Protection from H1N1 influenza virus infections in mice by supplementation with selenium: a comparison with selenium-deficient mice.
TL;DR: The data indicate that selenium supplementation may provide a feasible approach to improving the immune response to viral infections, such as lethal influenza infection.
Abstract: The present paper describes protective effects of supplemental selenium in mice infected with influenza virus. The effects of supplemental selenium on serum selenium levels, mortality, lung virus titers, and cytokine titers were investigated in mice inoculated intranasally with suspensions of influenza virus. Whereas the mortality of the virus-infected Se-deficient mice was 75%, along with a marked reduction in body weight, lower levels of TNF-α and IFN-γ and lower serum selenium concentrations, the mortality of mice maintained on feed containing 0.5 mg Se/kg in the form of sodium selenite was 25%.There were no significantly differences, however, in viral titer between the Se-adequate and the selenium-supplemented groups. The data indicate that selenium supplementation may provide a feasible approach to improving the immune response to viral infections, such as lethal influenza infection.
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TL;DR: Particular emphasis is given to how Se and selenoproteins are linked to redox signaling, oxidative burst, calcium flux, and the subsequent effector functions of immune cells, as well as the benefits and potential adverse effects of intervention with Se supplementation for various inflammatory or immune disorders.
Abstract: Dietary selenium (]Se), mainly through its incorporation into selenoproteins, plays an important role in inflammation and immunity. Adequate levels of Se are important for initiating immunity, but they are also involved in regulating excessive immune responses and chronic inflammation. Evidence has emerged regarding roles for individual selenoproteins in regulating inflammation and immunity, and this has provided important insight into mechanisms by which Se influences these processes. Se deficiency has long been recognized to negatively impact immune cells during activation, differentiation, and proliferation. This is related to increased oxidative stress, but additional functions such as protein folding and calcium flux may also be impaired in immune cells under Se deficient conditions. Supplementing diets with above-adequate levels of Se can also impinge on immune cell function, with some types of inflammation and immunity particularly affected and sexually dimorphic effects of Se levels in so...
612 citations
TL;DR: This review summarizes the survey of knowledge on selenium nanoparticles, their biological effects in the organism, advantages, absorption mechanisms, and nanotechnological applications for peroral administration and explores the possibilities of a more effective way of administration, especially in seenium-deficient organisms.
Abstract: Traditional supplements of selenium generally have a low degree of absorption and increased toxicity. Therefore, it is imperative to develop innovative systems as transporters of selenium compounds, which would raise the bioavailability of this element and allow its controlled release in the organism. Nanoscale selenium has attracted a great interest as a food additive especially in individuals with selenium deficiency, but also as a therapeutic agent without significant side effects in medicine. This review is focused on the incorporation of nanotechnological applications, in particular exploring the possibilities of a more effective way of administration, especially in selenium-deficient organisms. In addition, this review summarizes the survey of knowledge on selenium nanoparticles, their biological effects in the organism, advantages, absorption mechanisms, and nanotechnological applications for peroral administration.
359 citations
Cites background from "Protection from H1N1 influenza viru..."
...5 mg Se⋅kg−1, and mice with low serum selenium concentrations showed a marked reduction in body weight (BW) and lower levels of TNF-α and IFN-γ.(120) For improving the immune response in the body, the administration of SeNPs can also be an efficient realizable approach....
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...The mortality of the H1N1 influenza virus-infected selenium-deficient mice was 3 times higher compared to those receiving Na 2 SeO 3 at the dose of 0.5 mg Se⋅kg−1, and mice with low serum selenium concentrations showed a marked reduction in body weight (BW) and lower levels of TNF-α and IFN-γ.120 For improving the immune response in the body, the administration of SeNPs can also be an efficient realizable approach....
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TL;DR: The formal identification of viral selenoproteins in the genome of molluscum contagiosum and fowlpox viruses demonstrated the importance of selenocsteine in viral cycle.
