Antioxidant status and lipid peroxidation in human feto-placental unit

Evaluation of thiol-disulfide homeostasis and oxidative stress parameters in newborns receiving phototherapy

The aim of our study was to evaluate oxidative stress and thiol-disulfide homeostasis in term newborns receiving phototherapy. The study was planned as a single-blind, intervention study in a single center with level 3 neonatal intensive care unit to investigate the effect of phototherapy on the oxidative system in term newborns with hyperbilirubinemia. Neonates with hyperbilirubinemia were treated with total body exposure phototherapy technique for 18 h using a Novos^® device. Blood samples of 28 term newborns were taken before and after phototherapy. Total and native thiol, total antioxidant status (TAS) and total oxidant status (TOS), and oxidative stress index (OSI) levels were measured. The 28 newborn patients included 15 (54%) males and 13 (46%) females with a mean birthweight of 3080.1 ± 366.5 g. Native and total thiol levels were found to be decreased in patients receiving phototherapy (p = 0.021, p = 0.010). Besides, significantly lower TAS and TOS levels were found after phototherapy (p < 0.001, p < 0.001). We found that decreased thiol levels were related to increased oxidative stress. We also determined significantly the lower bilirubin levels after phototherapy (p < 0.001). In conclusion, we found that phototherapy treatment induced decreased oxidative stress associated with hyperbilirubinemia in neonates. Thiol-disulfide homeostasis can be used as a marker of oxidative stress due to hyperbilirubinemia in the early period.

Antioxidant Activity and Oxidative Stress Status in Maternal Serum of β-thalassemic Mothers Carrying β-thalassemic Major and Normal Fetuses

Objectiveβ-thalassemia is a genetic disorder characterized by reduction or absence of β-globin chain with mutations in both copies (β-thalassemia major) or in one copy (β-thalassemia minor). Pregnancies in β- thalassemic carrier women are considered symptom free but have risk of inheriting β-thalassemic fetuses. Current study was designed to compare oxidative stress and antioxidants status in maternal serum from β-thalassemic minor mothers having β-thalassemic major and normal fetuses. Method: We investigated paraoxonase (PON1) and arylesterase (ARE) activities along with malondialdehyde (MDA) and reactive oxygen species (ROS) in maternal serum of β-thalassemic carrier women. Results: PON1 and ARE activities were found to be significantly decreased, whereas the concentration of MDA and ROS were significantly increased in β-thalassemic minor mothers with β-thalassemic major fetuses. Conclusion: The study concludes that redox imbalance in β-thalassemic trait mothers carrying thalassemic fetuses is higher than in mothers carrying normal fetuses.

Maternal and Neonatal Evaluation of Derived Reactive Oxygen Metabolites and Biological Antioxidant Potential in Donkey Mares and Foals

Our aim was to measure the concentrations of derived reactive oxygen metabolite (d-ROMs) and biological antioxidant potential (BAP) of donkey mares and foals at delivery and to verify the protective role of the placenta against fetal oxidative stress. A total of 15 Amiata jennies with a physiological gestation length and delivery were included together with 17 foals (two twin foalings). After delivery, maternal and foal venous blood samples were collected along with blood from the artery. Circulating lactate and plasma d-ROMs and BAP were evaluated. The Wilcoxon test for paired data was applied to verify differences in d-ROMs and BAP values, while the Spearman test was used to evaluate correlations. A significantly higher d-ROMs concentration was found in jennies compared to their foals, and to the umbilical artery blood. The BAP was higher in jennies than in their foals, but no differences were observed in the umbilical artery blood. No difference was found between foals and their umbilical cord. Blood lactate was higher in foals than in their dams. Positive correlations were found between mares and umbilical cord for BAP and d-ROMs, and between mares and foals and umbilical cord for BAP. In conclusion, the placenta may be a protective factor for the fetus. As with equine foals, the antioxidant system of donkey foals does not seems to be effective at birth.

