Efeitos antioxidantes do selênio e seu elo com a inflamação e síndrome metabólica

Associations between Components of Metabolic Syndrome and Demographic, Nutritional, and Lifestyle Factors

Objectives

To evaluate the associations between individuals with and without changes in components of metabolic syndrome (MetS) and demographic, nutritional, and lifestyle factors.

Methods

A cross-sectional study was conducted with 224 individuals followed-up at a public hospital in Northeast Brazil. We used National Cholesterol Education Program-Adult Treatment Panel III (NCEP) criteria to diagnose MetS. We assessed components of MetS as dependent variables, while sex, age, food consumption, smoking, alcohol intake, physical activity, anthropometric parameters, and sleep hours were independent variables.

Results

Comparing individuals with and without changes in components of MetS, the logistic regression models revealed that female sex was predictive of increased waist circumference and low HDL-c levels while advanced age was predictive of increased blood pressure and blood glucose levels. BMI emerged as a predictor for waist circumference and a protective factor for triglyceride levels. In addition, potassium intake, physical activity, and sleep duration were protective against decreased HDL-c, elevated triglyceride, and elevated blood pressure levels, respectively.

Conclusion

This study demonstrated that sex, age, BMI, dietary potassium intake, physical activity, and hours of sleep are factors to be targeted in public health actions for prevention and treatment of MetS.

Selenium alleviates biological toxicity of thiamethoxam (TMX): Bioaccumulation of TMX, organ damage, and antioxidant response of red swamp crayfish (Procambarus clarkii)

Pesticides are important for agricultural development; however, animals involved in rice-fish farming absorb the pesticides used during the farming process. Thiamethoxam (TMX) is extensively used in agriculture and is gradually occupying the market for traditional pesticides. Therefore, this study aimed to investigate whether selenomethionine (SeMet) could affect the survival rate, bioaccumulation of TMX, serum biochemical parameters, lipid peroxidation, antioxidants in the hepatopancreas, and expression of stress genes after exposure of red swamp crayfish to 10 ppt TMX for 7 days. The results showed that the survival rate significantly increased and the bioaccumulation of TMX significantly decreased with SeMet administration (P < 0.05). Furthermore, severe histological damage to the hepatopancreas of red crayfish was observed after exposure to TMX; however, this damage was alleviated after SeMet administration. SeMet also significantly reduced the TMX-induced changes in serum biochemical parameters, malondialdehyde content, and antioxidant enzyme activity in crayfish hepatopancreas (P < 0.05). Notably, analysis of the expression of 10 stress response genes showed that 0.5 mg/kg SeMet might decrease cell damage in the hepatopancreas. Consequently, our findings suggest that higher levels of TMX in crayfish may cause hepatopancreatic cell toxicity, which can be harmful to human health; however, SeMet could mitigate these effects, providing an understanding of pesticide compounds and food safety.

The health risk for consumers under heavy metal scenarios: Reduce bioaccumulation of Cd in estuary mud crab (Scylla paramamosain) through the antagonism of Se

Heavy metal pollution has gained increasing attention over past years, and notably, cadmium (Cd) is a non-essential heavy metal that can be toxic to human and wildlife. Furthermore, selenium (Se) is a component of the selenoproteins and influences the toxicity of Cd in different organisms, and protect organisms as a kind of heavy metal antagonist. This study exposed mud crab to 5.0 mg/L Cd for 28 days, and investigated whether different concentrations (0.1, 0.2, 0.3 mg/kg) of selenite (Na₂SeO₃) or selenomethionine (SeMet) affect the bioaccumulation of Cd, serum biochemical index, antioxidant and stress-response genes of S. paramamosain. The results showed that the Cd concentration in Cd group was significantly higher than the organic or inorganic Se group. Serum biochemical index demonstrated that Se might relieve the damage or dysfunction of hepatopancreas caused by both Cd accumulation and toxicity. Furthermore, Se improved CAT, GPx T-AOC and SOD activity, and decreased MDA concentrations and the lipid peroxidation levels, antagonistic to Cd. Then, this study analyzed the expression of 26 stress-related genes, the results indicated that the inorganic and organic Se might reduce the damage of cell and the toxicity of heavy metals in the hepatopancreas after Cd exposure. Therefore, this study indicated that Se might alleviate Cd toxicity via the different antioxidative mechanisms, and increased the understanding of environmental toxins on estuary crustaceans.

