Reduced Serum Selenium Concentration in Miscarriage Incidence of Indonesian Subjects

Selenium is an essential nutrient for human health, and maternal selenium concentration has been reported to be associated with pregnancy outcome. To further investigate the possible role of selenium (Se) in miscarriage, we conducted a case–control study to evaluate the correlations among selenium status, glutathione peroxidase activity, and spontaneous abortion. A total of 46 subjects with normal pregnancies and 25 subjects with spontaneous abortion were recruited, and their serum selenium concentrations and serum glutathione peroxidase activities were analyzed. The total serum selenium concentrations in subjects with normal pregnancies were significantly higher than those of subjects with spontaneous abortion; however, the glutathione peroxidase activities were similar in both groups. We further separated the subjects into smoking and nonsmoking groups, and the logistic regression analysis suggested that total serum selenium concentration, but not serum glutathione peroxidase activity or smoking, was significantly correlated with the incidence of miscarriage. The present study thus reaffirms that low serum selenium levels are associated with miscarriage and that selenium plays an important role in pregnancy maintenance.     

Selenium-dependent Glutathione Peroxidase Activity is Increased in Healthy Post-menopausal Women

Selenium helps protect against peroxidation during aging as part of the glutathione peroxidase (GPx) antioxidant system. Selenium status, however, is often low in elderly persons who have low selenium intake, live in institutions, and have certain chronic diseases. In addition, a relationship has been observed between the female reproductive hormone, estrogen, and selenium status, with blood selenium and GPx activity coinciding with fluctuations in estrogen during the menstrual cycle. These findings suggest that the decrease in estrogen following menopause may cause a decrease in selenium status, and thus accelerate the process of aging and increase the risk of certain diseases. The current study compared selenium status in healthy premenopausal (n = 13, 21 to 43 years) and postmenopausal (n = 10, 57 to 86 years) women. Selenium intakes of both groups were similar and greater than the recommended dietary allowance (RDA) of 55 μg/day for adult women. Although neither plasma nor RBC selenium concentrations were significantly different between groups, postmenopausal women had significantly greater plasma (p < 0.02), and RBC (p < 0.05) GPx activities compared to premenopausal women possibly in response to oxidative processes associated with aging. These results indicate that the selenium status of healthy postmenopausal women did not decline with menopause and that their antioxidant capability, as measured by GPx activity, was preserved with dietary intake of selenium greater than the RDA. Presented in part at the Experimental Biology 2000, April 2000, San Diego, CA [Smith AM, Ha EJ, Medeiros LC. Selenium-dependent glutathione peroxidase activity is increased in healthy post-menopausal women. FASEB J 2000;14:A513.].     

Influence of oral contraceptives on changes of the carbohydrate metabolism

Serum glucose and serum insulin levels were measured during oral glucose tolerance tests in 100 women, 20-39 years of age, who used the OC (oral contraceptive) preparation Stediril and in a control group of 96 women of the same age group. Significantly lower fasting serum glucose levels were observed after 6 months of OC use. Significant decreases in glucose tolerance were observed among OC users who had taken OCs for longer than 6 months. The blood glucose levels were elevated significantly in this group 60 and 120 minutes after the beginning of the test. No correlation could be found between age and changes in glucose tolerance. No significant differences in fasting serum insulin levels were found in either group. A significant increase in serum insulin levels was observed among women who had used OCs longer than 6 months; this increase was apparent only 120 minutes after the beginning of the test. These changes in glucose tolerance were found to be reversible. Glucose tolerance tests should be preformed once a year on OC users, more often if an abnormality in glucose metabolism, e.g. latent diabetes, is present.     

Selenium Status in Patients with Turner Syndrome: a Biochemical Assessment Related with Body Composition

Studies about selenium status in patients with Turner syndrome (TS) are non-existent in the literature. The aim of this study was to evaluate selenium status in patients with TS, while considering the different ages of the studied population and the relation with body composition. In total, 33 patients with TS were evaluated and grouped according to their developmental stages (children, adolescents, and adults). Selenium concentrations in their plasma, erythrocytes, urine, and nails were determined by using hydride generation atomic absorption spectrometry and erythrocyte glutathione peroxidase activity were measured by using Randox commercial kits. Additionally, height, weight, body fat percentage, waist circumference, and waist-height ratio were measured to characterize the patients. No differences in the selenium concentrations in the plasma, erythrocyte, urine, and nails or in the glutathione peroxidase activity were observed among the age groups (p > 0.05). The evaluated selenium levels were less than the established normal ones. The patients with larger waist circumference, body fat percentage, body mass index, and waist-height ratio showed lower glutathione peroxidase enzyme activity (p = 0.023). The present study shows that most patients with TS are deficient in selenium and that those with a greater accumulation of body fat have a lower GPx activity.     

