vitamin) concentrations within milk and serum from dairy cows is important for both the health of the cow and the nutritive value of the milk for human consumption. However, a good understanding of the genetics underlying the micronutrient content in dairy cattle is needed to facilitate such enhancements through feeding or breeding practices. In this study, milk (n = 950) and serum (n = 766) samples were collected from Holstein-Friesian dairy cows (n = 479) on 19 occasions over a 59-mo period and analyzed for concentrations of important elements. Additionally, a subset of 256 milk samples was analyzed for concentrations of vitamin B₁₂. Cows belonged to 2 genetic lines (average and highest genetic merit for milk fat plus protein yield) and were assigned to 1 of 2 diets based on either a by-product or homegrown ration. Univariate models accounting for repeated records were used to analyze element and vitamin B₁₂ data and investigate the effect of genotype and feeding system as well as derive estimates of variance components and genetic parameters. Bivariate models were used to study correlations both within and between milk and serum. Only concentrations of Hg in milk were seen to be affected by genotype, with higher concentrations in cows with high genetic merit. In contrast, element concentrations were influenced by feeding system such that cows fed the homegrown diet had increased milk concentrations of Ca, Cu, I, Mn, Mo, P, and K and increased serum concentrations of Cd, Cu, Fe, Mo, and V. Cows on the by-product diet had increased milk concentrations of Mg, Se, and Na and increased serum concentrations of P and Se. Heritability (h²) estimates were obtained for 6 milk and 4 serum elements, including Mg (h²_milk = 0.30), K (h²_serum = 0.18), Ca (h²_milk = 0.20; h²_serum = 0.12), Mn (h²_milk = 0.14), Cu (h²_serum = 0.22), Zn (h²_milk = 0.24), Se (h²_milk = 0.15; h²_serum = 0.10), and Mo (h²_milk = 0.19). Significant estimates of repeatability were observed in all milk and serum quantity elements (Na, Mg, P, K, and Ca) as well as 5 milk and 7 serum trace elements. Only K in milk and serum was found to have a significant positive genetic and phenotypic correlation (0.52 and 0.22, respectively). Significant phenotypic associations were noted between milk and serum Ca (0.17), Mo (0.19), and Na (-0.79). Additional multivariate analyses between measures within sample type (i.e., milk or serum) revealed significant positive associations, both phenotypic and genetic, between some of the elements. In milk, Se was genetically correlated with Ca (0.63), Mg (0.59), Mn (0.40), P (0.53), and Zn (0.52), whereas in serum, V showed strong genetic associations with Cd (0.71), Ca (0.53), Mn (0.63), Mo (0.57), P (0.42), K (0.45), and Hg (-0.44). These results provide evidence that element concentrations in milk and blood of dairy cows are significantly influenced by both diet and genetics and demonstrate the potential for genetic selection and dietary manipulation to alter nutrient concentration to improve both cow health and the healthfulness of milk for human consumption.

Food as medicine: Selenium enriched lentils offer relief against chronic arsenic poisoning in Bangladesh

Chronic arsenic (As) exposure is a major environmental threat to human health affecting >100 million people worldwide. Low blood selenium (Se) increases the risk of As-induced health problems. Our aim was to reduce As toxicity through a naturally Se-rich lentil diet. In a randomized, double-blind, placebo-control trial in Bangladesh, 405 participants chronically exposed to As were enrolled. The intervention arm (Se-group) consumed Se-rich lentils (55 μg Se/day); the control arm received lentils of similar nutrient profile except with low Se (1.5 μg Se/day). Anthropometric measurements, blood, urine and stool samples, were taken at baseline, 3 and 6 months; hair at baseline and 6 months after intervention. Morbidity data were collected fortnightly. Measurements included total As in all biological samples, As metabolites in urine, and total Se in blood and urine. Intervention with Se-rich lentils resulted in higher urinary As excretion (p = 0.001); increased body mass index (p ≤ 0.01), and lower incidence of asthma (p = 0.05) and allergy (p = 0.02) compared to the control group. The Se-group demonstrated increased excretion of urinary As metabolite, dimethylarsinic acid (DMA) at 6 months compared to control group (p = 0.008). Consuming Se-rich lentils can increase As excretion and improve the health indicators in the presence of continued As exposure.

A pilot study on the beneficial effects of additional selenium supplementation to methimazole for treating patients with Graves’ disease

Background/aim

The aim of this study was to assess the effect of a combination use of methimazole (MMI) and selenium (Se) in the treatment of Graves’ disease (GD).

