Variability of lipid hydroperoxides in pregnant and nonpregnant women

Redox status of pregnant women with thrombophilia

Background/Aim. Since the role of oxidative stress in the pathogenesis of thrombophilia in pregnancy has still not been clarified, the aim of the study was to assess the redox status of pregnant women with thrombophilia. Methods. The study involved 120 pregnant women divided into two groups: pregnant women with thrombophilia (n = 60) and women with normal pregnancy (n = 60). Blood samples for biochemical analysis were collected at the end of the first, second, and third trimester of pregnancy. Concentrations of hydrogen peroxide (H2O2), nitrites (NO2-), and the index of lipid peroxidation measured as thiobarbituric acid reactive substances (TBARS) were measured in plasma. Levels of reduced glutathione (GSH), activities of superoxide dismutase (SOD) and catalase (CAT) were measured in erythrocytes. Results. In women with thrombophilia, NO2- values were increased in the first and third trimester compared to healthy pregnant women (p < 0.05). The higher levels of TBARS and H2O2 were noticed in women with thrombophilia in the first trimester compared to healthy pregnant women (p < 0.05). The values of SOD and CAT were lower in women with thrombophilia in the third and GSH in the first trimester compared to the control group (p < 0.05). Conclusion. Our results suggest an increased generation of prooxidants in thrombophilia at the beginning of gestation, which declines as gestation progresses and reaches similar values as in normal pregnancy at the end of pregnancy. Generally viewed, pregnant women with thrombophilia was associated with impaired antioxidant capacity ? activities of SOD and CAT were lower in the third and GSH in the first trimester compared to their values in healthy pregnant women.

Vitamin C Deficiency in the Young Brain-Findings from Experimental Animal Models

Severe and long-term vitamin C deficiency can lead to fatal scurvy, which is fortunately considered rare today. However, a moderate state of vitamin C (vitC) deficiency (hypovitaminosis C)-defined as a plasma concentration below 23 μM-is estimated to affect up to 10% of the population in the Western world, albeit clinical hallmarks in addition to scurvy have not been linked to vitC deficiency. The brain maintains a high vitC content and uniquely high levels during deficiency, supporting vitC's importance in the brain. Actions include both antioxidant and co-factor functions, rendering vitamin C deficiency likely to affect several targets in the brain, and it could be particularly significant during development where a high cellular metabolism and an immature antioxidant system might increase sensitivity. However, investigations of a non-scorbutic state of vitC deficiency and effects on the developing young brain are scarce. This narrative review provides a comprehensive overview of the complex mechanisms that regulate vitC homeostasis in vivo and in the brain in particular. Functions of vitC in the brain and the potential consequences of deficiency during brain development are highlighted, based primarily on findings from experimental animal models. Perspectives for future investigations of vitC are outlined.

Endocrine Disruptors in Water and Their Effects on the Reproductive System

Anthropogenic contaminants in water can impose risks to reproductive health. Most of these compounds are known to be endocrine disrupting chemicals (EDCs). EDCs can impact the endocrine system and subsequently impair the development and fertility of non-human animals and humans. The source of chemical contamination in water is diverse, originating from byproducts formed during water disinfection processes, release from industry and livestock activity, or therapeutic drugs released into sewage. This review discusses the occurrence of EDCs in water such as disinfection byproducts, fluorinated compounds, bisphenol A, phthalates, pesticides, and estrogens, and it outlines their adverse reproductive effects in non-human animals and humans.

Serum Malondialdehyde Concentration and Glutathione Peroxidase Activity in a Longitudinal Study of Gestational Diabetes

Aims

The main goal of this study was to evaluate the presence of oxidative damage and to quantify its level in gestational diabetes.

Methods

Thirty-six healthy women and thirty-six women with gestational diabetes were studied in the three trimesters of pregnancy regarding their levels of oxidative stress markers. These women were diagnosed with diabetes in the second trimester of pregnancy. Blood glucose levels after 100g glucose tolerance test were higher than 190, 165 or 145 mg/dl, 1, 2 or 3 hours after glucose intake.

Results

The group of women with gestational diabetes had higher serum malondialdehyde levels, with significant differences between groups in the first and second trimester. The mean values of serum glutathione peroxidase activity in the diabetic women were significantly lower in the first trimester. In the group of women with gestational diabetes there was a negative linear correlation between serum malondialdehyde concentration and glutathione peroxidase activity in the second and third trimester.

