Inorganic Forms Of Selenium Research Articles

Selenite ameliorates the ATP hydrolysis of mitochondrial F1FO-ATPase by changing the redox state of thiol groups and impairs the ADP phosphorylation

Selenite as an inorganic form of selenium can affect the redox state of mitochondria by modifying the thiol groups of cysteines. The F1FO-ATPase has been identified as a mitochondrial target of this compound. Indeed, the bifunctional mechanism of ATP turnover of F1FO-ATPase was differently modified by selenite. The activity of ATP hydrolysis was stimulated, whereas the ADP phosphorylation was inhibited. We ascertain that a possible new protein adduct identified as seleno-dithiol (-S-Se-S-) mercaptoethanol-sensitive caused the activation of F-ATPase activity and the oxidation of free –SH groups in mitochondria. Conversely, the inhibition of ATP synthesis by selenite might be irreversible. The kinetic analysis of the activation mechanism was an uncompetitive mixed type with respect to the ATP substrate. Selenite bound more selectively to the F1FO-ATPase loaded with the substrate by preferentially forming a tertiary (enzyme-ATP-selenite) complex. Otherwise, the selenite was a competitive mixed-type activator with respect to the Mg2+ cofactor. Thus, selenite more specifically bound to the free enzyme forming the complex enzyme-selenite. However, even if the selenite impaired the catalysis of F1FO-ATPase, the mitochondrial permeability transition pore phenomenon was unaffected. Therefore, the reversible energy transduction mechanism of F1FO-ATPase can be oppositely regulated by selenite.

Combination of Selenite and Butyrate Enhances Efficacy Against Colon Cancer by Targeting ASCT2-Mediated Amino Acid Metabolism.

Drug combination is considered to be an effective approach to improve the efficacy of cancer therapy and chemoprevention. Selenite, a representative of inorganic form of selenium, and butyrate, a major short-chain fatty acid, are two well-documented colon cancer dietary chemopreventive agents with distinct molecular mechanisms. We hypothesized that combination of selenite and butyrate might produce improved outcome against colon cancer. This hypothesis was tested using both HCT116 human colon cancer cells and its xenograft mouse model in the present study. The in vitro study showed a synergistically inhibitory effect on HCT116 colon cancer cells but not on NCM460 normal human colon mucosal epithelial cells. Consistent with the in vitro study, results of the xenograft mouse model further demonstrated that combination of selenite and butyrate led to improved efficacy in comparison with each agent alone. Mechanistically, the induction of alanine-serine-cysteine transporter 2 (ASCT2) by selenite repressed its inhibitory effect on colon cancer cells, which was reversed by its co-treatment with butyrate. The findings of the present study denote the likely potential for developing selenite/butyrate combination remedy to combat against colon cancer.

Influence different form of selenium to production and metatabolic process of young cattle

Relevance. In modern conditions of intensive animal husbandry, primary importance is attached to the feeding of chelated forms of trace elements, in particular selenium. The purpose of the research was to develop norms for feeding organic selenium for calves in the dairy and post-dairy growing periods.Materials and methods. Scientific, economic and balance experience in JSC «Molodi» of the Chekhov district of the Moscow region on 55 heads of young cattle of a black-and-white Holstein breed. During the studies, the calves of the 1st control group (C-) were fed the feed of the main diet (OR) without any Se additives, while the calves of the 2nd experimental group (C+) were fed OR and Se in an amount of 0.30 mg/kg of dry matter (CB) of the diet (additionally, a premix was set, containing sodium selenite), animals of the 3rd experimental group (E100) were fed in addition to OR Se in organic form plus 0.30 mg/kg of the ration (in the dairy and post-dairy periods, analogues from the 4th experimental group (E75) were fed OR plus 0.22 mg/kg of the Se ration (in organic form), calves of the 5th experimental group (E50) were fed as a part of OR 0.15 mg/kg Se (in organic form).Results. On average, over the period of the experiment, the total average daily increase in live weight of calves of the experimental groups was, respectively, 719 g, 736 g, 781 g, 710 g (or by 6,8%, 9,4%, 16%, 5,5%) and by 8.6% more compared to the control and calves of the 2nd an experimental group that received an inorganic form of selenium according to the norms of the needs of dairy cattle.

