Effects of selenium supplementation on expression of SEPP1 in mRNA and protein levels in subjects with and without metabolic syndrome suffering from coronary artery disease: Selenegene study a double-blind randomized controlled trial

Selenoprotein-P1 (SEPP1) Expression in Human Proximal Tubule Cells after Ischemia-Reperfusion Injury: An In Vitro Model

Background and Objectives: Selenium deficiency represents a risk factor for the occurrence of severe diseases, such as acute kidney injury (AKI). Recently, selenoprotein-p1 (SEPP1), a selenium transporter, mainly released by the liver, has emerged as a promising plasmatic biomarker of AKI as a consequence of cardio-surgery operations. The aim of the present study was to investigate, on an in vitro model of hypoxia induced in renal tubular cells, HK-2, the effects of sodium selenite (Na2SeO3) and to evaluate the expression of SEPP1 as a marker of injury. Materials and Methods: HK-2 cells were pre-incubated with 100 nM Na2SeO3 for 24 h, and then, treated for 24 h with CoCl2 (500 µM), a chemical hypoxia inducer. The results were derived from an ROS assay, MTT, and Western blot analysis. Results: The pre-treatment determined an increase in cells' viability and a reduction in reactive oxygen species (ROS), as shown by MTT and the ROS assay. Moreover, by Western blot an increase in SEPP1 expression was observed after hypoxic injury as after adding sodium selenite. Conclusions: Our preliminary results shed light on the possible role of selenium supplementation as a means to prevent oxidative damage and to increase SEPP1 after acute kidney injury. In our in vitro model, SEPP1 emerges as a promising biomarker of kidney injury, although further studies in vivo are necessary to validate our findings.

Selenoprotein P in a Rodent Model of Exercise; Theorizing Its Interaction with Brain Reward Dysregulation, Addictive Behavior, and Aging

Exercise promotes health and wellness, including its operation as a protective factor against a variety of psychological, neurological, and chronic diseases. Selenium and its biomarker, selenoprotein P (SEPP1), have been implicated in health, including cancer prevention, neurological function, and dopamine signaling. SEPP1 blood serum levels were compared with a one-way ANOVA between sedentary (SED), moderately exercised (MOD) [10 m/min starting at 10 min, increasing to 60 min], and high-intensity interval training (HIIT) exercised rats [30 min in intervals of 2-min followed by a 1-min break, speed progressively increased from 10 to 21 m/min]. HIIT rats showed significantly higher serum SEPP1 concentrations compared to MOD and SED. More specifically, HIIT exercise showed an 84% increase in SEPP1 levels compared to sedentary controls. MOD rats had greater serum SEPP1 concentrations compared to SED, a 33% increase. The results indicated that increased exercise intensity increases SEPP1 levels. Exercise-induced increases in SEPP1 may indicate an adaptive response to the heightened oxidative stress. Previous studies found a significant increase in dopamine D2 receptor (D2R) binding in these same rats, suggesting a potential association between SEPP1 and dopamine signaling during exercise. Modulating antioxidants like SEPP1 through personalized therapies, including exercise, has broad implications for health, disease, and addiction.

The Role of Selenium in Atherosclerosis Development, Progression, Prevention and Treatment

Selenium is an essential trace element that is essential for various metabolic processes, protection from oxidative stress and proper functioning of the cardiovascular system. Se deficiency has long been associated with multiple cardiovascular diseases, including endemic Keshan's disease, common heart failure, coronary heart disease, myocardial infarction and atherosclerosis. Through selenoenzymes and selenoproteins, Se is involved in numerous crucial processes, such as redox homeostasis regulation, oxidative stress, calcium flux and thyroid hormone metabolism; an unbalanced Se supply may disrupt these processes. In this review, we focus on the importance of Se in cardiovascular health and provide updated information on the role of Se in specific processes involved in the development and pathogenesis of atherosclerosis (oxidative stress, inflammation, endothelial dysfunction, vascular calcification and vascular cell apoptosis). We also discuss recent randomised trials investigating Se supplementation as a potential therapeutic and preventive agent for atherosclerosis treatment.

