Selenium-Dependent Antioxidant Enzymes: Actions and Properties of Selenoproteins

Tracing links between micronutrients and type 2 diabetes risk: the singular role of selenium

Background

Type 2 diabetes (T2D) is a growing global health concern. While micronutrients are crucial for physiological functions and metabolic balance, their precise links to T2D are not fully understood.

Methods

We investigated the causal relationships between 15 key micronutrients and T2D risk using both univariate and multivariate Mendelian randomization (MR) methods. Our analysis leveraged data from a large prospective cohort genome-wide association study (GWAS) on these micronutrients and T2D. We employed MR techniques such as inverse variance weighting (IVW), MR Egger, weighted median, and simple models. Multivariate analysis adjusted for diabetes-related factors like body mass index (BMI) and hypertension to assess the independent effects of micronutrients, particularly selenium, on T2D risk.

Results

Selenium intake was associated with an increased risk of T2D, with an odds ratio (OR) of 1.045, a 95% confidence interval (CI) ranging from 1.009 to 1.082, and a P-value of 0.015. This association was consistent in multivariate analyses, suggesting an independent effect of selenium on T2D risk after adjusting for confounders.

Conclusion

Our study presents novel evidence of a positive correlation between selenium intake and T2D risk, underscoring the importance of micronutrients in diabetes prevention and treatment strategies. Further research is necessary to confirm these findings and to clarify the specific biological mechanisms through which selenium influences diabetes risk.

Oxidative stress: fundamentals and advances in quantification techniques

Oxidative species, generated endogenously via metabolism or from exogenous sources, play crucial roles in the body. At low levels, these species support immune functions by participating in phagocytosis. They also aid in cellular signaling and contribute to vasomodulation. However, when the levels of oxidative species exceed the body's antioxidant capacity to neutralize them, oxidative stress occurs. This stress can damage cellular macromolecules such as lipids, DNA, RNA, and proteins, driving the pathogenesis of diseases and aging through the progressive deterioration of physiological functions and cellular structures. Therefore, the body's ability to manage oxidative stress and maintain it at optimal levels is essential for overall health. Understanding the fundamentals of oxidative stress, along with its reliable quantification, can enable consistency and comparability in clinical practice across various diseases. While direct quantification of oxidant species in the body would be ideal for assessing oxidative stress, it is not feasible due to their high reactivity, short half-life, and the challenges of quantification using conventional techniques. Alternatively, quantifying lipid peroxidation, damage products of nucleic acids and proteins, as well as endogenous and exogenous antioxidants, serves as appropriate markers for indicating the degree of oxidative stress in the body. Along with the conventional oxidative stress markers, this review also discusses the role of novel markers, focusing on their biological samples and detection techniques. Effective quantification of oxidative stress may enhance the understanding of this phenomenon, aiding in the maintenance of cellular integrity, prevention of age-associated diseases, and promotion of longevity.

Prevalence and prognostic value of zinc and selenium deficiency in advanced chronic liver disease

BACKGROUND AND AIMS

Zinc and selenium are essential trace elements involved in important (patho)physiological processes. The prevalence and prognostic implications of zinc and selenium deficiency in patients with advanced chronic liver disease (ACLD) remain unknown.

METHODS

We determined serum zinc and selenium concentrations in 309 patients with ACLD undergoing hepatic venous pressure gradient (HVPG) measurement between 2019 and 2022. We evaluated the prevalence of zinc/selenium deficiency and assessed its association with severity of ACLD and liver-related events (LRE, i.e. first/further hepatic decompensation/liver-related death).

RESULTS

Among 309 ACLD patients (median: age: 57 [IQR: 50-64], MELD: 11 [IQR: 9-16], HVPG: 17 [IQR: 11-20]), 73% (227) and 63% (195) were deficient in zinc and selenium, respectively. Decompensated (dACLD) patients showed significantly lower serum zinc (median: 48 [IQR: 38-59] vs. compensated, cACLD: 65 [IQR: 54-78], p < 0.001) and selenium levels (median: 4.9 [IQR 4.0-6.2] vs. cACLD: 6.1 [IQR 5.1-7.3], p < 0.001). Significant correlations of zinc/selenium levels were found with MELD (zinc: ρ = -0.498, p < 0.001; selenium: ρ = -0.295, p < 0.001), HVPG (zinc: ρ = -0.400, p < 0.001; selenium: ρ = -0.157, p = 0.006) and liver disease-driving mechanisms (IL6, bile-acid homeostasis). On multivariable analysis, low zinc/selenium levels, age and MELD remained independently associated with LRE.

CONCLUSION

Zinc and selenium deficiencies are common in ACLD patients especially with higher MELD and HVPG. Low zinc and selenium levels independently predicted hepatic decompensation and liver-related death. The effect of zinc/selenium supplementation in ACLD should be investigated in future trials.

The Immunomodulatory Effects of Selenium: A Journey from the Environment to the Human Immune System

Selenium (Se) is an essential nutrient that has gained attention for its impact on the human immune system. The purpose of this review is to explore Se's immunomodulatory properties and to make up-to-date information available so novel therapeutic applications may emerge. People acquire Se through dietary ingestion, supplementation, or nanoparticle applications. These forms of Se can beneficially modulate the immune system by enhancing antioxidant activity, optimizing the innate immune response, improving the adaptive immune response, and promoting healthy gut microbiota. Because of these many actions, Se supplementation can help prevent and treat pathogenic diseases, autoimmune diseases, and cancers. This review will discuss Se as a key micronutrient with versatile applications that supports disease management due to its beneficial immunomodulatory effects. Further research is warranted to determine safe dosing guidelines to avoid toxicity and refine the application of Se in medical treatments.

Development of a sensor to detect methylmercury toxicity

Methylmercury (MeHg) is a well-known neurotoxicant that induces various cellular functions depending on cellular- and developmental-specific vulnerabilities. MeHg has a high affinity for selenol and thiol groups, thus impairing the antioxidant system. Such affinity characteristics of MeHg led us to develop sensor vectors to assess MeHg toxicity. In this study, MeHg-mediated defects in selenocysteine (Sec) incorporation were demonstrated using thioredoxin reductase 1 cDNA fused with the hemagglutinin tag sequence at the C-terminus. Taking advantage of such MeHg-mediated defects in Sec incorporation, a cDNA encoding luciferase with a Sec substituted for cysteine-491 was constructed. This construct showed MeHg-induced decreases in signaling in a dose-dependent manner. To directly detect truncated luciferase under MeHg exposure, we further constructed a new sensor vector fused with a target for proteasomal degradation. However, this construct was inadequate because of the low rate of Sec insertion, even in the absence of MeHg. Finally, a Krab transcriptional suppressor fused with Sec was constructed and assessed to demonstrate MeHg-dependent increases in signal intensity. We confirmed that the vector responded specifically and in a dose-dependent manner to MeHg in cultured cerebellar granule cells. This vector is expected to allow monitoring of MeHg-specific toxicity via spatial and temporal imaging.

An Updated Review of Emerging Sources of Selenium in Weaned Piglet Nutrition

The antioxidant and immune systems of weaned piglets are not fully mature and are also subjected to serious stress challenges related to oxidative stress and inflammation. Selenium (Se) is an essential element for pigs, with documented roles encompassing antioxidative and anti-inflammatory properties via selenoproteins. Sodium selenite and Se-enriched yeast are commonly acknowledged as conventional sources of Se for piglets. In the past decade, several novel Se sources have emerged in the field of weaned piglet nutrition. In this review, we will initially outline the historical timeline of Se sources as reported in weaned piglet nutrition. Afterwards, our attention will turn towards the nutritional regulation of Se sources in relation to the antioxidant and anti-inflammatory aspects of healthy weaned piglets. Ultimately, we will provide a detailed review highlighting the potential of emerging Se sources in alleviating various adverse effects of stress challenges faced by weaned piglets. These challenges include oxidative stress, enterotoxigenic Escherichia coli infection, lipopolysaccharide-induced inflammation, heat stress, and exposure to feed mycotoxins. The output of this review will emphasize the fundamental importance of incorporating emerging Se sources in the diet of weaned piglets.

The effects of high doses of selenium supplementation on mRNA and protein levels of cMLCK levels and total antioxidant capacity in rat heart tissue

BACKGROUND

High doses of selenium are associated with heart disease prevalence in high-risk areas. Cardiac myosin light chain kinase (cMLCK) is an essential enzyme for normal function of heart tissue. Therefore, we studied the effect of high doses of selenium on the expression of cMLCK gene and its protein in normal heart tissue in rats.

MATERIALS AND METHODS

Twenty male rats were randomly divided into four groups: control, Se 0.3mg/kg, Se 1.5mg/kg, and Se 3mg/kg. Sodium-selenite was administered orally into drinking water for 20 weeks. Se levels of heart tissue were measured by atomic absorption. Serum creatine phosphokinase (CPK) and total serum antioxidant capacity were measured. Moreover, the concentration of MLCK protein and the gene expression level of cMLCK in normal heart tissue were analyzed.