Materials and methods

A total of 103 newly diagnosed hyperthyroidism patients were randomized to MMI and MMI + Se combination groups. After treatment for 6 months, the levels of triiodothyronine (FT3), free thyroxine (FT4), thyrotropin receptor antibody (TRAb), thyroid peroxidase antibody (TPOAb), and thyroglobulin antibody (TGAb) were observed. An in vitro culture model of thyroid cells was established and the protein expression and mRNA levels of TRAb, TPOAb, and TGAb were determined by western blot and RT-PCR.

Results

A significant decrease in the levels of FT3, FT4, TRAb, TPOAb, and TGAb were observed in both groups along with a marked increase in TSH levels. Furthermore, the in vitro experiments showed that the protein expression and mRNA levels of TRAb, TPOAb, and TGAb decreased significantly. Also, compared to the MMI group, there was a greater improvement of these indices in the MMI + Se group.

Conclusion

We suggest that the combined use of MMI and Se could improve the thyroid activity in patients, which may provide an effective therapy for the treatment of GD in clinical settings.

The Role of Micronutrients in the Infection and Subsequent Response to Hepatitis C Virus

Micronutrient deficiencies develop for a variety of reasons, whether geographic, socioeconomic, nutritional, or as a result of disease pathologies such as chronic viral infection. As micronutrients are essential for a strong immune response, deficiencies can significantly dampen both the innate and the adaptive arms of antiviral immunity. The innate immune response in particular is crucial to protect against hepatitis C virus (HCV), a hepatotropic virus that maintains chronic infection in up to 80% of individuals if left untreated. While many micronutrients are required for HCV replication, an overlapping group of micronutrients are also necessary to enact a potent immune response. As the liver is responsible for the storage and metabolism of many micronutrients, HCV persistence can influence the micronutrients' steady state to benefit viral persistence both directly and by weakening the antiviral response. This review will focus on common micronutrients such as zinc, iron, copper, selenium, vitamin A, vitamin B12, vitamin D and vitamin E. We will explore their role in the pathogenesis of HCV infection and in the response to antiviral therapy. While chronic hepatitis C virus infection drives deficiencies in micronutrients such as zinc, selenium, vitamin A and B12, it also stimulates copper and iron excess; these micronutrients influence antioxidant, inflammatory and immune responses to HCV.

Spatial Variation of Human Selenium in Ethiopia

Selenium is an important nutrient for humans and livestock. Soil selenium concentration in the world is highly variable; deficiency and toxicity occur in populations living short distance apart. Knowledge of Se concentrations in humans and the environments, especially because the range for toxicity and deficiency is narrow, is important for effective intervention. Dietary data and serum samples were collected from children (n = 555) 69-78 months old from rural villages of the Amhara Region, Ethiopia. In addition, information on the socio-demography of households was collected. Serum Se was analyzed by inductively coupled plasma mass spectrometer. Almost all (90.3%) of participants reported eating grain, roots, or tubers 24 h preceding the survey followed by legumes, nuts, and seeds (64.6%). Consumption of animal source foods was very low (4.6%). Compared to children from the western part of the region, children from eastern Amhara had higher dietary diversity score (2.1 ± 0.9 vs 1.8 ± 0.7; p < 0.001).The median serum Se concentration was 70.6 μg/l (IQR 48.2, 96.6). Selenium inadequacy (serum Se < 70 μg/l) was detected in 49.1% of children. However, the distribution had an important geographical pattern across administrative zones. Children from the western part of the Amhara Region were highly deficient (up to 91.1% prevalence), while there was little or no Se deficiency in children from the eastern part of the region. Serum Se level exhibited an important spatial variation in the Amhara Region, Ethiopia. Further studies investigating contributing factors for the variation such as soil characteristics and Se concentration in staple crops are needed.

Assessment of 7 trace elements in serum of patients with nontuberculous mycobacterial lung disease

