Selenium levels, thiobarbituric acid-reactive substance concentrations and glutathione peroxidase activity in the blood of women with gestosis and imminent premature labour

Investigation of the levels of essential and non-essential metals in women with and without abortion history: A study based on the Persian population of the Shahrekord cohort

Spontaneous abortion is a serious threat to the mothers' physical and mental well-being. The cause of spontaneous abortion is multifactorial disease. Prenatal non-essential metal exposure, particularly heavy metals, has been suggested to be associated with adverse pregnancy and birth outcomes. The purpose of this study was to investigate the relationship between the concentration of essential and non-essential metals including Pb, As, Zn, and Se and the risk of spontaneous abortion. In this case-control study the levels of Pb, As, Zn, and Se in the whole blood of 60 women with spontaneous abortion (case group) and also 60 women without spontaneous abortion (control group) were measured by atomic absorption spectrophotometry. Results revealed statistically significant reductions (P < 0.001) in whole blood levels of Zn and Se as well as the levels of As and Pb had a substantial elevation (P < 0.001) in cases compared to controls. According to the findings, repeated spontaneous abortion may be influenced by increasing whole blood levels of heavy metals such as As (OR = 17.53, P = 0.001) and Pb (OR = 15.58, P = 0.001) as well as decreasing levels of vital micronutrients Zn (OR = 0.20, P = 0.001) and Se (OR = 0.14, P = 0.001). The results of this study support the idea that limiting intake of non-essential metals during pregnancy can decrease the risk of spontaneous abortion. Overall, the information presented is expected to help plan future fundamental and applied investigations on the spontaneous abortion.

Association of Selenium Levels with Preeclampsia: A Systematic Review and Meta-analysis

Several observational studies have shown inconclusive findings on the association between selenium levels and preeclampsia. This systematic review and meta-analysis was conducted to clarify the association between selenium levels and preeclampsia. The databases PubMed, Google Scholar, ScienceDirect, and the Cochrane Library were searched for studies which investigated selenium levels with preeclampsia and which were published up to April 2022. The overall standardized mean differences (SMD) of selenium levels between cases and controls were measured. Sensitivity analysis, reporting bias, subgroup analysis, and meta-regression were performed for the estimate. The meta-analysis was calculated using the "meta" package in the open-source software R. A total of 26 studies with 1855 preeclampsia cases compared with 3728 healthy pregnant controls were included. The level of selenium was significantly lower in cases of preeclampsia compared with the controls [SMD =  - 0.85; 95% confidence interval (CI): (- 1.46, - 0.25); P =  < 0.01). As there was significant heterogeneity [I² = 96%, Cochran's Q = 620.47; P =  < 0.01], the random effects model was used. A stratified meta-analysis revealed that selenium levels were significantly lower in the cases compared with the controls among pregnant women from the African continent [SMD =  - 1.15 (- 1.65, - 0.65); P =  < 0.01]. Likewise, the same pattern was observed among women from middle- and low-income countries [SMD =  - 1.32 (- 2.22, - 0.42); P =  < 0.01]. None of the investigated factors (Modified Newcastle-Ottawa Scale quality score, year of publication, and sample size) showed significant association with the selenium SMD. The level of certainty of this evidence is "low certainty," as calculated by the GRADEpro GDT online tool. This meta-analysis with low level of evidence certainty revealed that low selenium level is associated significantly with preeclampsia. This pattern is also observed in women from the African continent and women from low- or middle-income countries. Further studies with different prospective designs and detailed patient characteristics are needed to consolidate this evidence.

Antioxidant status in women who have had a miscarriage

PURPOSE

During normal pregnancy there is an oxido-reductive balance between action of pro-oxidative factors. The aim of this study was to evaluate the total antioxidant status (TAS) and glutathione peroxidase (GSH-Px) activity, and the content of selenium (Se), zinc (Zn), copper (Cu) and manganese (Mn) in women who have had a miscarriage.

PATIENTS AND METHODS

The study group consisted of 83 women who had had miscarriages. The control group included 35 women in the first trimester of pregnancy, and 35 pregnant women after childbirth.

RESULTS

TAS activity and Cu concentration in serum in women who experienced a miscarriage were significantly lower, but Mn level - higher, than in women in the first trimester of pregnancy. The content of Se, Cu and Mn in placental tissue in patients who have had a miscarriage was significantly higher, while Zn content was lower than in pregnant women at full-term delivery.