RESULTS

Excess Se in dietary can significantly increase CPK. Se concentration of heart tissue in the Se 3mg/kg group was significantly higher than the control. cMLCK mRNA levels were decreased by 0.3mg/kg and 3mg/kg sodium selenite intake. There was no significant difference between the three groups for total antioxidant capacity and MLCK protein.

CONCLUSION

High concentrations of selenium can probably effect on normal function of the heart tissue by changing the expression levels of cMLCK.

SEPHS1 Gene: A new master key for neurodevelopmental disorders

The SEPHS1 (Selenophosphate Synthetase 1) gene encodes a critical enzyme for synthesizing selenophosphate, the active donor of selenium (Se) necessary for selenoprotein biosynthesis. Selenoproteins are vital for antioxidant defense, thyroid hormone metabolism, and cellular homeostasis. Mutations in SEPHS1 gene, are associated with neurodevelopmental disorders with developmental delay, poor growth, hypotonia, and dysmorphic features. Due to Se's critical role in brain development and function, SEPHS1 gene has taken center stage in neurodevelopmental research. This review explores the structure and function of the SEPHS1 gene, its role in neurodevelopment, and the implications of its dysregulation for neurodevelopmental disorders. Therapeutic strategies, including Se supplementation, gene therapy, and targeted therapies, are discussed as potential interventions to address SEPHS1 associated neurodevelopmental dysfunction. The study's findings reveal how SEPHS1 mutations disrupt neurodevelopment, emphasizing the gene's intolerance to loss of function. Future research should focus on functional characterization of SEPHS1 variants, broader genetic screenings, and therapeutic developments.

Beneficial Effects of Selenium on Kidney Injury via Nf-Kb and Aquaporin-1 Levels

Systemic inflammation is a serious condition that can affect various tissues and organs, such as the kidneys, and can be life-threatening. Selenium (Se) is an antioxidant and anti-inflammatory trace element. In this study, we aimed to examine the effects of Se, which has antioxidant and anti-inflammatory properties, on lipopolysaccharide (LPS)-induced kidney damage to maintain aquaporin-1 (AQP-1) levels. Four experimental rat groups (n = 8) consisting of the control, LPS alone, LPS + Se, and Se alone were so applied for 7 consecutive days. Upon sacrifice, histopathological results, diagnostic markers of kidney functions, oxidative stress, and inflammation were analyzed. Our results showed that LPS induced mononuclear cell infiltration, cellular residue, and protein deposition in the kidney proximal tubules, and also decreased total antioxidant status levels and increased total antioxidant status and oxidative stress index values. LPS increased the level of creatinine, increased the level of Nuclear Factor kappa B, which has an important role in the inflammation process, and decreased the levels of AQP-1 due to the damage it caused. Se has shown its effect by reversing all these situations. This data suggests that Se can be used as an additive to mitigate LPS-induced toxicity in the kidney.

Molecular mechanisms underlying cyclophosphamide-induced cognitive impairment and strategies for neuroprotection in preclinical models

Cyclophosphamide has drastically enhanced the expectancy and quality of life of cancer patients. However, it is accompanied by diverse neurological complications which are considered a dose-limiting adverse effect. Neurotoxicity caused by cyclophosphamide can manifest in numerous manners including anxiety, depression, motor dysfunction and cognitive deficits. This review article offers an overview on cyclophosphamide-induced neurotoxicity, providing a unified point of view on the possible underlying molecular mechanisms including oxidative brain damage, neuroinflammation, apoptotic neuronal cell death as well as disruption of the balance of brain neurotransmitters and neurotrophic factors. Besides, this review sheds light on the promising protective agents that have been investigated using preclinical animal models as well as their biological targets and protection mechanisms. Despite promising results in experimental models, none of these agents has been studied in clinical trials. Thus, there is lack of evidence to advocate the use of any neuroprotective agent in the clinical setting. Furthermore, none of the protective agents has been evaluated for its effect on the anticancer activity of cyclophosphamide in tumor-bearing animals. Therefore, there is a great necessity for adequate well-designed clinical studies for evaluation of the therapeutic values of these candidates. Conclusively, this review summarizes the molecular mechanisms accounting for cyclophosphamide-induced neurotoxicity together with the potential protective strategies seeking for downgrading this neurological complication, thus enhancing the quality of life and well-being of cancer patients treated with cyclophosphamide.

SELENOI Functions as a Key Modulator of Ferroptosis Pathway in Colitis and Colorectal Cancer

Ferroptosis plays important roles both in normal physiology and multiple human diseases. It is well known that selenoprotein named glutathione peroxidase 4 (GPX4) is a crucial regulator for ferroptosis. However, it remains unknown whether other selenoproteins responsible for the regulation of ferroptosis, particularly in gut diseases. In this study, it is observed that Selenoprotein I (Selenoi) prevents ferroptosis by maintaining ether lipids homeostasis. Specific deletion of Selenoi in intestinal epithelial cells induced the occurrence of ferroptosis, leading to impaired intestinal regeneration and compromised colonic tumor growth. Mechanistically, Selenoi deficiency causes a remarkable decrease in ether-linked phosphatidylethanolamine (ePE) and a marked increase in ether-linked phosphatidylcholine (ePC). The imbalance of ePE and ePC results in the upregulation of phospholipase A2, group IIA (Pla2g2a) and group V (Pla2g5), as well as arachidonate-15-lipoxygenase (Alox15), which give rise to excessive lipid peroxidation. Knockdown of PLA2G2A, PLA2G5, or ALOX15 can reverse the ferroptosis phenotypes, suggesting that they are downstream effectors of SELENOI. Strikingly, GPX4 overexpression cannot rescue the ferroptosis phenotypes of SELENOI-knockdown cells, while SELENOI overexpression can partially rescue GPX4-knockdown-induced ferroptosis. It suggests that SELENOI prevents ferroptosis independent of GPX4. Taken together, these findings strongly support the notion that SELENOI functions as a novel suppressor of ferroptosis during colitis and colon tumorigenesis.

The effect of hydroxy-selenomethionine on the productive and reproductive performance of old broiler breeders

BACKGROUND

Selenium (Se) is a rare essential element that plays a vital role in the health and performance of animals. By interfering in the production of antioxidant enzymes such as glutathione peroxidase, thioredoxin reductase and methionine sulfoxide, Se plays a role in reducing the effects of oxidative stress and animal performance.

OBJECTIVES

This study aimed to investigate the effect of hydroxy-selenomethionine (OH-SeMet) in the diet of broiler breeder and old broiler breeder roosters on productive performance, reproduction and sperm quality parameters.

METHODS

For this purpose, 260 broiler breeders of the Ross 308 strain were used in a completely randomized design with four treatments and five replications (13 hens and one rooster in each replication). Experimental treatments included: (1) a basal diet without OH-SeMet (T1:control), (2) a broiler breeder diet without OH-SeMet and a rooster diet containing 0.1 mg/kg OH-SeMet (T2), (3) broiler breeder diet containing 0.1 mg/kg OH-SeMet and rooster diet without OH-SeMet (T3) and (4) broiler breeder and rooster diet contained 0.1 mg/kg OH-SeMet (T4).

RESULTS

The results showed that T3 and T4 treatments improved egg production, egg weight, egg mass and feed conversion ratio (FCR) compared to the control treatment (p < 0.05). The fertility and hatchability percentages of T4 and T2 treatments increased compared to T1 and T3 treatments (p < 0.05). The rate of embryonic losses in T1 was higher than in other treatments. However, grade one chickens were higher in T4 than in other treatments (p < 0.05). Total motility and viability of sperms were significantly higher in T2 and T4 treatments than in T1 and T3 treatments. The sperm abnormality percentage and sperm MDA concentration decreased in T2 and T4 treatments.

CONCLUSIONS

Therefore, using OH-SeMet may be a practical approach to help old broiler breeders' production and reproduction performance.

Development potential of selenium in the prevention and treatment of bovine endometritis

Endometritis is a common postpartum disease in cows. It delays uterine involution and impairs normal physiological function. This can result in long-term or even lifelong infertility and cause significant losses to the dairy farming industry. Traditional treatments like antibiotics possess certain shortcomings, such as antibiotic residues, the abuse of antibiotics, and increased antimicrobial resistance of pathogens. Alternative treatment strategies are needed to minimize the utilization of antibiotics in dairy production. As an essential trace element in animals, selenium (Se) plays a vital role in regulating immune function, the inflammatory response, and oxidative stress, affecting the speed and completeness of tissue repair. This paper reviewed previous studies to analyse the potential of Se in the prevention and treatment of bovine endometritis, aiming to provide a new direction to increase production capacity in the future.

