Selenium: an essential element for immune function

A novel diselenide attenuates the carrageenan-induced inflammation by reducing neutrophil infiltration and the resulting tissue damage in mice

Selenium-containing compounds have emerged as promising treatment for redox-based and inflammatory diseases. This study aimed to investigate the in vitro and in vivo anti-inflammatory activity of a novel diselenide named as dibenzyl[diselanediyIbis(propane-3-1diyl)] dicarbamate (DD). DD reacted with HOCl (k = 9.2 x 107 M-1s-1), like glutathione (k = 1.2 x 108 M-1s-1), yielding seleninic and selenonic acid derivatives, and it also decreased HOCl formation by activated human neutrophils (IC50=4.6 μM) and purified myeloperoxidase (MPO) (IC50=3.8 μM). However, tyrosine, MPO-I and MPO-II substrates, did not restore HOCl formation in presence of DD. DD inhibited the oxidative burst in dHL-60 cells with no toxicity up to 25 µM for 48h. Next, an intraperitoneal administration of 25, 50, and 75 mg/kg DD decreased total leukocyte, neutrophil chemotaxis, and inflammation markers (MPO activity, lipid peroxidation, albumin exudation, nitrite, TNF-α, IL-1β, CXCL1/KC, and CXCL2/MIP-2) on a murine model of carrageenan-induced peritonitis. Likewise, 50 mg/kg DD (i.p.) decreased carrageenan-induced paw edema over 5h. Histological and immunohistochemistry analyses of the paw tissue showed decreased neutrophil count, edema area, and MPO, carbonylated, and nitrated protein staining. Furthermore, DD treatment decreased the fMLP-induced chemotaxis of human neutrophils (IC50=3.7 μM) in vitro with no toxicity. Lastly, DD presented no toxicity in a single-dose model using mice (50 mg/kg, i.p.) over 15 days and in Artemia salina bioassay (50 to 2000 µM), corroborating findings from in silico toxicological study. Altogether, these results demonstrate that DD attenuates carrageenan-induced inflammation mainly by reducing neutrophil migration and the resulting damage from MPO-mediated oxidative burst.

Review on the health-promoting effect of adequate selenium status

Selenium is an essential microelement involved in various biological processes. Selenium deficiency increases the risk of human immunodeficiency virus infection, cancer, cardiovascular disease, and inflammatory bowel disease. Selenium possesses anti-oxidant, anti-cancer, immunomodulatory, hypoglycemic, and intestinal microbiota-regulating properties. The non-linear dose-response relationship between selenium status and health effects is U-shaped; individuals with low baseline selenium levels may benefit from supplementation, whereas those with acceptable or high selenium levels may face possible health hazards. Selenium supplementation is beneficial in various populations and conditions; however, given its small safety window, the safety of selenium supplementation is still a subject of debate. This review summarizes the current understanding of the health-promoting effects of selenium on the human body, the dietary reference intake, and evidence of the association between selenium deficiency and disease.

Antibody response and abomasal histopathology of lambs with haemonchosis during supplementation with medicinal plants and organic selenium

We evaluated the effects of dietary supplementation with medicinal plants (Herbmix) or organic selenium (Selplex) on the immune responses and histopathology of lambs infected with Haemonchus contortus. Twenty-seven lambs were infected and reinfected with approximately 11,000 third-stage larvae of H. contortus during the experiment (on days 0, 49 and 77). Lambs were divided into two supplemented experimental groups (Herbmix and Selplex) and unsupplemented group (Control). The abomasal worm counts at necropsy on day 119 were lower for Herbmix (4230) and Selplex group (3220) than to the Control (6613) which resulted in 51.3% and 36.0% of reduction, respectively. The mean length of adult female worms was in the order Control > Herbmix > Selplex (2.1, 2.08, and 2.01 cm, respectively). The specific IgG response against adults was significantly affected by time (P < 0.001). Serum-specific and total mucus levels of IgA in the Herbmix group were highest on day 15. Mean levels of serum IgM against adults were influenced by treatment (P = 0.048) and time (P < 0.001). The Herbmix group had strong local inflammation in the abomasal tissue, with the formation of lymphoid aggregates and the infiltration of immune cells, but the tissues of the Selplex group had higher numbers of eosinophils, globule leukocytes, and plasma cells. The lymph nodes of each animal had reactive follicular hyperplasia due to the infection. Dietary nutritional supplementation with a mixture of medicinal plants or organic selenium could improve local immune responses and thus enhance the resistance of animals to this parasitic infection.

Probability of cultivating Se-rich maize in Se-poor farmland based on intensive field sampling and artificial neural network modelling

Selenium (Se) is a necessary micronutrient for humans, and its supplementation from crop grains is important to address the ubiquitous Se deficiency in people worldwide. Se uptake by crops largely depend on soil bioavailable Se rather than soil total Se content, which provides possibilities to explore the Se-rich crops in Se-poor area. Here, the possibility of cultivating Se-rich maize grains in Se-poor farmland was tested based on intensive field sampling and mathematical modelling. Sampling was conducted at county scale, and a total of 7779 topsoil samples and 109 maize samples with paired rhizosphere soils samples were collected. Results showed that although the soil Se content in the study county from southwestern China was at a low level (0.01-2.75 mg kg^-1), 54.1% of the maize grain samples satisfied the standard for Se-rich products (0.02-0.30 mg kg^-1). Soil organic matter, iron oxide, and phosphorus levels were correlated negatively with Se bioconcentration factor (BCF) of maize grain. Compared with the multivariate linear regression model, the artificial neural network (ANN) model was more accurate and reliable in predicting maize Se BCF. Prediction using the ANN model showed that 22.7% of the county's farmland was suitable for cultivating naturally Se-rich maize, which increased 21.3% growing areas than that from cultivation based on simply soil total Se. This study provided a new methodological framework for natural Se-rich maize production and verified the probability of cultivating naturally Se-rich maize in Se-poor farmland.

Correlation of Serum Selenium in Asthma Patients with Severity of the Disorder

Asthma is characterized by reversible airway obstruction, increased bronchial hyper-responsiveness and chronic inflammation, as well as higher levels of oxidative stress mainly due to decreased antioxidant defenses. Our primary aim was to investigate the correlation of serum selenium (Se) levels with the severity of asthma across gender, age, family history, and prevalence from childhood. Selenium levels in blood samples in 103 asthmatic patients and 103 healthy individuals were evaluated. The obtained data indicated that the mean serum Se levels in asthma patients were found to be twofold lower as compared to the controls (p < 0.001). However, there were no significant differences in the asthmatic patients when gender and age were considered. Patients characterized by family history of asthma and inhaler usage had 8% and 7% lower serum Se concentrations, although the difference was only border significant (p = 0.05). Multiple regression analysis demonstrated a significant inverse association of inhaler usage (β =  - 0.226; p < 0.001) with serum Se levels even after adjustment for asthma severity (β =  - 0.644; p < 0.001). While this report clearly necessitates a more detailed study, it is plausible that Se deficiency leads to impaired immune response, and therefore, Se supplementation might modulate oxidative stress in the lung and could potentially alleviate asthma pathophysiology.

The effects of selenium supplementation on blood lipids and blood pressure in adults: A systematic review and dose-response meta-analysis of randomized control trials

BACKGROUND

Previous studies evaluating the effects of selenium supplementation on lipid profile and blood pressure (BP) offer contradictory findings. This systematic review and meta-analysis assessed the effects of selenium supplementation on these lipid profile and BP.

METHODS

In order to identify interrelated clinical trials, we performed a comprehensive literature search in the online databases, including PubMed, Scopus, Embase, and ISI web of science, up to December 2021.