Conclusions

In this observational and longitudinal study in pregnant women, the alterations attributable to oxidative stress were present before the biochemical detection of the HbA1c increase. Usual recommendations once GD is detected (adequate metabolic control, as well as any other normally proposed to these patients) lowered the concentration of malondialdehyde at the end of pregnancy to the same levels of the healthy controls. Serum glutathione peroxidase activity in women with gestational diabetes increased during the gestational period.

Lipid peroxidation in the first trimester of pregnancy

AIM

To determine the existence and level of oxidative stress caused by lipid peroxidation in pregnancy.

METHODS

The research was conducted as prospective examination that included 60 healthy women (age 18-45). The women included in the examination were divided into two groups. The group I (N-31) included women in the first trimester of normal, healthy pregnancy. The group II included healthy nongravid women (N-29). Concentrations of markers of lipid peroxidation malondialdehyde (MDA) and thiobarbituric acid (TBARS) were determined using commercial ELISA tests OxiSelect(™) TBARS Assay Kit and OxiSelect(™) MDA ELISA Kit.

RESULTS

The results of this research indicate that the concentrations of the markers of lipid peroxidation TBARS and MDA are detectable in both groups. Higher mean values of MDA (>20 pmol/mg) were measured in the group of pregnant women, than in the group of nongravid women. The results indicate that mean values of TBARS markers are lower in pregnant women (≤50 µM) than in nongravid women (>100 µM).

CONCLUSION

The marker of lipid peroxidation MDA proved to be a sensitive marker for following lipid peroxidation during pregnancy, therefore it can be considered as a good predictor of possible complications during pregnancy.

Exposure to phthalates: reproductive outcome and children health. A review of epidemiological studies

Phthalates are a family of industrial chemicals that have been used for a variety of purposes. As the potential consequences of human exposure to phthalates have raised concerns in the general population, they have been studied in susceptible subjects such as pregnant women, infants and children. This article aims at evaluating the impact of exposure to phthalates on reproductive outcomes and children health by reviewing most recent published literature. Epidemiological studies focusing on exposure to phthalates and pregnancy outcome, genital development, semen quality, precocious puberty, thyroid function, respiratory symptoms and neurodevelopment in children for the last ten years were identified by a search of the PubMed, Medline, Ebsco, Agricola and Toxnet literature bases. The results from the presented studies suggest that there are strong and rather consistent indications that phthalates increase the risk of allergy and asthma and have an adverse impact on children's neurodevelopment reflected by quality of alertness among girls, decreased (less masculine) composite score in boys and attention deficit hyperactivity disorder. Results of few studies demonstrate negative associations between phthalate levels commonly experienced by the public and impaired sperm quality (concentration, morphology, motility). Phthalates negatively impact also on gestational age and head circumference; however, the results of the studies were not consistent. In all the reviewed studies, exposure to phthalates adversely affected the level of reproductive hormones (luteinizing hormone, free testosterone, sex hormone-binding globulin), anogenital distance and thyroid function. The urinary levels of phthalates were significantly higher in the pubertal gynecomastia group, in serum in girls with premature thelarche and in girls with precocious puberty. Epidemiological studies, in spite of their limitations, suggest that phthalates may affect reproductive outcome and children health. Considering the suggested health effects, more epidemiologic data is urgently needed and, in the meantime, precautionary policies must be implemented.

Phthalates exposure and attention-deficit/hyperactivity disorder in school-age children

BACKGROUND

Very few studies have examined the association between attention-deficit/hyperactivity disorder (ADHD) and phthalate exposure in humans. The aim of this study was to investigate the impact of phthalates on symptoms of ADHD in school-age children.

METHODS

A cross-sectional examination of urine phthalate concentrations was performed, and scores on measures of ADHD symptoms and neuropsychological dysfunction with regard to attention and impulsivity were obtained from 261 Korean children, age 8-11 years.

RESULTS

Mono-2-ethylheyl phthalate (MEHP) and mono-2-ethyl-5-oxohexylphthalate (MEOP) for metabolites of Di-2-ethylhexylphthalate (DEHP) and mono-n-butyl phthalate (MNBP) for metabolites of dibutyl phthalate (DBP) were measured in urine samples. The mean concentrations of MEHP, MEOP, and MNBP were 34.0 microg/dL (SD = 36.3; range: 2.1-386.7), 23.4 microg/dL (SD = 23.0; range: .75-244.8), and 46.7 microg/L (SD = 21.4; range: 13.2-159.3), respectively. After adjustment for covariates, teacher-rated ADHD scores were significantly associated with DEHP metabolites but not with DBP metabolites. We also found significant relationships between the urine concentrations of metabolites for DBP and the number of omission and commission errors in continuous performance tests (CPT) after adjustment for covariates.

