Increased ascorbate radical formation and ascorbate depletion in plasma from women with preeclampsia: implications for oxidative stress

Can N-acetylcysteine reduce red blood cell transfusion burden in patients with transfusion-dependent β-thalassemia?

Patients with beta-thalassemia major require lifelong and frequent red blood cell transfusions for survival, impacting their quality of life and life expectancy. This treatment approach poses risks of organ damage, iron overload, and increased transfusion-transmitted diseases. N-acetylcysteine (NAC) has been studied for its potential antioxidant effects on hemoglobin stability, aiming to reduce the burden of red blood cell transfusions. To explore this possibility further, we conducted a quasi-experimental study involving 35 individuals with thalassemia major over six months All subjects were already receiving iron chelators and blood transfusions. They were given a daily oral dose of 10 mg/kg NAC for three months. After three months of treatment with NAC, the serum levels of ferritin and liver enzymes (SGOT and SGPT) did not show significant changes (p = 0.35, p = 0.352, and p = 0.686, respectively). However, the red blood cell transfusion burden was significantly reduced in all patients after NAC therapy (p = 0.029), with no corresponding decrease in serum hemoglobin levels (p = 0.931), indicating maintained hemoglobin concentration despite reduced transfusion volume. The study indicates that NAC can effectively decrease the burden of red blood cell transfusions without significant toxicity in these patients. This finding suggests the potential for NAC as a cost-effective and manageable treatment option for these patients. A larger clinical trial with more robust statistical methods could further confirm these results and pave the way for using NAC as a valuable therapeutic agent for managing beta-thalassemia major patients.

Ascorbate and its transporter SVCT2: The dynamic duo's integrated roles in CNS neurobiology and pathophysiology

Ascorbate is a small antioxidant molecule essential for the proper development and function of the brain. Ascorbate is transported into the brain and between brain cells via the Sodium vitamin C co-transporter 2 (SVCT2). This review provides an in-depth analysis of ascorbate's physiology, including how ascorbate is absorbed from food into the CNS, emphasizing cellular mechanisms of ascorbate recycling and release in different CNS compartments. Additionally, the review delves into the various functions of ascorbate in the CNS, including its impact on epigenetic modulation, synaptic plasticity, and neurotransmission. It also emphasizes ascorbate's role on neuromodulation and its involvement in neurodevelopmental processes and disorders. Furthermore, it analyzes the relationship between the duo ascorbate/SVCT2 in neuroinflammation, particularly its effects on microglial activation, cytokine release, and oxidative stress responses, highlighting its association with neurodegenerative diseases, such as Alzheimer's disease (AD). Overall, this review emphasizes the crucial role of the dynamic duo ascorbate/SVCT2 in CNS physiology and pathology and the need for further research to fully comprehend its significance in a neurobiological context and its potential therapeutic applications.

S-Nitrosoglutathione Reductase Deficiency Causes Aberrant Placental S-Nitrosylation and Preeclampsia

Background

Preeclampsia, a leading cause of maternal and fetal mortality and morbidity, is characterized by an increase in S‐nitrosylated proteins and reactive oxygen species, suggesting a pathophysiologic role for dysregulation in nitrosylation and nitrosative stress.

Methods and Results

Here, we show that mice lacking S‐nitrosoglutathione reductase (GSNOR^−⁄−), a denitrosylase regulating protein S‐nitrosylation, exhibit a preeclampsia phenotype, including hypertension, proteinuria, renal pathology, cardiac concentric hypertrophy, decreased placental vascularization, and fetal growth retardation. Reactive oxygen species, NO, and peroxynitrite levels are elevated. Importantly, mass spectrometry reveals elevated placental S‐nitrosylated amino acid residues in GSNOR^−⁄− mice. Ascorbate reverses the phenotype except for fetal weight, reduces the difference in the S‐nitrosoproteome, and identifies a unique set of S‐nitrosylated proteins in GSNOR^−⁄− mice. Importantly, human preeclamptic placentas exhibit decreased GSNOR activity and increased nitrosative stress.