RESULTS

The analysis of the data established that selenium supplementation did not significantly affect TG level (WMD: -0.84 mg/dL; 95 % CI: -4.74, 3.05, p = 0.671), LDL-C (WMD: 0.86 mg/dL; 95 % CI: -1.21, 2.95, p = 0.416), and HDL-C (WMD: 0.3 mg/dL; 95 % CI: -0.66, 1.27, p = 0.535). however, there was a significant reduction in TC levels following selenium supplementation (WMD: -2.11 mg/dL; 95 % CI: -4.09, -0.13, p = 0.037). After subgroup analysis, when the baseline levels of LDL-C were < 130 mg/dL, selenium supplementation elicited a significant increase in LDL-C levels (WMD: 2.89 mg/dL; 95 % CI: 0.26, 5.51, p = 0.031). For BP, selenium supplementation significantly increased SBP (WMD: 2.02 mmHg; 95 % CI: 0.50, 3.55, p = 0.009), while it had no significant effect on DBP (WMD: 0.39 mmHg; 95 % CI: (-0.89, 1.68, p = 0.551)).

CONCLUSION

Although our findings suggest selenium may have possible therapeutic effects in improving TC and VLDL, because of its negative effects on LDL and BP, selenium supplementation for cardiovascular protection should be recommended with caution.

The Potential Antiviral Effects of Selenium Nanoparticles and Coated Surfaces

Modern epidemics quickly spread across borders and continents with devastating effects on both human health and the world economy. This issue is made worse by the various ways that infections are spread, including through aerosol, droplets, and fomites. The antibacterial qualities of various surface materials and coatings have been the subject of much research. However, the antiviral activity of metal coatings can be heavily influenced by imbalances in metal distribution and the presence of other metal impurities. As such, there is interest in developing novel surface coatings that can reduce the transmission of active viral particles in healthcare facilities. In recent years, the non-metals, such as selenium and nanoparticles, have acquired greater interest from the medical and scientific community for their antiviral surface activity. In this review, we will discuss the cellular and physiological functions of selenium in mammalian cells and against viral infections. We then discuss the mechanism behind selenium coated surfaces and their efficacy against bacterial infections. Lastly, we examine the antiviral activity of selenium, and the potential antiviral activity of selenium nanoparticles and coatings.

Dietary selenium sources alleviate immune challenge induced by Salmonella Enteritidis potentially through improving the host immune response and gut microbiota in laying hens

The aim of this study was to evaluate the effects of different selenium (Se) sources on the immune responses and gut microbiota of laying hens challenged with Salmonella enteritidis (S. Enteritidis). A total of 240 45-week-old layers were randomly divided into eight groups with six replicates per group according to a 4 × 2 factorial design, including a blank diet without Se supplementation (CON group) and three diets with 0.3 mg/kg Se supplementation from sodium selenite (IS group), yeast Se (YS group), and selenium-enriched yeast culture (SYC group), respectively. After 8 weeks of feeding, half of them were orally challenged with 1.0 ml suspension of 109 colony-forming units per milliliter of S. Enteritidis daily for 3 days. The serum was collected on days 3, 7, and 14, and the cecum content was collected on day 14 after challenge. There was no significant difference in laying performance among the eight groups before challenge. The S. Enteritidis challenge significantly decreased the laying performance, egg quality, GSH-Px, IgG, and IgM and increased the ratio of feed and egg, malondialdehyde (MDA), Salmonella-specific antibody (SA) titers, IL-6, IL-2, IL-1β, and INF-γ. However, SYC increased the level of GSH-Px and IgG and decreased IL-6, while YS decreased the level of IL-2 and IL-1β. What is more, Se supplementation decreased the SA titers to varying degrees and reduced the inflammatory cell infiltration in the lamina propria caused by S. Enteritidis infection. In addition, the S. Enteritidis challenge disrupted the intestinal flora balance by reducing the abundance of the genera Clostridium innocuum, Lachnospiraceae, and Bifidobacterium and increasing the genera Butyricimonas and Brachyspira, while Se supplementation increased the gut microbial alpha diversity whether challenged or not. Under the S. Enteritidis challenge condition, the alteration of microbial composition by the administration of different Se sources mainly manifested as IS increased the relative abundance of the genera Lachnospiraceae and Christensenellaceae, YS increased the relative abundance of the genera Megamonas and Sphingomonas, and SYC increased the genera Fusobacterium and Lactococcus. The alteration of gut microbial composition had a close relationship with antioxidant or immune response. To summarize, different Se sources can improve the egg quality of layers challenged by S. Enteritidis that involves elevating the immunity level and regulating the intestinal microbiota.

Egyptian propolis and selenium nanoparticles against murine trichinosis: a novel therapeutic insight

Trichinosis is a serious zoonotic disease that causes human morbidity and mortality. New effective natural remedies with minimal side effects that are well tolerated are needed to treat both enteral and parenteral trichinosis. This study evaluated the efficacy of selenium (Se), Se nanoparticles (SeNPs) and Egyptian propolis compared with albendazole as antiparasitic, anti-inflammatory and anti-angiogenic agents for treating murine trichinosis. We used parasitological, histopathological and immunohistochemical assays, as well as scanning electron microscopy, to examine adult worms. Overall, 80 Swiss albino male mice were divided into eight groups, with ten mice in each group, as follows: negative control, positive control, albendazole, propolis, Se, combination of propolis and Se, SeNPs and combination of SeNPs and propolis. Mice were slaughtered seven and 35 days after infection to examine the intestinal and muscular phases, respectively. This study demonstrated the efficacy of the combination of SeNPs and propolis. As revealed by electron microscopy, this combination caused damage to the adult worm cuticle. Additionally, compared with albendazole, it resulted in a significant reduction in adult worm and total larval counts; moreover, it caused a decrease in the number of larvae deposited in muscles, with a highly significant decrease in the inflammatory cell infiltrate around the larvae and a considerable decrease in the expression of the angiogenic marker vascular endothelial growth factor in muscles. In conclusion, the combination of SeNPs and propolis had antiparasitic, anti-inflammatory and anti-angiogenic effects on trichinosis. Consequently, this combination could be used as a natural alternative therapy to albendazole for treating trichinosis.

Chicken Incubation Conditions: Role in Embryo Development, Physiology and Adaptation to the Post-Hatch Environment

The chicken hatching egg is a self-contained life-supporting system for the developing embryo. However, the post-hatch performance of birds depends on several factors, including the breeder management and age, egg storage conditions and duration before incubation, and the incubation conditions. Studies have determined the effect of incubation factors on chick post-hatch growth potential. Therefore, chick physical quality at hatch is receiving increasing attention. Indeed, although incubation temperature, humidity, turning and ventilation are widely investigated, the effects of several variables such as exposure of the embryo to high or low levels, time of exposure, the amplitude of variations and stage exposures on embryo development and post-hatch performance remain poorly understood. This review paper focuses on chick quality and post-hatch performance as affected by incubation conditions. Also, chick physical quality parameters are discussed in the context of the parameters for determining chick quality and the factors that may affect it. These include incubation factors such as relative humidity, temperature, turning requirements, ventilation, in ovo feeding and delay in feed access. All these factors affect chick embryo physiology and development trajectory and consequently the quality of the hatched chicks and post-hatch performance. The potential application of adapted incubation conditions for improvement of post-hatch performance up to slaughter age is also discussed. It is concluded that incubation conditions affect embryo parameters and consequently post-hatch growth differentially according to exposure time and stage of exposure. Therefore, classical physical conditions are required to improve hatchability, chick quality and post-hatch growth.

A Review on Measures to Rejuvenate Immune System: Natural Mode of Protection Against Coronavirus Infection

SARS-CoV-2, a novel Corona virus strain, was first detected in Wuhan, China, in December 2019. As of December 16, 2021, almost 4,822,472 people had died and over 236,132,082 were infected with this lethal viral infection. It is believed that the human immune system is thought to play a critical role in the initial phase of infection when the viruses invade the host cells. Although some effective vaccines have already been on the market, researchers and many bio-pharmaceuticals are still working hard to develop a fully functional vaccine or more effective therapeutic agent against the COVID-19. Other efforts, in addition to functional vaccines, can help strengthen the immune system to defeat the corona virus infection. Herein, we have reviewed some of those proven measures, following which a more efficient immune system can be better prepared to fight viral infection. Among these, dietary supplements like- fresh vegetables and fruits offer a plentiful of vitamins and antioxidants, enabling to build of a healthy immune system. While the pharmacologically active components of medicinal plants directly aid in fighting against viral infection, supplementary supplements combined with a healthy diet will assist to regulate the immune system and will prevent viral infection. In addition, some personal habits, like- regular physical exercise, intermittent fasting, and adequate sleep, had also been proven to aid the immune system in becoming an efficient one. Maintaining each of these will strengthen the immune system, allowing innate immunity to become a more defensive and active antagonistic mechanism against corona-virus infection. However, because dietary treatments take longer to produce beneficial effects in adaptive maturation, personalized nutrition cannot be expected to have an immediate impact on the global outbreak.