Nontuberculous mycobacterial (NTM) lung diseases are an emerging cause of pulmonary infection, becoming more common in the clinical setting as incidence of NTM lung diseases steadily increases worldwide. Trace elements are essential micronutrients and are known to play many important roles in infectious diseases. We investigated the concentrations of trace elements in patients with NTM lung disease and compared these values to patients with pulmonary tuberculosis and healthy controls. A case-control study was conducted to evaluate the serum trace element concentrations in 95 patients with NTM lung disease, 97 patients with pulmonary tuberculosis, and 99 healthy control subjects. The serum concentrations of 7 trace elements (cobalt, copper, chromium, manganese, molybdenum, selenium, and zinc) were measured using inductively coupled plasma-mass spectrometry. We also analyzed demographic data, clinical outcomes, and other biochemical parameters. The median serum concentrations of copper and molybdenum were higher in patients with NTM lung disease (109 vs. 91 μg/dL, p < 0.001 and 1.70 vs. 0.96 μg/L, p < 0.001). In contrast, the median serum concentrations of selenium and zinc were significantly lower in patients with NTM lung disease than in healthy controls (105 vs. 115 μg/L, p < 0.001 and 94 vs. 102 μg/dL, p < 0.001). Compared to patients with pulmonary tuberculosis, the serum concentrations of molybdenum and zinc were higher in patients with NTM lung disease, while cobalt and copper concentrations were lower (p < 0.001). Correlations among trace element concentrations were observed (copper and zinc, r = -0.367; cobalt and molybdenum, r = -0.360; selenium and zinc, r = 0.335; and manganese and zinc, r = 0.327, respectively). None of the 7 trace elements were associated with treatment outcomes. Patients with NTM lung disease showed different serum trace element concentrations. Our study indicates that altered trace element status is associated with mycobacterial disease. Further study investigating the clinical significance of individual trace elements and their association with nutritional status in patients with NTM lung disease would be required.

Plasma Selenium and Cadmium Levels in Patients with Chronic Otitis Media in a Turkish Population and Their Relation to Inflammation Markers

Chronic otitis media (COM) is a multifactorial process, for which a clear etiology has not yet been established. The aims of the present study were to evaluate selenium (Se) and cadmium (Cd) levels in patients with COM and to analyze the correlation between Se and Cd with inflammation markers. The study population consisted of 88 participants: 45 healthy controls (group 1) and 43 patients with COM (group 2). Demographic data, Se, Cd, C-reactive protein (CRP), and white blood cell count (WBC) levels were all recorded. Se and Cd measurements were performed in a graphite furnace atomic absorption spectrophotometer (Perkin Elmer Analyst 800) using Zeeman background correction. The Se and Cd levels were compared between the groups and the correlation between Se and Cd with inflammation markers was analyzed. No statistically significant difference was determined between the groups in terms of demographic data (p > 0.05). CRP and WBC levels were significantly higher in group 2 than in group 1 (p < 0.05). Se levels were significantly lower in group 2 than in group 1, at 23.40 ± 12.08 μg/L vs. 37.31 ± 22.44 μg/L (p < 0.05). Cd levels were significantly higher in group 2 than in group 1, at 1.79 ± 1.63 μg/L vs. 0.68 ± 0.45 μg/L (p < 0.05). When all the cases were evaluated together, a statistically significant negative correlation was determined between Se and CRP (r = - 0.239, p = 0.013) and a positive correlation between Cd and CRP (r = 0.266, p = 0.006), WBC (r = 0.258, p = 0.008). Our results could propose that Se deficiency and Cd excess could play a crucial and additive role in the etiopathogenesis of COM. However, further investigations with larger numbers of patients are warranted to determine the exact role of these elements.

Tissue and Serum Trace Elements Concentration among Colorectal Patients: A Systematic Review of Case-Control Studies

BACKGROUND

Trace elements play a pivotal role in Colorectal Cancer (CRC) inhibition and development process. This systematic review provides the basic comparison of case-control studies focusing on concentration of trace elements between those with CRC and controls.

METHODS

The systematic review searched through two databases of Medline and Cochrane up to 24^th June 2017. The search strategy focused on Population, Intervention, Comparison, and Outcomes (PICO). We searched the role of trace elements in cancer and focusing on case-control studies in CRC to obtain an insight into the differences in trace element concentrations between those with and without cancer.

RESULTS

The serum concentrations of Ca, Cu, Mg, Mn, Se, Si, and Zn were lower in CRC patients but for Co and S the levels were higher in CRC patients. The concentrations of Cd, Cr, Cu, Mg, Mn, Pb, and Zn were increased in patients with metastasis, but not in Se. As for colon tissue specimens, inconsistent levels were reported between studies, notably in Cu, Se, and Zn. No changes were reported for B and Ca levels. Most of the trace elements in the tissue specimens showed higher concentrations of Cr, Fe, K, Mg, P, Rb, S, and Si compared to Br.

CONCLUSION

With the growing interest to understand the link between trace elements in carcinogenesis and the possible interactions, multi assessment analysis of a larger cohort of samples is necessary.