CONCLUSION

The present study showed a strong positive association between phthalate metabolites in urine and symptoms of ADHD among school-age children.

Effect of regular maternal exercise on lipid peroxidation levels and antioxidant enzymatic activities before and after delivery

This study was designed to investigate the influence of maternal aerobic exercise on lipid peroxidation levels and antioxidant enzymatic activities before and after delivery. Predelivery and 1- and 24-hour post partum blood samples were collected from 18 nulliparous healthy pregnant women who exercised regularly throughout the whole period of pregnancy and from 22 matched controls. The plasma concentration of malondialdehyde (MDA) was measured as an indicator of lipid peroxidation. Erythrocyte enzymes, superoxide dismutase (SOD), glutathione peroxidase (GSHPx) and catalase (CAT), were measured as intracellular antioxidant markers. In the control group, MDA increased slightly from predelivery to 1 hour post partum and then increased significantly at 24 hours post partum, with significant increase in SOD and CAT activities. On the other hand, MDA of the exercise group remained unaltered at 1 and 24 hours after delivery. At 1 hour post partum, the SOD and CAT levels of the exercise group increased markedly and then decreased to predelivery levels. The present results indicate that uncontrolled lipid peroxidation occurs during labor and suggest that continuing regular maternal exercise may reduce labor-induced lipid peroxidation by improving the defense capabilities against free radical generation.

Oxidative stress and normal pregnancy

OBJECTIVE

To determine whether, in normal pregnancies, there is evidence of oxidative stress that is related to the lipid changes observed in pregnancy.

DESIGN

Longitudinal study of healthy women having a normal pregnancy. Samples were obtained towards the end of each trimester and after 8 weeks postpartum.

PATIENTS

Seventeen healthy women during a normal singleton pregnancy were compared with 12 healthy, non-pregnant women.

MEASUREMENTS

Oxidative stress was determined by measuring total antioxidant capacity (TAC), uric acid and lipid hydroperoxides (LHP). Lipid status was evaluated by measuring total and high-density lipoprotein cholesterol, triglycerides and low-density lipoprotein (LDL) subfractions.

RESULTS

Pregnancy was associated with decreased TAC and uric acid in the first trimester, which gradually increased during pregnancy, reaching normal values during the postpartum period. LHP significantly increased towards the end of pregnancy. The changes observed in LHP were significantly correlated with increases in LDL subfraction profile.

CONCLUSIONS

Late pregnancy was associated with the formation of susceptible, oxidisable particles (high LDL score) and an increase in oxidative damage. These biochemical changes may be relevant for the long-term cardiovascular health of women, especially those of high parity or those who are at high risk for cardiovascular disease (e.g. women with diabetes).

Protein carbonyls in decidua and placenta of pre-eclamptic women as markers for oxidative stress

Enhanced levels of reactive oxygen species (ROS) and decreased levels of antioxidants may contribute to the development of pre-eclampsia. Protein carbonyls may be sensitive biomarkers for ROS-mediated protein damage, whereas the ferric reducing ability of plasma (FRAP) value may serve as marker for antioxidant capacity.Twenty-two healthy pregnant women and 50 patients with severe pre-eclampsia, 25 of whom with concurrent (haemolysis, elevated liver enzymes, low platelets) HELLP syndrome were investigated prospectively with respect to placental and decidual levels of protein carbonyls and FRAP antioxidant capacity. Measurements were evaluated using the Kruskal-Wallis or Mann-Whitney U -tests for comparison between groups, and the Wilcoxon signed-rank test for comparison within groups. Spearman's correlation tests were used for correlation analyses. Placental and decidual protein carbonyl levels were higher in pre-eclampsia with HELLP than in healthy pregnancy, whereas FRAP levels were lower. Differences between pre-eclampsia and healthy pregnancy showed the same trend, but did not reach statistical significance. In pre-eclampsia with HELLP syndrome carbonyl levels as well as FRAP levels were significantly higher in placenta as compared with decidua.Higher levels of protein carbonyls and lower antioxidant capacity in both placenta and decidua in pre-eclampsia with concurrent HELLP syndrome as compared to healthy pregnancy may indicate that considerable ROS-mediated damage occurs in this disorder.