Hydrolysis-Based Small-Molecule Hydrogen Selenide (H2Se) Donors for Intracellular H2Se Delivery

Hydrogen selenide (H₂Se) is a central metabolite in the biological processing of selenium for incorporation into selenoproteins, which play crucial antioxidant roles in biological systems. Despite being integral to proper physiological function, this reactive selenium species (RSeS) has received limited attention. We recently reported an early example of a H₂Se donor (TDN1042) that exhibited slow, sustained release through hydrolysis. Here we expand that technology based on the P═Se motif to develop cyclic-PSe compounds with increased rates of hydrolysis and function through well-defined mechanisms as monitored by ³¹P and ⁷⁷Se NMR spectroscopy. In addition, we report a colorimetric method based on the reaction of H₂Se with NBD-Cl to generate NBD-SeH (λ_max = 551 nm), which can be used to detect free H₂Se. Furthermore, we use TOF-SIMS (time of flight secondary ion mass spectroscopy) to demonstrate that these H₂Se donors are cell permeable and use this technique for spatial mapping of the intracellular Se content after H₂Se delivery. Moreover, these H₂Se donors reduce endogenous intracellular reactive oxygen species (ROS) levels. Taken together, this work expands the toolbox of H₂Se donor technology and sets the stage for future work focused on the biological activity and beneficial applications of H₂Se and related bioinorganic RSeS.

Dietary Intake and Serum Selenium Levels Influence the Outcome of HTLV-1 Infection

Human T cell leukemia virus type 1 (HTLV-1)-associated myelopathy/tropical spastic paraparesis (HAM/TSP), as the most common neurological emersion related to HTLV-1, is a debilitating and lifelong treating disease with no definitive treatment. Furthermore, it has been determined that dietary compositions (inflammatory and anti-inflammatory) and some micronutrients (such as vitamin D and selenium) have an effect on inflammatory and immune processes and with this background; the study was done to compare the nutritional status between age- and sex-matched with infected and non-infected HTLV-1. In a multi-center setting, 70 healthy controls (HCs), 35 asymptomatic carriers (ACs), and 35 HAM/TSP patients were recruited in the HTLV-1 Foundation, Ghaem Hospital, Mashhad University of Medical Sciences, Mashhad, Iran. Nutritional status including anthropometric indices, dietary (micro- and macronutrient) intake, and serum vitamin D, vitamin B12, zinc, and selenium were measured. In anthropometric indices, mean waist circumference (WC) in the carrier group was significantly higher than the patient and the control groups (p = 0.008). In the dietary intake, the patient group received less energy, protein, mono-unsaturated fatty acids (MUFA), and oleic, but more fat than the HTLV-1 carrier and control groups, and these differences were remarkable in three groups (p = 0.002, 0.005, 0.001, 0.01, and 0.001, respectively), whereas the carrier group received more saturated fatty acid and less poly-unsaturated fatty acids (PUFA), linoleic, and linolenic than patient and control groups with a different significant (p = 0.01, 0.007, 0.005, and 0.006, respectively) in three groups. In micronutrient intake, although selenium, zinc, and vitamins B12 and D were lower in the patient group than the carrier and control group, however, no significant differences were observed. In comparison with micronutrient serum concentrations, vitamins B12 and D and selenium in the patient group were lower than the carrier and control groups, but statistically, the considerable difference was found only in the selenium concentration (p = 0.001). The study showed that there were differences in dietary intake (including energy, macronutrients, and fatty acids), WC, and selenium serum levels between HAM/TSP patients and HTLV-1 carriers, suggesting that nutritional statues influence the inflammatory immune response in HTLV-1 infection.

Effects of Cadmium Exposure on the Immune System and Immunoregulation

Cadmium (Cd), a biologically non-essential heavy metal, is widespread in the environment, including the air, water, and soil, and is widely present in foods and quantum dot preparations. Cd enters the body primarily through inhalation and ingestion. Its biological half-life in humans is 10-35 years; therefore, Cd poses long-term health risks. While most studies on Cd toxicity have focused on organ and tissue damage, the immunotoxicity of Cd has drawn increasing attention recently. Cd accumulates in immune cells, modulates the function of the immune system, triggers immunological responses, and leads to diverse health problems. Cd acts as an immunotoxic agent by regulating the activity and apoptosis of immune cells, altering the secretion of immune cytokines, inducing reactive oxygen species (ROS) production and oxidative stress, changing the frequency of T lymphocyte subsets, and altering the production of selective antibodies in immune cells. This review summarizes the immunological toxicity of Cd, elucidates the mechanisms underlying Cd toxicity in terms of innate immunity and adaptive immunity, and discusses potential strategies to alleviate the adverse effects of Cd on the immune system.

Metal Bioaccumulation in the Gill, Liver, and Muscle of Bluefish (Pomatomus saltatrix) From the Northeastern Mediterranean and Human Health Risk Assessment Associated with Their Seasonal Consumption

Heavy metals are continuously released into the oceans from both natural and anthropogenic sources. They are serious threats to both ecosystem and human health because of their toxicity, persistence, bioaccumulation, and biomagnification. We present metal concentrations in the economically important bluefish from Iskenderun Bay, providing valuable information on Northeastern Mediterranean aquatic ecosystem health, as well as the human health risk. The concentrations of manganese, iron, copper, zinc, selenium, cadmium, lead, and mercury were determined in the gill, liver, and muscle tissues of bluefish (Pomatomus saltatrix) caught in Iskenderun Bay (Turkey) during four seasons. Samples were analysed via inductively coupled plasma mass spectrometer. Fe and Zn were detected in the highest concentrations during all four seasons. The ranges of Fe concentrations were 61.15-108.76, 229.78-377.02, and 6.35-8.63 and those of Zn were 25.21-44.25, 42.25-76.08, and 6.27-13.59 in the gills, livers, and muscles, respectively. In contrast, Hg and Cd were not found in the bluefish tissues in any season with the exception of Cd in the gills during the spring (0.757 mg/kg, above the legal limit of 0.5 mg/kg). On a seasonal basis, no meaningful accumulation trend was observed for the muscles or gills, while the highest concentrations of Mn, Fe, Cu, Zn, and Se in the liver were found in the spring. Liver tissues possessed higher metal concentrations than gill and muscle tissues. Estimated daily and weekly intakes of the metals due to human consumption of the bluefish were considerably lower than the provisional tolerable intake. In this study, there was an inflow of metals into Iskenderun Bay; however, no significant metal accumulation was found in bluefish tissues at a rate that would harm human health.

Association Between Serum Selenium Level and Subclinical Mastitis in Dairy Cattle

Selenium is an important element in nutrition, showing great potential in the udder health of dairy cattle and in the control of subclinical mastitis. However, there are few studies on selenium and subclinical mastitis in cows, and the correlation is not clear. A trial was designed to investigate the association between serum selenium levels and the immune and antioxidant capacity of dairy cattle with subclinical mastitis. Fifty cattle in early lactation with similar background information were selected randomly from an intensive dairy farm. Blood samples were collected for the detection of serum selenium levels by ICP-optic emission spectrometer. The cattle were divided into a low-selenium group (< 0.05 mg/L) and three normal selenium groups with different serum selenium levels (0.05-0.08 mg/L). The somatic cell count, immune indexes, and other indexes in the milk of each group were detected. The somatic cell count was found to be negatively correlated with serum selenium level. GSH-Px had a low positive correlation and IL-6 had a low negative correlation with serum selenium level. With a serum glutathione peroxidase < 148 U/L and IL-6 > 451 pg/mL, the risk of subclinical mastitis in dairy cattle increased.