Phyto-Assisted Synthesis of Nanoselenium–Surface Modification and Stabilization by Polyphenols and Pectins Derived from Agricultural Wastes

Raw and purified mandarin peel-derived pectins were characterized and combined with olive pomace extract (OPE) in the green synthesis of selenium nanoparticles (SeNPs). SeNPs were characterized in terms of size distribution and zeta potential, and their stability was monitored during 30 days of storage. HepG2 and Caco-2 cell models were used for the assessment of biocompatibility, while antioxidant activity was investigated by the combination of chemical and cellular-based assays. SeNP average diameters ranged from 171.3 nm up to 216.9 nm; smaller SeNPs were obtained by the utilization of purified pectins, and functionalization with OPE slightly increased the average. At concentrations of 15 mg/L SeNPs were found to be biocompatible, and their toxicity was significantly lower in comparison to inorganic selenium forms. Functionalization of SeNPs with OPE increased their antioxidant activity in chemical models. The effect was not clear in cell-based models, even though all investigated SeNPs improved cell viability and protected intracellular reduced GSH under induced oxidative stress conditions in both investigated cell lines. Exposure of cell lines to SeNPs did not prevent ROS formation after exposure to prooxidant, probably due to low transepithelial permeability. Future studies should focus on further improving the bioavailability/permeability of SeNPs and enhancing the utilization of easily available secondary raw materials in the process of phyto-mediated SeNP synthesis.

Selenium exposure and urinary 8-oxo-7,8-dihydro-2′-deoxyguanosine: Major effects of chemical species and sex

Selenium is an element present in trace amounts and different chemical forms. It may exert both beneficial and adverse effects on cellular redox status and on the generation of reactive oxygen species. 8-oxo-7,8-dihydro-2′deoxyguanosine (8-oxodG) is an oxidized derivative of deoxyguanosine, and a sensitive biomarker of oxidative stress and genotoxicity.The present study assessed the extent to which selenium status was associated with urinary 8-oxodG concentrations in a Northern Italian population.We recruited healthy, non-smoking blood donors living in the Reggio Emilia province during 2017–2019. We measured urinary 8-oxodG concentrations and used restricted cubic spline regression analyses to investigate the association between selenium status (estimated using food frequency questionnaires, urinary concentrations, and serum concentrations of selenium and selenium species) and 8-oxodG/g creatinine.Among 137 participants aged 30–60 years, median urinary selenium and 8-oxodG concentrations were 22.02 μg/L and 3.21 μg/g creatinine, respectively. Serum samples and selenium speciation analyses were available for 104 participants. Median total serum selenium levels and dietary intake were 116.5 μg/L and 78.7 μg/day, respectively. In spline regression analysis, there was little association between dietary, serum, or urinary selenium with 8-oxodG concentrations. In sex-specific analyses, urinary selenium showed a positive association with the endpoint among males. For single selenium species, we observed positive associations with urinary 8-oxodG for serum organic selenium species, and negative associations for inorganic selenium forms. In the most adjusted analysis, urinary 8-oxodG concentrations showed a strong positive association with selenomethione-bound selenium (Se-Met) and a negative association with inorganic tetravalent selenium, selenite. In sex-specific analyses, these associations were considerably stronger in males than in females.Overall, study findings indicate that selenium species exhibited very different patterns of associations with the biomarker of oxidative stress, and that these associations also depended on sex. Background exposure to Se-Met appears to be strongly and positively associated with oxidative stress.

