The relationship between serum selenium concentration and neutrophil function in peripheral blood

Thyroid hormones and minerals in immunocorrection of disorders in autoimmune thyroid diseases

Thyroid hormones and essential elements iodine (I), selenium (Se), iron (Fe), copper (Cu), zinc (Zn), calcium (Ca), magnesium (Mg), etc. play an important role in the work of many organs and systems of the body, including the immune system and the thyroid gland, and a violation of their supply can be the cause of pathological changes in them. In pathology, the interaction between thyroid hormones (TG), minerals and the immune system is disturbed. The review of the literature examines the immunomodulatory role of TG, minerals, their properties, and their participation in the pathogenesis of autoimmune thyroid diseases (AITD). The study of the relationship between the excess or deficiency of minerals and AITD is described. The basis of the development of AITD - Hashimoto's thyroiditis (HT), Graves' disease (GD), Graves' ophthalmopathy (GO) is the loss of immune tolerance to thyroid antigens - thyroid peroxidase (TPO), thyroglobulin (Tg) and thyroid-stimulating hormone receptor (TSH-R). Immune-mediated mechanisms - production of autoantibodies to thyroid antigens and lymphocytic thyroid infiltration - are involved in the pathogenesis of AITD. Insufficiency of regulatory T cells (Treg) and regulatory B cells (Breg), imbalance between Th17-lymphocytes and Treg-lymphocytes, abnormal production of pro-inflammatory cytokines has a significant influence on the progression of AITD. With AITD, the balance between oxidants and antioxidants is disturbed and oxidative stress (OS) occurs. The lack of modern effective pharmacological therapy of AITD prompted us to consider the mechanisms of influence, possibilities of immunocorrection of pathogenetic factors using TG, micro/macronutrients. In order to develop a more effective treatment strategy, as well as approaches to prevention, a critical analysis of the ways of immunotherapeutic use of dietary supplements of I, Se, Zn, Mg and other minerals in AITD was carried out.

Relationship between selenium status, selenoproteins and COVID-19 and other inflammatory diseases: A critical review

The antioxidant effects of selenium as a component of selenoproteins has been thought to modulate host immunity and viral pathogenesis. Accordingly, the association of low dietary selenium status with inflammatory and immunodeficiency has been reported in the literature; however, the causal role of selenium deficiency in chronic inflammatory diseases and viral infection is still undefined. The COVID-19, characterized by acute respiratory syndrome and caused by the novel coronavirus 2, SARS-CoV-2, has infected millions of individuals worldwide since late 2019. The severity and mortality from COVID-19 have been associated with several factor, including age, sex and selenium deficiency. However, available data on selenium status and COVID-19 are limited, and a possible causative role for selenium deficiency in COVID-19 severity has yet to be fully addressed. In this context, we review the relationship between selenium, selenoproteins, COVID-19, immune and inflammatory responses, viral infection, and aging. Regardless of the role of selenium in immune and inflammatory responses, we emphasize that selenium supplementation should be indicated after a selenium deficiency be detected, particularly, in view of the critical role played by selenoproteins in human health. In addition, the levels of selenium should be monitored after the start of supplementation and discontinued as soon as normal levels are reached. Periodic assessment of selenium levels after supplementation is a critical issue to avoid over production of toxic metabolites of selenide because under normal conditions, selenoproteins attain saturated expression levels that limits their potential deleterious metabolic effects.

The role of selenoproteins in neutrophils during inflammation

Polymorphonuclear neutrophils (PMNs)-derived ROS are involved in the regulation of multiple functions of PMNs critical in both inflammation and its timely resolution. Selenium is an essential trace element that functions as a gatekeeper of cellular redox homeostasis in the form of selenoproteins. Despite their well-studied involvement in regulating functions of various immune cells, limited studies have focused on the regulation of selenoproteins in PMN and their associated functions. Ex-vivo treatment of murine primary bone marrow derived PMNs with bacterial endotoxin lipopolysaccharide (LPS) indicated temporal regulation of several selenoprotein genes at the mRNA level. However, only glutathione peroxidase 4 (Gpx4) was significantly upregulated, while Selenof, Selenow, and Gpx1 were significantly downregulated in a temporal manner at the protein level. Exposure of PMNs isolated from tRNASec (Trsp)fl/fl S100A8Cre (TrspN) PMN-specific selenoprotein knockout mice, to the Gram-negative bacterium, Citrobacter rodentium, showed decreased bacterial growth, reduced phagocytosis, as well as impaired neutrophil extracellular trap (NET) formation ability, when compared to the wild-type PMNs. Increased extracellular ROS production upon LPS stimulation was also observed in TrspN PMNs that was associated with upregulation of Alox12, Cox2, and iNOS, as well as proinflammatory cytokines such as TNFα and IL-1β. Our data indicate that the inhibition of selenoproteome expression results in alteration of PMN proinflammatory functions, suggesting a potential role of selenoproteins in the continuum of inflammation and resolution.