The Protective Effect of Sesamol in the Selenite-induced Experimental Cataract Model

Objectives:

To investigate the potential protective effects of sesamol in an experimental cataract model.

Materials and Methods:

Twenty-one Spraque Dawley rat pups were randomly assigned into three groups, seven rats in each. All the rats except for those in the control group were injected subcutaneously with a single dose of sodium selenite on postpartum day 9. On days 10-14, rats in the sham group were intraperitoneally administered 50 mg/kg/day saline solution, while rats in the sesamol group were given 50 mg/kg/day sesamol by the same route. Following cataract grading, the lenses and capsules were extracted and the mean levels of reduced glutathione (GSH), malondialdehyde (MDA), total antioxidant status (TAS) and total oxidant status (TOS) in lens supernatants were biochemically analyzed.

Results:

The control group did not show any development of cataract. It was found that the mean cataract grade in the sesamol group was significantly lower than that of the sham group (p<0.05). The mean GSH level and TAS in the sesamol group were significantly higher than those of the sham group while the mean TOS and MDA level in the sesamol group were significantly lower than those of the sham group (p<0.05).

Conclusion:

Our study shows that sesamol reduces TOS and MDA level and increases TAS and GSH level in the lens and inhibits cataract formation.

Higher Level of Oxidative Stress Markers in Small for Gestational Age Newborns Delivered by Cesarean Section at Term

INTRODUCTION

The aim of our study was to determine lipid peroxidation products and antioxidant enzyme activity in umbilical cord blood of small for gestational age (SGA) neonates.

MATERIALS AND METHODS

Umbilical cord arterial blood samples were collected from 21-term singleton SGA newborn infants and 21 age- and sex-matched appropriate for gestational age (AGA) term neonates prospectively born by elective cesarean section for determination of malondialdehyde (MDA) as a marker of lipid peroxidation and superoxide dismutase (SOD) for antioxidant activity.

RESULTS

MDA levels were increased (5.20 vs. 3.52 nmol/mL; p < 0.001), while levels of SOD (6.24 vs. 8.99 U/mL; p < 0.01) were decreased in SGA neonates when compared with AGA newborn infants.

CONCLUSIONS

Elevated MDA levels and decreased SOD activity in umbilical cord blood may show the possibility of insufficient protective mechanisms against increased oxidative stress in SGA neonates born by cesarean section.

Abortion-prone mating influences placental antioxidant status and adversely affects placental and foetal development

Oxidative stress is associated with decreased female fertility and adversely affects prenatal development. Mammalian cells have developed a network of enzymatic and non-enzymatic antioxidant defence systems to prevent oxidative stress. Little attention has been paid to the antioxidative pathways in placentas of normal and disturbed pregnancies, leaving a gap in our knowledge about the role of antioxidants in the control of foeto-placental development. The challenges in studying early human pregnancy can partly be overcome by designing animal models of abnormal pregnancy. We aimed to determine whether the antioxidant status of placentas from the CBA/J × DBA/2 abortion-prone pregnant mice differed from that of normal pregnant mice. The foetal/placental weight ratio was lower in abortion-prone matings compared with that in non-abortion-prone matings. The increased placental malondialdehyde (MDA) content, the end products of lipid peroxidation, with concomitants alterations in placental antioxidants, namely copper-zinc containing superoxide dismutase (SOD1), manganese containing (SOD2), glutathione peroxidases (GPX), glutathione reductase (GR) and catalase (CAT) activities may be involved in placental and foetal growth restriction. We show that placental oxidative stress is linked with poor prenatal development and pregnancy losses in CBA/J × DBA/2 mice matings. This animal model may be useful in the evaluation of nutritional antioxidant therapies for oxidative stress and associated prenatal developmental disorders.