Changes in maternal lipid peroxidation levels and antioxidant enzymatic activities before and after delivery

OBJECTIVE

Our goal was to characterize the changes in maternal lipid peroxidation levels and antioxidant enzymatic activities before and after delivery.

METHODS

Predelivery and 1, 24, and 48 hours post-partum plasma concentrations of malondialdehyde, erythrocyte enzyme superoxide dismutase, glutathione peroxidase and catalase were measured in uncomplicated pregnancies.

RESULTS

Malondialdehyde levels increased slightly from predelivery to 24 hours post-partum and then decreased significantly at 48 hours post-partum. At one hour post-partum superoxide dismutase and catalase levels increased significantly to about 125% and 170% of predelivery levels, respectively. Thereafter, these values decreased significantly from one hour to 48 hours post-partum. The relative changes in superoxide dismutase and catalase levels at one hour post-partum compared to predelivery values correlated significantly with the duration of labor.

CONCLUSION

The results suggest that the uncontrolled lipid peroxidation caused by reactive oxygen species, which are produced in consequence of tissue reoxygenation, may occur during labor and that prolonged labor, may cause maternal oxidative stress.

Plasma protein carbonyls in nonpregnant, healthy pregnant and preeclamptic women

Increased reactive oxygen species (ROS) and lipid peroxidation may be implicated in the pathogenesis of preeclampsia by causing cell (membrane) damage and impaired endothelial function. Carbonyl derivatives of proteins, or protein carbonyls, may be sensitive biomarkers of ROS-mediated damage. The aim of the study was to compare levels of protein carbonyls in plasma of preeclamptic, healthy pregnant and healthy nonpregnant women. Plasma protein carbonyls were measured in 47 preeclamptic, 45 healthy pregnant and 22 healthy nonpregnant women by using a sensitive ELISA-method. ANOVA, the unpaired t-test and Pearson's correlation were used for statistical analysis. Preeclamptic women had significantly higher plasma protein carbonyl levels than healthy pregnant women (P < 0.0001). Healthy pregnant women showed significantly higher protein carbonyl levels (P < 0.001) as compared to nonpregnant controls. The higher levels of protein carbonyls as compared to nonpregnant controls suggest that increased oxygen free radical damage occurs in normal pregnancy and to a much higher extent in preeclampsia.

Circaannual changes in antioxidants and oxidative stress in the heart and liver in rats

Reactive oxygen species are formed in physiological and pathological conditions in mammalian tissues. Because of their high reactivity, they may interact with biomolecules, inducing oxidative injury. Increases in lipid peroxidation can result in oxidative damage to cellular membranes. Protection against oxidative damage is provided by enzymatic and non-enzymatic antioxidant defenses. Antioxidant enzyme activities and lipid peroxidation, as an index of oxidative stress injury, were evaluated in different seasons over one year in the heart and liver of rats, maintained on a 12 h light and dark cycle. Glutathione peroxidase and catalase activities, in both tissues, were maximal in the summer season. Lipid peroxidation in the heart was maximal in the spring as compared to the other seasons and it did not vary in the liver during the year. These findings suggest that any study of antioxidants or oxidative stress must take into account such seasonal variations for a more precise analysis of changes due to any pathological condition.

Levels of lipid peroxides in uncomplicated pregnancy: a review of the literature

The literature on lipid peroxide levels in uncomplicated pregnancy is limited, but some reasonable conclusions are possible. Despite the lack of precision in the predominant measure of lipid oxidation, there is agreement across a large number of studies that the level of lipid peroxides in blood is generally higher in pregnant women than in nonpregnant women. During gestation, elevations appear by the second trimester and may taper off later in gestation, decreasing further after delivery. Lipid peroxides also are produced in placenta, but their pattern of change over the course of pregnancy is unclear. Lipid peroxides are important because their uncontrolled production can result in oxidative stress, with significant damage to cell integrity. There is a growing literature that associates oxidative stress with preeclampsia, a major cause of maternal and fetal morbidity. The higher levels of lipid peroxides seen in blood and the production of lipid peroxides in the placenta, even in uncomplicated pregnancies, make new baseline studies a priority. These studies should include measurements of lipids and blood volume, because they can influence marker values, with sensitive and specific measures of lipid peroxidation made at various points of gestation. From our review of the existing literature we conclude that the importance of oxidative stress in reproduction is just beginning to be appreciated and studied.