Selenium and Selenoproteins in Health

Selenium is a trace mineral that is essential for health. After being obtained from food and taken up by the liver, selenium performs various physiological functions in the body in the form of selenoproteins, which are best known for their redox activity and anti-inflammatory properties. Selenium stimulates the activation of immune cells and is important for the activation of the immune system. Selenium is also essential for the maintenance of brain function. Selenium supplements can regulate lipid metabolism, cell apoptosis, and autophagy, and have displayed significant alleviating effects in most cardiovascular diseases. However, the effect of increased selenium intake on the risk of cancer remains unclear. Elevated serum selenium levels are associated with an increased risk of type 2 diabetes, and this relationship is complex and nonlinear. Selenium supplementation seems beneficial to some extent; however, existing studies have not fully explained the influence of selenium on various diseases. Further, more intervention trials are needed to verify the beneficial or harmful effects of selenium supplementation in various diseases.

Selenium, Selenoproteins and 10-year Cardiovascular Risk: Results from the ATTICA Study

BACKGROUND

Selenium (Se) is an essential trace element that is involved in several pathophysiological functions. The relationship of Se with cardiovascular disease remains inconclusive, especially regarding the role of different selenospecies.

OBJECTIVE

The present study assessed the levels of Se distribution in plasma selenoproteins, namely glutathione peroxidase 3 (GPx3), selenoprotein P (SelP) and selenoalbumin (SeAlb) and total Se in selenoproteins in relation to 10-year cardiovascular risk in the ATTICA prospective study.

METHODS

A sub-sample from the ATTICA Study's database, consisting of 278 subjects (114 women and 164 men) with data on Se and selenoproteins levels, was considered. SeGPx3, SelP, and SeAlb in human plasma were simultaneously determined by high-performance liquid chromatography (HPLC) coupled with inductively coupled plasma mass spectrometry (ICP-MS) at baseline. The duration of the follow-up was 8.74 ±2.36 years (mean± standard deviation) and cardiovascular outcomes were recorded. Cox proportional hazards models were applied with total Se or selenoprotein Se as independent variables adjusted for several covariates.

RESULTS

Total Se in selenoproteins was positively related to 10-year relative risk of cardiovascular disease (Hazard Ratios of 3rd vs 2nd tertile 10.02, 95% CI:1.15, 92.34). Subjects with high Se but low SeGPx3, as identified by discordant percentiles in the distribution of SeGPx3 and Se, had a higher cardiovascular risk.

CONCLUSION

The differentiated effects of circulating selenoproteins on cardiovascular disease risk in the present study, suggest the importance of redox regulation by specific selenoproteins.

The Role of Selenoprotein Tissue Homeostasis in MetS Programming: Energy Balance and Cardiometabolic Implications

Selenium (Se) is an essential trace element mainly known for its antioxidant, anti-inflammatory, and anti-apoptotic properties, as it is part of the catalytic center of 25 different selenoproteins. Some of them are related to insulin resistance (IR) and metabolic syndrome (MetS) generation, modulating reactive oxygen species (ROS), and the energetic sensor AMP-activated protein kinase (AMPK); they can also regulate the nuclear transcription factor kappa-B (NF-kB), leading to changes in inflammation production. Selenoproteins are also necessary for the correct synthesis of insulin and thyroid hormones. They are also involved in endocrine central regulation of appetite and energy homeostasis, affecting growth and development. MetS, a complex metabolic disorder, can appear during gestation and lactation in mothers, leading to energetic and metabolic changes in their offspring that, according to the metabolic programming theory, will produce cardiovascular and metabolic diseases later in life. However, there is a gap concerning Se tissue levels and selenoproteins’ implications in MetS generation, which is even greater during MetS programming. This narrative review also provides an overview of the existing evidence, based on experimental research from our laboratory, which strengthens the fact that maternal MetS leads to changes in Se tissue deposits and antioxidant selenoproteins’ expression in their offspring. These changes contribute to alterations in tissues’ oxidative damage, inflammation, energy balance, and tissue function, mainly in the heart. Se imbalance also could modulate appetite and endocrine energy balance, affecting pups’ growth and development. MetS pups present a profile similar to that of diabetes type 1, which also appeared when dams were exposed to low-Se dietary supply. Maternal Se supplementation should be taken into account if, during gestation and/or lactation periods, there are suspicions of endocrine energy imbalance in the offspring, such as MetS. It could be an interesting therapy to induce heart reprogramming. However, more studies are necessary.