Dietary chitosan-selenium nanoparticle (CTS-SeNP) enhance immunity and disease resistance in zebrafish

Selenium (Se) is an essential micronutrient for human and animals. It plays an important role in antioxidative stress, selenoenzymes regulation and immunomodulation. In this study, two common immunostimulants chitosan (CTS) and Se were used to synthesize nanoparticles (CTS-SeNP). Immunomodulation of CTS-SeNP were explored in wild-type zebrafish (Danio rerio). Dietary supplementation of CTS-SeNP enhanced lysozyme activity, phagocytic respiratory burst as well as splenocytes proliferation stimulated by LPS and ConA. CTS-SeNP showed immunomodulation effect from 5 to 20 μg/g but the best outcome was observed at 10 μg/g. Immunomodulation effect were rapidly induced after 3-9d and can sustain to 60. The zebrafish fed with 10 μg/g CTS-SeNP also showed 26.7% higher survival rate than the control after intraperitoneal injection of common bacterium Aeromonas hydrophila. Our results suggested that CTS-SeNP is an effective immunostimulant to fish and has potential application in aquaculture.

Construction of arabinogalactans/selenium nanoparticles composites for enhancement of the antitumor activity

Selenium nanoparticles (SeNPs) were synthesized using arabinogalactans (LAG) as a formation scaffolding and particle stabilizer to investigate their anti-tumor properties. The formation, morphology, size, and in vitro biological activity of LAG-SeNPs were characterized by UV-vis, FT-IR, scanning electron microscopy (SEM), transmission electron microscopy (TEM), dynamic light scattering (DLS) and cell toxicity assays. SEM and TEM of LAG-SeNPs visualized the individual spherical nanoparticles, while the spectroscopic characterization revealed the modes of interaction which lead to the stable particle properties of the LAG-SeNPs. Cell toxicity assays indicated that the products had significant inhibitory effect on A549, HepG-2 and MCF-7 cells with a dose-dependent effect. The toxicity mechanisms of LAG-SeNPs were further investigated, and assay results revealed that LAG-SeNPs mainly induced cancer cellular apoptosis to promote atrophy and inhibit cell proliferation. The sum of these findings demonstrates the positive effects that a biomass-derived polysaccharide exert upon non-metal/metalloid-based nanoparticles and the ensuing material's viability as treatment against human cancers.

The hydroxy-analogue of selenomethionine alleviated lipopolysaccharide-induced inflammatory responses is associated with recover expression of several selenoprotein encoding genes in the spleens of Kunming mice

This study aimed to determine whether hydroxy-analogue of selenomethionine (HMSeBA) supplementation could alleviate LPS-induced immunological stress in mice. A total of 90 Kunming mice were randomly assigned into 5 groups. The CON-LPS and CON+LPS groups were fed basal diet (BD), the others were fed BD with different levels of HMSeBA (0.15, 0.30 and 0.45 mg Se per kg) for 4 weeks. Mice were injected with LPS (3 mg per kg BW) or the corresponding physiological saline at 14 d and 28 d. Plasma and spleens were collected at 28 d. The results showed that: (1) LPS injection decreased ADG of mice at the 3^rd week, and increased the concentration of IL-6 and TNF-α in plasma and the spleen index; (2) LPS injection induced immunological stress, up-regulated 8 inflammation-related genes and 3 selenoprotein encoding genes, and down-regulated 16 selenoprotein encoding genes in spleens; (3) compared with the CON+LPS group, HMSeBA supplementation increased ADG of mice at 3 weeks and GSH-Px activity in plasma and spleens, decreased spleen index and plasma IL-6 and TNF-α levels, down-regulated mRNA levels of COX-2, ICAM-1, TNF-α, IL-6, and MCP-1, and up-regulated IL-10 and iNOS in spleens. 0.30 mg Se per kg of HMSeBA exhibited the optimal protective effect; (4) HMSeBA supplementation modestly recovered the expression of 8 selenoprotein encoding genes in the spleens of the stressed mice. The results indicated that HMSeBA supplementation alleviated LPS-induced immunological stress accompanied up-regulation of a subset of selenoprotein encoding genes in spleens of mice.

This study aimed to determine whether hydroxy-analogue of selenomethionine (HMSeBA) supplementation could alleviate LPS-induced immunological stress in mice.