Modulation of the Functional State of Mouse Neutrophils by Selenium Nanoparticles In Vivo

This study aimed to discover the immunomodulatory effect of selenium nanoparticles (SeNPs) on the functional state of neutrophils in vivo. Intraperitoneal injections of SeNPs (size 100 nm) 2.5 mg/kg/daily to BALB/c mice for a duration of 7-28 days led to the development of an inflammatory reaction, which was registered by a significant increase in the number of neutrophils released from the peritoneal cavity, as well as their activated state, without additional effects. At the same time, subcutaneous injections of the same SeNPs preparations at concentrations of 0.1, 0.5, and 2.5 mg/kg, on the contrary, modulated the functional state of neutrophils depending on the concentration and duration of SeNPs administration. With the use of fluorescence spectroscopy, chemiluminescence, biochemical methods, and PCR analysis, it was found that subcutaneous administration of SeNPs (0.1, 0.5, and 2.5 mg/kg) to mice for a short period of time (7-14 days) leads to modification of important neutrophil functions (adhesion, the number of migrating cells into the peritoneal cell cavity, ROS production, and NET formation). The obtained results indicated the immunostimulatory and antioxidant effects of SeNPs in vivo during short-term administration, while the most pronounced immunomodulatory effects of SeNPs were observed with the introduction of a low concentration of SeNPs (0.1 mg/kg). Increase in the administration time of SeNPs (0.1 mg/kg or 2.5 mg/kg) up to 28 days led to a decrease in the adhesive abilities of neutrophils and suppression of the expression of mRNA of adhesive molecules, as well as proteins involved in the generation of ROS, with the exception of NOX2; there was a tendency to suppress gene expression pro-inflammatory factors, which indicates the possible manifestation of immunosuppressive and anti-inflammatory effects of SeNPs during their long-term administration. Changes in the expression of selenoproteins also had features depending on the concentration and duration of the administered SeNPs. Selenoprotein P, selenoprotein M, selenoprotein S, selenoprotein K, and selenoprotein T were the most sensitive to the introduction of SeNPs into the mouse organism, which indicates their participation in maintaining the functional status of neutrophils, and possibly mediated the immunomodulatory effect of SeNPs.

Assessment of physical stress during the perioperative period of endoscopic submucosal dissection

The advantage of endoscopic submucosal dissection (ESD) is that it is less invasive than surgery. ESD is one of the best treatments for older patients as surgery in this age group of patients is difficult. However, it is unclear how much lower the physical stress of ESD is compared with that of surgery. Thus, objective methods are required to assess physical stress in patients who have undergone ESD. The current review of ESD aimed to summarize the recent advancements in the assessment of physical stress during the perioperative period, focusing on changes in energy metabolism and serum opsonic activity (SOA). Based on metabolic changes, resting energy expenditure (REE) was measured using an indirect calorimeter. The stress factor calculated from the REE and the basal energy expenditure computed using the Harris-Benedict equation can be used to assess physical stress. SOA was assessed using the chemiluminescence method, wherein the use of chemiluminescent probes (i.e., lucigenin and luminol) allowed quantification of reactive oxygen species generated by neutrophils. Using an auto luminescence analyzer, the results were evaluated based on the maximum light emission and area under the emission curve. These quantifiable results revealed the minimal invasiveness of ESD.

Association between Polyunsaturated Fatty Acid and Reactive Oxygen Species Production of Neutrophils in the General Population

Little is known about the relationship between polyunsaturated fatty acids (PUFAs) and reactive oxygen species (ROS) in the general population. Therefore this study aimed to describe the association of PUFAs with ROS according to age and sex in the general population and to determine whether PUFA levels are indicators of ROS. This cross-sectional study included 895 participants recruited from a 2015 community health project. Participants were divided into 6 groups based on sex and age (less than 45 years old (young), aged 45–64 years (middle-aged), and 65 years or older (old)) as follows: male, young (n = 136); middle-aged (n = 133); old (n = 82); female, young (n = 159); middle-aged (n = 228); and old (n = 157). The PUFAs measured were arachidonic acid (AA), dihomo gamma linolenic acid (DGLA), AA/DGLA ratio, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). ROS considered in the analysis were basal ROS and stimulated ROS levels. Multiple linear analyses showed: (1) significant correlations between PUFA levels, especially DGLA and AA/DGLA ratio, and neutrophil function in the young and middle-aged groups; (2) no significant correlations in old age groups for either sex. Because PUFAs have associated with the ROS production, recommendation for controlled PUFA intake from a young age should be considered.