Improving asthma during pregnancy with dietary antioxidants: the current evidence

The complication of asthma during pregnancy is associated with a number of poor outcomes for the mother and fetus. This may be partially driven by increased oxidative stress induced by the combination of asthma and pregnancy. Asthma is a chronic inflammatory disease of the airways associated with systemic inflammation and oxidative stress, which contributes to worsening asthma symptoms. Pregnancy alone also intensifies oxidative stress through the systemic generation of excess reactive oxidative species (ROS). Antioxidants combat the damaging effects of ROS; yet antioxidant defenses are reduced in asthma. Diet and nutrition have been postulated as potential factors to combat the damaging effects of asthma. In particular, dietary antioxidants may play a role in alleviating the heightened oxidative stress in asthma. Although there are some observational and interventional studies that have shown protective effects of antioxidants in asthma, assessment of antioxidants in pregnancy are limited and there are no antioxidant intervention studies in asthmatic pregnancies on asthma outcomes. The aims of this paper are to (i) review the relationships between oxidative stress and dietary antioxidants in adults with asthma and asthma during pregnancy, and (ii) provide the rationale for which dietary management strategies, specifically increased dietary antioxidants, might positively impact maternal asthma outcomes. Improving asthma control through a holistic antioxidant dietary approach might be valuable in reducing asthma exacerbations and improving asthma management during pregnancy, subsequently impacting perinatal health.

Antioxidant adaptive responses of extraembryonic tissues from cloned and non-cloned bovine conceptuses to oxidative stress during early pregnancy

Placental oxidative stress has been suggested as a key factor in early pregnancy failure. Abnormal placental development limits success in pregnancies obtained by somatic cell nuclear transfer (SCNT). Malondialdehyde (MDA) content, an index of oxidative stress, and superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) activities were determined in bovine extraembryonic tissues of SCNT or artificial insemination (AI) conceptuses. Chorionic tissues of SCNT and AI conceptuses show no difference in MDA content at day 32 of pregnancy. MDA content in chorionic tissues of SCNT and AI conceptuses decreased from day 32 to 62 of pregnancy. MDA content was lower in chorionic tissues of SCNT conceptuses than that in chorionic tissues of AI conceptuses at day 62 of pregnancy. SOD1, SOD2 and GPX activities in chorionic tissues of SCNT conceptuses were not different from those in chorionic tissues of AI conceptuses at both gestational ages. CAT activity in chorionic tissues of SCNT conceptuses was lower at day 32, and it was higher at day 62 of pregnancy than that in chorionic tissues of AI conceptuses. CAT and GPX activities increased in chorionic tissues of SCNT conceptuses with gestational age. SOD1 activity decreased while that of SOD2 and GPX increased in chorionic tissues of AI conceptuses with gestational age. At day 62 of pregnancy, MDA content and enzyme activities in cotyledonary tissues were not different between AI and SCNT conceptuses. Different antioxidant mechanisms may operate within the chorion of AI and SCNT conceptuses. Further experiments are required to elucidate this point.

Prenatal exposure to pesticides: analysis of human placental acetylcholinesterase, glutathione S-transferase and catalase as biomarkers of effect

Pre- and perinatal exposure to pesticides is deleterious on foetal and neonatal development, but information regarding possible effects on environmental low-dose exposure to pesticides is scarce. Most epidemiological studies of the health effect of pesticides have been based on self-reported information. However, detailed information on past pesticide use is difficult to reconstruct. This is a current study conducted among pregnant mothers attending a delivery care and perinatal programme at a public hospital. The study investigates biomarkers of early effects in placentas from women living in an area with an intensive use of pesticides in the northern part of Patagonia, province of Río Negro, Argentina, and it assesses the consistency of the information provided by self-reports. The study confirms that placental acetylcholinesterase and catalase activities are significantly associated with periods of organophosphorus pesticides application, while glutathione S-transferase is not affected. We found a positive correlation between environmental exposure to organophosphorus pesticides and carbamate insecticides and newborn head circumference. The findings provide a further indication of a link between placenta acetylcholinesterase and catalase activity and prenatal exposure to pesticides in population studies. Both placenta enzymes may be used as biomarkers in health surveillance programmes for early diagnosis of exposure related alterations produced by organophosphorus pesticides and carbamate pesticides.