Study of selenium enrichment metabolomics in Bacillus subtilis BSN313 via transcriptome analysis

In this study, the transcriptome analysis was practiced to identify potential genes of probiotic Bacillus subtilis BSN313 involved in selenium (Se) enrichment metabolism. The transcriptomic variation of the strain was deliberated in presence of three different sodium selenite concentrations (0, 3, and 20 μg/mL). The samples were taken at 1 and 13 h subsequent to inoculation of selenite and gene expression profiles in Se metabolism were analyzed through RNA sequencing. The gene expression levels of the pre log phase were lower than the stationary phase. It is because, the bacteria has maximum grown with high concentration of Se (enriched with organic Se), at stationary phase. Bacterial culture containing 3 μg/mL concentration of inorganic Se (sodium selenite) has shown highest gene expression as compared to no or high concentration of Se. This concentration (3 μg/mL) of sodium selenite (as Se) in the medium promoted the upregulation of thioredoxin reductase expression, whereas its higher Se concentration inhibited the formation of selenomethionine (SeMet). The result of 5 L bioreactor fermentation showed that SeMet was also detected in the fermentation supernatant as the growth entered in the late stationary phase and reached up to 857.3 ng/mL. The overall intracellular SeMet enriched content in BSN313 was extended up to 23.4 μg/g dry cell weight. The other two selenoamino acids (Se-AAs), methyl-selenocysteine, and selenocysteine were hardly detected in medium supernatant. From this study, it was concluded that SeMet was the highest content of organic Se byproduct biosynthesized by B. subtilis BSN313 strain in Se-enriched medium during stationary phase. Thus, B. subtilis BSN313 can be considered a commercial probiotic strain that can be used in the food and pharmaceutical industries. This is because it can meet the commercial demand for Se-AAs (SeMet) in both industries.

Selenium in plants: A nexus of growth, antioxidants, and phytohormones

Selenium (Se) is an essential micronutrient for both human and animals. Plants serve as the primary source of Se in the food chain. Se concentration and availability in plants is influenced by soil properties and environmental conditions. Optimal Se levels promote plant growth and enhance stress tolerance, while excessive Se concentration can result in toxicity. Se enhances plants ROS scavenging ability by promoting antioxidant compound synthesis. The ability of Se to maintain redox balance depends upon ROS compounds, stress conditions and Se application rate. Furthermore, Se-dependent antioxidant compound synthesis is critically reliant on plant macro and micro nutritional status. As these nutrients are fundamental for different co-factors and amino acid synthesis. Additionally, phytohormones also interact with Se to promote plant growth. Hence, utilization of phytohormones and modified crop nutrition can improve Se-dependent crop growth and plant stress tolerance. This review aims to explore the assimilation of Se into plant proteins, its intricate effect on plant redox status, and the specific interactions between Se and phytohormones. Furthermore, we highlight the proposed physiological and genetic mechanisms underlying Se-mediated phytohormone-dependent plant growth modulation and identified research opportunities that could contribute to sustainable agricultural production in the future.

Alleviation potential of green-synthesized selenium nanoparticles for cadmium stress in Solanum lycopersicum L: modulation of secondary metabolites and physiochemical attributes

KEY MESSAGE

Selenium nanoparticles reduce cadmium absorption in tomato roots, mitigating heavy metal effects. SeNPs can efficiently help to enhance growth, yield, and biomolecule markers in cadmium-stressed tomato plants. In the present study, the effects of selenium nanoparticles (SeNPs) were investigated on the tomato plants grown in cadmium-contaminated soil. Nanoparticles were synthesized using water extract of Nigella sativa and were characterized for their size and shape. Two application methods (foliar spray and soil drench) with nanoparticle concentrations of 0, 100, and 300 mg/L were used to observe their effects on cadmium-stressed plants. Growth, yield, biochemical, and stress parameters were studied. Results showed that SeNPs positively affected plant growth, mitigating the negative effects of cadmium stress. Shoot length (SL), root length (RL), number of branches (NB), number of leaves per plant (NL), and leaf area (LA) were significantly reduced by cadmium stress but enhanced by 45, 51, 506, 208, and 82%, respectively, by soil drench treatment of SeNPs. Similarly, SeNPs increased the fruit yield (> 100%) and fruit weight (> 100%), and decreased the days to fruit initiation in tomato plants. Pigments were also positively affected by the SeNPs, particularly in foliar treatment. Lycopene content was also enhanced by the addition of NPs (75%). Furthermore, the addition of SeNPs improved the ascorbic acid, protein, phenolic, flavonoid, and proline contents of the tomato plants under cadmium stress, whereas stress enzymes also showed enhanced activities under cadmium stress. It is concluded from the present study that the addition of selenium nanoparticles enhanced the growth and yield of Cd-stressed plants by reducing the absorption of cadmium and increasing the stress management of plants.

Harmony in Motion: Unraveling the Nexus of Sports, Plant-Based Nutrition, and Antioxidants for Peak Performance

The intricate interplay between plant-based nutrition, antioxidants, and their impact on athletic performance forms the cornerstone of this comprehensive review. Emphasizing the pivotal importance of dietary choices in the realm of sports, this paper sets the stage for an in-depth exploration of how stress and physical performance are interconnected through the lens of nutrition. The increasing interest among athletes in plant-based diets presents an opportunity with benefits for health, performance, and recovery. It is essential to investigate the connection between sports, plants, and antioxidants. Highlighting the impact of nutrition on recovery and well-being, this review emphasizes how antioxidants can help mitigate oxidative stress. Furthermore, it discusses the growing popularity of plant-based diets among athletes. It elaborates on the importance of antioxidants in combating radicals addressing stress levels while promoting cellular health. By identifying rich foods, it emphasizes the role of a balanced diet in ensuring sufficient intake of these beneficial compounds. Examining stress within the context of sports activities, this review provides insights into its mechanisms and its impact on athletic performance as well as recovery processes. This study explores the impact of plant-based diets on athletes including their types, potential advantages and challenges. It also addresses the drawbacks of relying on plant-based diets, concerns related to antioxidant supplementation and identifies areas where further research is needed. Furthermore, the review suggests directions for research and potential innovations in sports nutrition. Ultimately it brings together the aspects of sports, plant-based nutrition, and antioxidants to provide a perspective for athletes, researchers and practitioners. By consolidating existing knowledge, it offers insights that can pave the way for advancements in the ever-evolving field of sports nutrition.

Selenium Deficiency Promotes Dilatation of the Aorta by Increasing Expression and Activity of Vascular Smooth Muscle Cell Derived Matrix Metalloproteinase-2

OBJECTIVE

Selenium (Se) is a key part of the body's oxidation defence system. However, it is unclear whether Se affects the development of aortic aneurysm (AA). An animal experiment was conducted to clarify the role of Se in AA development.

METHODS

C57BL/6N male mice were fed with a Se deficient (Se-D, < 0.05 mg/kg), Se adequate (Se-A, 0.2 mg/kg), or Se supplemented (Se-S, 1 mg/kg) diet for 8 weeks. Subsequently, an AA murine model (Se-D, n = 11; Se-A, n = 12; Se-S, n = 15) was established using angiotensin II (Ang II, 1 mg/kg/min) for four weeks plus β-aminopropionitrile (BAPN, 1 mg/mL) for the first two weeks. Saline replaced Ang II, and BAPN was removed during the modelling process for sham mice (Se-A, n = 9). To determine whether Se deficiency promoted aortic dilation via matrix metalloproteinase-2 (MMP-2), the non-specific MMP inhibitor doxycycline (Dox, 100 mg/kg/day) was given to Se-D AA mice (n = 7) for two weeks.

RESULTS

The maximum aortic diameter in Se-D AA model mice was significantly increased compared with Se-A AA model mice. MMP-2 expression and activity in the aortic media of Se-D AA model mice was significantly increased compared with Se-A AA model mice. A large number of vascular smooth muscle cells (VSMCs) were found aggregating in the media of the non-dilated aorta of Se-D AA model mice, which was completely inhibited by Dox. The percentage of VSMCs in aortic media of Se-D AA model mice was significantly higher than in Se-A AA model mice. The maximum aortic diameter and occurrence rate of AA in Se-D AA model mice with Dox were significantly reduced compared with Se-D AA model mice.

CONCLUSION

Se deficiency promoted dilatation of the aorta in AA model mice by increasing expression and activity of VSMC derived MMP-2, causing abnormal aggregation and proliferation of VSMCs in aortic media.