CONCLUSIONS

Our findings, provided in the research, enable us to claim that the total antioxidative status is significantly lower in women who have had a miscarriage. Low level of Zn but high of Mn in the examined biological material may be indicative to the incidence of miscarriage.

The role of selenium in human conception and pregnancy

Selenium (Se) is a trace element essential for the appropriate course of vital processes in the human body. It is also a constituent of the active center of glutathione peroxidase that protects cellular membranes against the adverse effects of H2O2 lipid peroxides. Epidemiological surveys have demonstrated that selenium deficiency in the body may contribute to an increased risk for certain neoplasmic diseases (including colonic carcinoma, gastric carcinoma, pulmonary carcinoma and prostate carcinoma), as well as diseases of the cardiovascular, osseous and nervous systems. Apart from its cancer prevention and antioxidative activities, selenium protects the body against detrimental effects of heavy metals and determines the proper functioning of the immunological system. Furthermore, selenium plays a significant role in the undisturbed functioning of the reproductive system. Many studies have addressed correlations between its intake and fertility as well as disorders of procreation processes. Selenium deficiencies may lead to gestational complications, miscarriages and the damaging of the nervous and immune systems of the fetus. A low concentration of selenium in blood serum in the early stage of pregnancy has been proved to be a predictor of low birth weight of a newborn. A deficiency of this element may also cause infertility in men by causing a deterioration in the quality of semen and in sperm motility. For this reason, supplementation in the case of selenium deficiencies in the procreation period of both women and men is of utmost significance.

A prospective study of selenium concentration and risk of preeclampsia in pregnant Iranian women: a nested case-control study

Preeclampsia remains a leading cause of maternal and perinatal mortality and morbidity worldwide; however, its specific etiology still remains obscure. Some studies implicate poor maternal selenium status predisposing the mother to preeclampsia. This study was designed to determine changes in plasma selenium levels in women having preeclampsia as compared with those with normal pregnancy. In a nested case-control study, 650 normal primigravida in their first 24-28 weeks participated in the study. After 3 months of follow-up of all subjects, blood selenium levels were measured in 38 women presenting consecutively with preeclampsia and in 38 women having a normal pregnancy by atomic absorption spectrophotometry. Birth outcomes were recorded, such as gestational age at delivery, height, weight, birth head circumflex and 1-min Apgar score. Preeclampsia affects about 5.84 % of pregnancies, and in our study, there were no significant differences in age, anthropometric indices, and family history of preeclampsia between the preeclamptic and control groups. The selenium concentrations in plasma in women with preeclampsia were significantly lower as compared with those in women with normal pregnancy (70.63 ± 21.41 versus 82.03 ± 15.54 μg/L, p < 0.05). Being in the bottom tertile of selenium concentration (less than 62.2 μg/L) was associated with greater risk of preeclampsia in pregnant women. The reduced selenium in the maternal circulations observed in the preeclamptic mothers support the hypothesis that insufficient selenium concentration may be a contributing factor to the pathophysiological mechanisms associated with preeclampsia, and optimizing the dietary selenium intake through supplementation could produce demonstrable clinical benefits.

The possible role of selenium status in adverse pregnancy outcomes

The present study reviews the possible role of Se status during pregnancy regarding adverse pregnancy outcomes, with emphasis on those related to diminished antioxidant activity and increased oxidative stress. Studies have reported that Se could play an important role in adverse outcomes such as miscarriages, neural tube defects, diaphragmatic hernia, premature birth, low birth weight, pre-eclampsia, glucose intolerance and gestational diabetes. Also, low Se status has been associated with adverse outcomes among HIV-infected pregnant women and their offspring. Nevertheless, the function of Se in the aetiology of pregnancy complications is yet to be elucidated. Available evidence presents the following limitations: most study designs do not allow conclusions about causal relationships; study populations, selection of subjects, research setting, procedures for defining sample size and analytical methods are often poorly described; many studies fail to adjust for important confounding variables. In addition, population studies assessing the relationship between Se intake during pregnancy and health outcomes are scarce. Further research is still needed to clarify the role of Se status in adverse pregnancy outcomes, especially those related to augmented oxidative stress.

The relationship between plasma level of Se and preeclampsia

OBJECTIVE

To determine the relationship of selenium plasma level and preeclampsia, as an antioxidant, against reduction damage of free radicals.