MEAT QUALITY OF BROILER CHICKENS BY FEEDING INORGANIC FORM OF SELENIUM

The addition of selenium is necessary to maintain the health and high productivity of broiler chickens and to improve the palatability and chemical composition of the meat. This helps to increase the content of dry matter, protein and fat in the breast and thigh muscles, and also increases the nutritional and biological value of poultry meat. Determination of the optimal dose of the inorganic form of selenium in the feed of broiler chickens remains a problematic issue. The purpose of the study is to investigate the effect of different doses of selenium (0.2 mg/kg, 0.3 and 0.4 mg/kg) on the chemical composition, energy and biological value of muscle tissue of broiler chickens. Broiler chickens in the amount of 40 heads served as the research material. Poultry of the control group (10 heads) received compound feed according to the growing periods, and experimental groups (30 heads) received compound feed with the addition of different amounts of sodium selenite: group 2 – 0.2 mg/kg, group 3 – 0.3 mg/kg and group 4 – 0.4 mg/kg. Current methods were used to determine the chemical composition of the pectoral and femoral muscles of broiler chickens, in particular, the mass fraction of moisture, the total content of fat, nitrogen, and the mass fraction of total ash. The content of selenium was determined by the method of atomic emission spectrometry with inductively coupled plasma, the toxicological assessment was carried out using Tetrachimena piriformis strain WH14 ciliates, the energy value was determined by the calculation method, according to the chemical composition of muscle tissue. It was found that the fat content increased in the pectoral muscles of broiler chickens of experimental group 2 by 0.1% (p < 0.05), 3 – by 0.3 (p < 0.01) and 4 – by 0.3 % (p < 0.05) compared to the control group. The indicator of energy value of breast muscles of broiler chickens of experimental group 3 increased by 2.2% (p < 0.05), and 4 – by 2.8% (p < 0.05) compared to the control group. Selenium concentration increased in the pectoral muscles of broiler chickens of experimental group 2 by 21.7% (p < 0.05), 3 – by 70% (p < 0.01), 4 – by 106% (p < 0.001) compared to the control group. At the same time, the concentration of selenium in the femoral muscles of broiler chickens of experimental group 2 increased by 12.9% (p < 0.01), 3 – by 57.1 (p < 0.001), 4 – by 85.7% (p < 0.001) compared to the control group. Therefore, the concentration of selenium in the muscle tissue of the pectoral and thigh muscles depends on the dose of this trace element in feed. The quality of meat of broiler chickens improved with the addition of inorganic form of selenium to compound feed at a dose of 0.3 and 0.4 mg/kg.

Effect of various forms and levels of selenium on milk productivity and resistance of lactating cows

The effect of two forms of selenium, inorganic and organic, was evaluated in the study. Lactating cows of the 1st control group were fed 4.9 mg/head/day of inorganic form of selenium, cows of the 2nd, 3rd and 4th experimental groups received organic form of selenium in the amounts of 2.5, 3.7 and 4.9 mg/head/day. Researches show that application of organic form of selenium permits to increase average daily milk yield by 3.3, 12.9 and 10.8% (р < 0.05), while increasing of dry matter concentration in milk by 0.57% (р < 0.05) in comparison with the 1st control group. When administering selenium in organic form 3.7 mg/head/day, there was a tendency to increase in amount of casein and decrease in amount of somatic cells in milk by 0.13% and 33.7 thousand/ cm3 respectively (р < 0.1). A dose of 4.9 mg/head/day of organic selenium contributed to a decrease in amount of somatic cells by 29.3 thousand/cm3 (р < 0.05). Feeding experimental groups with organic form of selenium in different doses had a positive effect on the immune status and antioxidant activity of blood serum. The content of free water-soluble antioxidants (TAWSA) in blood serum was higher by 39.3 and 53.5% (р < 0.001) in cows of the 3rd and 4th experimental groups fed 3.7 and 4.9 mg/head/day of organic selenium. Thus, the use of selenium in organic form is the most effective and allows to reduce the amount of used micronutrient for replenishment of animal needs.