The actinomycete Kitasatospora sp. SeTe27, subjected to adaptive laboratory evolution (ALE) in the presence of selenite, varies its cellular morphology, redox stability, and tolerance to the toxic oxyanion

The effects of oxyanions selenite (SeO32-) in soils are of high concern in ecotoxicology and microbiology as they can react with mineral particles and microorganisms. This study investigated the evolution of the actinomycete Kitasatospora sp. SeTe27 in response to selenite. To this aim, we used the Adaptive Laboratory Evolution (ALE) technique, an experimental approach that mimics natural evolution and enhances microbial fitness for specific growth conditions. The original strain (wild type; WT) isolated from uncontaminated soil gave us a unique model system as it has never encountered the oxidative damage generated by the prooxidant nature of selenite. The WT strain exhibited a good basal level of selenite tolerance, although its growth and oxyanion removal capacity were limited compared to other environmental isolates. Based on these premises, the WT and the ALE strains, the latter isolated at the end of the laboratory evolution procedure, were compared. While both bacterial strains had similar fatty acid profiles, only WT cells exhibited hyphae aggregation and extensively produced membrane-like vesicles when grown in the presence of selenite (challenged conditions). Conversely, ALE selenite-grown cells showed morphological adaptation responses similar to the WT strain under unchallenged conditions, demonstrating the ALE strain improved resilience against selenite toxicity. Whole-genome sequencing revealed specific missense mutations in genes associated with anion transport and primary and secondary metabolisms in the ALE variant. These results were interpreted to show that some energy-demanding processes are attenuated in the ALE strain, prioritizing selenite bioprocessing to guarantee cell survival in the presence of selenite. The present study indicates some crucial points for adapting Kitasatospora sp. SeTe27 to selenite oxidative stress to best deal with selenium pollution. Moreover, the importance of exploring non-conventional bacterial genera, like Kitasatospora, for biotechnological applications is emphasized.

Chromosome-scale assembly of the streamlined picoeukaryote Picochlorum sp. SENEW3 genome reveals Rabl-like chromatin structure and potential for C4 photosynthesis

Genome sequencing and assembly of the photosynthetic picoeukaryotic Picochlorum sp. SENEW3 revealed a compact genome with a reduced gene set, few repetitive sequences, and an organized Rabl-like chromatin structure. Hi-C chromosome conformation capture revealed evidence of possible chromosomal translocations, as well as putative centromere locations. Maintenance of a relatively few selenoproteins, as compared to similarly sized marine picoprasinophytes Mamiellales, and broad halotolerance compared to others in Trebouxiophyceae, suggests evolutionary adaptation to variable salinity environments. Such adaptation may have driven size and genome minimization and have been enabled by the retention of a high number of membrane transporters. Identification of required pathway genes for both CAM and C4 photosynthetic carbon fixation, known to exist in the marine mamiellale pico-prasinophytes and seaweed Ulva, but few other chlorophyte species, further highlights the unique adaptations of this robust alga. This high-quality assembly provides a significant advance in the resources available for genomic investigations of this and other photosynthetic picoeukaryotes.

Selenium enriched bifidobacteria and lactobacilli as potential dietary supplements

In this study, we tested the ability of lactobacilli and bifidobacteria strains to accumulate and biotransform sodium selenite into various selenium species, including selenium nanoparticles (SeNPs). Selenium tolerance and cytotoxicity of selenized strains towards human adenocarcinoma Caco-2 and HT29 cells were determined for all tested strains. Furthermore, the influence of selenium enrichment on the antioxidant activity of selenized strains and hydrophobicity of the bacterial cell surfaces were evaluated. Both hydrophobicity and antioxidant activity increased significantly in the selenized L. paracasei strain and decreased significantly in the selenized L. helveticus strain. The concentrations of 5 and 10 mg/L Na2SeO3 in the growth media were safer for Caco-2 and HT29 cell growth than higher concentrations. At higher concentrations (30, 50, and 100 mg/L), the cell viability was reduced. All the tested strains showed differences in antioxidant potential and hydrophobicity after selenium enrichment. In addition to selenocystine ​​and selenomethionine, the tested bacterial strains produced significant amounts of SeNPs. Our results show that the tested bacterial strains can accumulate and biotransform inorganic selenium, which allows them to become a potential source of selenium.

Reactions of hypobromous acid with dimethyl selenide, dimethyl diselenide and other organic selenium compounds: kinetics and product formation

Selenium (Se) is an essential micronutrient for many living organisms particularly due to its unique redox properties. We recently found that the sulfur (S) analog for dimethyl selenide (DMSe), i.e. dimethyl sulfide (DMS), reacts fast with the marine oxidant hypobromous acid (HOBr) which likely serves as a sink of marine DMS. Here we investigated the reactivity of HOBr with dimethyl selenide and dimethyl diselenide (DMDSe), which are the main volatile Se compounds biogenically produced in marine waters. In addition, the reactivity of HOBr with further organic Se compounds was tested, i.e., SeMet (as N-acetylated-SeMet), and selenocystine (SeCys2 as N-acetylated-SeCys2), as well as the phenyl-analogs of DMSe and DMDSe, respectively, diphenyl selenide (DPSe) and diphenyl diselenide (DPDSe). Apparent second-order rate constants at pH 8 for the reactions of HOBr with the studied Se compounds were (7.1 ± 0.7) × 107 M-1 s-1 for DMSe, (4.3 ± 0.4) × 107 M-1 s-1 for DMDSe, (2.8 ± 0.3) × 108 M-1 s-1 for SeMet, (3.8 ± 0.2) × 107 M-1 s-1 for SeCys2, (3.5 ± 0.1) × 107 M-1 s-1 for DPSe, and (8.0 ± 0.4) × 106 M-1 s-1 for DPDSe, indicating a very high reactivity of all selected Se compounds with HOBr. The reactivity between HOBr and DMSe is lower than for DMS and therefore this reaction is likely not relevant for marine DMSe abatement. However, the high reactivity of SeMet with HOBr suggests that SeMet may act as a relevant quencher of HOBr.

Protective effect of selenium and vitamin C on the fertility of male rats given penconazole

OBJECTIVE

Penconazole is used in agriculture and human and veterinary medicine applications. It has been included in the acute toxicity hazard category by the WHO. This study examines the protective effect of selenium and vitamin C on the fertility of male rats given penconazole.

METHODS

Nine groups of rats were given penconazole at concentrations of 50 and 75 mg/ml and selenium and vitamin C at concentrations of 0.5 and 100 mg/ml, respectively. Serum levels of LH and FSH were measured with ELISA kits; β-actin, GPX4, AQP7, PRM2, and BAX gene expression was evaluated with real-time PCR performed on the left testis of each rat.

RESULTS

LH, FSH, and testosterone levels were lower in the groups given penconazole (50 and 75 mg/kg). Histopathology showed that the groups given penconazole had the lowest number of spermatogonia and primary spermatocytes; these numbers were greater in the groups receiving penconazole together with selenium or vitamin C; and the highest counts were observed in separate groups given Se and vitamin C. GPX4, AQP7, PRM2 and BAX gene expression in the groups receiving penconazole was different from controls and was modulated by treatment with selenium or vitamin C.

CONCLUSIONS

This study showed that antioxidant compounds have a strengthening effect on the reproductive system and can mitigate the destructive effects of chemical fungicides.

Selenium Lessens Osteoarthritis by Protecting Articular Chondrocytes from Oxidative Damage through Nrf2 and NF-κB Pathways

Osteoarthritis (OA) causes joint pain and disability due to the abnormal production of inflammatory cytokines and reactive oxygen species (ROS) in chondrocytes, leading to cell death and cartilage matrix destruction. Selenium (Se) intake can protect cells against oxidative damage. It is still unknown whether Se supplementation is beneficial for OA. This study investigated the effects of Se on sodium iodoacetate (MIA)-imitated OA progress in human chondrocyte cell line (SW1353 cells) and rats. The results showed that 0.3 μM of Se treatment could protect SW1353 cells from MIA-induced damage by the Nrf2 pathway by promoting the gene expression of glutathione-synthesis-related enzymes such as the glutamate-cysteine ligase catalytic subunit, the glutamate-cysteine ligase modifier subunit, and glutathione synthetase. In addition, glutathione, superoxide dismutase, glutathione peroxidase, and glutathione reductase expressions are also elevated to eliminate excessive ROS production. Moreover, Se could downregulate NF-κB, leading to a decrease in cytokines, matrix proteases, and glycosaminoglycans. In the rats, MIA-induced cartilage loss was lessened after 2 weeks of Se supplementation by oral gavage; meanwhile, glutathione synthesis was increased, and the expressions of pro-inflammatory cytokines were decreased. These results suggest that Se intake is beneficial for OA due to its effects of decreasing cartilage loss by enhancing antioxidant capacity and reducing inflammation.

Seleno-Warfare against Cancer: Decoding Antitumor Activity of Novel Acylselenoureas and Se-Acylisoselenoureas

Currently, cancer remains a global health problem. Despite the existence of several treatments, including chemotherapy, immunotherapy, and radiation therapy, the survival rate for most cancer patients, particularly those with metastasis, remains unsatisfactory. Thus, there is a continuous need to develop novel, effective therapies. In this work, 22 novel molecules containing selenium are reported, including seven Se-acylisoselenoureas synthesized from aliphatic carbodiimides as well as acylselenoureas with the same carbo- and heterocycles and aliphatic amines. After an initial screening at two doses (50 and 10 µM) in MDA-MB-231 (breast), HTB-54 (lung), DU-145 (prostate), and HCT-116 (colon) tumor cell lines, the ten most active compounds were identified. Additionally, these ten hits were also submitted to the DTP program of the NCI to study their cytotoxicity in a panel of 60 cancer cell lines. Compound 4 was identified as the most potent antiproliferative compound. The results obtained showed that compound 4 presented IC50 values lower than 10 µM in the cancer cell lines, although it was not the most selective one. Furthermore, compound 4 was found to inhibit cell growth and cause cell death by inducing apoptosis partially via ROS production. Overall, our results suggest that compound 4 could be a potential chemotherapeutic drug for different types of cancer.