Immunohistochemical localization of alpha-tocopherol transfer protein and lipoperoxidation products in human first-trimester and term placenta

OBJECTIVE

Pregnancy is described as a state of oxidative stress arising from the high metabolic turnover taking place during feto-placental development and little is known about the balance of oxidation and antioxidation in early human pregnancy. The aim of this study was to analyze placental expression of alpha-tocopherol transfer protein (alpha-TTP) as the major transport protein for the antioxidant alpha-tocopherol as well as the placental expression of two lipoperoxidation products, malondialdehyde (MDA) and 4-hydroxy-2-nonenal (HNE) in early first-trimester and term human placenta.

STUDY DESIGN

Placental tissue was obtained from 10 pregnancy interruptions at 6-8 weeks gestational age and 10 samples were obtained from term pregnancies after routine cesarean section. The placental expression of alpha-TTP, MDA and HNE has been investigated with immunohistochemistry by the use of specific human alpha-TTP, MDA and HNE antibodies.

RESULTS

While MDA and HNE showed similar expression in first-trimester and term placenta, alpha-TTP expression was less in first-trimester syncytiotrophoblast as compared to term. In first-trimester specimen, alpha-TTP showed major expression in extravillous trophoblast. In amniotic epithelial cells, a rising tendency in all three parameters investigated from immature to mature cells could be documented. No direct correlation between alpha-TTP, MDA and HNE expression was detected.

CONCLUSIONS

Our study shows the presence of alpha-TTP not only in term, but in first-trimester extravillous trophoblast, syncytiotrophoblast and amniotic epithelium. Furthermore, lipoperoxidation products MDA and HNE are also present in first-trimester and term placenta, documenting the presence of oxidative processes in the placenta from early on. It therefore seems possible that scavenging of reactive oxygen species (ROS) by alpha-tocopherol is already required in first-trimester human pregnancy, but the missing correlation to MDA and HNE expression leads to the speculation that alpha-TTP and its ligand alpha-tocopherol have functions beyond the antioxidative capacity of alpha-tocopherol in early pregnancy.

Alpha-Tocopherol Transfer Protein (alpha-TTP): Insights from Alpha-Tocopherol Transfer Protein Knockout Mice

Alpha-tocopherol transfer protein (alpha-TTP) is a liver cytosolic transport protein that faciliates alpha-tocopherol (alpha-T) transfer into liver secreted plasma lipoproteins. Genetic defects in alpha-TTP, like dietary vitamin E deficiency, are associated with infertility, muscular weakness and neurological disorders. Both human and alpha-TTP deficient (alpha-TTP(-/-)) mice exhibit severe plasma and tissue vitamin E deficiency that can be attenuated by sufficient dietary alpha-T supplementations. In this review, we summarize the literature concerning studies utilizing the alpha-TTP(-/-) mice. Levels of vitamin E in the alpha-TTP(-/-) mice do not appear to be directly related to the amounts of dietary alpha-T or to the levels of alpha-TTP protein in tissues. The alpha-TTP(-/-) mice appear to present a good model for investigating the specific role of alpha-T in tissue vitamin E metabolism. Furthermore, alpha-TTP(-/-) mice appear to be useful to elucidate functions of alpha-TTP beyond its well recognized functions of transferring alpha-T from liver to plasma lipoprotein fractions.