Selenium inhibits ferroptosis and ameliorates autistic-like behaviors of BTBR mice by regulating the Nrf2/GPx4 pathway

BackgroundAutism spectrum disorder (ASD) is a group of extensive neurodevelopmental disorders for which few efficacious drugs are available. Sodium selenite (Se), the most common inorganic form of selenium given to humans and animals, has antioxidant, anti-inflammatory, and neuroprotective effects in several psychiatric and neurological disorders. However, the effect of Se on ASD is unclear. MethodsUsing the BTBR T + tf/J (BTBR) mouse model of ASD, we investigated the therapeutic effects and underlying mechanism of action of Se on ASD. BTBR mice were randomly divided into four groups: BTBR, BTBR+Se, BTBR+Se+ML385, and BTBR+Se+RSL3. The normal control group was composed of C57BL/6 (B6) mice. Se, Nuclear factor erythroid 2-related factor 2 (Nrf2), and glutathione peroxidase 4 (GPx4) inhibitors were administered separately for 28 days using oral gavage. After 28 days, social behavior, ferroptosis indices, and gene and protein expression levels for components of the Nrf2/GPx4 pathway were assessed to explore the correlation between Se levels and ASD. ResultsWe demonstrated that Se significantly mitigated impairments in learning and memory, improved social functions, reduced repetitive behaviors, and inhibited ferroptosis in the CA1 area of the hippocampus. We also found that the Nrf2/GPX4 pathway was a target for Se. Treatment with Se increased levels of Nrf2 and GPX4. The Nrf2 inhibitor ML385 reduced the effect of Se on ferroptosis and abnormal behaviors in BTBR mice. In addition, the GPx4 inhibitor RSL3 revealed similar efficacy to ML385 ConclusionWe determined that Se exhibited a beneficial effect on autism-relevant behaviors and inhibited ferroptosis in the BTBR mouse model of ASD, possibly through modulation of the Nrf2/GPX4 signaling pathway.

Glucose Limitation Sensitizes Cancer Cells to Selenite-Induced Cytotoxicity via SLC7A11-Mediated Redox Collapse.

Simple SummarySelenite, a representative inorganic form of selenium, is preferentially accumulated in tumors. The therapeutic potential of sodium selenite in tumors has received significant attention. However, the effect of sodium selenite in the treatment of established tumors is hampered by its systemic toxicities. In this study, we found selenite exerted a stronger lethality to the cancer cells under the condition of glucose limitation in vitro and an enhanced inhibitory effect on tumor growth when combined with intermittent fasting in vivo. In addition, this treatment showed no obvious toxicity to normal cells and mice. The findings of the present study provide an effective and practical approach for increasing the therapeutic window of selenite and imply that combination of selenite and fasting holds promising potential to be developed a clinically useful regimen for treating certain types of cancer.Combination of intermittent fasting and chemotherapy has been drawn an increasing attention because of the encouraging efficacy. In this study, we evaluated the anti-cancer effect of combination of glucose limitation and selenite (Se), a representative inorganic form of selenium, that is preferentially accumulated in tumors. Results showed that cytotoxic effect of selenite on cancer cells, but not on normal cells, was significantly enhanced in response to the combination of selenite and glucose limitation. Furthermore, in vivo therapeutic efficacy of combining selenite with fasting was dramatically improved in xenograft models of lung and colon cancer. Mechanistically, we found that SLC7A11 expression in cancer cells was up-regulated by selenite both in vitro and in vivo. The elevated SLC7A11 led to cystine accumulation, NADPH depletion and the conversion of cystine to cysteine inhibition, which in turn boosted selenite-mediated reactive oxygen species (ROS), followed by enhancement of selenite-mediated cytotoxic effect. The findings of the present study provide an effective and practical approach for increasing the therapeutic window of selenite and imply that combination of selenite and fasting holds promising potential to be developed a clinically useful regimen for treating certain types of cancer.

Anticancer Properties of Selenium-Enriched Oyster Culinary-Medicinal Mushroom, Pleurotus ostreatus (Agaricomycetes), in Colon Cancer In Vitro.