Effects of Dietary Selenium Sources on Physiological Status of Laying Hens and Production of Selenium-Enriched Eggs

Developing new sources of organic selenium (Se) has potential benefits for animal production and human nutrition via animal-based foods enriched with Se. The objective of this study was to evaluate the effects of Se-enriched insect protein (SEIP) in comparison with other sources, such as sodium selenite (SS) and selenium-enriched yeast (SEY), on performance, egg quality, selenium concentration in eggs, serum biochemical indices, immune capacity, and intestinal morphology of laying hens. Four hundred and fifty 24-week-old Hy-Line Brown laying hens with 94.0 ± 1.5% laying rate were randomly allocated to five groups with six replicates of 15 hens each. The control diet was prepared without adding exogenous selenium (calculated basal Se content of 0.08 mg/kg). The normal group was fed basal diets supplemented with 0.3 mg/kg of Se provided by sodium selenite. Three treatment groups (SS, SEY, and SEIP, respectively) were fed basal diets supplemented with 2 mg/kg of Se provided by sodium selenite, Se-enriched yeast, and SEIP, respectively. The feeding trial lasted for 12 weeks. Results revealed that dietary supplementation of 2 mg/kg of Se increased egg weight, decreased feed conversion ratio, and enhanced the antioxidant capacity of eggs in laying hens relative to the control group, whereas no significant differences were observed among SS, SEY, and SEIP treatment groups for the same. The organic source of Se provided by SEY or SEIP showed higher bio efficiency, as indicated by higher selenium content in eggs of SEY and SEIP compared with SS, although higher content was observed in SEY compared with SEIP. Also, the organic Se source significantly improved antioxidant capacity and immune functions of laying hens than the inorganic Se source. Diets supplemented with SEIP and SS significantly improved jejunal morphology of the laying hens compared with SEY, whereas SEIP was more effective than SEY to improve the oviduct health of laying hens. The results of this work evidently points the additive effect and nontoxicity of SEIP. Thus, SEIP could be used as another organic source of Se in the diet of laying hens and production of selenium-enriched eggs for humans.

Effects of Selenium Conjugated to Insect Protein on Pharmacokinetics of Florfenicol and Enrofloxacin in Laying Hens

In the context of increasing awareness on the dietary supplementation of organic selenium in commercial poultry production and ensuring safe egg production, the present study investigated the effects of selenium on the pharmacokinetics of the therapeutic use of florfenicol and enrofloxacin from perspectives of laying performance, selenium deposition in eggs, and drug residue in plasma, organs, and eggs. A 2 × 3 factorial arrangement with two kinds of drugs (florfenicol vs. enrofloxacin, 200 mg/kg) and three levels of dietary organic selenium SCIP (selenium conjugated to insect protein) (0, 2, and 5 mg/kg) was designed together with a blank control group. Healthy Hy-Line Brown laying hens (n = 252, 40-week-old and 90.0 ± 1.7% of egg production rate) were randomly allocated into one of seven treatments with six replicates and six hens per replicate. The experiment lasted for 42 days and consisted of three periods (adjusted stage, depositional stage, and eliminating stage) of 14 days each. These stages entail feeding of the laying hens with basal diets, addition of drugs and selenium synchronously into the diets, drug withdrawal from diet, and supply of selenium uninterruptedly in the diet. Egg production and feed intake were recorded on daily and weekly bases, respectively. The selenium content in egg yolk, egg white, and whole eggs and the drug residues in eggs, plasma, liver, kidney, and breast muscle were determined on days 2, 3, 5, 6, 7, 9, 11, and 14 of the depositional and eliminating stages. There was no significant difference (p > 0.05) in egg production among the dietary treatments, but feed intake decreased significantly (p < 0.05) in the drug treatment group compared to other groups. Dietary organic selenium decreased the residue of drugs in tissues and eggs, while the metabolism and deposition of selenium in laying hens were suppressed due to drug effects. The results of the present study are of significance to enrich the knowledge of the pharmacokinetics of florfenicol and enrofloxacin in laying hens and ensure the quality of poultry products.

Application of Selenium Conjugated to Animal Protein in Laying Hens' Diet for the Production of Selenium-Enriched Eggs

The current experiment was conducted to investigate the application effects of selenium conjugated to insect protein (SCIP) in the production of selenium-enriched eggs. A total of 450 laying hens were randomly assigned to five dietary groups, each group consisting of six replicates. Hens in the control group received a diet without selenium supplementation, whereas hens in the other four groups received diets supplemented with either 1, 2, 5, or 10 mg/kg of selenium from SCIP. The productive performance, egg quality, antioxidant and immune capacity, biochemical indices, intestinal morphology, and oviduct health of laying hens were evaluated. The results showed that the supplementation of organic selenium provided by SCIP in the diets of laying hens enhanced performance and egg quality without any toxicity effect, even at the 10 mg/kg inclusion level. A level of 2 mg/kg of selenium provided by SCIP in diets tentatively improved the serum antioxidant and immune capacity, intestinal development, and oviduct health of laying hens in a conspicuous manner. Hence, the biosafety and positive effects of SCIP as a feed additive supplement in laying hens' diet have been demonstrated with the enhanced production of safe and selenium-enriched eggs.