Beneficial effects of Se/Zn co-supplementation on body weight and adipose tissue inflammation in high-fat diet-induced obese rats

This research investigated the effect of co-supplementation of selenium with zinc on weight control and the inflammatory and oxidative status in relation to obesity. Male Wistar rats (N = 32) were randomly divided into four groups after induction of obesity model: 1) "Zn" was supplemented with zinc sulfate (15 mg/kg BW), 2) "Se" supplemented with selenium as sodium selenate (0.5 mg/kg BW), 3) "Zn + Se" which received Zn (15 mg/kg BW) + Se (0.5 mg/kg BW), and 4) "HFD" as the control group. The intervention was done for eight weeks. At the end of treatment, serum and tissue level of Zn, Se, SOD, GSH-Px, MDA, leptin, TNF-α, and IL-6 was evaluated. Weight and food intake were significantly reduced in the Se group(p < .001), while in the Zn group, weight gain due to obesity was prevented compared to the control group (p = .48). There was a significant and stronger increase in SOD, GSH-Px levels and a remarkable decrease in MDA, leptin, TNF-α, and IL-6 in the group receiving the combination of two supplements than either alone(p < .001). Leptin had a positive correlation with inflammatory factors and lipid peroxidation marker and showed an inverse relationship with Zn and Se levels and anti-oxidative enzymes(p < .05). The analysis showed the mediating role of leptin in the effects of zinc. Co-supplementation of selenium and zinc may have a synergistic effect in reduction of oxidative and inflammatory markers. Regarding the effect of zinc on inflammatory factors and lipid peroxidation, leptin can play a mediating role.

Resistance Training Associated with Dietetic Advice Reduces Inflammatory Biomarkers in the Elderly

Aging is a biological process during which chronic low-grade inflammation is present due to changes in the immune system of the elderly. The main objective of this study is to evaluate the effects of resistance training associated with dietary advice on chronic inflammation in the elderly. We conducted a prospective intervention study in which we evaluated anthropometric parameters and inflammatory biomarkers (CRP, IL-8, CCL-2, and leptin) in 40 elderly people before and after long-term progressive resistance training (19 weeks) associated with dietary advice. The participants trained twice a week on nonconsecutive days, and the training lasted one hour with an intensity of 60-85% of 1-MR. Dietary advice was explained in person and individually focusing on foods rich in compounds with anti-inflammatory and antioxidant properties. Participants were instructed at the beginning of the training program, and dietary advice was reinforced verbally weekly. There was an improvement in body composition evidenced by a reduction in waist circumference and body fat percentage and by the increase in arm circumference, calf circumference, and corrected arm muscle area. In addition, there was a reduction in the inflammatory biomarkers CCL-2 (p = 0.01) and leptin (p < 0.01). Resistance training associated with dietary guidance can contribute to a healthy aging due to observed improvements in body composition and in the inflammatory profile of the elderly.

Relationship between selenium status and biomarkers of oxidative stress in Crohn's disease

OBJECTIVE

Crohn disease (CD) is characterized by chronic intestinal inflammation and various factors involved in its pathogenesis including oxidative stress. The oxidative stress in CD may compromise antioxidant nutrients, such as selenium. The aim of this study was to assess the status of selenium and its relationship with markers of oxidative stress in patients with CD in comparison to controls.

METHODS

The study included 47 patients with CD (20 with active disease and 27 in remission) and 25 healthy individuals. Blood samples were collected for the analysis of plasma and erythrocyte selenium concentrations using inductively coupled plasma optical emission spectrometry (ICP-OES). Selenoprotein P (SepP) was evaluated by sandwich enzyme-linked immunosorbent assay, erythrocyte glutathione peroxidase (GPx1) activity was assessed by using an automatic biochemistry analyzer, and the concentration of thiobarbituric acid reactive substances (TBARS) was measured. Comparative analyses were performed using one-way analysis of variance and Tukey's post hoc test. For correlations, Pearson's coefficient test was used. The determinants for CD and lipid peroxidation were indicated by odds ratio.

RESULTS

Plasma and erythrocyte selenium levels and SepP concentrations were lower in the CD patient groups than in the healthy group. GPx1 activity and the concentration of TBARS were significantly higher in the CD groups. In the univariate analysis, plasma and erythrocyte selenium and TBARS were associated with CD.

CONCLUSION

Patients with CD have impaired selenium status, which is related to the increased oxidative stress observed in these patients.