Mushrooms have become an important way to safely supply the body with the daily needs of organic selenium and they also possess remarkable medicinal properties. In this study, we examined the ability of the Pleurotus ostreatus mushroom to grow in selenium (Se) and its ability to accumulate and convert Se from inorganic form to organic form during growth. Additionally, we achieved the potential anticancer properties of mushroom extract in colon cancer cells using the CaCo-2 cell and the normal human colon mucosal epithelial cell line, NCM-460 cell line. Interestingly, Se-enriched mushroom extract (SME) showed a competitive regulation in colon cancer cell line; CaCo-2 cell line indicated by cell morphology, the number of survived cells, lactate dehydrogenase (LDH) production, and cell viability rate. Moreover, SME treatment regulates the expression profile of the cancer cell proliferation factor Raf-1 and pro-apoptotic related factors P53 and Caspase-3 Furthermore, the production of inflammatory-regulated cytokines, including interleukin 6 (IL-6) and IL-10, increased. At the same time, the level of produced tumor necrosis factor-alpha (TNF-α) markedly decreased in a dose and time-dependent of colon cancer-treated cells. Notably, the purified selenomethionine (SeMe) showed sufficient inhibition of colon cancer proliferation compared with the inorganic form of selenium (sodium selenite) via blocking the Raf/MEK/ERK signaling pathway. In addition, SeMe treatment also stimulated the production of IL-6 and IL-10 while decreasing the production of TNF-α, which plays a crucial role in the necrotic event. Meanwhile, the SeMe treatment showed a neglected cytotoxic effect in the normal colon epithelial cells. Collectively, these findings indicate that the fruiting bodies of Se-enriched mushrooms revealed anti-colon cancer activity via targeting Raf-1 signaling pathway and increasing the production of IL-6 and IL-10.

Differences in the effects of sodium selenate and sodium selenite on the mortality, reproduction, lipid peroxidation and glutathione redox status of Folsomia candida Willem 1902 (Collembola)

The average selenium content of the soils worldwide is 0.4 mg kg−1; however, the selenium concentration can be much higher in some areas. Selenium is essential to humans and animals, but it can also be a risk based on the narrow gap between the beneficial and toxic concentrations. There is scarce information in the literature on the effects of various inorganic forms of selenium on soil invertebrates, such as collembolans. Consequently, the goal of our study was to determine if selenium has a negative effect on the collembolan species Folsomia candida and to verify if there is a difference between the effects of the two oxidation forms. The effect of sodium selenite and sodium selenate on Folsomia candida was studied in the laboratory by mortality and reproduction tests also by various sub-lethal and biochemical methods. The methods used in our study included a standard OECD test according to the 232 guideline, and we measured the life history parameters such as relative growth, egg production, and egg volume. For the investigation of lipid peroxidation and glutathione redox status, malondialdehyde (MDA) content, reduced glutathione (GSH) concentration and glutathione peroxidase (GPx) activity were measured. Our results showed that up to a concentration of 0.5 mg kg−1 Se in soil, both selenium forms were beneficial for F. candida. For mortality, the LOAEC (lowest observable adverse effect concentration) was 8 mg kg−1 Se in the soil in the experiments according to the OECD 232 test for both selenium forms. In case of juveniles, sodium selenite was much more toxic than sodium selenate. The LOAEC was 0.5 mg kg−1 for sodium selenite and 8 mg kg−1 in the case of sodium selenate. Sub-lethal parameters showed to be potentially more sensitive than the parameters measured in the OECD 232 test in the case of sodium selenate contamination. For instance, both the number of eggs laid and the relative growth showed significant differences compared to the control group in lower concentrations than the juvenile number or mortality. In the groups treated with sodium selenite, the juvenile number was the most sensitive parameter. Based on our results, it can be stated that sodium selenite may be potentially more toxic to collembolans than sodium selenate. Lipid peroxidation was not initiated by selenium exposure. The glutathione redox system also did not activate either, which suggested that selenium toxicity in collembola is not a consequence of selenium-induced oxidative stress.

In vitro biosynthesis of organic selenium by Lactobacillus casei from inorganic selenium forms