Selenium Ameliorates AFB1-Induced Excess Apoptosis in Chicken Splenocytes Through Death Receptor and Endoplasmic Reticulum Pathways

Aflatoxin B₁ (AFB₁) can cause hepatotoxicity, genotoxicity, and immunosuppressive effects for a variety of organisms. Selenium (Se), as an essential nutrient element, plays important protective effects against cell apoptosis induced by AFB₁. This research aimed to reveal the ameliorative effects of selenium on AFB₁-induced excess apoptosis in chicken splenocytes through death receptor and endoplasmic reticulum pathways in vivo. Two hundred sixteen neonatal chickens, randomized into four treatments, were fed with basal diet (control treatment), 0.4 mg/kg Se supplement (+Se treatment), 0.6 mg/kg AFB₁ (AFB₁ treatment), and 0.6 mg/kg AFB₁ + 0.4 mg/kg Se (AFB₁ + Se treatment) during 21 days of experiment, respectively. Compared with the AFB₁ treatment, the levels of splenocyte apoptosis in the AFB₁ + Se treatment were obviously dropped by flow cytometry and TUNEL assays although they were still significantly higher than those in the control or + Se treatments. Furthermore, the mRNA expressions of CASP-3, CASP-8 and CASP-10, GRP78, GRP94, TNF-α, TNF-R1, FAS, and FASL of splenocytes in the AFB₁ + Se treatment by qRT-PCR assay were significantly decreased compared with the AFB₁ treatment. These results indicate that Se could partially ameliorate the AFB₁-caused excessive apoptosis of chicken splenocytes through downregulation of endoplasmic reticulum and death receptor pathway molecules. This research may rich the knowledge of the detoxification mechanism of Se on AFB₁-induced apoptosis.

Dietary selenium supplementation enhances antiviral immunity in chickens challenged with low pathogenic avian influenza virus subtype H9N2

Selenium supplementation in poultry feeds has been known to have beneficial effects on the bird health and performance; however antiviral effects of selenium have remained largely unknown. In this study, we have evaluated the effects of supplementation of chicken diets with organic (Selenium Enriched Yeast; SEY) and inorganic selenium (Sodium Selenite; SS) on low pathogenicity avian influenza virus (H9N2) shedding in the cloacal and oropharyngeal swab samples as well as examined the expression of immune related genes. Chickens were fed two doses (High- 0.30 mg/kg of feed; Low- 0.15 mg/kg of feed) of selenium supplementation for 2 weeks followed by low pathogenicity avian influenza virus challenge. Our results showed that the cloacal shedding of virus in all the selenium supplemented groups was significantly lower when compared to the non-supplemented control groups. In addition, the oropharyngeal shedding of virus in chickens fed with organic selenium supplementation was significantly lower than that in the chickens that received either inorganic selenium supplemented feed or controls. Furthermore, the expression of interferon stimulated genes (Viperin, OAS: 2'-5' oligoadenylate synthetase and MDA5: melanoma differentiation-associated gene) in the cecal tonsils was significantly elevated in the selenium treated groups when compared to controls. Additionally, a significantly higher transcription of interferon (IFN)-α, IFN-β and IFN-γ genes in the cecal tonsils and spleens of chickens receiving SEY-L and SS-H supplemented feed was also observed at post virus challenge time points compared to untreated controls. The results of this study demonstrated that supplementation of chicken diets with selenium, can enhance antiviral defense and thus, may have a beneficial effect in controlling viral infections in poultry.

Changes in serum level of trace elements in pulmonary tuberculosis patients during anti-tuberculosis treatment

INTRODUCTIONS

Tuberculosis is spreading throughout the globe, while it is a crucial cause of death in developing countries. In this study, trace elements concentrations and their alterations were determined in TB patients during anti-tuberculosis treatment period.

MATERIALS AND METHODS

We have collected blood samples from a total of 180 TB patients with pulmonary Tuberculosis, and 180 healthy controls in Sistan, Iran. The serum iron, copper, lead, calcium, arsenic and selenium concentrations were detected at the beginning of anti-TB chemotherapy, at the end of 2nd, 4th and 6th month after treatment initiation. Data were then analyzed using SPSS version 20.

RESULTS AND DISCUSSIONS

Although Ca, Pb, and As levels did not change during the treatment period, serum concentrations of Fe, Zn, Cu, and Se were diminished in TB patients significantly during treatment in comparison with controls (P < 0.001).We also found that there was a significant difference in the ^Cu/_Se and ^Cu/_Zn ratios in tuberculosis patients in comparison with healthy individuals (P < 0.001).

CONCLUSIONS

Trace elements serum concentrations are affected by TB infection and anti-TB therapy. Their serum levels were strongly perturbed during infection as well as anti-TB treatment.

A decade of thyroidology

Significant scientific progress has been achieved in the past decade in thyroidology driven by scholarly enquiry, unmet patient needs, and investment by the pharmaceutical and diagnostics industry. In this review, nine publications have been selected for their impact in pushing the frontiers of knowledge and understanding. They include new perspectives in the diagnosis, pathophysiology, epidemiology and management of thyroid cancer, understanding of thyroid hormone physiology, and new treatments for Graves' orbitopathy.

