Hypercholesterolemia and LDL receptor mRNA expression: modulation by selenium supplementation

Metal mixture exposures and serum lipid levels in childhood: the Rhea mother-child cohort in Greece

BACKGROUND

Growing evidence suggests that cardiovascular disease develops over the lifetime, often beginning in childhood. Metal exposures have been associated with cardiovascular disease and important risk factors, including dyslipidemia, but prior studies have largely focused on adult populations and single metal exposures.

OBJECTIVE

To investigate the individual and joint impacts of multiple metal exposures on lipid levels during childhood.

METHODS

This cross-sectional study included 291 4-year-old children from the Rhea Cohort Study in Heraklion, Greece. Seven metals (manganese, cobalt, selenium, molybdenum, cadmium, mercury, and lead) were measured in whole blood using inductively coupled plasma mass spectrometry. Serum lipid levels included total cholesterol, triglycerides, high-density lipoprotein (HDL) cholesterol, and low-density lipoprotein (LDL) cholesterol. To determine the joint and individual impacts of child metal exposures (log2-transformed) on lipid levels, Bayesian kernel machine regression (BKMR) was employed as the primary multi-pollutant approach. Potential effect modification by child sex and childhood environmental tobacco smoke exposure was also evaluated.

RESULTS

BKMR identified a positive association between the metal mixture and both total and LDL cholesterol. Of the seven metals examined, selenium (median 90.6 [IQR = 83.6, 96.5] µg/L) was assigned the highest posterior inclusion probability for both total and LDL cholesterol. A difference in LDL cholesterol of 8.22 mg/dL (95% CI = 1.85, 14.59) was observed when blood selenium was set to its 75th versus 25th percentile, holding all other metals at their median values. In stratified analyses, the positive association between selenium and LDL cholesterol was only observed among boys or among children exposed to environmental tobacco smoke during childhood.

IMPACT STATEMENT

Growing evidence indicates that cardiovascular events in adulthood are the consequence of the lifelong atherosclerotic process that begins in childhood. Therefore, public health interventions targeting childhood cardiovascular risk factors may have a particularly profound impact on reducing the burden of cardiovascular disease. Although growing evidence supports that both essential and nonessential metals contribute to cardiovascular disease and risk factors, such as dyslipidemia, prior studies have mainly focused on single metal exposures in adult populations. To address this research gap, the current study investigated the joint impacts of multiple metal exposures on lipid concentrations in early childhood.

Selenium Biomarkers and Their Relationship to Cardiovascular Risk Parameters in Obese Women

A cross-sectional study was carried out with 210 women divided into a case group (obese, n = 84) and a control group (eutrophic, n = 126). Body weight, height, waist circumference (WC), and hip and neck circumference were measured and the waist-hip ratio and conicity index were calculated. Selenium in plasma, erythrocytes and urine, erythrocyte GPx activity, lipid profile, Castelli I and II indices, and systolic and diastolic blood (DBP) pressure were evaluated. Mean dietary selenium intake (µg/kg/day) and plasma and erythrocyte concentrations were lower in the obese group compared to the healthy group (p < 0.001). while urinary selenium concentrations were higher (p < 0.001). There was a statistical difference between groups regarding cardiovascular risk parameters: waist circumference, neck circumference, waist-hip ratio, conicity index, triacylglycerols (TGC), and lipoproteins rich in triacylglycerols (VLDL-c) (p > 0.05). There was a negative correlation between plasma selenium concentrations and total cholesterol (TC), non-high-density lipoprotein (non-HDL), low-density lipoprotein (LDL-c), and systolic blood pressure (SBP). Urinary selenium correlated negatively with waist circumference and hip circumference and positively with neck circumference, TC, TGC, high-density lipoprotein (HDL-c), non-HDL, and VLDL-c. There was a negative correlation between dietary selenium and waist circumference, waist-hip ratio, neck circumference, conicity index, non-HDL cholesterol, LDL-c, and Castelli indices I and II, as well as a positive correlation with HDL-c and diastolic blood pressure. Women with obesity present changes in their nutritional status related to selenium, as well as increased cardiovascular risk parameters. Thus, the positive role of selenium in protecting the risk of cardiovascular disease is likely.