METHODS

A case control study was carried out on 40 preeclamptic, and 40 healthy pregnant women in 34-39(th) week of gestation who were matched on the age of pregnancy and mineral supplements intake, in Iran. The plasma level of selenium measured by atomic absorption. Data was analyzed by using the statistical tests (t-test, chi-square, regression), α = 0 .05.

RESULTS

The mean plasma level of selenium significantly decreased in preeclamptic women compared to healthy pregnant women (p = 0.001). There was a relationship between plasma levels of selenium and preeclampsia. The odds of having preeclampsia in women who were at the bottom tertile of plasma selenium was 4.96-fold (OR = 4.96, CI 95%; 1.56-15.6, P = 0.006) and in the second tertile 3.94-fold greater (OR = 3.94, CI 95%; 1.26-12.33, P = 0.019) than third tertile of plasma selenium. Selenium plasma level under 60 μg/L has a sensitivity of 87.5%, a positive predictive value of 64.8% and Youden index was 0.4.

CONCLUSION

The result of this study shows that the reduction of selenium plasma level in preeclamptic women in comparison with healthy pregnant women may demonstrate a higher demand of Se in preeclamptic pregnancies. Selenium plasma level <60 μg/l might be a favorite cut-off point for screening of preeclampsia specially in pregnancies with low selenium plasma level; however, it may not be a favorite predictive.

Aluminum accumulation induced testicular oxidative stress and altered selenium metabolism in mice

Present work was carried out to investigate how testicular selenium (Se) metabolisms respond to oxidative stress induced by aluminum (Al). Mice were intraperitoneally exposed to 0, 7, or 35mg Al/kg/d for 14 days (CNL, LAL and HAL groups). Al administration significantly increased Al, reactive oxygen radical and malondialdehyde (MDA) levels, as well as decreased glutathione peroxidase (GPx) and glutathione reductase (GR) activities in serum and testes. The serum concentrations of Se were remarkably lower at LAL and HAL groups compared to the controls, whereas the testicular Se levels significantly reduced only in the HAL group. In addition, RT-PCR analysis revealed an increased testicular selenoprotein P (SelP) expression by Al treatment. Western blot analysis showed increased levels of SelP protein expression in the LAL group, but the expression levels were significantly reduced in HAL group. It was suggested that altered metabolism of Se, further stimulated testicular SelP transcription that may compensate for the loss of SelP protein resulted from Al-induced oxidative damage.

Antioxidant levels in the cord blood of term fetus

The aim of this study was to compare the differences in the total antioxidant levels in the cord blood after a normal vaginal delivery and after an elective caesarean section. This was a prospective study approved by the Wirral Hospital ethical research committee. The study was carried out in a district general hospital. We investigated 96 healthy pregnant women who had normal antenatal period with singleton pregnancies between 37 and 42 completed weeks of gestation. Sixty-five women had a spontaneous normal vaginal delivery and 31 underwent elective caesarean section. Umbilical cord blood was obtained immediately after delivery. Antioxidants such as glutathione peroxidase (GPX) and superoxide dismutase (SOD) were measured and compared between the normal vaginal delivery and elective ceasarean sections. The mean values for GPx in umbilical cord arterial blood (95; 86-103, n=74) was found to be significantly higher (P=0.0133) than that found in umbilical cord venous blood (84; 80-88, n=95). The arterial SOD values were found to be significantly higher (P=0.0337) in infants who had been delivered by caesarean section (1188; 1065-1311, n=22) than by vaginal delivery (1021;958-1083, n=39). The differences in the levels of GPX between the arterial and venous systems is not well documented but may be due to differences in the level of selenium, hydroperoxides or glutathione. In addition, why infants delivered by ceasarian section have a higher level of arterial SOD than those delivered by vaginal delivery remains unclear, but it may be a reflection of a relatively low level in infants subjected to the stress of labour.

Comparison of the serum selenium content of healthy adults living in the Antwerp region (Belgium) with recent literature data

Graphite furnace atomic absorption spectrometry, after improved matrix modification and using Zeeman background correction, was used to measure the serum selenium content of healthy adults living in the Antwerp region (Belgium). The mean serum concentration of 13 men and 13 women, sampled once a month during 1 year, was 84.3 +/- 9.4ng/ml with a broad range of 51.4-121.7 ng/ml. The intra-individual variation was remarkably high. Recent literature on selenium concentrations is reviewed and values are tabulated, with limitation to healthy adults and European countries. The mean serum selenium concentration measured corresponded well to older literature data for Belgium. The obtained values were found to be in the medium range compared with the literature data for other European countries.