Effects of oral selenium and magnesium co-supplementation on lipid metabolism, antioxidative status, histopathological lesions, and related gene expression in rats fed a high-fat diet

Background

Supplementation with Selenium (Se) has been shown to lower blood cholesterol and increase tissue concentrations of the antioxidant glutathione (GSH); however, the effects of Se supplementation, in combination with supplemental magnesium, on high fat-induced hyperlipidemia have not been studied. This study was designed to elucidate the effects of oral selenium and magnesium co-supplementation on antihyperlipidemic and hepatoprotective, antioxidative activities, and related gene expression in a hyperlipidemic rat model.

Methods

Forty male Sprague Dawley rats were divided into 4 groups: one group served as control group (CT), provided control diet; The other groups were made hyperlipidemic with high-fat diet; specifically, a high-fat diet group (HF); low-dose selenium (0.05 mg/kg·bw) + low-dose magnesium (5.83 mg/kg·bw) supplement high-fat diet group (HF + LSe + LMg) and high-dose selenium (0.10 mg/kg·bw) + high-dose magnesium (58.33 mg/kg·bw) supplement high-fat diet group (HF + HSe + HMg). The first 4 weeks of the experiment was a hyperlipidemia inducing period using high-fat diet and the following 8 weeks involved in selenium and magnesium co-supplementation. On day 0, 20, 40 and 60 of the intervention, lipid profile was measured. At the end of the 12-week experiments, final blood and liver samples were collected for the measurements of lipid profile, antioxidative indexes, pathological examination, and liver lipid metabolism related gene expression.

Results

The elevated levels of serum and liver total cholesterol (TC) and serum LDL-C induced by feeding high-fat diets were significantly reduced by low-dose Se and Mg co-supplementation. Both doses of selenium and magnesium co-supplementation notably decreased the blood and liver TG levels, liver function indexes ALT and AST and the ratio of TC/HDL-C and TG/HDL-C. In contrast, Se and Mg supplementation showed a substantial increase in Se-dependent glutathione peroxidase (GSH-Px) and SOD activities and an significant reduce of level of MDA of hyperlipidemic rats. Oil Red O staining showed that selenium and magnesium co-supplementation significantly reduced hepatic intracellular triacylglycerol accumulation. H&E staining also showed that selenium and magnesium co-supplementation can attenuate liver steatosis. Selenium and magnesium co-supplementation remarkably inhibited the mRNA expression level of hepatic lipogenesis genes liver X receptor alpha (LXRα),SREBP-1c and FASN (fatty acid synthase), regulated the mRNA expression levels of liver enzymes related to cholesterol metabolism, including the down regulation of 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) and the upregulation of cholesterol 7α-hydroxylase (CYP7A1) and lecithin cholesterol acyltransferase (LCAT) in the liver of hyperlipidemia rats.

Conclusions

Oral selenium and magnesium co-supplementation inhibited an increase of lipid and liver profile and liver function index induced by a high-fat diet, and enhanced the activity of the antioxidant enzymes. Selenium combined with magnesium is a promising therapeutic strategy with lipid-lowering and antioxidative effects that protects the liver against hyperlipidemia.

Selenium intake and metabolic syndrome: A systematic review

BACKGROUND & AIMS

Metabolic syndrome is a multi-causal disease. Its treatment includes lifestyle changes with a focus on weight loss. This systematic review assessed the association between Selenium intake and metabolic syndrome.

METHODS

Data were collected mainly from four databases: PubMed, CENTRAL (Cochrane), Scopus and Web of Knowledge. Keywords related to metabolic syndrome, selenium, as well as metabolic syndrome features were searched. This review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Statement. A systematic review protocol was registered at PROSPERO (n. 42016046321). Two reviewers independently screened 2957 abstracts. Six studies were included to perform data extraction with standardized spreadsheets. The risk of bias was assessed by using specific tools according to the design of the relevant studies. An assessment was carried out based on the appropriateness of the study reports accordingly to STROBE and the CONSORT-based checklist for each study design.

RESULTS

Three studies found no association between Selenium intake and metabolic syndrome; two of them found an inverse association; and one study found a direct association between Selenium intake and metabolic syndrome. One study also showed an inverse association between Selenium intake and the prevalence of high waist circumference, high diastolic blood pressure, and hyperglycaemia in women.

CONCLUSIONS

Overall, based on the argumentation and results of this study, it is possible to conclude that Selenium intake and metabolic syndrome are not clearly associated in adults and elderly.