Coix lacryma-jobi Seed Oil Reduces Fat Accumulation in Nonalcoholic Fatty Liver Disease by Inhibiting the Activation of the p-AMPK/SePP1/apoER2 Pathway

The lipid metabolism disorder is the key role of Nonalcoholic fatty liver disease (NAFLD). Selenoprotein P plays an important role in the pathological process of lipid accumulation. Coix lacryma-jboi seed oil (CLSO) is an active component extracted from Coix lacryma-jobi seed (CLS) which has been found to be effective of reducing blood fat and antioxidative. But the effect and mechanism of CLSO on NAFLD are not clear. The aim of this study was to explore the therapeutic effect and mechanism of CLSO in the treatment of NAFLD. Our result showed that CLSO decreased the liver/body weight ratio, lowered the total cholesterol (TC) and triacylglycerol (TG), and elevated the high density lipoprotein (HDL) in serum. CLSO reduced the lipid deposition in the liver of NAFLD rats. In addition, CLSO could bring down the abnormal expression of superoxide dismutase (SOD) and malondialdehyde (MDA). Moreover, CLSO significantly declined the liver apolipoprotein E (apoE), apolipoprotein E receptor (apoER) and selenoprotein P 1 (SePP1) expression. In vivo, CLSO decreased the lipid droplets and TG level, reduced the protein expression of SePP1, apoER, phosphor-adenosine 5'-monophosphate (AMP)-activated protein kinase (p-AMPK) in the cytoplasm of HepG2 cells induced by oleic acid and palmitic acid (OP). At the same time, lipid accumulation was observed in the Sepp1 high expression cells induced by endoplasmic reticulum (ER) activator tunicamycin (Tm). CLSO could identically reduce the protein expression of SePP1, apoER, p-AMPK in the cytoplasm of HepG2 cells induced by Tm. This result not only proved the CLSO had therapeutic effect on NAFLD, but also confirmed its mechanism associated with degrading the phosphorylation of adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) which led to the decrease of the expression SePP1/apoER2 in order to reduce lipid accumulation. The study suggests CLSO has great medicinal value in treating NAFLD besides its edibility.

Effects of selenium supplementation on paraoxonase-1 and myeloperoxidase activity in subjects with cardiovascular disease: the Selenegene study, a double-blind randomized controlled trial

Introduction

We previously highlighted the potential link between supplementation with selenium, as an antioxidant trace element, and changes in the levels of paraoxonase (POX1) and myeloperoxidase (MPO), as an antioxidant enzyme, in patients with documented cardiovascular disease (CVD). The aim of this study was to determine the effects of selenium supplementation on POX1 and MPO activity in patients with cardiovascular diseases (CVDs).

Material and methods

A total of 160 eligible patients were enrolled in the study. After performing some laboratory tests, including the measurement of blood selenium, triglyceride, cholesterol, and low- and high-density lipoprotein levels, the patients received 200 mg tablets of either selenium yeast or placebo. The medicines were taken orally, once daily after a meal for 60 days. Four weeks after the initial visit, the patients were invited for a follow-up visit, and interviews and non-laboratory evaluations, similar to those performed at baseline, were repeated. Compliance of patients for using selenium and placebo was measured by telephone. Medication compliance rates were monitored by telephone. The final assessments were conducted eight weeks after the beginning of the study.

Results

There was no significant difference in cholesterol levels between intervention and control groups (p = 0.87). No significant changes in selenium levels were observed in either the selenium or the placebo group after the intervention (p = 0.44 and p = 0.48, respectively). The two groups had a significant difference in terms of POX1 level (p = 0.039). No such difference was present in the case of MPO levels. Moreover, comparison of the values before and after the intervention showed no significant differences in the mean levels of any of the measured parameters.

Conclusions

According to the obtained results, the increased POX1 levels after selenium supplementation could be attributed to the positive effect of selenium on inhibiting lipid peroxidation as part of the complicated pathophysiology of CVD.