Brazil Nut-Enriched Diet Modulates Enteric Glial Cells and Gut Microbiota in an Experimental Model of Chronic Kidney Disease

Introduction: Chronic kidney disease (CKD) promotes gut dysbiosis, and enteric glial reactivity, a feature of intestinal inflammation. Brazil nut modulated enteric glial profile in healthy animals and could modulate these cells in 5/6 nephrectomized rats.Methods: A 5/6 nephrectomy-induced CKD and Sham-operated rats were divided as follows: CKD and Sham received a standard diet and CKD-BN and Sham-BN received a 5% Brazil nut enriched-diet. The protein content of glial fibrillary acid protein (GFAP), enteric glial marker, and GPx protein content and activity were assessed in the colon. The major phyla of gut microbiota were assessed.Results: CKD-BN group presented a decrease in GFAP content (p = 0.0001). The CKD-BN group modulated the abundance of Firmicutes, increasing its proportion compared to the CKD group. The CKD-BN group showed increased GPx activity in the colon (p = 0.0192), despite no significant difference in protein content.Conclusion: Brazil nut-enriched diet consumption decreased enteric glial reactivity and modulated gut microbiota in the CKD experimental model.

The selenium-independent phospholipid hydroperoxide glutathione peroxidase from Theobroma cacao (TcPHGPX) protects plant cells against damages and cell death

Proteins from the glutathione peroxidase (GPX) family, such as GPX4 or PHGPX in animals, are extensively studied for their antioxidant functions and apoptosis inhibition. GPXs can be selenium-independent or selenium-dependent, with selenium acting as a potential cofactor for GPX activity. However, the relationship of plant GPXs to these functions remains unclear. Recent research indicated an upregulation of Theobroma cacao phospholipid hydroperoxide glutathione peroxidase gene (TcPHGPX) expression during early witches' broom disease stages, suggesting the use of antioxidant mechanisms as a plant defense strategy to reduce disease progression. Witches' broom disease, caused by the hemibiotrophic fungus Moniliophthora perniciosa, induces cell death through elicitors like MpNEP2 in advanced infection stages. In this context, in silico and in vitro analyses of TcPHGPX's physicochemical and functional characteristics may elucidate its antioxidant potential and effects against cell death, enhancing understanding of plant GPXs and informing strategies to control witches' broom disease. Results indicated TcPHGPX interaction with selenium compounds, mainly sodium selenite, but without improving the protein function. Protein-protein interaction network suggested cacao GPXs association with glutathione and thioredoxin metabolism, engaging in pathways like signaling, peroxide detection for ABA pathway components, and anthocyanin transport. Tests on tobacco cells revealed that TcPHGPX reduced cell death, associated with decreased membrane damage and H2O2 production induced by MpNEP2. This study is the first functional analysis of TcPHGPX, contributing to knowledge about plant GPXs and supporting studies for witches' broom disease control.

Effects of different selenium sources and levels on the physiological state, selenoprotein expression, and production and preservation of selenium-enriched eggs in laying hens

Selenium (i.e., Se) is a trace element that is vital in poultry nutrition, and optimal forms and levels of Se are critical for poultry productivity and health. This study aimed to compare the effects of sodium selenite (SS), yeast selenium (SY), and methionine selenium (SM) at selenium levels of 0.15 mg/kg and 0.30 mg/kg on production performance, egg quality, egg selenium content, antioxidant capacity, immunity and selenoprotein expression in laying hens. The trial was conducted in a 3 × 2 factorial arrangement, and a total of 576 forty-three-wk-old Hyland Brown laying hens were randomly assigned into 6 treatment groups, with diets supplemented with 0.15 mg Se/kg and 0.3 mg Se/kg of SS, SY and SM for 8 wk, respectively. Results revealed that SM increased the laying rate compared to SS and SY (P < 0.05), whereas different selenium levels had no effect. Organic selenium improved egg quality, preservation performance, and selenium deposition compared to SS (P < 0.05), while SY and SM had different preferences for Se deposition in the yolk and albumen. Also, organic selenium enhanced the antioxidant capacity and immune functions of laying hens at 0.15 mg Se/kg, whereas no obvious improvement was observed at 0.30 mg Se/kg. Moreover, SY and SM increased the mRNA expression of most selenoproteins compared to SS (P < 0.05), with SM exhibiting a more pronounced effect. Correlation analysis revealed a strong positive association between glutathione peroxidase 2 (GPx2), thioredoxin reductases (TrxRs), selenoprotein K (SelK), selenoprotein S (SelS), and antioxidant and immune properties. In conclusion, the use of low-dose organic selenium is recommended as a more effective alternative to inorganic selenium, and a dosage of 0.15 mg Se/kg from SM is recommended based on the trail conditions.

A combination of silymarin and garlic extract enhances thyroid hormone activation and body metabolism in orally intoxicated male rats with atrazine: Impact on hepatic iodothyronine deiodinase type 1

Atrazine is a widely applied herbicide to improve crop yield and maintain general health. It has been reported to impair thyroid function and architecture in experimental animals. Alterations in thyroid hormones disrupt normal body function and metabolism. Silymarin, a hepatoprotective flavonolignan, was found to improve thyroid function and body metabolism. Additionally, garlic displays several protective effects on body organs. Therefore, this study explored the prophylactic impact of natural compounds comprising silymarin and garlic extract on disrupted thyroid function, hepatic iodothyronine deiodinase type 1, and metabolic parameters in atrazine-intoxicated male rats. We found that daily pre- and co-treatment of atrazine-intoxicated male rats with silymarin (100 mg/kg, p.o) and/or garlic extract (10 mg/kg, p.o) significantly improved thyroid activation and hepatic functionality as evidenced by the re-establishment of T3, T3/T4, and TSH values as well as ALT and AST activities. Interestingly, individual or concurrent supplementation of the atrazine group with silymarin and garlic extract prevented the down-regulation in hepatic iodothyronine deiodinase type 1. These effects were coupled with the repletion of serum and hepatic antioxidants and the amelioration of lipid peroxidation. In addition, current natural products markedly alleviated weight gain, dyslipidemia, hyperglycemia, glucose intolerance, and insulin resistance. Notably, a cocktail of silymarin and garlic extract exerted superior protection against atrazine-triggered deterioration of thyroid, hepatic, and metabolic functioning to individual treatments. Present findings pinpoint the prophylactic and synergistic influence of silymarin and garlic extract combinatorial regimen on thyroid activation and body metabolism via enhancing antioxidant potential, maintaining hepatic function, and iodothyronine deiodinase type 1.

Recent Advances on Selenium Nutrition and Keshan Disease

Keshan disease (KD) is a type of endemic cardiomyopathy with an unknown cause. It is primarily found in areas in China with low selenium levels, from northeast to southwest. The nutritional biogeochemical etiology hypothesis suggests that selenium deficiency is a major factor in KD development. Selenium is important in removing free radicals and protecting cells and tissues from peroxide-induced damage. Thus, low environmental selenium may affect the selenium level within the human body, and selenium level differences are commonly observed between healthy people in KD and nonKD areas. From the 1970s to the 1990s, China successfully reduced KD incidence in endemic KD areas through a selenium supplementation program. After years of implementing prevention and control measures, the selenium level of the population in the KD areas has gradually increased, and the prevalence of KD in China has remained low and stable in recent years. Currently, the pathogenesis of KD remains vague, and the effect of selenium supplementation on the prognosis of KD still needs further study. This paper comprehensively reviews selenium deficiency and its connection to KD. Thus, this study aims to offer novel ideas and directions to effectively prevent and treat KD in light of the current situation.