The bioconversion of selenium in the form of sodium selenite (Na2 SeO3 ) (SeIV) or sodium selenate (Na2 SeO4 ) (SeVI) to organic form by Lactobacillus casei (L. casei) was investigated in vitro. MRS media was supplemented with 1, 2, 5, 10 or 20 ppm of Se, inoculated with 2% starter culture with about 105 cfu/ ml of L. casei and then incubated up to 24 hrs at 37o C. Increasing of selenite “Se(IV)” concentrations in the media markedly reduced the bacterial growth compared to selenate “Se(VI)” indicating cytotoxic effect of selenite. The media supplemented with 5 ppm or more of Se(IV) became reddish after 24 hr of incubation as a result of the formation of 100-200 nanometer particles of selenium (SeNPs). Se speciation of the cultured media supernatants and its corresponding cell fractions was carried out by HPLC-ICP-MS technique. The bioconversion rate of Se to organic form by L. casei was extremely higher in Se(IV) than Se(VI) in both fractions, however the media supernatant contained the highest content. Increasing the media Se content resulted in gradual increase of organic Se concentration in both cells and supernatant fractions. The medium supplemented with 1 ppm Se(IV) was completely depleted from the inorganic Se as it completely converted to organic form. Although the cell fractions from all Se(VI) supplemented media contained only organic Se, the media supernatant contained significant residual amount of the inorganic form. Our results demonstrate the ability of L. casei to convert Se(IV) or Se(VI) up to 20 ppm to organic form(s) either in the cultured media or inside the bacterial cells. However, Se(IV) but not Se(VI), at a limit concentration of 1 ppm, was completely converted and accumulated in an organic form in the cell fraction and the cultured medium.

Selenite Inhibits Notch Signaling in Cells and Mice.

Selenium is an essential micronutrient with a wide range of biological effects in mammals. The inorganic form of selenium, selenite, is supplemented to relieve individuals with selenium deficiency and to alleviate associated symptoms. Additionally, physiological and supranutritional selenite have shown selectively higher affinity and toxicity towards cancer cells, highlighting their potential to serve as chemotherapeutic agents or adjuvants. At varying doses, selenite extensively regulates cellular signaling and modulates many cellular processes. In this study, we report the identification of Delta–Notch signaling as a previously uncharacterized selenite inhibited target. Our transcriptomic results in selenite treated primary mouse hepatocytes revealed that the transcription of Notch1, Notch2, Hes1, Maml1, Furin and c-Myc were all decreased following selenite treatment. We further showed that selenite can inhibit Notch1 expression in cultured MCF7 breast adenocarcinoma cells and HEPG2 liver carcinoma cells. In mice acutely treated with 2.5 mg/kg selenite via intraperitoneal injection, we found that Notch1 expression was drastically lowered in liver and kidney tissues by 90% and 70%, respectively. Combined, these results support selenite as a novel inhibitor of Notch signaling, and a plausible mechanism of inhibition has been proposed. This discovery highlights the potential value of selenite applied in a pathological context where Notch is a key drug target in diseases such as cancer, fibrosis, and neurodegenerative disorders.

ВЛИЯНИЕ РАЗЛИЧНЫХ ФОРМ СЕЛЕНА НА ПРОДУКТИВНОСТЬ И ОБМЕН ВЕЩЕСТВ ОТКАРМЛИВАЕМОГО МОЛОДНЯКА СВИНЕЙ В УСЛОВИЯХ ПРОИЗВОДСТВА

Selenium plays an important role for maintaining complex and adequate nutrition of fattened young pigs. It also has a big biological importance to maintain growth and health, as well as for biochemical and physiological processes This study presents the results of a production experiment to determine the effect of organic and inorganic forms of selenium on growth indicators, immunohematological blood parameters and slaughter qualities of fattened pigs in period I and II. Test feeding with various forms of selenium has been implemented with two groups of analogs (N = 60; n = 30), taking into account age and live weight. The experiment was conducted on castrates of large white breed, which were divided into two groups of 30 heads each following the principle of analogues (taking into account their age, live weight). The studied fattened pigs received standard complete feeds of the SK-5 and SK-6 types for a period of 105 days. Growing pigs were fed with organic selenium for 20 mg/kg as part of the feed 64 mixture per head in the first and second period of fattening, while the animals of the control group were fed with 0.3 mg/kg of the inorganic form of selenium. Including a chelated form of selenium in the complete feed of castrates at the rate established in the course of scientific and economic studies has led to 757 g of average daily gain, which is 8.1% more as compared to the control group. The concentration of red blood cells in the blood of growing pigs fed with 20 mg/kg of selenium chelate increased by 6.3%, hemoglobin – by 2.4%, and white blood cells – by 7.1% as compared to the control. Feeding organic selenium to fattened young pigs contributed to a significant increase in specific units of protein activity by 38.65% (p < 0.01), BASC – by 7.63%, as well as lysis – by 40.06% (p < 0.05), and phagocytic activity by 3.33% in blood serum as compared to the control. The half-carcasses of hogs who had received fed rations including selenium chelate fetured slaughter weight and slaughter yield, respectively, higher – by 6.4 and 0.6% as compared with the control analogues. The use of the established norm of organic selenium in the diets of fattened young pigs according to the results of production testing is economically profitable and contributes to a per-head profit of 420 rubles.