Antioxidant compounds and oxidative stress in female dogs during pregnancy

Pregnancy is a physiological period during which different metabolic pathways are altered, resulting in greater oxygen consumption and modifications of the consumption of energy substrates, with a consequent greater exposure to oxidative stress. The objective of the present study was to determine and describe the serum profile of some antioxidant biomarkers and of oxidative stress markers during pregnancy in healthy dogs. Twenty nonpregnant (NP) and 20 pregnant (P) female dogs were studied. Serum samples were obtained from the animals during the 1st, 3rd, 5th and 7th weeks of pregnancy or during diestrus for the dosage of antioxidant molecules (vitamin E, vitamin A, zinc and magnesium) and oxidative stress markers (TBARS and carbonyl protein). The results revealed a statistically significant difference (p<0.05) between the P and NP groups during the 3rd and 5th week for vitamins A and E (NP>P), and between the 1st and 3rd week for magnesium (NP>P). The other parameters did not differ between weeks within the same group or between groups. The present study shows that the levels of antioxidant molecules of pregnant dogs differed from that of nonpregnant dogs. These mechanisms may represent a protection against oxidative stress during this period for this species, a fact that definitely deserves further study. Also, the participation of other protective mechanisms and the interference of the fetal-placental unit with oxidative stress are still unknown.

Investigation of free radical scavenging enzyme activities and lipid peroxidation in human placental tissues with miscarriage

BACKGROUND

Miscarriage (early pregnancy failure) is a pregnancy-related disease, the pathophysiology of which is still not completely understood. Lipid peroxidation and alterations in antioxidant enzyme activities may be of importance in the pathogenesis of this disorder. This study was planned to investigate the possible relation between free radical scavenging enzyme activities and lipid peroxidation levels in placenta tissues with miscarriage.

METHODS

Placental tissue samples were obtained from 21 patients who had miscarried and 25 normal pregnant women undergoing elective abortion as a control group. Total superoxide dismutase (T-SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) enzyme activities and levels of thiobarbituric acid reactive substances (TBARS), antioxidant potential (AOP), and nonenzymatic superoxide radical scavenger activity (NSSA) were measured in the placental tissues.

RESULTS

GSH-Px, CAT activities, and TBARS levels were found to be significantly increased, while T-SOD and NSSA values decreased in patients with early pregnancy failure when compared with women undergoing elective abortion (control group). However, there were no significant differences in AOP levels between the groups.

CONCLUSIONS

Our results reflect oxidative stress in placenta tissues of early pregnancy failure, as the oxidative processes seem to be counteracted by the physiologic activation of antioxidant enzymes such as CAT and GSH-Px. Moreover, a compensatory mechanism might be developed against possible oxidative damage in patients with miscarriage.

Effect of co-exposure to lead and cadmium on antioxidant status in rat ovarian granulose cells

The effects of combined exposure to lead and cadmium on granulose cells were studied. Adult female rats were treated i.p. with either lead acetate (LA) or cadmium acetate (CA) both, alone, or in combination at a dose of 0.05 mg/kg body weight on a daily basis for 15 days. Both metals were accumulated in the ovary after metal exposure. Metal exposure caused a decrease in reduced glutathione content along with elevated lipid peroxidation in all groups. Granulose cells of both cadmium as well as combination group demonstrated a maximum increase in lipid peroxides and catalase activity, along with decreased glutathione status and superoxide dismutase activities. Combined treated animals exhibited an intermediate effect in antioxidant status. However, "in vitro" exposure showed no significant change in antioxidant enzymes in all metal exposed cells. Data from the present study indicates that lead and cadmium in isolation and in combination cause oxidative stress. Lead and cadmium in combination do not show additive or synergistic effect indicating the competition between them due to similarity in electronic affinities. Present study highlights the effects of toxic metals that disturb membrane integrity of cells via ROS and thereby classifying mechanism for altered receptor binding, steroidogenesis, and hormone production.

Lipid peroxidation and antioxidant activity in patients in labor with nonreassuring fetal status

OBJECTIVE

The aim of our study was to evaluate lipid peroxidation products and antioxidant enzyme activity in placental tissue and umbilical cord blood, as a marker for fetal hypoxia in patients in labor with nonreassuring fetal status.