Low serum selenium concentration and glutathione peroxidase activity in intrahepatic cholestasis of pregnancy.

Serum selenium concentrations were found to be significantly lower in women with intrahepatic cholestasis of pregnancy than in women with normal pregnancies during the last trimester of pregnancy and post partum. The activity of the selenoenzyme glutathione peroxidase had a significant positive correlation with selenium concentration and it was also significantly lower in women with the disease. These findings suggest that selenium deficiency and reduced glutathione peroxidase activity are associated with the aetiopathogenesis of intrahepatic cholestasis of pregnancy.     

Selenium status of healthy immigrant parisian preschool children

Plasma selenium (Se) concentration and erythrocyte glutathione peroxidase activity (GPx) were assessed in a population of healthy preschool children two to five years old, residing in the city of Paris. In the 118 subjects, mean (±SD) plasma Se concentration was 62.10 ±13.96 μg/L, and mean GPx activity was 23.58±8.52 U/g Hb. Mean plasma Se of male children was significantly (p=0.001) higher (12%) than levels of girls. Plasma selenium levels were not correlated with erythrocyte GPx activity. Children from Mediterranean origin had a slightly lower erythrocyte GPx activity (p<0.05) than children from other regions. Mean plasma Se concentration of this group corresponded to the lower limit of intervals, which characterizes geographical regions of intermediate selenium concentrations.     

Plasma and erythrocyte selenium and glutathione peroxidase activity in preterm infants at risk for bronchopulmonary dysplasia

The purpose of this study was to examine the relationships between selenium status, as measured by plasma and erythrocyte selenium and glutathione peroxidase (GPx) activity, and other postnatal factors, including selenium intake, gestational age, and oxygen dependence in preterm infants at risk for bronchopulmonary dysplsia. Eighteen preterm infants of 30 wk gestational age or less were included. At postnatal wk 1 and 4, selenium concentrations and GPx activity were measured and oxygen dependence and daily selenium intakes were determined from the medical chart. Plasma and erythrocyte selenium concentrations decreased from wk 1 to wk 4, whereas erythrocyte GPx activity increased. Increased selenium intakes during wk 1 were associated with increased erythrocyte GPx activity at both time-points, as well as a decreased need for supplemental oxygen on d 28. Preterm infants display increasing erythrocyte GPx activity despite declines in plasma and erythrocyte selenium. GPx activity might be enhanced by very early selenium supplementation.     

Oral contraceptives and fat patterning in young adult women

90 nulliparous white female college students, selected from 2 undergraduate introductory courses at Kansas University, participated in a cross-sectional study designed to compare the fat distribution of oral contraceptive (OC) users to that of nonusers matched for height and weight. The subjects ranged in age from 18-26 years. The 30 OC users had been using the same brand of OCs for an average of 17.7 months (range of 3-36 months) and had not used another brand previously. Each OC user was matched to 2 nonusers. Each subject's height was measured to the nearest cm. A Detecto sliding-weight balance was used to measure body weights of the women (in light clothing) to the nearest 0.1 kg. Circumference measurements also were taken to determine body shape and fat distribution. The waist girth to hip ratio (WHR) also was calculated. Fat distribution of the OC users was similar to that of nonusers matched for height and weight. Both groups were comparable in their circumference and skinfold measurements, except that the OC users had larger axilla skinfolds. Progestational activity of the combined OCs was not associated with any of the physical measurements. Estrogenic activity of the combined OCs was correlated positively with body mass index, arm and thigh circumference, and peripheral fat distribution. Estrogenic activity also was associated weakly with hip and low chest circumferences but no with any of the 7 skinfold thickness measurements. The women taking the higher estrogen OCs were more likely to have circumference measurements consistent with a more gynoid shape. Thigh skinfold thickness was consistent with those findings, though not statistically significant.     

Influence of a low-selenium diet on erythrocyte glutathione peroxidase and alkane production in exhaled air of rats as a measure of lipid peroxidation in vivo during growth

Erythrocyte glutathione peroxidase activity and alkane production in exhaled air of growing rats were studied as a measure of lipid peroxidation in vivo. When 4-weeks-old, rats were fed a low-selenium (0.05 mg/kg) refined soy concentrate-based diet but adequate in vitamin E and other nutrients. Rats of control groups were fed the same diet supplemented with varying amounts of selenium as sodium selenite. After 10 weeks, erythrocyte glutathione peroxidase activity in the group fed the low selenium diet had decreased to about 40% of the original level. Feeding this diet for a longer period resulted in a slow increase of the glutathione peroxidase level. After about 37 weeks, this level was equal to the initial level. During the same period of rapid growth, ethane and pentane production in the exhaled air of a group of similar animals on the diet containing 0.05 mg Se per kg was slightly although significantly higher compared with the levels of animals on a supplemented (0.4 mg Se per kg) diet. Differences were highest when glutathione peroxidase activity levels in the erythrocytes were lowest and negligible at the start of the experiment and after the period of rapid growth. These results support the view that the seleno-enzyme glutathione peroxidase is active in the defense mechanism of the cell against lipid proxidation.     