Conclusions

Therefore, deficiency of GSNOR creates dysregulation of placental S‐nitrosylation and preeclampsia in mice, which can be rescued by ascorbate. Coupled with similar findings in human placentas, these findings offer valuable insights and therapeutic implications for preeclampsia.

Assessment of oxidative balance in hydrophilic cellular environment in Chlorella vulgaris exposed to glyphosate

The studied hypothesis is that glyphosate (GLY) can affect the oxidative balance in the hydrophilic intracellular medium in non-target Chlorella vulgaris cells. Analytical GLY (5 μM) and a commercial product (RUP) (5 μM) supplementation, did not affect the growth profile. Neither in latent (Lag) nor in exponential (Exp) phase of development, there were significant differences in the cellular abundance, evaluated as cell number, after the supplementation with GLY or RUP. The ascorbyl (A•) content was significantly increased in the presence of GLY or RUP, in Lag and Exp phase of growth. No changes were observed in stationary (St) phase after supplementation with either GLY or RUP. Ascorbate (AH-) content was decreased by 30% in Exp phase of development the presence of RUP. In St phase of the development both, the administration of either GLY or RUP decreased the antioxidant content by 34 and 37%, respectively. The supplementation with GLY and RUP lead to a significant 5- and 10-fold increase in Exp phase, respectively in the A•/AH-content ratio, assessed as a damage/protection ratio in the hydrophilic fraction of the cells, as compared to controls. Neither GLY nor RUP affected the ratio in cells in St phase of development. The data presented here showed experimental evidence that suggested that oxidative balance in the hydrophilic environment is affected by GLY, even at the low to medium concentrations currently used. The effect seems as reversible either because of the magnitude of the herbicide-dependent damage or the antioxidant activity activated.

Nitric oxide and reactive oxygen species in the pathogenesis of preeclampsia

Preeclampsia (PE) is characterized by disturbed extravillous trophoblast migration toward uterine spiral arteries leading to increased uteroplacental vascular resistance and by vascular dysfunction resulting in reduced systemic vasodilatory properties. Its pathogenesis is mediated by an altered bioavailability of nitric oxide (NO) and tissue damage caused by increased levels of reactive oxygen species (ROS). Furthermore, superoxide (O₂⁻) rapidly inactivates NO and forms peroxynitrite (ONOO⁻). It is known that ONOO⁻ accumulates in the placental tissues and injures the placental function in PE. In addition, ROS could stimulate platelet adhesion and aggregation leading to intravascular coagulopathy. ROS-induced coagulopathy causes placental infarction and impairs the uteroplacental blood flow in PE. The disorders could lead to the reduction of oxygen and nutrients required for normal fetal development resulting in fetal growth restriction. On the other hand, several antioxidants scavenge ROS and protect tissues against oxidative damage. Placental antioxidants including catalase, superoxide dismutase (SOD), and glutathione peroxidase (GPx) protect the vasculature from ROS and maintain the vascular function. However, placental ischemia in PE decreases the antioxidant activity resulting in further elevated oxidative stress, which leads to the appearance of the pathological conditions of PE including hypertension and proteinuria. Oxidative stress is defined as an imbalance between ROS and antioxidant activity. This review provides new insights about roles of oxidative stress in the pathophysiology of PE.

Review: maternal and placental antioxidant response to preeclampsia - impact on vasoactive eicosanoids

The abnormally developed placenta is believed to be the pathophysiological cause of preeclampsia (PE). The resulting malperfusion of the placenta in PE can be associated with fluctuations in oxygen levels, leading to oxidative stress. How then do the placenta and the circulatory system of the mother adapt and respond to the increased oxidative challenge associated with PE? Many antioxidant systems have been shown to be upregulated or downregulated in the placenta and/or the maternal circulation during PE. Such altered antioxidant response can lead to increased lipid peroxidation. Oxidation of arachidonoyl residues in phospholipids generates bioactive lipids such as F2-isoprostanes, which are known vasoconstrictors. The consequences of changes in antioxidant status can also affect signal transduction and enzymatic pathways related to eicosanoid synthesis.