In vitro selenium supplementation suppresses key mediators involved in myometrial activation and rupture of fetal membranes.

Spontaneous preterm birth, which can affect up to 20% of all pregnancies, is the greatest contributor to perinatal morbidity and mortality. Infection is the leading pathological cause of spontaneous preterm birth. Infection activates the maternal immune system, resulting in the upregulation of pro-inflammatory and pro-labor mediators that activate myometrial contractions and rupture of fetal membranes. Anti-inflammatory agents therefore have the potential for the prevention of spontaneous preterm birth. Selenium, an essential micronutrient, has been shown to be a potent anti-inflammatory regulator. Notably, clinical and epidemiological studies have suggested a link between selenium and preterm birth. Thus, the aim of this study was to assess the effect of selenite (an inorganic form of selenium) on the expression of pro-inflammatory and pro-labor mediators in human gestational tissues. Human fetal membranes and myometrium were pre-incubated with or without selenite before incubation with the bacterial product lipopolysaccharide (LPS) to stimulate inflammation associated with preterm birth. Selenite blocked LPS-induced expression of pro-inflammatory cytokines and chemokines and enzymes involved in remodelling of myometrium and degradation of fetal membranes. Of note, selenite also suppressed myometrial activation induced by inflammation as evidenced by a decrease in LPS-induced prostaglandin signalling and myometrial cell contractility. These effects of selenite were mediated by the MAPK protein ERK as selenite blunted LPS induced activation of ERK. In conclusion, selenite suppresses key mediators involved in inflammation induced activation of mediators involved in active labor in human fetal membranes and myometrium. These findings support recent clinical studies demonstrating selenium supplementation is associated with decreased incidence of spontaneous preterm birth.

Comparative Study on Diet Added with Organic and Inorganic Selenium Forms Provided to Carps Exposed to Fipronil Insecticide

Carps belonging to species Cyprinus carpio (carp) were fed on organic and inorganic selenium forms for 60 days to enable evaluating the biochemical profile of tissues exposed to fipronil (FPN) insecticide. Diphenyl diselenide [(PhSe)2] (3.0 mg/kg) and sodium selenite (Na2SeO3) (0.75 mg/kg) were used as organic and inorganic selenium forms, respectively. Overall, the adopted organic and inorganic selenium forms were similarly capable of reestablishing oxidant and antioxidant stress parameters close to control levels. Fish exposed to fipronil have shown decreased acetylcholinesterase (AChE) activity in brain and muscle tissues. Brain tissues of fish supplemented with Na2SeO3 or (PhSe)2 diets presented reestablished AChE levels in comparison to those of fish fed on standard diet. Liver tissues of fish fed on standard diet presented decreased δ-ALA-D activity after their exposure to FPN, whereas diets added with two selenium forms were efficient in reestablishing the levels of standard diets. Therefore, (PhSe)2 and Na2SeO3 have potential to be used as supplementation factors in diets to feed C. carpio.

Selenium⁻Fascinating Microelement, Properties and Sources in Food.

Selenium is a micronutrient that is essential for the proper functioning of all organisms. Studies on the functions of selenium are rapidly developing. This element is a cofactor of many enzymes, for example, glutathione peroxidase or thioredoxin reductase. Insufficient supplementation of this element results in the increased risk of developing many chronic degenerative diseases. Selenium is important for the protection against oxidative stress, demonstrating the highest activity as a free radical scavenger and anti-cancer agent. In food, it is present in organic forms, as exemplified by selenomethionine and selenocysteine. In dietary supplementation, the inorganic forms of selenium (selenite and selenate) are used. Organic compounds are more easily absorbed by human organisms in comparison with inorganic compounds. Currently, selenium is considered an essential trace element of fundamental importance for human health. Extreme selenium deficiencies are widespread among people all over the world. Therefore, it is essential to supplement the deficiency of this micronutrient with selenium-enriched food or yeast cell biomass in the diet.