Effects of Selenium on Arsenic-Induced Liver Lesions in Broilers

The aim of the present study was to investigate the abilities of selenium to counteract the toxic damage of arsenic (As). Two hundred 1-day-old healthy male broilers were randomly divided into five groups and fed the following diets: control group (0.1 mg/kg As + 0.2 mg/kg Se), As group (3 mg/kg As + 0.2 mg/kg Se), As + Se group I (3 mg/kg As + 5 mg/kg Se), As + Se group II (3 mg/kg As + 10 mg/kg Se), and As + Se group III (3 mg/kg As + 15 mg/kg Se), respectively. The relative weight of the liver, hepatic protein content, GSH-Px levels, SOD activities, NO contents, iNOS and tNOS activities, and increased malondialdehyde contents, ALT and AST activities, and the apoptotic hepatocytes were analyzed. Adding 3 mg/kg arsenic to the diet caused the growth and development of chicken liver to be blocked, resulting in decrease of protein contents in liver tissue, decrease of SOD and GSH-Px activities, increase of MDA contents, decrease of NO contents, decrease of iNOS and TNOs activities, increase of ALT and AST activities, increase of apoptosis rates of liver cells. Compared to the 3-mg/kg arsenic group, adding 5 mg/kg and 10 mg/kg selenium, respectively, could repair the liver growth retardation and steatosis caused by arsenic, increase the protein contents in liver tissue, increase the activities of SOD and GSH-Px, reduce the contents of MDA, increase the contents of NO, enhance the activities of iNOS and TNOs, reduce the activities of ALT and AST, and reduce the rates of apoptosis of liver cells, in which the best effects are to add 10 mg/kg selenium. While 15 mg/kg of sodium selenite may induce progression of As-induced hepatic lesions, the results indicated that 5 and 10 mg/kg of sodium selenite supplied in the diet, through mechanisms of oxidative stress and apoptosis regulation, may ameliorate As-induced hepatic lesions in a dose-dependent manner.

Immunoinflammatory effects of dietary bioactive compounds

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

Roles of selenoprotein T and transglutaminase in active immunization against entomopathogenic fungi in the termite Reticulitermes chinensis

Active immunization can protect individuals from infectious diseases in social insects. It is well established that trace elements are essential to the host immune system, but the related gene functions in insect social immunity are unknown. Here, we found that the levels of three free elements (Se, Ca and Cr) and selenoprotein T (SELT) expression were significantly decreased in the termite Reticulitermes chinensis Snyder during active immunization against the entomopathogenic fungus Metarhizium anisopliae (Metchnikoff) Sorokin. Thus, we further explored the role of the SELT gene in the active immunization of termites. After SELT was significantly silenced by RNAi, the nestmates of fungus-contaminated termites exhibited reduced antifungal activity and increased mortality, along with increased expression of the immune genes transglutaminase (TG) and transferrin (Tsf), indicating that the active immunization of termites was disrupted by SELT silencing. Moreover, the TG-knockdown nestmates of fungus-contaminated termites significantly decreased grooming behavior, antifungal activity and survival, despite the upregulation of SELT expression, also suggesting that the active immunization of termites was disrupted by the silencing of TG. These findings demonstrated that both SELT gene and TG gene play important roles in driving active immunization against the entomopathogenic fungus M. anisopliae in R. chinensis.

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.

Impact of Maternal Selenium Supplementation from Late Gestation and Lactation on Piglet Immune Function

The present work aimed at assessing passive, innate, and acquired immunity in piglets from sows supplemented with either organic or inorganic selenium (Se). A total of 12 multiparous pregnant sows were randomly allocated to three groups: selenium-deficient, corn and soy-based diet base diet (BD), 0.3 mg Se/kg as hydroxy-selenomethionine (OH-SeMet), and 0.3 mg Se/kg as sodium selenite (SS). The feeding trial was carried out from gd 84 to weaning on postpartum day 21 (ppd 21). On gd 98 and 105, sows were vaccinated with hen egg white lysozyme (HEWL) to assess passive immunity. On ppd 23, weaned piglets were intramuscularly challenged with lipopolysaccharide (LPS) to trigger an acute-phase response. On ppd 14, 28, and 35, piglets were vaccinated with ovalbumin (OVA) to assess OVA-specific immunoglobulin G (IgG) and dermal hypersensitivity responses. Se levels in piglet plasma, muscle, and liver on ppd 21 were higher in OH-SeMet group. On ppd 2, piglet HEWL-specific IgG levels in OH-SeMet group were significantly increased. IL-10 and haptoglobin (HP) levels in OH-SeMet group were significantly increased 2 h and 48 h post-LPS simulation, respectively. The OVA-specific IgG levels in BD group were significantly higher than the other two groups, and the IL-4 concentration following whole blood ex vivo challenge with either OVA or mitogen was significantly increased in OH-SeMet group. OVA-specific skin swelling was lower in OH-SeMet and SS groups at 3 h and 6 h. This suggests that sow supplementation with OH-SeMet enhances mainly passive immunity through IgG maternal transfer and can influence piglet innate and acquired immunity.

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.

Development of a hydrolysis-based small-molecule hydrogen selenide (H2Se) donor

Selenium is essential to human physiology and has recently shown potential in the treatment of common pathophysiological conditions ranging from arsenic poisoning to cancer. Although the precise metabolic and chemical pathways of selenium incorporation into biomolecules remain somewhat unclear, many such pathways proceed through hydrogen selenide (H2Se/HSe-) formation. Despite this importance, well-characterized chemistry that enables H2Se release under controlled conditions remains lacking. Motivated by this need, we report here the development of a hydrolysis-based H2Se donor (TDN1042). Utilizing 31P and 77Se NMR experiments, we demonstrate the pH dependence of H2Se release and characterize observed reaction intermediates during the hydrolysis mechanism. Finally, we confirm H2Se release using electrophilic trapping reagents, which not only demonstrates the fidelity of this donor platform but also provides an efficient method for investigating future H2Se donor motifs. Taken together, this work provides an early example of an H2Se donor that functions through a well-defined and characterized mechanism.

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.

Selenium and selenoproteins in prostanoid metabolism and immunity

Selenium (Se) is an essential trace element that functions in the form of the 21st amino acid, selenocysteine (Sec) in a defined set of proteins. Se deficiency is associated with pathological conditions in humans and animals, where incorporation of Sec into selenoproteins is reduced along with their expression and catalytic activity. Supplementation of Se-deficient population with Se has shown health benefits suggesting the importance of Se in physiology. An interesting paradigm to explain, in part, the health benefits of Se stems from the observations that selenoprotein-dependent modulation of inflammation and efficient resolution of inflammation relies on mechanisms involving a group of bioactive lipid mediators, prostanoids, which orchestrate a concerted action toward maintenance and restoration of homeostatic immune responses. Such an effect involves the interaction of various immune cells with these lipid mediators where cellular redox gatekeeper functions of selenoproteins further aid in not only dampening inflammation, but also initiating an effective and active resolution process. Here we have summarized the current literature on the multifaceted roles of Se/selenoproteins in the regulation of these bioactive lipid mediators and their immunomodulatory effects.

Redox-Active Selenium in Health and Disease: A Conceptual Review

Although it is generally accepted that selenium (Se) is important for life, it is not well known which forms of organic and/or inorganic Se compound are the most biologically active. In nature Se exists mostly in two forms, namely as selenite with fourvalent and selenate with sixvalent cations, from which all other inorganic and organic species are derived. Despite a small difference in their electronic structure, these two inorganic parent compounds differ significantly in their redox properties. Hence, only selenite can act as an oxidant, particularly in the reaction with free and/or protein- bound sulhydryl (SH) groups. For example, selenite was shown to inhibit the hydroxyl radicalinduced reduction and scrambled reoxidation of disulfides in human fibrinogen thus preventing the formation of highly hydrophobic polymer, termed parafibrin. Such a polymer, when deposited within peripheral and/or cerebral circulation, may cause irreversible damage resulting in the development of cardiovascular, neurological and other degenerative diseases. In addition, parafibrin deposited around tumor cells produces a protease-resistant coat protecting them against immune recognition and elimination. On the other hand, parafibrin generated by Ebola's protein disulfide isomerase can form a hydrophobic 'spike' that facilitates virus attachment and entry to the host cell. In view of these specific properties of selenite this compound is a potential candidate as an inexpensive and readily available food supplement in the prevention and/or treatment of cardiovascular, neoplastic, neurological and infectious diseases.