STUDY DESIGN

Umbilical cord arterial blood and placental tissue samples were collected from 24 patients with term pregnancies in labor and nonreassuring fetal heart rate (FHR) patterns (study) and 24 women with normal pregnancies in labor and normal FHR tracings (controls) for determination of malondialdehyde (MDA) as a marker for lipid peroxidation and superoxide dismutase (SOD) for the antioxidant activity. Measured values were compared statistically between two groups using independent samples t-test or Mann-Whitney U-test.

RESULTS

The median 1min Apgar score was 8 (range 4-9) in the study group and 9 (range 8-10) in the control group, respectively (p < 0.001). There was no statistically significant difference between study and control groups in terms of mean 5 min Apgar scores (p > 0.05). Placental MDA levels in patients with nonreassuring fetal status were found to be significantly elevated compared to the control group (12.14 nmol/g tissue versus 9.75 nmol/g tissue; p < 0.01). The placental SOD activity in the study group was significantly higher (p < 0.01) compared to controls (3.57 U/mg protein versus 2.63 U/mg protein). The umbilical cord blood MDA levels in the study group were higher than in normal pregnancies (4.99 nmol/mL, 3.88 nmol/mL; p < 0.05). The activity of SOD in umbilical cord blood was significantly higher (p < 0.001) in patients with nonreassuring fetal status when compared with the control group (11.62 versus 6.95 U/mL).

CONCLUSION

Lipid peroxidation products and antioxidant functions were elevated in the umbilical cord blood and placenta of patients having nonreassuring FHR tracings during labor. These findings indicate that lipid peroxidation products in placenta and umbilical cord blood can be used as a possible marker for fetal hypoxia during labor and SOD levels may discriminate acute from chronic hypoxia. Further investigations are needed with large number of series to clarify the variations of lipid peroxidation and antioxidant activity due to acute or chronic fetal hypoxia.

Increased anti-oxidant enzyme activity and biological oxidation in placentae of pregnancies complicated by maternal asthma

Our previous work has demonstrated that alterations in placental function are associated with changes in fetal development in pregnancies complicated by asthma. The pathophysiology of asthma in adults and children and intrauterine growth restriction during pregnancy are associated with oxidative stress. Based on this information, we examined whether placental anti-oxidant pathways and markers of biological oxidation were altered in pregnancies complicated by asthma. Anti-oxidant enzyme activities of superoxide dismutase, glutathione peroxidase and thioredoxin reductase, thioredoxin concentrations, lipid and protein oxidation levels were measured in placentae of pregnancies complicated by asthma and compared to uncomplicated, non-asthmatic pregnancies. Placental tissue homogenates of pregnancies complicated by asthma demonstrated significantly increased levels of lipid peroxidation (25.7+/-1.8 micromol/mg protein versus 12.1+/-1.6 micromol/mg protein, P=0.008) and protein carbonyl concentrations (414.6+/-51.4 units/mg protein versus 222.3+/-32.6 units/mg protein, P=0.0032) when compared to non-asthmatic controls. The activities of the anti-oxidant proteins superoxide dismutase (2.17+/-0.09 units/mg protein versus 1.67+/-0.09 units/mg protein, P=0.014) and thioredoxin reductase (54.0+/-6.9 units/mg protein versus 28.7+/-6.0 units/mg protein, P=0.009) were significantly increased in the presence of maternal asthma. Placental thioredoxin levels (102.9+/-5.3 ng/mg protein versus 92.9+/-8.6 ng/mg protein, P=0.37) and glutathione peroxidase activity (27.3+/-2.2 mmol/min/mg protein versus 28.3+/-2.2 mmol/min/mg, P=0.83) were not significantly different in pregnancies complicated by asthma and non-asthmatic pregnancies. There was no effect of fetal sex, asthma severity or treatment for asthma on these pathways. Maternal asthma during pregnancy is associated with increased placental enzymatic anti-oxidant capacity and also increased protein oxidation suggesting there is a compensatory increase in anti-oxidant activity in response to increased oxidative stress.