Selenium Pretreatment Alleviated LPS-Induced Immunological Stress Via Upregulation of Several Selenoprotein Encoding Genes in Murine RAW264.7 Cells

This study was conducted to profile selenoprotein encoding genes in mouse RAW264.7 cells upon lipopolysaccharide (LPS) challenge and integrate their roles into immunological regulation in response to selenium (Se) pretreatment. LPS was used to develop immunological stress in macrophages. Cells were pretreated with different levels of Se (0, 0.5, 1.0, 1.5, 2.0 μmol Se/L) for 2 h, followed by LPS (100 ng/mL) stimulation for another 3 h. The mRNA expression of 24 selenoprotein encoding genes and 9 inflammation-related genes were investigated. The results showed that LPS (100 ng/mL) effectively induced immunological stress in RAW264.7 cells with induced inflammation cytokines, IL-6 and TNF-α, mRNA expression, and cellular secretion. LPS increased (P < 0.05) mRNA profiles of 9 inflammation-related genes in cells, while short-time Se pretreatment modestly reversed (P < 0.05) the LPS-induced upregulation of 7 genes (COX-2, ICAM-1, IL-1β, IL-6, IL-10, iNOS, and MCP-1) and further increased (P < 0.05) expression of IFN-β and TNF-α in stressed cells. Meanwhile, LPS decreased (P < 0.05) mRNA levels of 18 selenoprotein encoding genes and upregulated mRNA levels of TXNRD1 and TXNRD3 in cells. Se pretreatment recovered (P < 0.05) expression of 3 selenoprotein encoding genes (GPX1, SELENOH, and SELENOW) in a dose-dependent manner and increased (P < 0.05) expression of another 5 selenoprotein encoding genes (SELENOK, SELENOM, SELENOS, SELENOT, and TXNRD2) only at a high level (2.0 μmol Se/L). Taken together, LPS-induced immunological stress in RAW264.7 cells accompanied with the global downregulation of selenoprotein encoding genes and Se pretreatment alleviated immunological stress via upregulation of a subset of selenoprotein encoding genes.

Roles for selenium and selenoprotein P in the development, progression, and prevention of intestinal disease

Selenium (Se) is a micronutrient essential to human health, the function of which is mediated in part by incorporation into a class of proteins known as selenoproteins (SePs). As many SePs serve antioxidant functions, Se has long been postulated to protect against inflammation and cancer development in the gut by attenuating oxidative stress. Indeed, numerous studies over the years have correlated Se levels with incidence and severity of intestinal diseases such as inflammatory bowel disease (IBD) and colorectal cancer (CRC). Similar results have been obtained with the Se transport protein, selenoprotein P (SELENOP), which is decreased in the plasma of both IBD and CRC patients. While animal models further suggest that decreases in Se or SELENOP augment colitis and intestinal tumorigenesis, large-scale clinical trials have yet to show a protective effect in patient populations. In this review, we discuss the function of Se and SELENOP in intestinal diseases and how research into these mechanisms may impact patient treatment.

The intricate role of selenium and selenoproteins in erythropoiesis

Selenium (Se) is incorporated as the 21st amino acid selenocysteine (Sec) into the growing polypeptide chain of proteins involved in redox gatekeeper functions. Erythropoiesis presents a particular problem to redox regulation as the presence of iron, heme, and unpaired globin chains lead to high levels of free radical-mediated oxidative stress, which are detrimental to erythroid development and can lead to anemia. Under homeostatic conditions, bone marrow erythropoiesis produces sufficient erythrocytes to maintain homeostasis. In contrast, anemic stress induces an alternative pathway, stress erythropoiesis, which rapidly produces new erythrocytes at extramedullary sites, such as spleen, to alleviate anemia. Previous studies suggest that dietary Se protects erythrocytes from such oxidative damage and the absence of selenoproteins causes hemolysis of erythrocytes due to oxidative stress. Furthermore, Se deficiency or lack of selenoproteins severely impairs stress erythropoiesis exacerbating the anemia in rodent models and human patients. Interestingly, erythroid progenitors develop in close proximity with macrophages in structures referred to as erythroblastic islands (EBIs), where macrophage expression of selenoproteins appears to be critical for the expression of heme transporters to facilitate export of heme from macrophage stores to the developing erythroid cells. Here we review the role of Se and selenoproteins in the intrinsic development of erythroid cells in addition to their role in the development of the erythropoietic niche that supports the functional role of EBIs in erythroid expansion and maturation in the spleen during recovery from anemia.