Organic and Inorganic Selenium Compounds Affected Lipidomic Profile of Spleen of Lambs Fed with Diets Enriched in Carnosic Acid and Fish Oil

The purpose of our study was to investigate the effect of 0.35 mg Se/kg basal diet (BD) (Se as sodium selenate (Se6) and yeast rich in seleno-methionine (SeYe)) and 0.1% carnosic acid (CA) supplementation to the diet containing 1% fish oil (F-O) and 2% rapeseed oil (R-O) on the contents of fatty acids (FA), malondialdehyde (MDA), tocopherols (Ts), and total cholesterol (TCh) in lambs' spleens. A total of 24 male lambs (4 groups per 6 animals) have been fed: the control diet-the basal diet (BD) enriched in F-O and R-O; the CA diet-BD enriched in F-O, R-O, and CA; the SeYeCA diet-BD enriched in F-O, R-O, CA, and SeYe; the Se6CA diet-BD enriched in F-O, R-O, CA, and Se6. Dietary modifications affected the profiles of saturated (SFA), monounsaturated (MUFA), and polyunsaturated (PUFA) fatty acids in spleens. The SeYeCA and Se6CA diets increased the docosapentaenoic acid preference in Δ4-desaturase; hence, a higher content of docosahexaenoic acid was found in the spleens of SeYe- or Se6-treated lambs than in spleens of animals receiving the CA and control diets. The SeYeCA and Se6CA diets increased the concentration ratio of n-3long-chain PUFA (n-3LPUFA) to FA (n-3LPUFA/FA) in spleens compared to the control and CA diets. The content of n-3PUFA was higher in the spleens of Se6 treated lambs than in spleens of animals receiving the SeYeCA, CA, and control diets. The Se6CA diet increased the content of c9t11CLA in the spleen compared to the control, CA, and SeYeCA diets. Experimental diets reduced the level of atherogenic FA, the content ratios of n-6PUFA/n-3PUFA and n-6LPUFA/n-3LPUFA, and improved the content ratio of MUFA/FA and the value of the hypocholesterolemic/hypercholesterolemic FA ratio in the spleen in comparison with the control diet. The experimental diets supplemented with SeYe or Se6 increased levels of TCh and Ts in spleens in comparison with the CA and control CA diets. The present studies documented that Se6, SeYe, and CA influenced the metabolism of FA, Ts, and cholesterol in spleens.

Ameliorative and Neuroprotective Effect of Core-Shell Type Se@Au Conjugated Hesperidin Nanoparticles in Diabetes-Induced Cognitive Impairment

Diabetes mellitus is the most chronic metabolic ailment characterized by insulin deficiency leading to aberrant cognitive dysfunction in later stages. Hesperidin is a bioflavonoid, having different pharmacological activities, but its poor water solubility and short plasma half-life restrict its applications in the clinical field. So, the hesperidin was conjugated with gold, selenium, and core-shell bimetallic nanoparticles of gold and selenium. Different spectroscopic methods characterized the synthesized monometallic and bimetallic nanoparticles. The rats were injected with streptozotocin to induce cognitive dysfunction, followed by administering HSP, HSP-Au NPs, HSP-Se NPs, and Se@Au-HSP NPs daily for 21 days. Then, the neurobehavioral studies, oxidative stress parameters, AChE and nitrite levels, the content of amyloid-β42, and inflammatory mediators were accessed to evaluate the effect of the nanoparticles against the STZ rat model. The results showed a significant increase in oxidative stress, AChE activity, amyloid-β42, nitrite levels, and neuroinflammation by upregulating the inflammatory cytokines in the streptozotocin-administered rat brain. The HSP, HSP-Au NPs, HSP-Se NPs, and Se@Au-HSP NPs effectively reversed all these effects of streptozotocin. However, the bimetallic nanoparticle Se@Au-HSP NPs revealed better neuroprotective action than HSP-Au NPs and HSP-Se NPs. Hesperidin-conjugated bimetallic nanoparticles improved learning and memory in the STZ rat model and may be an alternative approach for neurodegenerative diseases, including Alzheimer's disease.

Association between dietary copper and cardiovascular disease: A narrative review

Cardiovascular disease (CVD) is a major cause of mortality and morbidity. Several studies have investigated the relationship between trace element status, including copper status, and CVDs in population studies; however, there are controversies about the role of dietary copper and CVD. We aimed to review the association between dietary copper intake with CVD and this association's related factors by reviewing both animal models and human studies. Some animal model studies have reported a strong relationship between dietary copper intake and atherogenesis based on the possible molecular pathways, whilst other studies have not confirmed this relationship. Human studies have not revealed a relationship between CVDs and dietary copper intake, but there is uncertainty about the optimal amount of dietary copper intake in relation reducing the risk of CVDs. These associations may be influenced by ethnicity, gender, underlying co-morbidities and the methods used for its measurement.

Relative bioavailability of selenium in rice using a rat model and its application to human health risk assessment

Deficiencies of selenium (Se), a necessary microelement for humans, can be remedied by appropriately supplying Se-enriched rice. However, overconsumption of Se-enriched rice poses a potential risk. To accurately assess Se human health risks associated with Se-enriched rice consumption, we developed a rat in vivo model to systematically explore the relative bioavailability of Se (Se-RBA) from Se-enriched rice from a wide geographic range. Se concentrations were in the range of 0.06 ± 0.05 to 0.15 ± 0.15 mg kg-1, averaging 0.12 ± 0.11 mg kg-1, in 196 rice samples from 21 Chinese provinces, and selenomethionine (SeMet) was the dominant Se fraction (58.0-96.5%). The Se-RBA of Se-enriched rice calculated from urine ranged from 34.86% to 102.29%, averaging 62.27% (n = 12), and was positively correlated with the proportion of SeMet in rice (p < 0.05, R2 = 0.51). Furthermore, the Se intake calculated based on the Se-RBA indicated that the Se intake of consumers of Se-enriched rice was far less than the tolerable upper intake level. Thus, the limits established by law assume overestimates of the actual nutritional value of the Se content in Se-enriched rice, and it is important to consider Se bioavailability. The current study offers suggestions for future research and provides methods to reduce the uncertainty in estimating the health risks associated with Se intake from rice.

Replacing dietary sodium selenite with biogenic selenium nanoparticles improves the growth performance and gut health of early-weaned piglets

Selenium nanoparticles (SeNPs) are proposed as a safer and more effective selenium delivery system than sodium selenite (Na2SeO3). Here, we investigated the effects of replacing dietary Na2SeO3 with SeNPs synthesized by Lactobacillus casei ATCC 393 on the growth performance and gut health of early-weaned piglets. Seventy-two piglets (Duroc × Landrace × Large Yorkshire) weaned at 21 d of age were divided into the control group (basal diet containing 0.3 mg Se/kg from Na2SeO3) and SeNPs group (basal diet containing 0.3 mg Se/kg from SeNPs) during a 14-d feeding period. The results revealed that SeNPs supplementation increased the average daily gain (P = 0.022) and average daily feed intake (P = 0.033), reduced (P = 0.056) the diarrhea incidence, and improved (P = 0.013) the feed conversion ratio compared with Na2SeO3. Additionally, SeNPs increased jejunal microvilli height (P = 0.006) and alleviated the intestinal barrier dysfunction by upregulating (P < 0.05) the expression levels of mucin 2 and tight junction proteins, increasing (P < 0.05) Se availability, and maintaining mitochondrial structure and function, thereby improving antioxidant capacity and immunity. Furthermore, metabolomics showed that SeNPs can regulate lipid metabolism and participate in the synthesis, secretion and action of parathyroid hormone, proximal tubule bicarbonate reclamation and tricarboxylic acid cycle. Moreover, SeNPs increased (P < 0.05) the abundance of Holdemanella and the levels of acetate and propionate. Correlation analysis suggested that Holdemanella was closely associated with the regulatory effects of SeNPs on early-weaned piglets through participating in lipid metabolism. Overall, replacing dietary Na2SeO3 with biogenic SeNPs could be a potential nutritional intervention strategy to prevent early-weaning syndrome in piglets.

Research progress on the hypoglycemic activity and mechanisms of natural polysaccharides

The incidence of diabetes, as a metabolic disease characterized by high blood sugar levels, is increasing every year. The predominantly western medicine treatment is associated with certain side effects, which has prompted people to turn their attention to natural active substances. Natural polysaccharide is a safe and low-toxic natural substance with various biological activities. Hypoglycemic activity is one of the important biological activities of natural polysaccharides, which has great potential for development. A systematic review of the latest research progress and possible molecular mechanisms of hypoglycemic activity of natural polysaccharides is of great significance for better understanding them. In this review, we systematically reviewed the relationship between the hypoglycemic activity of polysaccharides and their structure in terms of molecular weight, monosaccharide composition, and glycosidic bonds, and summarized underlying molecular mechanisms the hypoglycemic activity of natural polysaccharides. In addition, the potential mechanisms of natural polysaccharides improving the complications of diabetes were analyzed and discussed. This paper provides some valuable insights and important guidance for further research on the hypoglycemic mechanisms of natural polysaccharides.

Harnessing the power of nutritional antioxidants against adrenal hormone imbalance-associated oxidative stress

Oxidative stress, resulting from dysregulation in the secretion of adrenal hormones, represents a major concern in human health. The present review comprehensively examines various categories of endocrine dysregulation within the adrenal glands, encompassing glucocorticoids, mineralocorticoids, and androgens. Additionally, a comprehensive account of adrenal hormone disorders, including adrenal insufficiency, Cushing's syndrome, and adrenal tumors, is presented, with particular emphasis on their intricate association with oxidative stress. The review also delves into an examination of various nutritional antioxidants, namely vitamin C, vitamin E, carotenoids, selenium, zinc, polyphenols, coenzyme Q10, and probiotics, and elucidates their role in mitigating the adverse effects of oxidative stress arising from imbalances in adrenal hormone levels. In conclusion, harnessing the power of nutritional antioxidants has the potential to help with oxidative stress caused by an imbalance in adrenal hormones. This could lead to new research and therapeutic interventions.