Effects of nano-selenium on mRNA expression of markers for spermatogonial stem cells in the testis of broiler breeder males

Fertility is one of the most important parameters in breeder farms and cockerels play an outstanding role in the fertility of eggs in broiler breeder farms. Todays, supplementation of chicken diet with additives such as organic selenium is used to increase fertility. The aim of this study was to evaluate the effects of different levels of nano-selenium (Nano-Se) on the expression of molecular markers of spermatogonial stem cells (SSCs) in the testis of broiler breeder males. A total of 30 roosters of 40 weeks of age were randomly divided into five groups. Groups were as follows: 1) control (normal diet) group, 2) diet supplemented with 0.30 mg kg^-1 sodium selenite, 3) diet supplemented with 0.15 mg kg^-1 Nano-Se, 4) diet supplemented with 0.30 mg kg^-1 Nano-Se, and 5) diet supplemented with 0.60 mg kg^-1 Nano-Se. At the end of the experimental period (5^th week), birds were autopsied and samples from testis of all birds were collected. The testis samples were used to examine the β1-integrin (CD29), thy-1 (CD90) and NANOG mRNA expression by real-time PCR. The results showed that testis of the groups fed with the diets supplemented with 0.60 mg kg^-1 and 0.15 mg kg^-1 of Nano-Se had the highest and lowest mRNA expression of SSCs markers, respectively. In conclusion, the present study indicated that Nano-Se had advantages over sodium selenite. Diet supplemented with 0.60 mg kg^-1 of Nano-Se may contribute to optimal fertility via increasing the mRNA expression of SSCs markers of roosters’ testis and could be used to delay the reduction of fertility caused by aging in broiler breeder males.

NRT1.1B improves selenium concentrations in rice grains by facilitating selenomethinone translocation

Selenium (Se) is an essential trace element for humans and other animals, yet approximately one billion people worldwide suffer from Se deficiency. Rice is a staple food for over half of the world's population that is a major dietary source of Se. In paddy soils, rice roots mainly take up selenite. Se speciation analysis indicated that most of the selenite absorbed by rice is predominantly transformed into selenomethinone (SeMet) and retained in roots. However, the mechanism by which SeMet is transported in plants remains largely unknown. In this study, SeMet uptake was found to be an energy-dependent symport process involving H⁺ transport, with neutral amino acids strongly inhibiting SeMet uptake. We further revealed that NRT1.1B, a member of rice peptide transporter (PTR) family which plays an important role in nitrate uptake and transport in rice, displays SeMet transport activity in yeast and Xenopus oocyte. The uptake rate of SeMet in the roots and its accumulation rate in the shoots of nrt1.1b mutant were significantly repressed. Conversely, the overexpression of NRT1.1B in rice significantly promoted SeMet translocation from roots to shoots, resulting in increased Se concentrations in shoots and rice grains. With vascular-specific expression of NRT1.1B, the grain Se concentration was 1.83-fold higher than that of wild type. These results strongly demonstrate that NRT1.1B holds great potential for the improvement of Se concentrations in grains by facilitating SeMet translocation, and the findings provide novel insight into breeding of Se-enriched rice varieties.

Effects of selenium-enriched Bacillus sp. compounds on growth performance, antioxidant status, and lipid parameters breast meat quality of Chinese Huainan partridge chicks in winter cold stress

BACKGROUND

Both selenium (Se) and probiotic Bacillus regulate the metabolism to help defense clod stress and improve the meat quality in breeding chicks. The purpose of this study was to evaluate the effect of supplemental Se and Bacillus in the form of Se-enriched Bacillus (SECB) on the growth performance, lipid parameters, breast Se and antibiotic levels, and breast meat quality of chicken in winter cold stress.

METHODS

Five hundred 1-d-old chickens were divided into five groups randomly: Control, inorganic Se, compound Bacillus, SECB, and antibiotic. The feed duration was 56 d.

RESULTS

After 28 d of treatment, chicks feed SECB or compound Bacillus had higher body weights than the control, and after 56 d, chicks given either SECB or compound Bacillus had higher body weights than the control chicks or those given inorganic Se. Adding SECB to feed significantly increased the lightness, redness, and yellowness of breast meat, improved the water-holding capacity, and reduced the shear force and cooking loss. The concentration of Se in the breast muscle very significantly increased after SECB and inorganic Se supplementation, which was opposite to the concentration of flavomycin in antibiotic supplemented chicks. The antioxidative status of plasma and breast meat was significantly improved with added compound Bacillus and SECB: the total antioxidant capacity, total superoxide dismutase, and glutathione peroxidase ability in the breast muscle significantly improved, and the malondialdehyde concentration in plasma decreased. The levels of total cholesterol plasma triglyceride and very-low-density lipoprotein cholesterol in the plasma and breast muscle was decreased compared to that of the control, while the plasma high-density lipoprotein cholesterol concentration increased.

CONCLUSIONS

In conclusion, SECB supplementation promoted the body growth, antioxidative status, and Se concentrations in the plasma and breast meat, and also improved the breast meat quality.

Role of Zinc and Selenium in Oxidative Stress and Immunosenescence: Implications for Healthy Aging and Longevity

Aging is a complex process that includes gradual and spontaneous biochemical and physiological changes which contributes to a decline in performance and increased susceptibility to diseases. Zn and Se are essential trace elements that play a pivotal role in immune functions and antioxidant defense and, consequently, are claimed to play also a role in successful aging trajectories. Consistently with their nature of essential trace elements, a plethora of data obtained “in vitro” and “in vivo” (in humans and animal models) support the relevance of Zn and Se for both the innate and adoptive immune response. Moreover, Zn and Se are strictly involved in the synthesis and regulation of activity of proteins and enzymes, e.g., metallothioneins (MT) and glutathione peroxidase (GPX), that are necessary for our endogenous antioxidant response. This is clearly important to protect our cells from oxidative damage and to slow the decline of our immune system with aging. Age-related changes affecting tissue levels of Zn and Se may indicate that the risk of Zn and Se deficiency increases with aging. However, it is still unclear which of these changes can be the consequence of a “real deficiency” and which can be part of our physiological compensatory response to the accumulating damage occurring in aging. Furthermore, the upregulation of antioxidant proteins (Zn and Se dependent) may be a manifestation of self-induced oxidative stress. By the way, Zn and Se dependent proteins are modulated not only by nutritional status, but also by well-known hallmarks of aging that play antagonistic functions, such as the deregulated nutrient sensing pathways and cellular senescence. Thus, it is not an easy task to conduct Zn or Se supplementation in elderly and it is emerging consistent that these kind of supplementation requires an individualized approach. Anyway, there is consistent support that supplementation with Zn using doses around 10 mg/day is generally safe in elderly and may even improve part of immune performances in those subjects with a baseline deficiency. Regarding Se supplementation, it may induce both beneficial and detrimental effects on cellular immunity depending on the form of Se, supplemental dose, and delivery matrix. The nutritional association of supplements based on “Zn plus Se” is hypothesized to provide additional benefits, but this will likely need a more complex individualized approach. The improvement of our knowledge around screening and detection of Zn and Se deficiency in aging could lead to substantial benefits in terms of efficacy of nutritional supplements aimed at ameliorate performance and health in aging.

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.