Effects of sodium selenite and selenium-enriched yeast on cardiometabolic indices of patients with atherosclerosis: A double-blind randomized clinical trial study

Introduction: Atherosclerosis and related cardiovascular diseases (CVDs) are the major causes of mortality worldwide. The available reports regarding the effects of selenium (Se) supplementation in the realm of atherosclerosis have been equivocal. The present investigation is aimed to assess the effects of sodium selenite and Se-enriched yeast supplementation on metabolic parameters among atherosclerotic patients. Methods: In this double-blind placebo-controlled randomized clinical trial, 60 patients diagnosed with atherosclerosis were randomly allocated into either 200 μg/day selenite, yeast, or placebo groups for eight consecutive weeks. Serum levels of lipid profile and glycemic indices were measured at the baseline and end of the intervention. Results: There were no significant within-or between-group changes in levels of total cholesterol, triglycerides, high-density lipoprotein cholesterol (HDL-c), fasting blood sugar, insulin, and homeostatic model assessment for IR throughout the study (P≥0.05). Only the low density lipoprotein cholesterol (LDL-c) levels were significantly lower in the yeast group in comparison with the placebo group (P= 0.015). Conclusion: The administration of Se-enriched yeast is significantly effective in decreasing LDL-c levels in patients with atherosclerosis. Additional clinical trial studies investigating the effect of Se administration on glucose homeostasis parameters and lipid profiles in atherosclerotic patients are suggested for a more definitive conclusion.

Food Chemistry of Selenium and Controversial Roles of Selenium in Affecting Blood Cholesterol Concentrations

Hypercholesterolemia, one of the major risk factors of cardiovascular diseases, is a worldwide public health problem. Nutraceuticals and phytochemicals are attracting attention as a result of their cholesterol-lowering ability and minimal side effects. Among them, selenium (Se) is on the list. The amount of Se in foods varies by region. Se-enriched fertilizers and feeds can raise the Se content in plants and animals, while some processing methods decrease food Se content. This review summarizes recent studies on (1) the content distribution of Se in foods and factors influencing Se-enriched foods, (2) the bioavailability and metabolism of Se, and (3) the role of Se in affecting blood cholesterol and cholesterol metabolism. Although the hypocholesterolemic effect of Se is equivocal, its cholesterol-lowering activity may be more remarkable when the Se supplementation is 200 μg/day or the baseline blood total cholesterol is above 200 mg/dL in humans with low Se status.

Toxicology and pharmacology of synthetic organoselenium compounds: an update

Here, we addressed the pharmacology and toxicology of synthetic organoselenium compounds and some naturally occurring organoselenium amino acids. The use of selenium as a tool in organic synthesis and as a pharmacological agent goes back to the middle of the nineteenth and the beginning of the twentieth centuries. The rediscovery of ebselen and its investigation in clinical trials have motivated the search for new organoselenium molecules with pharmacological properties. Although ebselen and diselenides have some overlapping pharmacological properties, their molecular targets are not identical. However, they have similar anti-inflammatory and antioxidant activities, possibly, via activation of transcription factors, regulating the expression of antioxidant genes. In short, our knowledge about the pharmacological properties of simple organoselenium compounds is still elusive. However, contrary to our early expectations that they could imitate selenoproteins, organoselenium compounds seem to have non-specific modulatory activation of antioxidant pathways and specific inhibitory effects in some thiol-containing proteins. The thiol-oxidizing properties of organoselenium compounds are considered the molecular basis of their chronic toxicity; however, the acute use of organoselenium compounds as inhibitors of specific thiol-containing enzymes can be of therapeutic significance. In summary, the outcomes of the clinical trials of ebselen as a mimetic of lithium or as an inhibitor of SARS-CoV-2 proteases will be important to the field of organoselenium synthesis. The development of computational techniques that could predict rational modifications in the structure of organoselenium compounds to increase their specificity is required to construct a library of thiol-modifying agents with selectivity toward specific target proteins.

The effect of Bertholletia excelsa on body weight, cholestrol, and c-reactive protein: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND & OBJECTIVE(S)

Bertholletia excelsa is a rich herbal source of anti-oxidants and phenols. The goal of this study is to evaluation the effect of bertholletia excelsa nut on body weight, C-reactive protein (CRP) and lipid profile.

METHODS

A literature search was conducted in PubMed, Scopus and Web of sciences databases by two reviewers up to October 2019. Random effect model used to combine results.