Cellular mechanisms of vitamin E uptake: relevance in α-tocopherol metabolism and potential implications for disease

alpha-Tocopherol is an essential micronutrient involved in various oxidative stress-related processes. Because of its hydrophobic nature, alpha-tocopherol is transported in plasma lipoproteins, and the pathways involved in its cellular uptake are closely related to the lipoprotein metabolism. alpha-Tocopherol transfer from plasma to cells can occur by different mechanisms such as uptake facilitated by lipid transfer proteins and lipases, receptor-mediated lipoprotein endocytosis, and selective lipid uptake. Here we discuss recent progress in understanding the physiological and pathophysiological relevance of these different pathways for cellular uptake of vitamin E in vivo. This review is mainly focused on the role of the scavenger receptor class B type I (SR-BI) on alpha-tocopherol metabolism and its potential implications for disease conditions.

Effect of the new thiazolidinedione-pioglitazone on the development of oxidative stress in liver and kidney of diabetic rabbits

Impaired homeostasis under diabetic conditions is connected with the increased production of free radicals and deficiency of antioxidative systems. The aim of this study was to analyze the effect of new oral antidiabetic drug-pioglitazone on activity of antioxidant factors and lipid peroxidation in vivo. The liver and kidney of alloxan-induced diabetic rabbits were examined after 4 and 8 weeks of treatment. After 4 weeks of diabetes the superoxide dismutase (Cu,Zn-SOD) activity in the liver was diminished while the catalase (CAT) activity and the level of ascorbic acid (AA) were elevated in comparison with the control group. Pioglitazone treatment during 4 weeks decreased the catalase activity in relation to the control diabetic animals. After 8 weeks of diabetes the CAT activity in the liver was elevated in comparison with the control group. Pioglitazone treatment during 8 weeks decreased the CAT activity and the level of lipid peroxidation products (LPO), and increased the Cu,Zn-SOD activity in relation to control diabetic animals. After 4 weeks of diabetes in the kidney the Cu,Zn-SOD activity and the level of ascorbic acid (AA) were diminished while the CAT activity and the LPO level were elevated in comparison with the control group. Pioglitazone treatment during 4 weeks increased the AA and decreased the LPO levels in relation to non-treated diabetic animals. After 8 weeks of disease the Cu,Zn-SOD activity in the kidney was diminished in comparison with the control group. Pioglitazone during 8 weeks decreased the LPO level in relation to non-treated diabetic animals. This study shows that diabetic animals undergo an important oxidative stress, which is partially corrected by pioglitazone treatment.

Distribution of components of the glutathione detoxification system across the human placenta after uncomplicated vaginal deliveries

The function of the glutathione-related detoxification system plays an important role to ensure an uncomplicated pregnancy outcome. This study was performed to investigate whether the components of the glutathione-related detoxification system are equally distributed among the different cotelydons in the human placenta. We measured glutathione, cysteine, glutathione S-transferase (GST) isoenzyme levels (GSTA1+A2, GSTP1, GSTM1 and GSTT1), enzyme activities of glutathione S-transferase and glutathione peroxidases, protein carbonyl levels, and antioxidant capacities at twelve different standardized positions in six placentae from healthy women after uncomplicated pregnancy and vaginal delivery. Data were statistically evaluated with a Friedman two-way ANOVA with Bonferroni correction. 'Foetal'-side values were not significantly different from those at the 'maternal'-side. Except for GSTA1+A2, no significant differences were found between different sampling sites indicating that the distribution of all parameters measured was homogenous throughout the placenta. Since levels of GSTA1+A2 were minor compared to those of GSTP1 and GSTT1, the clinical relevance of this heterogeneity may be limited. These results implicate that the location of sampling is not important as long as biopsies are taken from physiological cotelydons.