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

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

Adsorption-desorption reactions of selenium (VI) in tropical cultivated and uncultivated soils under Cerrado biome

Soil management may affect selenium (Se) adsorption capacity. This study investigated adsorption and desorption of Se (VI) in selected Brazilian soils from the Cerrado biome, an area of ever increasing importance for agriculture expansion in Brazil. Soil samples were collected from cultivated and uncultivated soils, comprising clayed and sandy soils. Following chemical and mineralogical characterization, soil samples were subjected to Se adsorption and desorption tests. Adsorption was evaluated after a 72-h reaction with increasing concentrations of Se (0-2000 μg L^-1) added as Na₂SeO₄ in a NaCl electrolyte solution (pH 5.5; ionic strength 15 mmol L^-1). Desorption, as well as distribution coefficients (K_d) for selenate were also assessed. Soil management affected Se adsorption capacity, i.e., Se adsorbed amounts were higher for uncultivated soils, when compared to cultivated ones. Such results were also supported by data of K_d and maximum adsorption capacity of Se. This fact was attributed mainly to the presence of greater amounts of competing anions, especially phosphate, in cultivated soils, due to fertilizer application. Phosphate may compete with selenate for adsorption sites, decreasing Se retention. For the same group of soils (cultivated and uncultivated), Se adsorption was greater in the clayed soils compared to sandy ones. Our results support the idea that adding Se (VI) to the soil is a good strategy to increase Se levels in food crops (agronomic biofortification), especially when crops are grown in soils that have been cultivated over the time due to their low Se adsorption capacity (high Se availability).

Selenium and Zinc Status in Chronic Myofascial Pain: Serum and Erythrocyte Concentrations and Food Intake

INTRODUCTION

Nutritional disorders have been reported to be important causal factors that can intensify or cause a painful response in individuals with chronic musculoskeletal pain.

AIM

To assess the habitual intake of and the serum and erythrocyte levels of selenium and zinc in patients with chronic myofascial pain.

MATERIALS AND METHODS

A case-control study of 31 patients with chronic myofascial pain (group I) and 31 subjects without pain (group II). Dietary record in five days for assessing food intake were used. The serum and erythrocyte concentrations of selenium and zinc were analyzed using an atomic absorption spectrophotometry. Pain intensity was assessed using a visual analog scale.

RESULTS

The group of patients with chronic myofascial pain, compared with the control group, showed a lower erythrocyte concentration of selenium (79.46 ± 19.79 μg/L vs. 90.80 ± 23.12 μg/L; p = 0.041) and zinc (30.56 ± 7.74 μgZn/gHb vs. 38.48 ± 14.86 μgZn/gHb, respectively; p = 0.004). In this study, a compromised food intake of zinc was observed in the majority of the subjects in both groups. The selenium intake was considered to be safe in 80% of the subjects in both groups; however, the likelihood of inadequate intake of this mineral was twice as high in group I (49.5% vs. 24.4%, respectively). In the logistic regression analysis, the erythrocyte concentration of zinc was associated with the presence of pain. In each additional 1 mg of Zn2+ per gram of hemoglobin, a reduction of 12.5% was observed in the risk of the individual having chronic myofascial pain (B = -0.133; adjusted OR = 0.875, 95% CI = 0.803 to 0.954, Wald = 9.187, standard error = 0.044, p = 0.002). Physical inactivity and obesity were noted more commonly in group I compared with the control group.

CONCLUSION

In this study, patients with chronic myofascial pain showed lower intracellular stores of zinc and selenium and inadequate food intake of these nutrients.

Selenium Content in the Liver of Wistar Rats Fed Diets of Different Fatty Acid Quality

The purpose of this work was to measure the amounts of selected mineral elements (sodium, calcium, iron, selenium, magnesium, zinc, copper, and manganese) in the liver of Wistar rats and evaluate possible correlations between the levels of these minerals and the lipid metabolism in the studied animals. Three experimental groups each containing six Wistar rats were designed. Each group was fed a different diet. The control group was fed a diet prepared with fresh soybean oil and named control group--CG. The second group (named experimental group B--EGB) and third group (named experimental group C--EGC) were fed a diet containing soybean oil that had been used to fry different foods for four or ten cycles, respectively. The mineral elements in Wistar rat livers were measured by inductively coupled plasma optical emission spectrometry (ICP OES). Only the elements calcium and selenium differed significantly between the control and experimental groups. There was a significant reduction of 33% for Ca and 41% for Se in the EGB in comparison to the control group. The reduction in mineral concentration, especially Se, is the result of interactions with fatty acid metabolism. The animals in the EGC exhibited more intracytoplasmic accumulation of fat and more intense vasodilatation, in relation to the other groups. Collectively, evidence hereby collected suggests that impaired dietary lipid quality in otherwise balanced diets can reduce hepatic Se levels and potentially harm liver function.