RESULTS

Six studies included in analysis with 71 participants. The population was public population. Pooled results showed Bertholletia excelsa have reduction effect on triglyceride weighted mean difference (WMD: -8.23 mg/dl, 95 % CI -15.09, -1.38, I² = 0%), Cholesterol (WMD: -14.31 mg/dl, 95 % CI -23.38, -5.24, I² = 47 %), Low-density lipoprotein (LDL) (WMD: -9.27 mg/dl, 95 % CI -13.48, -5.06, I² = 0%).

CONCLUSION

This study provided an evidence that Bertholletia excelsa nuts have reduction effect on triglyceride, cholesterol, and LDL levels.

Beneficial Effects of Hydroalcoholic Extract from Rosa Roxburghii Tratt Fruit on Hyperlipidemia in High-Fat-Fed Rats

Background

Rosa roxburghii Tratt fruit is extensively used as a medicinal and edible resource in China due to its unique bioactivities. In this research, we aimed to characterize its phenolic acid composition and investigate the potential hypolipidemic effect of this plant in a rat model of hyperlipidemia.

Methods

We evaluated the effects of hydroalcoholic extract of Rosa roxburghii Tratt fruit (HRT) on serum lipids, body weight, activities of lipoprotein metabolism and antioxidant enzymes, and gene expression of lipid metabolism in hyperlipidemic rats.

Results

HRT significantly reduced body weight gain and decreased serum and liver lipid levels in the hyperlipidemic rats. In addition, HRT treatment improved the activities of antioxidant enzymes, lipoprotein lipase, and hepatic lipase, downregulated the mRNA and protein expressions of sterol regulatory element-binding protein 1c and acetyl CoA carboxylase, and upregulated the mRNA and protein expressions of peroxisome proliferator-activated receptor α and low-density lipoprotein receptor in hepatic tissue.

Conclusions

The results showed that Rosa roxburghii Tratt fruit is rich in phenolic acids, and that it exerted lipid lowering effects in the hyperlipidemic rats.

Methylophiopogonanone A, an Ophiopogon homoisoflavonoid, alleviates high-fat diet-induced hyperlipidemia: assessment of its potential mechanism

Methylophiopogonanone A (MO-A), a homoisoflavonoid extracted from Ophiopogon japonicus, has been shown to attenuate myocardial apoptosis and improve cerebral ischemia/reperfusion injury. However, the hypolipidemic effects remain unknown. This study was performed to investigate a potential hypolipidemic effect of MO-A in hyperlipidemia rats, as well as its underlying mechanism of action. A rat model of hyperlipidemia was induced by a high-fat diet (HFD). Animals were randomly divided into three groups (n=8/group): normal control group (NC), HFD group, and HFD+MO-A (10 mg·kg-1·d-1) treatment group. The effects of MO-A on serum lipids, body weight, activity of lipoprotein metabolism enzyme, and gene expression of lipid metabolism were evaluated in HFD-induced rats. In HFD-induced rats, pretreatment with MO-A decreased the body weight gain and reduced serum and hepatic lipid levels. In addition, pretreatment with MO-A improved the activities of lipoprotein lipase and hepatic lipase in serum and liver, down-regulated mRNA expression of acetyl CoA carboxylase and sterol regulatory element-binding protein 1c, and up-regulated mRNA expression of low-density lipoprotein receptor and peroxisome proliferator-activated receptor α in the liver. Our results indicated that MO-A showed strong ability to ameliorate the hyperlipidemia in HFD-induced rats. MO-A might be a potential candidate for prevention of overweight and dyslipidemia induced by HFD.

Association of circulating selenium concentration with dyslipidemia: Results from the NHANES

BACKGROUND

Observational studies have suggested that selenium levels might associate with the risk of cardio-metabolic diseases, but how circulating selenium is related to dyslipidemia remains inconclusive.

OBJECTIVES

To investigate the association of circulating selenium levels with lipid profiles and dyslipidemia among US adults.

METHODS

Using the data collected from the National Health and Nutrition Examination Survey (NHANES 1999-2006), we performed multivariate logistic regression to examine the association of circulating selenium levels (in quartiles) with total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), non-HDL-C, and atherogenic index (AI).