Selenium (Na2SeO3) Upregulates Expression of Immune Genes and Blood-Testis Barrier Constituent Proteins of Bovine Sertoli Cell In Vitro

Sertoli cells were isolated from newborn calves and cultured in a medium supplemented with 0, 0.25, 0.50, 0.75, and 1.00 mg/L of sodium selenite to study their immune stimulatory effect, influence on cell's viability, and expression of blood-testis barrier proteins (occludin, connexin-43, zonula occluden, E-cadherin) using quantitative PCR and western blot analyses. Results showed that medium supplemented with 0.50 mg/L of selenium significantly (P < 0.05) promoted cell viability, upregulated toll-like receptor gene (TLR4), anti-inflammatory cytokines (IL-4, IL-10, TGFβ1), and expressions of blood-testis barrier proteins, and modulated expressions of pro-inflammatory cytokines (TNF-α, IL-1β, IFN-γ). Sertoli cells grown in culture medium supplemented with 0.25 mg/L of selenium significantly upregulated TLR4, IL-4, IL-10, TGFβ1, and blood-testis barrier proteins compared to the control group. Sodium selenite supplementation at 0.75 and 1.00 mg/L levels was cytotoxic and temporarily downregulated the expression of blood-testis barrier protein within 24 h after culture; however, commencing from 72 h post culture, increased cell viability and upregulation of expression of blood-testis barrier proteins were observed. In conclusion, the results of this study showed that selenium supplementation in the culture medium up to 0.50 mg/L concentration upregulates immune genes and blood-testis barrier constituent proteins of bovine Sertoli cells.

Effects of vitamin E, inorganic selenium, bacterial organic selenium, and their combinations on immunity response in broiler chickens

Background

Selenium (Se) and vitamin E (Vit E) can act synergistically and affect biological processes, mainly antioxidant and immunity. The use of excess dietary Vit E and Se in animals’ feed could enhance immune response and induce disease resistance. Moreover, different Se sources may provide different alterations in the immune system. Accordingly, the aim of the current study was to assess the impact of dietary supplementation of Vit E, inorganic Se (sodium selenite, SS), bacterial organic Se of ADS18, and their different combinations on the plasma immunoglobulins, ceacum microbial population, and splenic cytokines gene expression in broiler chickens.

Results

Present results showed that, Se and Vit E synergistic effect was clear in plasma IgM level at day 42 and in splenic cytokines expression (TNF-α, IFN-γ, IL-2, IL-10). The combination of 0.3 mg/kg ADS18-Se with 100 mg/kg Vit E showed the highest IgM level compared to Vit E- SS complex. The combination of either SS or ADS18-Se with Vit E had no significant effect on IFN- γ and IL-10 compared to Vit E alone, while Vit E alone showed the significantly lowest TNF-α compared to the Se combinations. Supplementation of 100 mg/kg Vit E had no effect on microbial population except a slight reduction in Salmonella spp. The main effect of Se sources was that both sources increased the day 42 IgA and IgG level compared to NS group. ADS18-Se modulate the caecum microbial population via enhancing beneficial bacteria and suppressing the E-coli and Salmonella spp. while both Se and Vit E factors had no effect on lymphoid organ weights.

Conclusions

The inclusion of 100 mg/kg Vit E with 0.3 mg/kg ADS18-Se, effectively could support the immune system through regulation of some cytokines expression and immunoglobulin levels more than using ADS18-Se alone, while no difference was observed between using SS alone or combined with Vit E.

Selenium ameliorates Staphylococcus aureus-induced inflammation in bovine mammary epithelial cells by inhibiting activation of TLR2, NF-κB and MAPK signaling pathways

BACKGROUND

Staphylococcus aureus (S. aureus) internalization into bovine mammary epithelial cells (bMECs) is considered an important pathogenic mechanism for the establishment of mastitis. Given the interesting link between selenium (Se) status and mastitis, our objective was to prove that Se was essential to suppress pro-inflammatory mediators, in part, by modulation of Toll-like receptor2 (TLR2), nuclear factor kappaB (NF-κB) and mitogen activated protein kinase (MAPK) signal transduction pathway in bMECs.