The Relationship of Erythrocyte Glutathione Peroxidase to Blood Selenium in Swine

The erythrocyte glutathione peroxidase activity and blood selenium have been investigated in swine fed a Se deficient diet with, and without, selenium supplementation. A highly significant correlation (r = 0.90) between erythrocyte glutathione peroxidase and blood selenium was found.     

Antioxidant status and lipid peroxidation in type II diabetes mellitus

Diabetes Mellitus (DM), a state of chronic hyperglycaemia, is a common disease affecting over 124 million individuals worldwide. In this study, erythrocyte glutathione levels, lipid peroxidation, superoxide dismutase, catalase, and glutathione peroxidase and some extracellular antioxidant protein levels of patients with type II diabetes mellitus and healthy controls were investigated. Thirty-eight patients (21 males; with age of mean +/- SD, 53.1+/-9.7 years) and 18 clinically healthy subjects (10 males; with age of mean +/- SD, 49.3+/-15.2 years) were included in the study. Levels of erythrocyte lipid peroxidation, serum ceruloplasmin and glucose levels, HbA1C levels, and erythrocyte catalase activity were significantly increased, whereas serum albumin and transferrin levels, erythrocyte glutathione levels, and glutathione peroxidase activity were significantly decreased compared to those of controls. There was no significant difference in superoxide dismutase activity compared to controls. The results suggest that the antioxidant deficiency and excessive peroxide-mediated damage may appear in non-insulin dependent diabetes mellitus.     

Selenium status is decreased in patients with intrinsic asthma

Lowered selenium (Se) status has been observed in asthma patients. An increased production of reactive oxygen species (ROS) owing to inflammatory condition has also been found in these patients and thus antioxidant properties of Se via glutathione peroxidase (GPx) activity are of great importance. Concentrations of Se in plasma and erythrocytes as well as eryth-rocyte GPx activity in 22 intrinsic asthma patients (five patients; all women were aspirin-sensitive) were compared with those of 33 control subjects. Se concentrations in both plasma and erythrocytes and GPx activity were decreased in intrinsic asthma patients. There were no significant differences in investigated parameters of Se status between aspirin-tolerant and aspirin-intolerant patients within intrinsic asthma group. Significantly high positive correlation between plasma and erythrocyte Se concentrations was found when regarding all subjects as a whole. Se supplementation might be beneficial to patients with intrinsic asthma, which may be at risk of Se deficiency.     

Effect of selenium on resistance of hemoglobin to photooxidative processes

On an example of a guinea pig it is shown that exogenous selenium (0.5 mg Na2SeO3 per 1 kg of the animal weight) during 2-hour exposition in the animal organism increases the resistance to the photo-induced oxidation of haemoglobin in erythrocyte lysates without additional stimulation of glutathione peroxidase mechanism of haemoglobin protection by exogenous selenium. It is shown that the saturation of haemoglobin fractions by selenium hampers the oxidative modification of haemoglobin. Using pregnancy of women as a natural model of selenium-deficiency condition, it has been shown that physiological debilitation of saturation erythrocytes with selenium, including haemoglobin fractions of lysates erythrocytes caused debilitation of resistance of haemoglobin to photooxidative destruction. Under these conditions not only activity of enzyme glutathione peroxidise in erythrocyte lysates, but also the peroxidase activity of haemoglobin (in the presence of glutathione) were decreased. It is more characteristic of erythrocyte lysates with a less content of selenium, i.e. for the erythrocytes of women on late terms of pregnancy that testifies to the presence of certain relation between haemoglobin saturation with selenium and its peroxidase activity (in the presence of glutathione).     