RESULTS

We included 2903 adults (49.3 % male) (average age: 61.9) for analysis. Circulating selenium had non-linear association with TC, LDL-C, HDL-C, and AI (all p < 0.05). When comparing with the lowest quartile, subjects with the highest quartile of circulating selenium (>147.00 μg/L) had the higher odds of elevated TG (OR: 1.75, 95% CI = 1.14, 2.68), TC (OR: 2.47, 95% CI = 1.62, 3.76), LDL-C (OR: 2.52, 95% CI = 1.60, 3.96), non-HDL-C (OR: 2.17, 95% CI = 1.41, 3.33), AI (OR: 1.20, 95% CI = 0.73, 1.97) and low-HDL-C (OR: 2.10, 95% CI = 1.19, 3.72). Similar patterns were observed in subgroup analysis.

CONCLUSIONS

Higher circulating selenium levels had non-linear association with lipid profiles and the increased odds of dyslipidemia.

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.

Relationship between higher serum selenium level and adverse blood lipid profile

BACKGROUND

As the key component of glutathione peroxidase with unique antioxidant properties, selenium has been considered to play an important part on lipid metabolism. However, the associations of serum selenium concentrations with lipid concentrations and dyslipidemia are still controversial.

METHODS

We analyzed cross-sectional data including serum selenium levels, lipid concentrations and other related indexes of 8198 rural Chinese. Serum selenium was measured by inductively coupled plasma mass spectrometry, and total cholesterol (TC), triglyceride (TG), high density lipoprotein-cholesterol (HDL-c) and low density lipoprotein-cholesterol (LDL-c) of serum were measured with kits.

RESULTS

Overall, mean serum selenium was 120 μg/l. Multivariate liner regression revealed that selenium concentrations were positively correlated with TC (P < 0.001), HDL-c (P < 0.001), TG (P < 0.001) and LDL-c (P < 0.001). Compared with the lowest quintile of serum selenium, participants in quintile 3, 4 and 5 had higher risks of High-TC dyslipidemia (P ≤ 0.02) and High-LDLC dyslipidemia (P < 0.02) after adjusting for covariates. In the stratified analyses, we found that the selenium-dyslipidemia associations were significantly stronger in post-menopausal women (OR: 2.72; 95% CI: 1.97, 4.17) and diabetics (OR: 9.40; 95% CI: 3.02, 29.26).

CONCLUSION

Elevated serum selenium levels were correlated with the increased concentrations of TC, LDL-c, HDL-c and TG, and increased the risk of High-TC and High-LDLC dyslipidemia among rural Chinese. However, the real associations between serum selenium and lipid profile should be verified in specifically designed randomized trials in future.

Nanoselenium Supplementation of Heat-Stressed Broilers: Effects on Performance, Carcass Characteristics, Blood Metabolites, Immune Response, Antioxidant Status, and Jejunal Morphology

An experiment was conducted to investigate the effects of dietary nanoselenium supplementation at 0, 0.6 and 1.2 mg/kg of diet on growth performance, serum biochemical parameters, immune response, antioxidant capacity, and jejunal morphology of 29-d-old male broilers subjected to heat stress at 37 ± 1°C for 14 d. Broilers were fed for 42 d on the experimental diets. The results showed that nanoselenium supplementation had no effect on growth performance, but it supplementation at the rate of 1.2 mg/kg diet decreased the serum concentration of cholesterol prior to the heat exposure. Further, dietary nanoselenium supplementation linearly increased the high-density lipoprotein cholesterol concentration, while linearly decreased those of low-density lipoprotein cholesterol and aspartate aminotransferase in the serum before applying heat stress. Compared with thermoneutral temperature, heat stress reduced body mass gain, feed intake, percentages of carcass, breast, leg, abdominal fat, bursa of Fabricius, thymus, antibody response against sheep red blood cells, serum concentration of protein, erythrocyte activities of glutathione peroxidase and superoxide dismutase, jejunal villus height, and villus height to crypt depth ratio, while increased feed conversion ratio, percentages of liver, gizzard, pancreas, gallbladder, heart, and the concentrations of aspartate aminotransferase and malondialdehyde. Dietary supplementation of nanoselenium linearly reduced the abdominal fat and liver percentages, while linearly increased the activity of glutathione peroxidase and villus height in heat-stressed broilers. Furthermore, the lower level of nanoselenium decreased the percentages of gizzard and heart in broilers under heat stress. The diet supplemented with 1.2 mg/kg nanoselenium improved feed conversion ratio and increased antibody response against sheep red blood cells, activity of superoxide dismutase, and villus height to crypt depth ratio, but decreased the serum concentrations of cholesterol, low-density lipoprotein cholesterol, and malondialdehyde in heat-stressed broilers. The results suggest that supplemental nanoselenium improved growth performance, internal organs health, immune response, and jejunal morphology by alleviating the oxidative stress induced by heat stress.