Pharmacological evidence for glutamatergic pathway involvement in the antidepressant-like effects of 2-phenyl-3-(phenylselanyl)benzofuran in male Swiss mice

Depression is a multifactorial and heterogeneous disease with several neurobiological mechanisms underlying its pathophysiology, including dysfunctional glutamatergic neurotransmission, which makes the exploration of the glutamate pathway an interesting strategy for developing novel rapid-acting antidepressant treatments. In the present study, we aimed to evaluate the possible glutamatergic pathway relation in the antidepressant-like action of 2-phenyl-3-(phenylselanyl)benzofuran (SeBZF1) in Swiss mice employing the tail suspension test (TST). Male Swiss mice received drugs targeting glutamate receptors before acute SeBZF1 administration at effective (50 mg/kg) or subeffective (1 mg/kg) doses by intragastric route (ig). TST and the open-field test (OFT) were employed in all behavioral experiments. The pretreatment of mice with N-methyl-D-aspartate (NMDA) (0.1 pmol/site, intracerebroventricular, icv, a selective agonist of the NMDA receptors), D-serine (30 µg/site, icv, a co-agonist at the NMDA receptor), arcaine (1 mg/kg, intraperitoneal, ip, an antagonist of the polyamine-binding site at the NMDA receptor), and 6,7-dinitroquinoxaline-2,3-dione (DNQX) (2,5 µg/site, icv, an antagonist of the AMPA/kainate type of glutamate receptors) inhibited the antidepressant-like effects of SeBZF1 (50 mg/kg, ig) in the TST. Coadministration of a subeffective dose of SeBZF1 with low doses of MK-801 (0.001 mg/kg, ip, a non-competitive NMDA receptor antagonist) or ketamine (0.1 mg/kg, ip, a non-selective antagonist of the NMDA receptors) produced significant antidepressant-like effects (synergistic action). These findings suggest the involvement of the glutamatergic system, probably through modulation of ionotropic glutamate receptors, in the antidepressant-like action of SeBZF1 in mice and contribute to a better understanding of the mechanisms underlying its pharmacological effects.

Investigation of the Effect of Oral Selenium on the Reduction of Clinical Symptoms and Joint Pain in Patients With Rheumatoid Arthritis in the Iranian Population

Rheumatoid arthritis (RA) is a common inflammatory joint disease. Because inflammation and nitrosative stress play an important role in the pathogenesis of RA, drugs that have antioxidant and anti-inflammatory effects can be effective as adjuvant treatment in these patients. Selenium is a compound that has been shown in recent studies to have anti-inflammatory and antioxidant effects. Therefore, the aim of this study was to investigate the effect of oral selenium on the reduction of clinical symptoms and joint pain in patients with RA. Fifty-one patients with moderate and severe RA were randomly divided into selenium and placebo groups. The first group of patients received selenium at a dose of 200 μg twice a day for 12 weeks along with standard RA interventions and treatments, and the second group received standard treatments of RA along with a placebo. Clinical symptoms were evaluated with standard indicators to evaluate disease activity before and after the intervention in the 12th week. Examination of clinical symptoms at the end of the study showed that in the selenium group and after 12 weeks, a reduction in clinical symptoms and joint pain were observed, which was statistically significant compared with before the study began. Meanwhile, no significant changes were observed in the patients of the placebo group in terms of reducing symptoms and joint pains. A dose of 200 μg of oral selenium twice a day for 12 weeks can significantly reduce clinical symptoms and joint pain in patients with RA.

Recent Advances in the Synthesis and Antioxidant Activity of Low Molecular Mass Organoselenium Molecules

Selenium is an essential trace element in living organisms, and is present in selenoenzymes with antioxidant activity, like glutathione peroxidase (GPx) and thioredoxin reductase (TrxR). The search for small selenium-containing molecules that mimic selenoenzymes is a strong field of research in organic and medicinal chemistry. In this review, we review the synthesis and bioassays of new and known organoselenium compounds with antioxidant activity, covering the last five years. A detailed description of the synthetic procedures and the performed in vitro and in vivo bioassays is presented, highlighting the most active compounds in each series.

Tumor Microbial Communities and Thyroid Cancer Development-The Protective Role of Antioxidant Nutrients: Application Strategies and Future Directions

Thyroid cancer (TC), the most frequent malignancy of the endocrine system, has recorded an increasing incidence in the last decades. The etiology of TC remains at least partly unknown and, among modifiable risk factors, the gut microbiota and dietary nutrients (vitamins, essential microelements, polyphenols, probiotics) have been recognized to not only influence thyroid function, but exert critical effects on TC development and progression. Recent discoveries on the existence of tumor microbiota also in the TC microenvironment provide further evidence for the essential role of tumor microorganisms in TC etiology and severity, as well as acting as prognostic markers and as a potential target of adjuvant care in the treatment of TC patients. Therefore, in this review, we summarize current knowledge on the relationship of the tumor microbiome with the clinical tumor characteristics and TC progression, also illustrating the molecular mechanisms underlying this association, and how antioxidant nutrients may be used as a novel strategy to both control gut health and reduce the risk for TC. Furthermore, we discuss how new technologies might be exploited for the development of new foods with high nutritional values, antioxidant capability, and even attractiveness to the individual in terms of sensory and emotional features.

Pomegranate Peel Extract Stabilized Selenium Nanoparticles Synthesis: Promising Antimicrobial Potential, Antioxidant Activity, Biocompatibility, and Hemocompatibility

The green synthesis of selenium nanoparticles (Se NPs) had been synthesized by pomegranate peel extract (PPE). The antimicrobial, antioxidant, and anticancer activities of the synthesized Se NPs, as well as their hemocompatibility, were investigated. Se NPs were characterized by UV-Vis., SEM, XRD, HR-TEM, DLS, EDX, FTIR, and mapping techniques. HR-TEM image represented the spheroidal forms with moderately monodispersed NPs with a mean diameter 14.5 nm. The SEM image of Se NPs, incorporated with PPE, exhibits uniform NP surfaces, and the appearance was clear. The antimicrobial results confirmed the potential of Se NPs to hinder the growth of some tested pathogenic microbes. Results revealed that Se NPs exhibited promising antibacterial activity against Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, Staphylococcus aureus, and Streptococcus mutans where inhibition zones were 29, 16, 41, 22, and 54 mm, respectively. Likewise, it exhibited antifungal activity where the values of inhibition zones were 41, 40, 38, and 36 mm against Candida albicans, Cryptococcus neoformans, Aspergillus fumigatus, and A. niger, respectively. The antioxidant activities of Se NPs at concentrations 250-4000 µg/mL were greater than 90% in all cases. Se NP concentrations of 500 µg/mL or less are safe in usage according to hemocompatibility study. Se NPs had an IC50 of 113.73 µg/mL in a cytotoxicity experiment. Results revealed that Se NPs have promising anticancer activities against MCF7 and Mg63 cancerous cell line, where IC50 was 69.8 and 47.9 μg/mL, respectively. In conclusion, Se NPs were successfully biosynthesized using PPE for the first time; these Se NPs had promising antimicrobial, antioxidant, and anticancer activities.

Biofortification revisited: Addressing the role of beneficial soil microbes for enhancing trace elements concentration in staple crops

Trace element deficiency is a pervasive issue contributing to malnutrition on a global scale. The primary cause of this hidden hunger is related to low dietary intake of essential trace elements, which is highly prevalent in numerous regions across the world. To address deficiency diseases in humans, fortification of staple crops with vital trace elements has emerged as a viable solution. Current methods for fortifying crops encompass chemical amendments, genetic breeding, and transgenic approaches, yet these approaches possess certain limitations, constraining their agricultural application. In contrast, fortifying staple crops through the utilization of soil-beneficial microbes has emerged as a promising and economically feasible approach to enhance trace element content in crops. A specific subset of these beneficial soil microbes, referred to as plant growth-promoting microbes, have demonstrated their ability to influence the interactions between plants, soil, and minerals. These microbes facilitate the transport of essential soil minerals, such as zinc, iron, and selenium, into plants, offering the potential for the development of tailored bioinoculants that can enhance the nutritional quality of cereals, pulses, and vegetable crops. Nevertheless, further research efforts are necessary to comprehensively understand the molecular mechanisms underlying the uptake, transport, and augmentation of trace element concentrations in staple crops. By delving deeper into these mechanisms, customized bioinoculants of soil-beneficial microbes can be developed to serve as highly effective strategies in combating trace element deficiency and promoting global nutritional well-being.

Characterization of green synthesized selenium nanoparticles (SeNPs) in two different indigenous halophilic bacteria

BACKGROUND

In the biological method, using nonpathogenic and extremophile bacteria systems are not only safe and highly efficient but also a trump card for synthesizing nanoparticles. Halomonas elongata QW6 IBRC-M 10,214 (He10214) and Salinicoccus iranensis IBRC-M 10,198 (Si10198), indigenous halophilic bacteria, can be used for synthesizing selenium nanoparticles (SeNPs).