Alpha-tocopherol metabolism is abnormal in scavenger receptor class B type I (SR-BI)-deficient mice

Despite the physiologic importance of vitamin E, in particular its alpha-tocopherol (alpha-T) isoform, the molecular mechanisms involved in the cellular uptake of this antioxidant from plasma lipoproteins have not been well-defined. Recent studies have suggested that selective lipid uptake, rather than endocytosis, is important for alpha-T delivery to cells. Here we show that the scavenger receptor class B type I (SR-BI), which mediates cellular selective cholesteryl ester uptake from lipoproteins, facilitates efficient transfer of alpha-T from HDL to cultured cells. In SR-BI-deficient mutant mice, relative to wild-type control animals, there was a significant increase in plasma alpha-T levels (1.1- to 1.4-fold higher) that was mostly due to the elevated alpha-T content of their abnormally large plasma HDL-like particles. This increase in plasma alpha-T in SR-BI knockout mice was accompanied by a significant decrease (65-80%) in the alpha-T concentrations in bile and several tissues including ovary, testis, lung and brain. SR-BI deficiency did not alter the alpha-T concentrations of the liver, spleen, kidney or white fat. These data show that SR-BI plays an important role in transferring alpha-T from plasma lipoproteins to specific tissues. Also, in the case of the liver as was previously shown for SR-BI-dependent hepatic cholesterol transport, SR-BI-mediated uptake of alpha-T was primarily coupled to biliary excretion rather than to tissue accumulation. Defective tissue uptake of lipoprotein alpha-T in SR-BI-deficient mice may contribute to the reproductive and cardiovascular pathologies exhibited by these animals.

Alpha-tocopherol transfer protein is important for the normal development of placental labyrinthine trophoblasts in mice

Alpha-tocopherol transfer protein (alpha-TTP), a cytosolic protein that specifically binds alpha-tocopherol, is known as a product of the causative gene in patients with ataxia that is associated with vitamin E deficiency. Targeted disruption of the alpha-TTP gene revealed that alpha-tocopherol concentration in the circulation was regulated by alpha-TTP expression levels. Male alpha-TTP(-/-) mice were fertile; however, placentas of pregnant alpha-TTP(-/-) females were severely impaired with marked reduction of labyrinthine trophoblasts, and the embryos died at mid-gestation even when fertilized eggs of alpha-TTP(+/+) mice were transferred into alpha-TTP(-/-) recipients. The use of excess alpha-tocopherol or a synthetic antioxidant (BO-653) dietary supplement by alpha-TTP(-/-) females prevented placental failure and allowed full-term pregnancies. In alpha-TTP(+/+) animals, alpha-TTP gene expression was observed in the uterus, and its level transiently increased after implantation (4.5 days postcoitum). Our results suggest that oxidative stress in the labyrinth region of the placenta is protected by vitamin E during development and that in addition to the hepatic alpha-TTP, which governs plasma alpha-tocopherol level, the uterine alpha-TTP may also play an important role in supplying this vitamin.

Ontogenic profile of some antioxidants and lipid peroxidation in human placental and fetal tissues

Reactive oxygen species (ROS) pose a serious threat to maternal and fetal health during pregnancy. However, there is little information on the oxidative damage caused by ROS and its protection during prenatal life. The present study highlights the status of various antioxidants in human placental and fetal tissues at different phases of gestation. The activity profile of scavenging enzymes, superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase as well as the concentrations of non-enzymatic antioxidants, ascorbic acid, alpha-tocopherol, bilirubin and glutathione have been determined in human placental whole homogenate, placental brush border membrane and fetal liver over gestational periods ranging from 6 weeks of pregnancy till birth. The ontogenic profile of lipid peroxidation, a marker of oxidative damage has also been investigated in the feto-placental system. Catalase, superoxide dismutase and glutathione reductase activities increased significantly, but glutathione peroxidase activity remained almost the same throughout development. Except alpha-tocopherol and bilirubin, the concentrations of other non-enzymic scavengers followed a significant increasing trend with advancement of pregnancy. Results indicate that there is gradual suppression of lipoperoxide formation with the progress of gestation to protect the fetus against oxygen toxicity.