Selenium Level and Dyslipidemia in Rural Elderly Chinese

OBJECTIVE

Higher selenium level has been hypothesized to have the potential to reduce the risk of cardiovascular diseases including dyslipidemia. However, results from previous studies are inconsistent. This study aims to determine the association between selenium level and dyslipidemia in elderly Chinese with relatively low selenium status.

METHODS

A cross-sectional study of 1859 participants aged 65 or older from four rural counties in China was conducted. Serum total cholesterol (TC), triglycerides (TG), high density lipoprotein-cholesterol (HDLC) and low-density lipoprotein-cholesterol (LDLC), nail selenium concentration and APOE genotype were measured in all subjects. The four types of dyslipidemia were defined as >5.17 mmol/L for High-TC, >1.69 mmol/L for High-TG, >3.36 mmol/L for High-LDLC, and <1.04 mmol/L for Low-HDLC according to Chinese Guidelines on Prevention and Treatment of Dyslipidemia in Adults. Logistic models adjusting for age, gender, APOE genotype, body mass index, alcohol consumption, smoking, physical activity, medication use for cardiovascular diseases were used to examine the relationship between selenium levels and the risk of dyslipidemia.

RESULTS

Mean nail selenium concentration was 0.465 μg/gin this sample. Rates for High-TC, High-LDLC, High-TG, Low-HDLC were 18.13%, 13.23%, 12.21% and 32.76% respectively. Results from logistic models indicated that higher selenium levels were significantly associated with higher risk of High-TC, High-LDLC and lower risk of Low-HDLC adjusting for covariates (p < 0.0001). Compared with the lowest selenium quartile group, participants in selenium quartile groups 2, 3 and 4 had significantly higher rates of High-TC, High-LDLC, High-TG, and lower rate of Low-HDLC adjusting for covariates. No significant association was observed between selenium level and the risk of High-TG. APOEε4 carriers had higher rates of High-TC and High-LDLC. There was no interaction between selenium level and APOE with the rates of dyslipidemia.

CONCLUSIONS

Our results suggest long-term selenium exposure level may be associated with the risk of dyslipidemia in elderly population. Future studies are needed to examine the underlying mechanism of the association.

Beneficial effects of Yerba Mate tea (Ilex paraguariensis) on hyperlipidemia in high-fat-fed hamsters

Yerba Mate tea (Mate), an infusion made from the leaves of the tree Ilex paraguariensis, is a widely consumed beverage in South America. Mate has previously been shown to have hypolipidemic effects. However, its mechanism of action is not well understood. This study was conducted to determine the effect of Mate on hyperlipidemia induced in hamsters by a high-fat diet, as well as its mechanism of action. Fifty male hamsters were randomly assigned to normal control, high-fat control, and high-fat with Mate tea aqueous extract (1%, 2% or 4% w/v) groups. We evaluated the effects of Mate aqueous extract on body weight, serum lipids, antioxidant enzyme activity, lipoprotein metabolism enzyme activity, and gene expression involved in lipid metabolism in hyperlipidemic hamsters. Mate aqueous extract significantly decreased body-weight gain and lowered serum lipid levels in the hyperlipidemic hamster model. Meanwhile, Mate treatment increased antioxidant enzyme activity, improved lipoprotein lipase (LPL) and hepatic lipase (HL) activities in serum and liver, upregulated mRNA expression of peroxisome proliferator-activated receptor α and low density lipoprotein receptor, and downregulated mRNA expression of sterol regulatory element-binding protein 1c and acetyl CoA carboxylase in the liver. The results indicate that Mate tea ameliorates hyperlipidemia partly by reducing lipid peroxidation, improving endothelial function and LPL and HL activities, and modulating the expression levels of genes involved in lipid oxidation and lipogenesis.

Status of essential trace minerals and oxidative stress in viral hepatitis C patients with nonalcoholic fatty liver disease

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) may be an important factor leading to altered trace mineral homeostasis, thereby accelerating the progression of hepatitis C virus (HCV) infection. Our aim was to determine whether NAFLD influenced the status of certain essential trace minerals and oxidative stress in chronic HCV-infected patients.