Osteoblast cytoskeletal modulation in response to compressive stress at physiological levels

In this study we assessed activities of antioxidant enzymes, lipid peroxidation end-products, and nitric oxide (NO) levels in women with postmenopausal osteoporosis (PMO). Relationship between oxidative stress parameters and NO levels with bone mineral density (BMD) and clinical variables influencing bone mass and health related quality of life measures was also investigated in women with PMO. Postmenopausal women (n = 87), aged 40–65, without previous diagnosis or treatment for osteoporosis and independent in daily living activities were included. BMD was measured at the lumbar spine and proximal femur using dual-X-ray absorptiometry (DXA). Erythrocyte catalase (CATe) enzyme activity, erythrocyte and plasma enzyme activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and lipid peroxidation end-product malondialdehyde (MDA) and nitrite/nitrate levels, by product of NO were studied. A total of 23 healthy non-porotic women were included as controls. Women with PMO had significantly lower erythrocyte CATe enzyme activity and higher erythrocyte malondialdehyde (MDAe) and erythrocyte nitric oxide (NOe) levels in comparison to controls whereas erythrocyte SODe and GSH-Px enzyme activity was similar. In plasma, osteporotic women had significantly higher SOD enzyme activity and higher MDA levels whereas similar GSH-Px enzyme activity and NO levels compared to non-porotic controls. Significant correlation was found between erythrocyte SODe, CATe enzyme activity and NOe levels with proximal femur BMD. Some of the quality of life scores as pain, mental, and social functions correlated with antioxidant enzyme activities and NO levels. Consequently, oxidative stress markers may be an important indicator for bone loss in postmenopausal women. Further researches assessing the oxidative stress markers and NO in bone tissue and changes with anti-osteoporotic drugs would be valuable to better understand the role of free radicals, antioxidants, and NO in the regulation of bone mass.     

Glutathione level and its relation to radiation therapy in patients with cancer of uterine cervix

Glutathione functions as an important antioxidant in the destruction of hydrogen peroxide and lipid peroxides by providing substrate for the glutathione peroxidase and also promotes the ascorbic acid. Glutathione plays a vital role in detoxification of xenobiotics, carcinogens, free radicals and maintenance of immune functions. The study was aimed to determine plasma glutathione as well as erythrocyte glutathione and glutathione peroxidase in patients with invasive cervical carcinoma (n = 30) before initiation and after completion of radiotherapy and subsequently, at the time of first three monthly follow-up visit. The levels of plasma glutathione, erythrocyte glutathione and glutathione peroxidase activity were found to be lower in all cervical cancer patients as compared to age matched normal control women. The study indicates a change in antioxidant status in relation with the glutathione system among patients with invasive carcinoma of the uterine cervix. This study also demonstrates the effect of radiation therapy on this antioxidant system.     

Effect of age,sex, and race on selenium status of healthy residents of Augusta,Georgia

In this study we determined the possible effects of age, sex, and race on selenium (Se) concentration in plasma and erythrocytes and on glutathione peroxidase (GSH-Px) activity in erythrocytes. Two hundred six healthy blacks, whites, males, and females ranging in age from 11 to 60 yr were studied. For the entire population, mean±SDM Se concentrations were 0.104±0.021 μg/mL for plasma and 0.158±0.035 μg/mL for erythrocytes. Mean concentration of Se in plasma was higher in white subjects compared to black subjects (P<0.02). This difference was due exclusively to higher values in young adult white males (age, race, sex interaction). Neither plasma nor erythrocyte Se concentration nor erythrocyte GSH-Px activity were otherwise affected by age. In all groups plasma Se was correlated with erythrocyte Se (P<0.001), but not with glutathione peroxidase. Erythrocyte Se also was correlated inversely with years of smoking (P<0.033) and coffee intake (p<0.01). These results have defined the Se status in this healthy population in Augusta, Georgia as below the reported US mean. The factors underlying the age, race, sex interaction and the health significance of the low Se status in this population should be investigated.     

Haemoglobin oxidation in whole blood samples from sheep in relation to glutathione peroxidase activity

A high correlation was observed between H2O2-induced oxidation of haemoglobin and glutathione peroxidase activity in whole blood samples from sheep. A role of this enzyme in the prevention of oxidative damage to the erythrocyte and its contents has been previously demonstrated. The possibility of using haemoglobin oxidation in whole blood as an alternative assessment of glutathione peroxidase activity and hence of selenium status is proposed.     