The changes of trace elements, malondialdehyde levels and superoxide dismutase activities in pregnancy with or without preeclampsia

OBJECTIVES

Increased free radical activity and lipid peroxidation may be implicated in the pathogenesis of preeclampsia. This study was initiated to assess antioxidant enzyme and trace metals's status in preeclampsia.

DESIGN AND METHODS

The comparison was made between the pregnant women with or without preeclampsia and healthy controls in this study. Samples were obtained from 24 normal nonpregnant (controls), 30 normal pregnant and 21 preeclamptic women in the third trimester. Lipid peroxidation end product, malondialdehyde (MDA), free radical scavenging enzyme activity, superoxide dismutase (SOD) and serum zinc (Zn), copper (Cu) levels were measured in either plasma/serum or erythrocytes of patients. Data were analyzed statistically using Student's t-test.

RESULTS

In the preeclamptic group malondialdehyde, Cu levels were significantly increased, while Zn and SOD levels were significantly decreased compared to normal control group and healthy pregnant women.

CONCLUSIONS

Our findings give support that radical scavenging SOD is consumed by the increased lipid peroxidation in preeclampsia. This data may indicate an involvement of free radicals in the pathophysiology of preeclampsia. This study suggests a relationship between increased MDA, Cu levels and decreased SOD, Zn levels in pregnancy and preeclampsia.

Nutritional assessment and support during pregnancy

This article thoroughly updates the authors' previous review of nutritional assessment and support during pregnancy. After briefly reviewing nutrient metabolism and requirements, the authors discuss the nutritional assessment of the pregnant woman and review the nutritional support principles in hyperemesis gravidarum and other conditions that can compromise the nutritional health of mother or fetus.

Selenium, zinc and copper plasma levels in intrahepatic cholestasis of pregnancy, in normal pregnancies and in healthy individuals, in Chile

BACKGROUND/AIMS

Low blood Se levels have been previously shown in normal pregnancies (third trimester) and significantly lower levels in patients with intrahepatic cholestasis of pregnancy (ICP), in Finland and in Chile, suggesting that a low or marginal dietary availability of Se may contribute to the pathogenesis of this disease. The aim of this study was to investigate whether a temporal change in plasma concentration of Se, and seasonal fluctuations in plasma concentrations of Se, Zn and Cu, could coincide with changes in the prevalence of ICP.

METHODS

A cross-sectional cohort study was done including 21 ICP patients, 98 women in the third trimester of a normal pregnancy, 29 non-pregnant women, and also 13 individuals (seven non-pregnant women and six men) who had been studied 9 years before. Plasma Se, Zn and Cu were measured by atomic spectroscopy. Plasma Se levels in the present study were compared to the results obtained 5 to 7 years before, employing identical methodology in similar population samples.

RESULTS

Plasma Se concentrations in non-pregnant women were higher than in the previous study: 1.43+/-0.34 micromol/l vs 0.85+/-0.13; p<0.001. In comparison to non-pregnant women, normal pregnancies near term had lower plasma levels of Se: 1.08+/-0.25 micromol/l; p<0.01, and Zn: 17.90+/-3.61 micromol/l vs 19.71+/-3.21; p<0.05, but higher plasma levels of Cu: 34.35+/-7.12 micromol/l vs 20.62+/-3.34; p<0.01. In normal pregnancies, plasma Se concentration was significantly higher in summer (1.34+/-0.19 micromol/l) than in the other seasons, while Zn and Cu diminished. Similar to previous studies, ICP patients had significantly lower Se plasma levels than normal pregnancies: 0.94+/-0.12 micromol/l, p<0.05, and Cu levels were significantly higher: 50.80+/-7.02 micromol/l, p<0.01. Cu plasma levels correlated with the biochemical severity of the disease. Zn did not change in ICP.

CONCLUSIONS

The present study shows that the decrease in the prevalence of ICP in Chile during the last decade coincides with an increase in plasma Se levels. Its lower incidence during summer coincides with a higher plasma Se concentration in summer than in other seasons, as observed in normal pregnancies.