DESIGN AND METHODS

Blood biochemical parameters were determined in a group of 30 healthy, non-obese, non-diabetic participants (CNL group), and hepatitis C patients without NAFLD (HCV group, n = 30) and with NAFLD (HCV-NAFLD group, n = 32).

RESULTS

Concentrations of thiobarbituric acid reactive substances (TBARS; a measure of oxidative stress), C-reactive protein (CRP), ferritin, aminotransferases, lipid profiles, and insulin metabolism were markedly abnormal in both patient groups than in CNL subjects. Compared to patients in the HCV group, those with HCV-NAFLD group had lower high-density lipoprotein concentrations, higher low-density lipoprotein and homeostasis model assessment-insulin resistance (HOMA-IR) values, disrupted antioxidant enzyme activities, and elevated TBARS concentrations, as well as decreased plasma concentrations of trace minerals zinc (Zn) and selenium (Se) and increased copper (Cu). The alterations in mineral homeostasis were also linked to TBARS, CRP, ferritin, lipoproteins, and HOMA-IR values in the HCV-NAFLD group.

CONCLUSIONS

There is a progressive deterioration in the homeostasis of minerals (Zn, Se, and Cu) in HCV-NAFLD patients, which may reflect greater oxidative stress and inflammation. These results suggest that the disturbance in mineral metabolism by NAFLD has an impact on the effectiveness of treatment for chronic HCV infection.

High-dose supplemental selenite to male Syrian hamsters fed hypercholesterolaemic diets alters Ldlr, Abcg8 and Npc1l1 mRNA expression and lowers plasma cholesterol concentrations

The aim of the present study was to elucidate possible cholesterol-lowering mechanism(s) of high-dose supplemental Se in the form of selenite, a known hypocholesterolaemic agent. Male Syrian hamsters (four groups, ten per group) were fed semi-purified diets for 4 weeks containing 0·1 % cholesterol and 15 % saturated fat with selenite corresponding to varying levels of Se: (1) Se 0·15 parts per million (ppm), control diet; (2) Se 0·85 ppm; (3) Se 1·7 ppm; (4) Se 3·4 ppm. Lipids were measured in the bile, faeces, liver and plasma. The mRNA expression of several known regulators of cholesterol homeostasis (ATP-binding cassette transporters g5 (Abcg5) and g8 (Abcg8), 7-hydroxylase, 3-hydroxy-3-methylglutaryl-coenzyme A reductase, LDL receptor (LdLr) and Nieman-Pick C1-like 1 protein (Npc1l1)) were measured in the liver and/or jejunum. Oxysterols including 24-(S)-hydroxycholesterol, 25-hydroxycholesterol and 27-hydroxycholesterol (27-OHC) were measured in the liver. Significantly lower total plasma cholesterol concentrations were observed in hamsters consuming the low (0·85 ppm) and high (3·4 ppm) Se doses. The two highest doses of Se resulted in decreased plasma LDL-cholesterol concentrations and increased mRNA levels of hepatic Abcg8, Ldlr and jejunal Ldlr. Higher hepatic 27-OHC and TAG concentrations and lower levels of jejunal Npc1l1 mRNA expression were noted in the 1·7 and 3·4 ppm Se-treated hamsters. Overall, Se-induced tissue changes in mRNA expression including increased hepatic Abcg8 and Ldlr, increased jejunal Ldlr and decreased jejunal Npc1l1, provide further elucidation regarding the hypocholesterolaemic mechanisms of action of Se in the form of selenite.

Influence of selenium and/or magnesium on alleviation alcohol induced oxidative stress in rats, normalization function of liver and changes in serum lipid parameters