Distribution of Selenium in Bovine Milk and Selenium Deficiency in Rats Fed Casein-based Diets,Monitored by Lipid Peroxide Level and Glutathione Peroxidase Activity

A major proportion of selenium in bovine milk was found in fluorometric analysis to be associated with the casein fraction, largely in alkali-labile form, and the rest with the whey fraction mostly in free selenite form. This uneven distribution of milk selenium seems to provide an explanation for selenium deficiency in purified caseins. The activity of glutathione peroxidase, a selenoprotein, in the liver of growing male rats fed ad libitum low-selenium diets containing either vitamin-free casein or Torula yeast 0.065 ± 0.012 or 0.015 ± 0.004 μ g Se/g diet, respectively) for 3 weeks decreased to 4 to 6% of that of the control rats fed a commercial stock diet (0.185 ± 0.092 μ g Se/g diet). Selenium status was evaluated by three different parameters for the rats assigned under pair-feeding regimen to those vitamin-free casein-based diets which were supplemented with graded levels of selenium as sodium selenite. The hepatic levels of the thiobarbituric acid-reactive substance, an indication of lipid peroxidation, decreased to control level with selenium supplementation per g diet of 0.1 μ g and over. The hepatic glutathione peroxidase activity reached a plateau above a 0.1 μ g/g diet of selenium supplementation, whereas the erythrocyte enzyme activity increased with increasing levels of supplementary selenium. These results support the notion that semi-purified diets containing vitamin-free casein as a prime protein source would not satisfy the selenium requirement of growing animals unless deliberately supplemented with additional selenium.     

Whole blood glutathione peroxidase and erythrocyte superoxide dismutase activities,serum trace elements (Se,Cu, Zn) and cardiovascular risk factors in subjects from the city of Ponta Delgada,Island of San Miguel,The Azores Archipelago,Portugal

Activities of whole blood glutathione peroxidase (GSH-Px) and erythrocyte superoxide dismutase (SOD) and serum levels of selenium (Se), copper (Cu) and zinc (Zn) were measured in 118 apparently healthy subjects aged 20–60 years from the city of Ponta Delgada, Island of San Miguel, The Azores Archipelago, Portugal. Data were analysed by age/gender, lipid profile and blood pressure as cardiovascular risk factors searching for their relevance when assessing reference values for antioxidant biomarkers. GSH-Px was in the same range, but SOD was significantly lower than in other Portuguese populations. Neither activity differed with gender. GSH-Px activity increased with age, namely in normolipidemic men versus the hyperlipidemic group in which a decrease was observed. This suggests a progressive impairment of GSH-Px with age caused by an enhanced production of oxidant species in hyperlipidemia. GSH-Px was 30% lower in male hypertensives versus normotensives. SOD activity did not relate to age or blood pressure but was 17% higher in the hyperlipidemic men versus the normolipidemic group, suggesting a better antioxidant protection by SOD than by GSH-Px in hyperlipidemia and hypertension. Se was higher in men versus women, particularly in the older subjects, and partly related to hyperlipidemia. Zn levels showed a similar dependency on gender, not related to age or lipid profile. Cu levels were much higher in women than in men in all age or lipid profile classes and decreased in hyperlipidemia. They were lowered with age in both genders, particularly in normolipidemic women. The present research therefore suggests that hyperlipidemia and hypertension do affect antioxidant status and should be considered when assessing antioxidant biomarkers in blood.     

Whole blood glutathione peroxidase and erythrocyte superoxide dismutase activities, serum trace elements (Se, Cu, Zn) and cardiovascular risk factors in subjects from the city of Ponta Delgada, Island of San Miguel, The Azores Archipelago, Portugal

Activities of whole blood glutathione peroxidase (GSH-Px) and erythrocyte superoxide dismutase (SOD) and serum levels of selenium (Se), copper (Cu) and zinc (Zn) were measured in 118 apparently healthy subjects aged 20-60 years from the city of Ponta Delgada, Island of San Miguel, The Azores Archipelago, Portugal. Data were analysed by age/gender, lipid profile and blood pressure as cardiovascular risk factors searching for their relevance when assessing reference values for antioxidant biomarkers. GSH-Px was in the same range, but SOD was significantly lower than in other Portuguese populations. Neither activity differed with gender. GSH-Px activity increased with age, namely in normolipidemic men versus the hyperlipidemic group in which a decrease was observed. This suggests a progressive impairment of GSH-Px with age caused by an enhanced production of oxidant species in hyperlipidemia. GSH-Px was 30% lower in male hypertensives versus normotensives. SOD activity did not relate to age or blood pressure but was 17% higher in the hyperlipidemic men versus the normolipidemic group, suggesting a better antioxidant protection by SOD than by GSH-Px in hyperlipidemia and hypertension. Se was higher in men versus women, particularly in the older subjects, and partly related to hyperlipidemia. Zn levels showed a similar dependency on gender, not related to age or lipid profile. Cu levels were much higher in women than in men in all age or lipid profile classes and decreased in hyperlipidemia. They were lowered with age in both genders, particularly in normolipidemic women. The present research therefore suggests that hyperlipidemia and hypertension do affect antioxidant status and should be considered when assessing antioxidant biomarkers in blood.