RESULTS

Results showed that Se (0~ 16 μM) did not affect the growth of bMECs. The mRNA expression of TLR2, Myeloid differentiation factor 88 (Myd88), Interleukin-1 receptor-associated kinase4 (Irak4), Interleukin-1 receptor-associated kinase1 (Irak1) and TNF receptor-associated factor6 (Traf6) in TLR2 signal pathway were increased or significantly increased by S. aureus. Se played an important role in regulating the genes expression of TLR2, Myd88, Traf6 but not in controlling the expression of Irak4 and Irak1. In addition, Se exerted strong inhibitory effects on the genes expression of tumor necrosis factor-alpha (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6) induced by S. aureus. To further investigate the possible signaling mechanisms involved in the processes, we analyzed the role of MAPK and NF-κB signaling pathway in inflammation response in S. aureus-stimulated bMECs in vitro. Results showed that the phosphorylation of inhibitory kappaB alpha (IκBα), p65, p38 and extracellular regulated protein kinase (Erk) were significantly increased in S. aureus-stimulated bMECs. It indicated that S. aureus activated NF-κB and MAPK signaling pathway. We also examined the effects of Se on the phosphorylation of IκBα, p65, p38 and Erk in NF-κB and MAPK signaling pathway, which have well been proved to control the synthesis and release of pro-inflammatory mediators during inflammation. The findings are exciting, that pretreatment with Se (4, 8 μM) significantly suppressed the phosphorylation of IκBα, p65, p38 and Erk.

CONCLUSIONS

These results suggest that Se down-regulates inflammatory mediators TNF-α, IL-1β and IL-6 gene expressions via TLR2, NF-κB and MAPK signaling pathway in S. aureus-stimulated bMECs, which may be responsible for the anti-inflammatory effect of Se.

Inflammatory Response Occurs in Veins of Broiler Chickens Treated with a Selenium Deficiency Diet

Selenium (Se) has been indicated to prevent chronic diseases including cancer, cardiovascular disease, and type 2 diabetes. However, a few studies have indicated that Se deficiency can induce vascular diseases. Thus, in the present study, we investigated the effect of Se deficiency on vascular pathology. A total of 60 male broiler chickens were randomly divided into 2 groups (n = 30). The control group (C group) was fed a basic diet, and the Se-deficient group (L group) was fed a Se-deficient, corn-soy-based diet. Changes in messenger RNA (mRNA) and protein levels of inflammatory factors and inflammation-related cytokines were examined by both RT-PCR and Western blot analysis. Our results indicate that the mRNA and protein levels of inflammatory factors and inflammation-related cytokines in the L group were significantly changed in the vein. In addition, principal component analysis (PCA) was used to define the most important parameters that could be used as key factors. The in vitro experiments also demonstrated that Se can enhance the anti-inflammatory ability of vein endothelial cells. In conclusion, Se deficiency induces an inflammatory response by modulating inflammatory factors and inflammation-related cytokines.

A prophylactic protocol to stimulate the immune response also controls infectious disease and, consequently, minimizes diarrhea in newborn heifers

The immunostimulatory and immunomodulatory properties of selenium (Se), an essential trace element for animals, has increase its use because may prevent/or reduce the occurrence of infectious diseases. Thus, the aim of this study was to verify whether Se and vitamins (A and E) applied via subcutaneous associated with secnidazole via oral exert positive effects in the antioxidant and immune systems, as well as whether prevent infections caused by protozoan and bacteria, and consequently, reduce the number of cases of diarrhea in heifers. Thirty-two newborn Holstein heifers were divided into two groups with sixteen animals each: the control group and the treated group that received sodium selenite (0.2 mg/kg) and vitamins A (35 mg/kg) and E (1 mg/kg) with one day of life, and a second application associated with secnidazole (400 mg/animal) on day 10 of life. Sample collection (blood and feces) were performed on days 1, 15, 30, 45 and 60 of life. Heifers from the treated group showed higher hematocrit values compared to the control group on day 60 of life, while total serum protein levels were higher on days 15 and 30. The ceruloplasmin (days 15, 30 and 60), IgG of heavy chain (days 15, 30, 45 and 60), IgG of light chain (days 45 and 60) and haptoglobin (days 15, 30, 45 and 60) were higher in the treated group compared to the control group. Serum levels of glucose decreased in treated animals on day 60 of life, while serum levels of albumin, triglycerides, urea, cholesterol, thiobarbituric acid reactive substances, reactive oxygen species and glutathione S-transferase activity did not differ between groups. Secnidazole was able to prevent infections caused by Giardia duodenalis in the first few days of life, but no difference was observed between groups. Moreover, there was no difference on total bacteria count and the incidence of diarrhea between groups. No difference on weight gain was observed on day 60 of life, but on day 210 of life treated animals had higher weight gain compared to the control group. Based on these evidences, we concluded that the injectable application of Se and vitamins (A and E) associated to secnidazole can improve the immunological system, and consequently, favor animal's performance.