The aim of this study was to evaluate the attenuating effect of given selenium and/or magnesium on ethanol-induced oxidative stress, disturbances of liver function and cholesterol metabolism. Forty male rats were divided into five groups: C – control, Et – intoxicated with alcohol (15% solution in drinking water), Et + Mg, Et + Se, Et + Mg + Se – intoxicated with alcohol and supplemented with selenium (0.4 mg Se/l water), magnesium (100 mg Mg/l water) and combination of Se and Mg, respectively. The experiment was carried out over the 3 months. The results show that the chronic ingestion of alcohol induces lipid peroxidation and histopathological changes in liver. Supplementation with magnesium only partially alleviates oxidative stress and damages in this tissue. The both selenium alone and combination of magnesium and selenium significantly elevated total antioxidant status (TAS) in serum, activity of glutathione peroxidase and ratio of reduced glutathione to oxidized glutathione (GSH/GSSG) in liver and retarded oxidative stress and histopathological changes in this tissue. Chronic administration of ethanol (alone and with magnesium) resulted in significant decrease in the serum total cholesterol and retardation in the body weight gain in comparison with the control group. In the groups supplemented with selenium and selenium and magnesium simultaneously, concentration of total cholesterol in serum and body gains was similar to the control group. Supplementation of Se or selenium and magnesium simultaneously significantly enhances antioxidant defence and is more effective against alcohol-induced oxidative stress, disturbance of liver function and cholesterol metabolism than the separate use of magnesium.

Serum selenium concentration is associated with metabolic factors in the elderly: a cross-sectional study

Background

Selenium is an essential micronutrient known for its antioxidant function. However, the association of serum selenium with lipid profiles and fasting glucose are inconsistent in populations with average intake of selenium. Furthermore, there were few studies conducted specifically for the elderly. This study examined the relationship of serum selenium concentration with serum lipids and fasting glucose in the Taiwanese elderly population.

Methods

This was a cross-sectional study of 200 males and females aged 65-85 years (mean 71.5 ± 4.6 years) from Taipei, Taiwan. Serum selenium was measured by inductively coupled plasma-mass spectrometer. The association between serum selenium and metabolic factors was examined using a multivariate linear regression analysis after controlling several confounders.

Results

The mean serum selenium concentration was 1.14 μmol/L, without significant difference between sexes. Total cholesterol, triglycerides, and LDL cholesterol increased significantly with serum selenium concentration (P < 0.001, P < 0.05 and P < 0.001, respectively) after adjusting for age, gender, anthropometric indices, lifestyle factors, and cardio-vascular risk factors in several linear regression models. Furthermore, there was a significantly positive association between serum selenium and serum fasting glucose concentrations (P < 0.05).

Conclusions

Total cholesterol, triglycerides, and LDL cholesterol, and fasting serum glucose concentrations increased significantly with serum selenium concentration in the Taiwanese elderly. The underlying mechanism warrants further research.

Antioxidant Supplements Improve Profiles of Hepatic Oxysterols and Plasma Lipids in Butter-fed Hamsters

Hypercholesterolemic diets are associated with oxidative stress that may contribute to hypercholesterolemia by adversely affecting enzymatically-generated oxysterols involved in cholesterol homeostasis. An experiment was conducted to examine whether the cholesterol-lowering effects of the antioxidants selenium and α-tocopherol were related to hepatic oxysterol concentrations. Four groups of male Syrian hamsters (n = 7-8) were fed high cholesterol and saturated fat (0.46% cholesterol, 14.3% fat) hypercholesterolemic semi-purified diets: 1) Control; 2) Control + α-tocopherol (67 IU all-racemic-α-tocopheryl-acetate/kg diet); 3) Control + selenium (3.4 mg selenate/kg diet); and 4) Control + α-tocopherol + selenium. Antioxidant supplementation was associated with lowered plasma cholesterol concentrations, decreased tissue lipid peroxidation and higher hepatic oxysterol concentrations. A second experiment examined the effect of graded selenium doses (0.15, 0.85, 1.7 and 3.4 mg selenate/kg diet) on mRNA expression of the oxysterol-generating enzyme, hepatic 27-hydroxylase (CYP27A1, EC 1.14.13.15), in hamsters (n = 8-9) fed the hypercholesterolemic diets. Supplementation of selenium at 3.4 mg selenate/kg diet was not associated with increased hepatic 27-hydroxylase mRNA. In conclusion, the cholesterol lowering effects of selenium and α-tocopherol were associated with increased hepatic enzymatically generated oxysterol concentrations, which appears to be mediated via improved antioxidant status rather than increased enzymatic production.

Serum selenium and serum lipids in US adults

BACKGROUND

Selenium, an essential micronutrient, has received considerable attention for its antioxidant properties. In addition, selenium may affect several cardiometabolic risk factors, such as glucose homeostasis and lipid concentrations. However, the effects of selenium intake on the lipid profile in selenium-replete populations, such as the United States, are largely unknown.