Supplementation with selenium can influence nausea, fatigue, physical, renal, and liver function of children and adolescents with cancer

The drugs used in chemotherapy treatments have little specificity, attack tumor cells, and also injure proliferative tissues. Knowledge of the functions of micronutrients has greatly increased, especially of Selenium (Se) that presents immunomodulatory and antitumor functions. The present study evaluated the health-related quality of life of patients undergoing chemotherapy for the treatment of leukemias and lymphomas (LL) and solid tumors (ST) while receiving Selenium (Se) supplementation. This is a randomized, double-blind, crossover study that evaluated the quality of life (EORTC-QLQ-C30 questionnaire), renal and liver functions of patients supplemented with Se. There was no statistically significant alteration in LL patients. However, the fatigue and nausea scores after 30 days did decrease in this group as well as in the ST group. After 1 year supplementation with Selenium, a more noticeable decrease in the scores concerning fatigue and nausea could be observed in the ST group, when compared with the beginning of the study. The LL patients also presented a decrease in the fatigue scores and physical functions. The kidney function as well as liver function has improved after Selenium supplementation when compared with the placebo intake in LL and ST patients, more remarkably in the LL group. Supplementation with Selenium promotes the reduction of chemotherapy side effects in cancer patients, especially by improving the conditions of patients with fatigue, nausea, and impaired physical function. Renal and liver functions have also improved.

Discovery of potential targets of selenomethionine-mediated chemoprevention in colorectal carcinoma mouse model using proteomics analysis

Despite some controversy, selenomethionine (SeMet)-mediated protection against colorectal cancer (CRC) might be a very promising non-cytotoxic option. However, responsive molecular targets and underlying mechanisms of SeMet-mediated chemoprevention are still unclear. Our aim was to discover new targets of SeMet-mediated chemoprevention in CRC using proteomics analysis. We found dietary SeMet supplementation before carcinoma initiation effectively suppressed polyp incidence and dysplastic lesions without any adverse effects. To determine chemopreventive targets of SeMet, we employed two-dimensional gel electrophoresis-based proteomics analysis in CRC mouse model. Pretreatment with SeMet apparently modulated the expression of 30 proteins with functions in major processes like chronic inflammation, oxidative stress and apoptosis as discovered through pathway analysis with Pathway Studio software. We validated four proteins selected from pathway analysis including prohibitin, purine nucleoside phosphorylase, annexin 2 and c-reactive protein by immunohistochemistry. 8-Hydroxy-2'-deoxyguanosine (8-OHdG), a known oxidative stress marker, was decreased by SeMet treatment in CRC mice as seen by immunohistochemistry. Further network analysis was done among these new four validated proteins, 8-OHdG and colorectal cancer. These four proteins found by proteomics analysis might be considered as potential chemopreventive biomarkers of SeMet against colon cancer and can help develop and improve approaches in preventive, therapeutic and prognostic aspects.

Relationship of oxidized low density lipoprotein with lipid profile and oxidative stress markers in healthy young adults: a translational study

Background

Despite oxidized low density lipoprotein (ox-LDL) plays important roles in the pro-inflammatory and atherosclerotic processes, the relationships with metabolic and oxidative stress biomarkers have been only scarcely investigated in young adult people. Thus, the aim of this study was to assess plasma ox-LDL concentrations and the potential association with oxidative stress markers as well as with anthropometric and metabolic features in healthy young adults.

Methods

This study enrolled 160 healthy subjects (92 women/68 men; 23 ± 4 y; 22.0 ± 2.9 kg/m²). Anthropometry, body composition, blood pressure, lifestyle features, biochemical data, and oxidative stress markers were assessed with validated tools. Selenium, copper, and zinc nail concentrations were measured by atomic absorption spectrophotometry.

Results

Total cholesterol (TC), LDL-c and uric acid concentrations, TC-to-HDL-c ratio, and glutathione peroxidase (GPx) activity were positive predictors of ox-LDL concentrations, while nail selenium level (NSL) was a negative predictor, independently of gender, age, smoking status, physical activity. Those individuals included in the highest tertile of GPx activity (≥611 nmol/[mL/min]) and of NSL (≥430 ng/g of nail) had higher and lower ox-LDL concentrations, respectively, independently of the same covariates plus truncal fat or body mass index, and total cholesterol or LDL-c concentrations.

Conclusions

Ox-LDL concentrations were significantly associated with lipid biomarkers, GPx activity, uric acid concentration, and NSL, independently of different assayed covariates, in young healthy adults. These findings jointly suggest the early and complex relationship between lipid profile and redox status balance.