Protective Role of Selenium in Immune-Relevant Cytokine and Immunoglobulin Production by Piglet Splenic Lymphocytes Exposed to Deoxynivalenol

Deoxynivalenol (DON) is a mycotoxin that causes immunosuppression, especially in swine. Selenium (Se) is essential for proper functioning of the immune system in animals. However, little is known about the effects of DON and Se on cytokine or immunoglobulin production in piglets. Here, we addressed this gap by examining piglet splenic lymphocyte responses in vitro. Cells were stimulated with concanavalin A, a T cell stimulatory lectin, in the absence or presence of DON (0.1, 0.2, 0.4, and 0.8 μg/mL), Se (Na₂SeO₃, 2 μM), or combinations of Se 2 μM and DON 0.1-0.8 μg/mL for 12, 24, or 48 h. At each time point, supernatants and cells were collected and the expression of cytokine and immunoglobulin protein and mRNA was examined. Compared with control and Se-alone treatments, DON exposure significantly and dose dependently decreased the expression levels of IL-2, IL-4, IL-6, IL-10, IFN-γ, IgG, and IgM mRNA and protein. By contrast, co-treatment with DON + Se significantly increased the mRNA and protein levels of all factors examined, except IL-4 and IL-6, compared with DON treatment alone. The results of this investigation demonstrate that Se has the potential to counteract DON-induced immunosuppression in piglets and is a promising treatment for DON-mediated toxicity.

Supplemented Organic and Inorganic Selenium Affects Milk Performance and Selenium Concentration in Milk and Tissues in the Guanzhong Dairy Goat

Trace amounts of selenium (Se) are essential for several organisms, and deficiencies therein have adverse effects on growth, development, and reproduction; this is particularly significant in animals raised for milk and livestock production. To study the effect of Se on Guanzhong dairy goats, their diets were supplemented with different sources (inorganic or organic) and Se concentrations (0.2 or 0.4 mg Se/kg). A non-Se-fortified basal diet served as a negative control, and a sixth treatment group received both inorganic and organic Se sources (0.2 mg Se/kg diet each). Dietary Se supplementation increased milk production, with organic Se being more effective than inorganic Se. Selenium supplementation also increased Se concentration and glutathione peroxidase activity in whole blood, with organic Se more effective than inorganic Se at the same Se concentration. With increasing Se in diets, the Se content in milk increased markedly, reaching a plateau value at day 30 in all groups, and organic Se (0.4 mg/kg diet) had the best effect. In addition, dietary Se sources and concentrations markedly affected Se concentrations in different tissues and organs. Thus, organic Se supplementation of a basal diet at 0.4 mg/kg is practically applicable for Se-enriched milk and meat production in Guanzhong dairy goats.

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.

Role of Vital Trace Elements in Nanocurcumin-Centered Formulation: A Novel Approach to Resuscitate the Immune System

The present paper described the immunomodulatory potential of novel nanocurcumin-based formulation enriched with trace elements and vitamins on cyclophosphamide-induced immunosuppression in rat model. Major immune-related assays were monitored such as hemagglutination assay, delayed-type hypersensitivity (DTH) reaction, cellular immune response, IgG, IgE, IgM, cerebrospinal fluid biomarkers, hematological study, antioxidant profile, and lipid biomarkers. Chemical characterization of novel formulation showed retention time (R _t ) 18.98 of curcumin, while LC-MS data revealed the presence of the curcumin mass at m/z 369.01 [M + H]⁺ (calculated for C₂₁H₂₁O₆⁺, 369.13). This novel formulation exhibited significantly (p ≤ 0.001) increased primary and secondary antibody titer by 72.41% and 33.25%, respectively, while DTH response being improved by 87.50% (p ≤ 0.01). However, CD4⁺, CD8⁺, and CD28⁺ counts were significantly (p ≤ 0.05) increased by 76.46%, 68.21%, and 19.29%, respectively, while the concentrations of IgE, IgM, and IgG were significantly (p ≤ 0.05) increased by 40%, 28.43%, and 38.75%, respectively. CSF biomarkers analysis showed a decreased level of corticosterone, dopamine, serotonin, and tau protein by 29.38%, 51.73%, 29.93%, and 4.87%, respectively. Antioxidant enzymes such as CAT, GPx, and SOD were increased by 43.74%, 49.00%, and 40.84%, respectively, and non-enzymatic component, GSH, was increased by 55.52%. Similarly, free radical LPO was significantly (p ≤ 0.05) decreased by 40.37%, and acute inflammatory marker, MPO concentration, was reduced by 31.14%, compared with the disease control group. In addition, supportive hematology and lipid profile analysis showed promising results with improved overall animal profile. Thus, trace elements in novel formulation can be used in the various pharmacological activities and as dietary supplement due to its wide properties.

Immunomodulation by food: impact on gut immunity and immune cell function

Recent studies have revealed that various food components affect the immune response. These components act on various immune cells, and their effects are mediated through the intestinal immune system and, in some cases, the intestinal microbiota. In this review, we describe the immunomodulating effects of various food components, including probiotics, prebiotics, polysaccharides, vitamins, minerals, fatty acids, peptides, amino acids and polyphenols. Some of these components enhance immune responses, leading to host defense against infection, whereas others inhibit immune responses, thus suppressing allergy and inflammation.

The influence of selenium and selenoproteins on immune responses of poultry and pigs

Selenium is an essential nutrient for poultry and pigs, and is important for a number of physiological processes including regulation and function of the immune system. Through its incorporation into selenoproteins, Se is involved in the regulation of oxidative stress, redox mechanisms, and other crucial cellular processes involved in innate and adaptive immune response. This review provides current knowledge on the mechanisms by which selenium can modulate the resilience to infectious diseases, and how this micronutrient can influence the capacity of the bird or the pig to maintain its productivity during an infectious challenge. In relation to the most frequent and economically important infectious diseases in poultry and pig production, the present paper considers the influence of different selenium sources (organic vs. inorganic Se) as well as dietary concentrations on the immune responses of poultry and pigs with major emphasis on the potential beneficial impact on animal resilience to common infectious diseases.

Toxic elements and associations with hematology, plasma biochemistry, and protein electrophoresis in nesting loggerhead sea turtles (Caretta caretta) from Casey Key, Florida

Toxic elements (arsenic, cadmium, lead, mercury, selenium, thallium) are a group of contaminants that are known to elicit developmental, reproductive, general health, and immune system effects in reptiles, even at low concentrations. Reptiles, including marine turtles, are susceptible to accumulation of toxic elements due to their long life span, low metabolic rate, and highly efficient conversion of prey into biomass. The objectives of this study were to (1) document concentrations of arsenic, cadmium, lead, mercury, selenium, and thallium in whole blood and keratin from nesting loggerhead sea turtles (Caretta caretta) from Casey Key, Florida and document correlations thereof and (2) correlate whole blood toxic element concentrations to various hematological and plasma biochemistry analytes. Baselines for various hematological and plasma analytes and toxic elements in whole blood and keratin (i.e., scute) in nesting loggerheads are documented. Various correlations between the toxic elements and hematological and plasma biochemistry analytes were identified; however, the most intriguing were negative correlations between arsenic, cadmium, lead, and selenium with and α- and γ-globulins. Although various extrinsic and intrinsic variables such as dietary and feeding changes in nesting loggerheads need to be considered, this finding may suggest a link to altered humoral immunity. This study documents a suite of health variables of nesting loggerheads in correlation to contaminants and identifies the potential of toxic elements to impact the overall health of nesting turtles, thus presenting important implications for the conservation and management of this species.

Efficient induction of apoptosis in cancer cells by paclitaxel-loaded selenium nanoparticles

Aim: To develop selenium nanoparticles (SeNPs)-based delivery systems for paclitaxel (PTX) and assess their antiproliferative efficacy against cancer cells in vitro with potential mechanistic insight. Methods: Pluronic F-127 stabilized SeNPs were prepared and characterized. Effects of PTX-loaded SeNPs on lung (A549), breast (MCF7), cervical (HeLa) and colon (HT29) cancer cells were studied by viability assay complemented with flow-cytometric analyses of cell cycle, apoptosis, mitochondrial membrane potential, intracellular reactive oxygen species and caspase activity. Results: PTX-loaded SeNPs demonstrated significant antiproliferative activity against cancer cells. Cell cycle analyses of PTX-SeNPs treated cells established G2/M phase arrest in a dose-dependent manner leading to apoptosis. Further investigation revealed disruption of mitochondrial membrane potential orchestrated with induction of reactive oxygen species leading to the activation of caspases, key players of apoptotic cell death. Conclusion: Efficient induction of apoptosis in various cancer cells by PTX-loaded SeNPs, with appropriate future studies, might lead to potential anticancer strategies.