OBJECTIVE

We examined the relation of serum selenium concentrations with serum lipids in a representative sample of US adults.

DESIGN

This was a cross-sectional analysis of 5452 men and women aged >/= 20 y participating in the third National Health and Nutrition Examination survey. Serum selenium was measured by atomic absorption spectrometry.

RESULTS

The multivariable adjusted differences in total cholesterol, LDL cholesterol, HDL cholesterol, apolipoprotein B (apo B), and apolipoprotein A-I (apo A-I) comparing the highest with the lowest quartile of serum selenium were 16.6 mg/dL (95% CI: 11.6, 21.4 mg/dL), 10.9 mg/dL (95% CI: 6.4, 15.4 mg/dL), 3.2 mg/dL (95% CI: 1.6, 5.0 mg/dL), 8.9 mg/dL (95% CI: 5.6, 12.2 mg/dL), and 6.9 mg/dL (95% CI: 1.7, 12.1 mg/dL), respectively. Participants in the highest quartile of serum selenium had 10% higher concentrations of triacylglycerols than did participants in the lowest quartile (ratio of triacylglycerol concentrations: 1.10; 95% CI: 1.05, 1.17). The difference in the ratios of LDL cholesterol to HDL cholesterol and apo B to apo A-I that compared the highest with the lowest selenium quartiles were 0.11 (95% CI: -0.02, 0.25) and 0.03 (95% CI: 0.00, 0.06), respectively.

CONCLUSION

Elevated serum selenium was associated with elevated serum concentrations of total cholesterol, LDL cholesterol, HDL cholesterol, triacylglycerols, apo B, and apo A-I among US adults, a selenium-replete population. Experimental studies are needed to determine cause and effect relations and the potential mechanisms underlying these associations.

Protective effect of selenium on nicotine-induced testicular toxicity in rats

Effect of exogenous selenium at a dose of 10 mug/kg body weight on the testicular toxicity induced by nicotine in rats was investigated. Male albino rats were maintained for 60 days as follows: (1) control group (normal diet), (2) nicotine group (0.6 mg /kg body weight), (3) selenium (10 microg/kg body weight), and (4) nicotine (0.6 mg/kg body weight) + selenium (10 microg/ kg body weight). Administration of nicotine caused reduction in sperm count and sperm motility. Activity of HMG CoA reductase and concentration of cholesterol were increased in the testes of the nicotine administered group. Activities of testicular enzymes 3beta hydroxysteroid dehyrogenase (3 betaHSD), 17beta hydroxysteroid dehyrogenase (17 betaHSD) were decreased. Levels of testosterone in the serum were also reduced. However, the extent of these alterations was lesser in the group administered with nicotine along with selenium. Analysis of plasma revealed reduced quantity of cotinine in the group co-administered with nicotine along with selenium in comparison with the nicotine group. Nondetectable levels of nicotine were present in the co-administered group. This indicates altered metabolism of nicotine when administered along with selenium.

Modulation of hypercholesterolemia-induced alterations in apolipoprotein B and HMG-CoA reductase expression by selenium supplementation

Various studies demonstrated a significant association between the trace element selenium (Se), hypercholesterolemia and the risk of cardiovascular disorders. Present study was aimed to reveal the role of Se supplementation in modulation of hypercholesterolemia-induced changes in apolipoprotein B (apoB) and 3-hydroxy 3-methylglutaryl co-enzyme A (HMG-CoA) reductase expression during experimental hypercholesterolemia in Sprague-Dawley male rats. Animals were fed 0.2 and 1 ppm Se-supplemented control diet as well as 2% cholesterol-supplemented diet for 3 months. Apolipoprotein B levels were measured by ELISA and Western blot. HMG-CoA reductase mRNA expression was studied by RT-PCR. ApoB levels increased significantly on 2% cholesterol-supplemented diet feeding. On 1 ppm Se supplementation apoB levels decreased significantly. HMG-CoA reductase mRNA expression decreased significantly on cholesterol-supplemented diet feeding and on 1 ppm Se supplementation the mRNA expression further decreased. So the present results demonstrate that 1 ppm Se supplementation is responsible for down regulation of apoB and HMG-CoA reductase expression during hypercholesterolemia. These findings highlight the therapeutic potential of selenium supplementation in lipid metabolism.