Abstract: Reactive oxygen species (ROS) are frequently produced during viral infections. Generation of these ROS can be both beneficial and detrimental for many cellular functions. When overwhelming the antioxidant defense system, the excess of ROS induces oxidative stress. Viral infections lead to diseases characterized by a broad spectrum of clinical symptoms, with oxidative stress being one of their hallmarks. In many cases, ROS can, in turn, enhance viral replication leading to an amplification loop. Another important parameter for viral replication and pathogenicity is the nutritional status of the host. Viral infection simultaneously increases the demand for micronutrients and causes their loss, which leads to a deficiency that can be compensated by micronutrient supplementation. Among the nutrients implicated in viral infection, selenium (Se) has an important role in antioxidant defense, redox signaling and redox homeostasis. Most of biological activities of selenium is performed through its incorporation as a rare amino acid selenocysteine in the essential family of selenoproteins. Selenium deficiency, which is the main regulator of selenoprotein expression, has been associated with the pathogenicity of several viruses. In addition, several selenoprotein members, including glutathione peroxidases (GPX), thioredoxin reductases (TXNRD) seemed important in different models of viral replication. Finally, the formal identification of viral selenoproteins in the genome of molluscum contagiosum and fowlpox viruses demonstrated the importance of selenoproteins in viral cycle.
297 citations
Cites background from "Protection from H1N1 influenza viru..."
...↓ GPX activity in infected people [116] AM = KunMing Mice SS = Selenite Reduces mortality, ↑ levels of TNFalpha and IFNgamma No change in viral load [197]...
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TL;DR: The evidence is at present conflicting as to whether Se supplementation is of benefit in patients with HT, though there are indications that it is advantageous in cases of mild/moderate Graves’ Orbitopathy and the role of Se in type 2 diabetes mellitus is ambiguous.
Abstract: This review aims to illustrate the importance of selenium (Se) for maintenance of overall health, especially for the thyroid, immunity, and homeostasis. Furthermore, it outlines the role of Se in reproduction and in virology and discusses the effects of Se supplementation in critical illness. The multifaceted aspects of this essential nutrient have attracted worldwide clinical and research interest in the last few decades. Se exerts its activity in the form of the aminoacid selenocysteine incorporated in selenoproteins. The impact of Se administration should be considered in relation to its apparent U shaped effects, i.e., exhibiting major advantages in Se-deficient individuals but specific health risks in those with Se excess. Addition of selenium to the administration of levothyroxine may be useful in patients with low Se intake and with mild-form or early-stage Hashimoto’s thyroiditis (HT). Serum Se concentration (possibly also at tissue level) decreases in inflammatory conditions and may vary with the severity and duration of the inflammatory process. In such cases, the effect of Se supplementation seems to be useful and rational. Meanwhile, Se’s ability to improve the activity of T cells and the cytotoxicity of natural killer cells could render it effective in viral disease. However, the evidence, and this should be stressed, is at present conflicting as to whether Se supplementation is of benefit in patients with HT, though there are indications that it is advantageous in cases of mild/moderate Graves’ Orbitopathy. The role of Se in type 2 diabetes mellitus (T2DM) is ambiguous, driven by both Se intake and serum levels. The evidence that insulin and glycaemia influence the transport and activity of Se, via regulatory activity on selenoproteins, and that high serum Se may have a diabetogenic effect suggests a ‘Janus-effect’ of Se in T2DM. Though the evidence is not as yet clear-cut, the organic form (selenomethionine), due to its pharmacokinetics, is likely to be more advantageous in long-term prevention, and supplementation efforts, while the inorganic form (sodium selenite) has proven effective in an acute, e.g., sepsis, clinical setting. Recent data indicate that functional selenoprotein single-nucleotide polymorphisms (SNPs) may interfere with Se utilization and effectiveness.
272 citations
Cites background from "Protection from H1N1 influenza viru..."
...Though Se supplementation did not decrease the viral titer, it achieved 50 % reduction of mortality as compared to virus-infected Se-deficient mice, hence providing some evidence that Se supplementation improves the immune response to lethal influenza infection [165]....
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TL;DR: A recent review as mentioned in this paper provides an up-to-date overview on selenium in infectious diseases caused by viruses (e.g., HIV, IAV, hepatitis C virus, poliovirus, West Nile virus) and bacteria (i.e., M. tuberculosis, Helicobacter pylori).
216 citations
References
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TL;DR: The levels of four 75Se-containing proteins are lower in HIV-infected cell populations than in uninfected cells, and these major selenoproteins migrated as 57, 26, 21, and 15-kDa species on SDS/PAGE gels.