Intake of vitamin C, vitamin E, selenium, zinc and polyunsaturated fatty acids and upper respiratory tract infection-a prospective cohort study

BACKGROUND/OBJECTIVES

Antioxidants and polyunsaturated fatty acids (PUFAs) have a role in the human immune defense and may affect the susceptibility to upper respiratory tract infection (URTI). To examine dietary intake of vitamin C, vitamin E, selenium, zinc and PUFAs in relation to URTI incidence in a prospective cohort study.

SUBJECTS/METHODS

A total of 1533 Swedish women and men aged 25-64 years were followed for nine months during 2011-2012. Information on dietary intake was assessed through a web-based food frequency questionnaire, and events of URTI were self-reported prospectively as they occurred. Cox proportional hazards regression was applied to obtain incidence rate ratios with 95% confidence intervals.

RESULTS

The mean number of URTI events was 0.9 among all participants, 1.0 among women and 0.7 among men. In women, the incidence rate ratios (95% confidence interval) for high compared with low intake were 0.69 (0.55-0.88) for vitamin C, 0.77 (0.62-0.96) for vitamin E, 0.57 (0.39-0.83) for docosahexaenoic acid (DHA) and 0.80 (0.65-0.99) for arachidonic acid (AA). No association was found for selenium or zinc among women. In men, an increased URTI incidence was seen with medium vitamin E intake (1.42 (1.09-1.85)) and high zinc intake (1.50 (1.04-2.16)). No association was found for vitamin C, selenium or PUFAs among men.

CONCLUSIONS

We found an inverse association of URTI incidence among women for vitamin C, vitamin E, DHA and AA intake and a positive association among men for vitamin E and zinc intake. The observed gender differences warrant further investigation.

Selenium Levels in the Whole Blood of Children and Teenagers from Two Riparian Communities at the Madeira River Basin in the Western Brazilian Amazon

Selenium (Se) is an essential micronutrient that exerts multiple functions in the organism, and both its deficiency and excess can cause health impairments. Thus, it is important to monitor its levels in the population, especially in vulnerable groups, such as children from the Brazilian Amazon region, where there is a lack of information in this regard. The aim of this research was to study Se levels in the whole blood of children and teenagers (5-16 years old) from two riparian communities at the Madeira River (Cuniã RESEX and Belmont). Se level variations related to the communities' location, seasonality, diet, and body mass index (BMI) were assessed. Blood samples were collected in both communities for Se determinations, using ICP-MS and hemogram analyses, during May and September of 2011. Food frequency questionnaires were applied to assess consumption rates of specific food items. Non-parametric tests and linear multiple regressions were applied in the data analyses. Median Se levels were significantly higher during May (Cuniã RESEX 149 μg L^-1; Belmont 85 μg L^-1) compared to September (Cuniã RESEX 79 μg L^-1; Belmont 53 μg L^-1). No significant differences were found between the communities regarding BMI measurements and anemia prevalence. However, Se blood levels were significantly higher at the Cuniã RESEX compared to Belmont. In addition, the former showed higher fish and Brazil nut intakes, which may be the main Se sources for this community. These results contribute to a better understanding of Se reference levels for children and teenagers of Western Amazon riparian communities.

Analysis of whole human blood for Pb, Cd, Hg, Se, and Mn by ICP-DRC-MS for biomonitoring and acute exposures

We improved our inductively coupled plasma mass spectrometry (ICP-MS) whole blood method [1] for determination of lead (Pb), cadmium (Cd), and mercury (Hg) by including manganese (Mn) and selenium (Se), and expanding the calibration range of all analytes. The method is validated on a PerkinElmer (PE) ELAN® DRC II ICP-MS (ICP-DRC-MS) and uses the Dynamic Reaction Cell (DRC) technology to attenuate interfering background ion signals via ion-molecule reactions. Methane gas (CH4) eliminates background signal from 40Ar2+ to permit determination of 80Se+, and oxygen gas (O2) eliminates several polyatomic interferences (e.g. 40Ar15N+, 54Fe1H+) on 55Mn+. Hg sensitivity in DRC mode is a factor of two higher than vented mode when measured under the same DRC conditions as Mn due to collisional focusing of the ion beam. To compensate for the expanded method's longer analysis time (due to DRC mode pause delays), we implemented an SC4-FAST autosampler (ESI Scientific, Omaha, NE), which vacuum loads the sample onto a loop, to keep the sample-to-sample measurement time to less than 5min, allowing for preparation and analysis of 60 samples in an 8-h work shift. The longer analysis time also resulted in faster breakdown of the hydrocarbon oil in the interface roughing pump. The replacement of the standard roughing pump with a pump using a fluorinated lubricant, Fomblin®, extended the time between pump maintenance. We optimized the diluent and rinse solution components to reduce carryover from high concentration samples and prevent the formation of precipitates. We performed a robust calculation to determine the following limits of detection (LOD) in whole blood: 0.07µgdL-1 for Pb, 0.10µgL-1 for Cd, 0.28μgL-1 for Hg, 0.99µgL-1 for Mn, and 24.5µgL-1 for Se.

Porcine GPX1 enhances GP5-based DNA vaccination against porcine reproductive and respiratory syndrome virus

Porcine reproductive and respiratory syndrome virus (PRRSV) has been causing huge economic losses to the swine industry worldwide. Commercial PRRSV vaccines including killed and modified live ones are available. However the protective efficacy of these vaccines is incomplete. Thus, it is in urgent need to develop safer and more effective PRRSV vaccines. In this study, we constructed a recombinant plasmid co-expressing porcine glutathione peroxidase-1 (GPX1) and the envelope glycoprotein (GP5) encoding-gene of PRRSV (pcDNA3.1-GPX1-LSynORF5), and investigated the immune response induced following inoculation of mice and piglets. Significantly enhanced GP5-specific antibody, PRRSV-specific neutralizing antibody, IFN-γ level, as well as lymphocyte proliferation response, were induced in mice and pigs immunized with the DNA construct encoding GPX1 and GP5 compared with those inoculated with a construct encoding PRRSV GP5 only (pcDNA3.1-SynORF5). The enhanced cellular immune response in pigs induced by pcDNA3.1-GPX1-LSynORF5 was comparable to that induced by the attenuated virus vaccine JXA1-R, although the humoral immune response induced by the plasmid was much lower than the response induced by JXA1-R. Following the challenge with highly pathogenic PRRSV, less-severe clinical signs and rectal temperatures were observed in pigs immunized with the GPX1-GP5 construct compared with the control group. However, the viraemia of groups immunized with plasmid was more severe than that inoculated with JXA1-R, and it is likely that this could be attributed to the poor humoral response induced by the GPX1-GP5 construct. These results demonstrated that inclusion of GPX1 in a PRRSV DNA vaccine leads to an adjuvant effect, enhancing the humoral and cellular responses following vaccination.

Cellular Selenoprotein mRNA Tethering via Antisense Interactions with Ebola and HIV-1 mRNAs May Impact Host Selenium Biochemistry

Regulation of protein expression by non-coding RNAs typically involves effects on mRNA degradation and/or ribosomal translation. The possibility of virus-host mRNA-mRNA antisense tethering interactions (ATI) as a gain-of-function strategy, via the capture of functional RNA motifs, has not been hitherto considered. We present evidence that ATIs may be exploited by certain RNA viruses in order to tether the mRNAs of host selenoproteins, potentially exploiting the proximity of a captured host selenocysteine insertion sequence (SECIS) element to enable the expression of virally-encoded selenoprotein modules, via translation of in-frame UGA stop codons as selenocysteine. Computational analysis predicts thermodynamically stable ATIs between several widely expressed mammalian selenoprotein mRNAs (e.g., isoforms of thioredoxin reductase) and specific Ebola virus mRNAs, and HIV-1 mRNA, which we demonstrate via DNA gel shift assays. The probable functional significance of these ATIs is further supported by the observation that, in both viruses, they are located in close proximity to highly conserved in-frame UGA stop codons at the 3′ end of open reading frames that encode essential viral proteins (the HIV-1 nef protein and the Ebola nucleoprotein). Significantly, in HIV/AIDS patients, an inverse correlation between serum selenium and mortality has been repeatedly documented, and clinical benefits of selenium in the context of multi-micronutrient supplementation have been demonstrated in several well-controlled clinical trials. Hence, in the light of our findings, the possibility of a similar role for selenium in Ebola pathogenesis and treatment merits serious investigation.