METHODS

SeNP biosynthesis was optimized in two halophilic bacteria and characterized by UV-Vis, Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), X-ray powder diffraction (XRD), zeta potential, and energy dispersive X-ray (EDX).

RESULTS

Optimized conditions for synthesizing SeNPs was at 300 °C at 150 rpm for 72 h and 6 mM or 8 mM concentration of Na2SeO3. UV-Vis indicated a sharp absorption peak at 294 nm. Spherical-shaped nanoparticles by a diameter of 30-100 nm were observed in FESEM and TEM microscopy images. The produced SeNPs were identified by a peak in FTIR spectra. In XRD analysis, the highest peak diffraction had a relationship with SeNPs. The zeta potential analysis showed SeNP production, and elemental selenium was confirmed by EDX.

CONCLUSIONS

Halophilic bacteria, owing to easy manipulation to create optimization conditions and high resistance, could serve as appropriate organisms for the bioproduction of nanoparticles. The biological method, due to effectiveness, flexibility, biocompatibility, and low cost, could be used for the synthesis of reproducible and stable nanoparticles.

Organoselenium Compounds: Chemistry and Applications in Organic Synthesis

Selenium, originally described as a toxin, turns out to be a crucial trace element for life that appears as selenocysteine and its dimer, selenocystine. From the point of view of drug developments, selenium-containing drugs are isosteres of sulfur and oxygen with the advantage that the presence of the selenium atom confers antioxidant properties and high lipophilicity, which would increase cell membrane permeation leading to better oral bioavailability. In this article, we have focused on the relevant features of the selenium atom, above all, the corresponding synthetic approaches to access a variety of organoselenium molecules along with the proposed reaction mechanisms. The preparation and biological properties of selenosugars, including selenoglycosides, selenonucleosides, selenopeptides, and other selenium-containing compounds will be treated. We have attempted to condense the most important aspects and interesting examples of the chemistry of selenium into a single article.

Selenium supplementation effect on glycemic control: A GRADE-assessed systematic review and dose-response meta-analysis of randomized controlled trials

Results from different studies on the effects of selenium supplementation on glycemic control are still debated. To fill this knowledge gap, we investigated the overall effects of selenium supplementation on some glycemic parameters such as fasting blood sugar (FBS), hemoglobinA1c (HbA1c), fasting insulin, quantitative insulin sensitivity check index (QUICKI), and homeostatic model assessment of insulin resistance (HOMA-IR). A comprehensive literature search was conducted from inception to April 2023 on Scopus, Web of Science, PubMed, Google Scholar, and Cochrane databases. All randomized controlled trials (RCTs) which reported an effect of selenium supplementation on glycemic parameters were included. A random-effects model was used to estimate the weighted mean difference (WMD) and 95% CI for each outcome. Between-studies heterogeneity was assessed by the I2 and Cochran's Q test. 20 trials were included in the meta-analysis. Pooled analysis showed that selenium intake significantly reduced fasting insulin (WMD: -3.02 µIu/mL, 95% CI; -5.13, -0.90, P = 0.005) and increased QUICKI levels (WMD: 0.01, 95% CI: 0.01, 0.02, P = 0.005). However, selenium supplementation did not change FBS (WMD: -1.32 mg/dL, 95% CI; -4.02, 1.37, P = 0.332), HbA1c (WMD = 0.05%, 95% CI: -0.19, 0.28, p = 0.701), and HOMA-IR (WMD: -0.82, 95% CI; -2.14, 0.50, P = 0.223). Moreover, we found that there is a non-linear association between selenium supplementation dosage and FBS (P-nonlinearity = 0.008). In conclusion, our study findings indicate some benefits of selenium on fasting insulin, and QUICKI compared with placebo, but elicits no effect on HbA1c, HOMA-IR, and FBS. Further well-designed RCTs with larger samples are necessary to ascertain the effects of selenium supplementation on glycemic control.

Advances in selenium supplementation: From selenium-enriched yeast to potential selenium-enriched insects, and selenium nanoparticles

Selenium (Se) is an essential micronutrient that plays an important role in animal and human development and physiological homoeostasis. This review surveys the role of Se in the environment, plants and animal bodies, and discusses data on Se biofortification with different sources of supplementation, from inorganic to organic forms, with special focus on Se-enriched yeast (Se-yeast). Although Se-yeast remains one of the main sources of organic Se, other emerging and innovative sources are reviewed, such as Se-enriched insects and Se-nanoparticles and their potential use in animal nutrition. Se-enriched insects are discussed as an option for supplying Se in organic form to livestock diets. Se-nanoparticles are also discussed, as they represent a more biocompatible and less toxic source of inorganic Se for animal organisms, compared to selenite and selenate. We also provide up to date information on the legal framework in the EU, USA, and Canada of Se that is contained in feed additives. From the scientific evidence available in the literature, it can be concluded that among the inorganic forms, sodium selenite is still one of the main options, whereas Se-yeast remains the primary organic form. However, other potential sources such as Se-enriched insects and Se-nanoparticles are being investigated as they could potentially combine a high bioavailability and reduced Se emissions in the environment.

The effect of selenium supplementation on sonographic findings of salivary glands in papillary thyroid cancer (PTC) patients treated with radioactive iodine: study protocol for a double-blind, randomized, placebo-controlled clinical trial

BACKGROUND

Thyroid cancer is a very damaging disease. The most common treatment for this disease includes thyroidectomy and then using radioactive iodine (RAI). RAI has many side effects, including a decrease in salivary secretions, followed by dry mouth and oral and dental injuries, as well as increased inflammation and oxidative stress. Selenium can be effective in these patients by improving inflammation and oxidative stress and by modulating salivary secretions. So far, only one clinical trial has investigated the effect of selenium on thyroid cancer patients treated with radioiodine therapy (RIT) conducted on 16 patients; considering the importance of this issue, to show the potential efficacy of selenium in these patients, more high-quality trials with a larger sample size are warranted.

METHODS

This is a parallel double-blind randomized controlled clinical trial that includes 60 patients aged 20 to 65 years with papillary thyroid cancer (PTC) treated with RAI and will be conducted in Seyyed al-Shohada Center, an academic center for referral of patients to receive iodine, Isfahan, Iran. Thirty patients will receive 200 µg of selenium for 10 days (3 days before to 6 days after RAI treatment) and another 30 patients will receive a placebo for the same period. Sonographic findings of major salivary glands, salivary secretions, and sense of taste will be evaluated before and 6 months after 10-day supplementation.

DISCUSSION

Due to its anti-inflammatory and antioxidant effects, as well as improving salivary secretions, selenium may improve the symptoms of thyroid cancer treated with radioactive iodine. In past studies, selenium consumption has not reduced the therapeutic effects of radiation therapy, and at a dose of 300 to 500 μg/day, it has not had any significant side effects in many types of cancer under radiation therapy.

TRIAL REGISTRATION

Iranian Registry of Clinical Trials IRCT20201129049534N6 . Registered on 16 September 2021.

Catechins and Selenium Species-How They React with Each Other

The combination of selenium and tea infusion, both with antioxidant properties, has potentially complementary mechanisms of action. Se-enriched tea has been considered as a possible Se supplement and a functional beverage to reduce the health risk of Se deficiency. This work investigated the interactions between plant catechins present in tea infusions and selenium species based on changes in the concentration of both reagents, their stability in aqueous solutions, and the possibilities of selenonanoparticles (SeNPs) formation. Selenium species exhibited instability both alone in their standard solutions and in the presence of studied catechins; selenocystine appeared as the most unstable. The recorded UV-Vis absorption spectra indicated the formation of SeNPs in the binary mixtures of catechins and selenite. SeNPs have also formed with diameters smaller than 100 nm when selenite and selenomethionine were added to tea infusions. This is an advantage from the point of view of potential medical applications.

Neodymium affects the generation of reactive oxygen species via GSK-3β/Nrf2 signaling in the gill of zebrafish

Rare earth element neodymium (Nd) is widely used in industry and agriculture, which may result in the pollution of aquatic environment. In this study, we exposed zebrafish with 10, 50, and 100 μg/L Nd for four weeks. The results showed that Nd could be accumulated in fish gill and Nd accumulation affected the equilibrium of nutrient elements. Nd decreased the antioxidant enzymes' activity and gene expression level, but enhanced the generation of reactive oxygen species (ROS). Moreover, various concentration of Nd treatments inhibited Nrf2 signaling in gill. To examine the critical role of GSK-3β/Nrf2 signaling on ROS generation under Nd stress, we further interfered gsk-3β gene in zebrafish under 100 μg/L Nd exposure. The result showed that gsk-3β gene interference induced Nrf2 signaling as well as the expression and activity of antioxidant enzymes in fish gill. In all, Nd could be accumulated in fish gill, and the signaling of GSK-3β/Nrf2 was involved in regulating ROS generation under Nd treatments.