Trace element contents in toenails are related to regular physical activity in older adults

The aim was to assess the trace element contents in toenails of older adults and its association with regular physical activity. Cross-sectional multicentre study in Spain, collecting data from a random sample of 380 participants (54% female) aged 55–80 years (men) and 60–80 years (women) with no previously documented cardiovascular disease. Physical activity performed was measured using the Minnesota Leisure-time Physical Activity Questionnaire. The 25 most inactive and 25 most active individuals for each sex were selected for this study (final sample n = 100). Anthropometric measurements were performed and toenail samples collected for calcium (Ca), chromium (Cr), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), selenium (Se) and mercury (Hg) analysis. Significant differences between sexes were reported in Ca concentrations, women having lower concentrations than men. No differences were reported in trace element contents between active and inactive men. Active women showed higher Ca, Cr, Fe, Co, and Zn and lower Hg contents than their inactive peers (all p<0.05). Inactive women showed lower Ca and Co levels (735.0 mg/kg and 4.5 μg/kg, respectively) than inactive men (1170.0 mg/kg and 7.9 μg/kg, respectively). Active women had lower Ca and higher levels of Cr (936.0 mg/kg and 1230.0 μg/kg, respectively) than active men (1070.0 mg/kg and 522.0 μg/kg, respectively). The present data added new information on the element contents in toenails of healthy Spanish older adults. The concentration of trace elements was similar in both sexes except for Ca which were lower in women. The trace element contents in women’s toenails, but not in men, were markedly influenced by physical activity, with higher levels of Ca and Fe and lower Hg among active females.

Impact of Selenium Supplementation in Neutropenia and Immunoglobulin Production in Childhood Cancer Patients

Essential to human health, selenium (Se) has enzymatic functions of fundamental importance to human biology due to its effects on DNA damage repair, its antioxidant properties, and cancer prevention. The best studied relationships between Se and the immune system is its role in the functions of neutrophils and of lymphocytes. Despite these observations, it is not yet clear by which mechanism Se is able to modify the immune status. This was a double-blind, crossover study: Group 1 received Se and Group 2 received placebo (30 days). After this, Group 1 received placebo and Group 2 received Se (30 days). Every 30 days, blood samples were collected for white blood cell count, red blood cell count, and Ig level measurement (IgA, IgG, IgE, IgM). Of the 36 patients, 17 were suffering from leukemia/lymphomas (LL) and 19 from solid tumors (ST). In the ST group's leukogram, a significant increase in neutrophils was observed after Se usage (P = .0192). During the analyzed period, Se minimized the triggering of neutropenia cases in both groups. IgA and IgG levels in ST patients were significantly higher than those identified in LL patients after Se usage (P = .0051 and P = .0055). For IgA, a significant increase in its production, after Se usage, was observed in the ST group when compared to the LL (P = .0011). The same did not occur to the IgM and IgE immunoglobulins. In our study, the supplementation with Se reduced the neutropenic cases (LL and ST patients) and reduced IgG and IgA levels in LL and increased in ST group.

Effects of feeding selenium-enriched alfalfa hay on immunity and health of weaned beef calves

Previously, we reported that feeding selenium (Se)-enriched forage improves antibody titers in mature beef cows, and whole-blood Se concentrations and growth rates in weaned beef calves. Our current objective was to test whether beef calves fed Se-enriched alfalfa hay during the transition period between weaning and movement to a feedlot also have improved immune responses and slaughter weights. Recently weaned beef calves (n = 60) were fed an alfalfa-hay-based diet for 7 weeks, which was harvested from fields fertilized with sodium selenate at 0, 22.5, 45.0, or 89.9 g Se/ha. All calves were immunized with J-5 Escherichia coli bacterin. Serum was collected for antibody titers 2 weeks after the third immunization. Whole-blood neutrophils collected at 6 or 7 weeks were evaluated for total antioxidant potential, bacterial killing activity, and expression of genes associated with selenoproteins and innate immunity. Calves fed the highest versus the lowest level of Se-enriched alfalfa hay had higher antibody titers (P = 0.02), thioredoxin reductase-2 mRNA levels (P = 0.07), and a greater neutrophil total antioxidant potential (P = 0.10), whereas mRNA levels of interleukin-8 receptor (P = 0.02), L-selectin (P = 0.07), and thioredoxin reductase-1 (P = 0.07) were lower. In the feedlot, calves previously fed the highest-Se forage had lower mortality (P = 0.04) and greater slaughter weights (P = 0.02). Our results suggest that, in areas with low-forage Se concentrations, feeding beef calves Se-enriched alfalfa hay during the weaning transition period improves vaccination responses and subsequent growth and survival in the feedlot.