Abstract: It has been observed previously that plasma selenium and glutathione levels are subnormal in HIV-infected individuals, and plasma glutathione peroxidase activity is decreased. Under these conditions the survival rate of AIDS patients is reduced significantly. In the present study, using 75Se-labeled human Jurkat T cells, we show that the levels of four 75Se-containing proteins are lower in HIV-infected cell populations than in uninfected cells. These major selenoproteins migrated as 57-, 26-, 21-, and 15-kDa species on SDS/PAGE gels. In our earlier studies, the 57-kDa protein was purified from T cells and identified as a subunit of thioredoxin reductase. The 26- and 21-kDa proteins were identified in immunoblot assays as the glutathione peroxidase (cGPX or GPX1) subunit and phospholipid hydroperoxide glutathione peroxidase (PHGPX or GPX4), respectively. We recently purified the 15-kDa protein and characterized it as a selenoprotein of unknown function. In contrast to selenoproteins, low molecular mass [75Se]compounds accumulated during HIV infection and migrated as a diffuse band near the front of SDS/PAGE gels.
95 citations
TL;DR: Findings suggest a new mechanism through which selenium may affect HIV-1 disease progression, which has been associated with neurologic damage, Kaposi's sarcoma, wasting syndrome, and increased viral replication.
Abstract: An important role for selenium in human immunodeficiency virus (HIV) disease has been proposed. Decreased selenium levels, as found in persons with HIV infection or AIDS, are sensitive markers of disease progression. Selenium deficiency, an independent predictor of mortality in both HIV-1-infected adults and children, is an essential micronutrient that is associated with an improvement of T cell function and reduced apoptosis in animal models. In addition, adequate selenium may enhance resistance to infections through modulation of interleukin (IL) production and subsequently the Th1/Th2 response. Selenium supplementation up-regulates IL-2 and increases activation, proliferation, differentiation, and programmed cell death of T helper cells. Moreover, selenium supplementation may down-regulate the abnormally high levels of IL-8 and tumor necrosis factor-alpha observed in HIV disease, which has been associated with neurologic damage, Kaposi's sarcoma, wasting syndrome, and increased viral replication. Together, these findings suggest a new mechanism through which selenium may affect HIV-1 disease progression.
91 citations
TL;DR: WHO says that science wasn't the only factor and that the timing was carefully calibrated to ensure that countries were well-prepared to prevent overreaction.
Abstract: Swine FluWhen World Health Organization (WHO) chief Margaret Chan declared last week that for the first time in more than 40 years the world is facing an influenza pandemic, she simply stated what everybody already knew. Many leading influenza scientists and public health experts say that the scientific criteria for phase 6—the highest level in WHO's pandemic alert system—had been satisfied for several weeks and that WHO postponed its decision unnecessarily. But WHO says that science wasn't the only factor and that the timing was carefully calibrated to ensure that countries were well-prepared to prevent overreaction.
85 citations
"Protection from H1N1 influenza viru..." refers background in this paper
...The ongoing spread of the human swine-origin H1N1 influenza virus meets the WHO criteria for a pandemic [11]....
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TL;DR: It is reported that host genetic background as a determinant of viral infection outcome is superseded by feeding the host a diet nutritionally deficient in both selenium and vitamin E.
57 citations
TL;DR: This work validated doubly-labelled water (DLW) by comparison to indirect calorimetry and food intake–mass balance in eight Labrador dogs and used several alternative equations for calculating CO2 production, based on the single- and two-pool models and used two alternative methods for evaluating the elimination constants: two-sample and multiple-sampling.
Abstract: We validated doubly-labelled water (DLW) by comparison to indirect calorimetry and food intake-mass balance in eight Labrador dogs (24-32 kg) over 4 d. We used several alternative equations for calculating CO2 production, based on the single- and two-pool models and used two alternative methods for evaluating the elimination constants: two-sample and multiple-sampling. In all cases the DLW technique overestimated the direct estimate of CO2 production. The greatest overestimates occurred with the single-pool model. Using two samples, rather than multiple samples, to derive the elimination constants produced slightly more discrepant results. Discrepancies greatly exceeded the measured analytical precision of the DLW estimates. The higher values with DLW probably occurred because the dogs were extremely active during the 1 h in each 24 spent outside the chamber. Estimates of CO2 production from food intake-mass balance, which include this activity, produced a much closer comparison to DLW (lowest mean discrepancy 0.3 % using the observed group mean dilution space ratio and an assumption that the mass changes reflected changes in hydration for all except one animal). We recommend an equilibration time of 6 h and use of the two-pool model based on the observed population dilution space for future studies of energy demands in dogs of this body mass.
41 citations