Selenate Prevents Adipogenesis through Induction of Selenoprotein S and Attenuation of Endoplasmic Reticulum Stress.

The conversion of preadipocytes to adipocytes (adipogenesis) is a potential target to treat or prevent obesity. Selenate, an inorganic form of selenium, elicits diverse health benefits, mainly through its incorporation into selenoproteins. The individual roles of selenium and certain selenoproteins have been reported. However, the effects of selenate treatment on selenoproteins in adipocytes are unclear. In this study, the effects of selenate pretreatment on selenoprotein and endoplasmic reticulum (ER) stress during adipogenesis were examined in vitro. The selenate pretreatment dose-dependently suppressed the adipogenesis of 3T3-L1 preadipocytes. The selenate pretreatment at 50 μM for 24 h almost completely suppressed adipogenesis without cytotoxic effects. The expression of the adipogenic genes peroxisome proliferator-activated receptor gamma, CCAAT-enhancer binding protein alpha, and leptin was suppressed by selenate. This pretreatment also upregulated selenoprotein S (SEPS1), an ER resident selenoprotein that reduces ER stress, and prevented dexamethasone-induced SEPS1 degradation during the early stage of adipogenesis. The selenate-inhibited adipogenesis was associated with an attenuation of ER stress. The expression of the ER stress marker genes was upregulated during the early stage of differentiation, whereas the selenate pretreatment suppressed the mRNA expression of the XBP1 and C/EBP homologous protein. The collective data suggest a preventive role of selenate and SEPS1 in adipogenesis, and support a novel dietary approach to prevent obesity.

Combination cancer treatment through photothermally controlled release of selenous acid from gold nanocages

Selenite, one of the inorganic forms of selenium, is emerging as an attractive chemotherapeutic agent owing to its selectivity in eradicating cancer cells. Here we demonstrate a new formulation of nanomedicine based on selenous acid, which is mixed with lauric acid (a phase-change material with a melting point around 43 °C) and then loaded into the cavities of Au nanocages. The Au nanocages can serve as a carrier during cell endocytosis and then as a photothermal agent to melt the lauric acid upon the irradiation with a near-infrared laser, triggering the swift release of selenous acid. The photothermal and chemo therapies can also work synergistically, leading to enhanced destruction of cancer cells relative to normal cells. Our systematic study suggests that the impaired mitochondrial function arising from the ROS generated through combination treatment is responsible for the cell death. This study offers an appealing candidate that holds great promise for synergistic cancer treatment.

Dietary supplements based on selenium containing culture of lactic acid bacteria

The article describes the role of selenium in the humankind being. The analysis based on the published data shows that the biological synthesis is a perspective way to obtain an organic form of selenium, which can be used in dietary supplements. The ability of lactic acid bacteria (Lactobacillus acidophilus 412/307)to accumulate inorganic forms of selenium (selenites, selenates), turning them into organic forms, with purposeful trace element enrichment of culture medium is described in the article. The main organic forms of selenium, which are being used in the process of biotransformation from its inorganic forms by microorganisms, have been reorganized. The relationship between the increasing of concentrations of sodium selenite in the culture medium and the growth of biomass of lactic acid bacteria was established. It was found the depressing effect of increasing concentrations of sodium selenite on optical density rate. It was estabilished the optimal conditions for the maximum accumulation of selenium containing culture of lactic acid bacteria. The influence of selenium concentration on the lactic acid bacteria biomass accumulation was determined also by changing the values of optical density. Due to the obtained data, the selenium containing dietary supplement «Selenolakt» was created. The main microbiological indicators that characterize the quality of the obtained product are given. The content of organic form of selenium in products reaches –195 ± 1 mkg/g.