Critical Thresholds of Antioxidant and Immune Function Parameters for Se deficiency Prediction in Dairy Cows

The aim of this study was to determine the plasma selenium (Se) levels of lactating cows and to evaluate its association with antioxidant ability and immune function. In a descriptive study, 20 healthy Holstein cows with normal Se level (C) and 30 Holstein cows with subclinical Se deficiency (T) were randomly selected between 14 and 21 days postpartum from a dairy farm, according to a cutoff point of 70 mg/L Se in plasma. Analysis of biochemical parameters of antioxidant and immune function were performed on all the cows, and the risk prediction thresholds for subclinical Se deficiency were determined by area under receiver operating characteristic curve. Cows in the T group had significantly lower plasma Se concentrations compared with cows in the C group (52.16 ± 8.81 vs. 80.37 ± 8.46 μg/L, P = 0.02). There was a marked decrease in plasma glutathione peroxidase (GSH-Px) activity in the T group that correlated positively with the plasma Se level (R = 0.65, P = 0.00), and a significant increase of plasma methane dicarboxylic aldehyde (MDA), total nitric oxide synthase, and lipid peroxidation that correlated negatively with plasma Se levels (R = -0.47, P = 0.01; R = -0.33, P = 0.04; R = -0.40, P = 0.03). Furthermore, there were significantly lower plasma tumor necrosis factor-α and immunoglobulin G levels in the T group that correlated positively with plasma Se levels (R = 0.41, P = 0.01 and R = 0.45, P = 0.01), and a markedly lower plasma interleukin-6 level that correlated negatively with plasma Se levels (R = -0.38, P = 0.02). In addition, if plasma GSH-Px activity was less than 42.37 U/ml, the risk of Se deficiency was significantly increased in lactating cows. These results suggest that low plasma Se levels may reduce the antioxidant ability and immune function, and the risk of low plasma Se level may be predicted effectively by plasma GSH-Px activity in lactating cows.

Selenium Deficiency Mainly Influences Antioxidant Selenoproteins Expression in Broiler Immune Organs

Selenoprotein has many functions in chicken, and the expression of selenoproteins is closely associated with the selenium (Se) level. However, little is known about the expression patterns of selenoproteins in chicken immune organs. Here, we investigated the effect of dietary Se deficiency on the expressions of 23 selenoproteins in broiler immune organs. In this study, 150 broilers were randomly divided into two groups (75 chickens per group). The chickens were maintained either on a diet supplemented with Se through the addition of 0.2 mg/kg of Se (C group) via sodium selenite or on a Se-deficient granulated diet (L group) until the broilers exhibited an onset of exudative diathesis (ED). Following euthanasia, the samples from the immune tissues (including the spleen, thymus, and bursa of Fabricius) were quickly collected, and the messenger RNA (mRNA) expression levels of 23 selenoproteins were examined by real-time quantitative PCR and analyzed using principal component analysis. The results showed that Se deficiency decreased the mRNA levels of 23 selenoproteins in the thymus, spleen, and bursa of the Fabricius tissues of broiler chickens. Furthermore, we found that among 23 selenoproteins, the mRNA levels of Dio1 in the thymus, Txnrd2 in the spleen, and Txnrd3 in the bursa of Fabricius decreased significantly (90.9 %, 83.3 %, and 96.8 %, respectively). In addition, the principal component analysis (PCA) results suggested that Se deficiency mainly influenced the expression of antioxidative selenoproteins, especially glutathione peroxidases (Gpxs), thioredoxin reductases (Txnrds), and iodothyronine deiodinases (Dios) in chicken immune organs. The results of this study are valuable for understanding the relevance of selenoprotein activity in vivo.

Selenium-Containing Phycocyanin from Se-Enriched Spirulina platensis Reduces Inflammation in Dextran Sulfate Sodium-Induced Colitis by Inhibiting NF-κB Activation

Selenium (Se) plays an important role in fine-tuning immune responses. Inflammatory bowel disease (IBD) involves hyperresponsive immunity of the digestive tract, and a low Se level might aggravate IBD progression; however, the beneficial effects of natural Se-enriched diets on IBD remain unknown. Previously, we developed high-yield Se-enriched Spirulina platensis (Se-SP) as an excellent organic nutritional Se source. Here we prepared Se-containing phycocyanin (Se-PC) from Se-SP and observed that Se-PC administration effectively reduced the extent of colitis in mouse induced by dextran sulfate sodium. Supplementation with Se-PC resulted in significant protective effects, including mitigation of body weight loss, bloody diarrhea, and colonic inflammatory damage. The anti-inflammatory effects of Se-PC supplementation were found to involve modulation of cytokines, including IL-6, TNF-α, MCP-1, and IL-10. Mechanistically, Se-PC inhibited the activation of macrophages by suppressing the nuclear translocation of NF-κB, which is involved in the transcription of these pro-inflammatory cytokines. These results together suggest potential benefits of Se-PC as a functional Se supplement to reduce the symptoms of IBD.

Influence of Gender and SNPs in GPX1 Gene on Biomarkers of Selenium Status in Healthy Brazilians

Selenium (Se) status varies worldwide as a result of natural variation of Se content in soils, dietary pattern, and the presence of SNPs. Further, Se status in Brazilians and its relationship between genetic variation and Se biomarkers is unknown. This work investigated the association between SNPs in glutathione peroxidase genes and biomarkers of Se status in healthy Brazilians. The study was conducted in 116 healthy adults in São Paulo, Brazil. Plasma and erythrocyte Se were measured by HGFAAS. Erythrocyte GPx (eGPx) activity was measured spectrometrically in a biochemical analyzer. Genotypes were determined by real-time PCR using Taqman(®) Assays. eGPx activity was higher in females compared with males. Lower erythrocyte Se concentrations were found in heterozygous GC carriers for GPX1 rs8179169. eGPx activity was higher in females with the common genotypes, except for rs8179169. GC carriers for rs8179169 had lower erythrocyte Se in both genders, and only male carriers of the variant alleles of both rs1050450 and rs1800668 had higher eGPx activity. In conclusion, the genotype for SNPs in GPX1 and gender affected biomarkers of Se status in this pilot study with healthy Brazilians.

The Selenylation Modification of Epimedium Polysaccharide and Isatis Root Polysaccharide and the Immune-enhancing Activity Comparison of Their Modifiers

Epimedium polysaccharide (EPS) and isatis root polysaccharide (IRPS) were extracted, purified, and selenizingly modified by nitric acid-sodium selenite method to obtain nine selenizing EPSs (sEPSs), sEPS1-sEPS9 and nine selenizing IRPSs (sIRPSs), sIRPS1-sIRPS9, respectively. Their effects on chicken peripheral lymphocyte proliferation in vitro were compared by MTT assay. The results showed that selenium polysaccharides at appropriate concentration could promote lymphocyte proliferation more significantly than unmodified polysaccharides, sEPS5 and sIRPS5 with stronger actions were picked out and injected into the chickens vaccinated with Newcastle disease vaccine in vivo tests. The peripheral lymphocyte proliferation and serum antibody titer were determined. The results showed that sEPS5 and sIRPS5 could elevate serum antibody titer and promote lymphocyte proliferation more significantly than unmodified polysaccharides, sEPS5 possessed the strongest efficacy. These results indicate that selenylation modification can significantly enhance the immune-enhancing activity of EPS and IRPS, and sEPS5 can be as a new-type immunopotentiator of chickens.