Acute iron overload and oxidative stress in brain

An in vivo model in rat was developed by intraperitoneally administration of Fe-dextran to study oxidative stress triggered by Fe-overload in rat brain. Total Fe levels, as well as the labile iron pool (LIP) concentration, in brain from rats subjected to Fe-overload were markedly increased over control values, 6h after Fe administration. In this in vivo Fe overload model, the ascorbyl (A)/ascorbate (AH(-)) ratio, taken as oxidative stress index, was assessed. The A/AH(-) ratio in brain was significantly higher in Fe-dextran group, in relation to values in control rats. Brain lipid peroxidation indexes, thiobarbituric acid reactive substances (TBARS) generation rate and lipid radical (LR) content detected by Electron Paramagnetic Resonance (EPR), in Fe-dextran supplemented rats were similar to control values. However, values of nuclear factor-kappaB deoxyribonucleic acid (NFκB DNA) binding activity were significantly increased (30%) after 8h of Fe administration, and catalase (CAT) activity was significantly enhanced (62%) 21h after Fe administration. Significant enhancements in Fe content in cortex (2.4 fold), hippocampus (1.6 fold) and striatum (2.9 fold), were found at 6h after Fe administration. CAT activity was significantly increased after 8h of Fe administration in cortex, hippocampus and striatum (1.4 fold, 86, and 47%, respectively). Fe response in the whole brain seems to lead to enhanced NF-κB DNA binding activity, which may contribute to limit oxygen reactive species-dependent damage by effects on the antioxidant enzyme CAT activity. Moreover, data shown here clearly indicate that even though Fe increased in several isolated brain areas, this parameter was more drastically enhanced in striatum than in cortex and hippocampus. However, comparison among the net increase in LR generation rate, in different brain areas, showed enhancements in cortex lipid peroxidation, without changes in striatum and hippocampus LR generation rate after 6h of Fe overload. This information has potential clinical relevance, as it could be the key to understand specific brain damage occurring in conditions of Fe overload.

Electronic paramagnetic resonance (EPR) for the study of ascorbyl radical and lipid radicals in marine organisms

Electron paramagnetic resonance (EPR) spectroscopy detects the presence of radicals of biological interest, such as ascorbyl radical (A(•)) and lipid radicals. A(•) is easily detectable by EPR even in aqueous solution at room-temperature. Under oxidative conditions leading to changes in total ascorbate (AH(-)) content, the A(•)/AH(-) ratio could be used to estimate early oxidative stress in the hydrophilic milieu. This methodology was applied to a wide range of aquatic systems including algae, sea urchin, limpets, bivalves and fish, under physiological and oxidative stress conditions as well. The A(•)/AH(-) ratio reflected the state of one part of the oxidative defense system and provided an early and simple diagnosis of environmental stressing conditions. Oxidative damage to lipids was assessed by the EPR-sensitive adduct formation that correlates well with cell membrane damage with no interference from other biological compounds. Probe instability, tissue metabolism, and lack of spin specificity are drawback factors for employing EPR for in vivo determination of free radicals. However, the dependability of this technique, mostly by combining it with other biochemical strategies, enhances the value of these procedures as contributors to the knowledge of oxidative condition in aquatic organisms.

A kinetic approach to assess oxidative metabolism related features in the bivalve Mya arenaria

Electron paramagnetic resonance uses the resonant microwave radiation absorption of paramagnetic substances to detect highly reactive and, therefore, short-lived oxygen and nitrogen centered radicals. Previously, steady state concentrations of nitric oxide, ascorbyl radical (A·) and the labile iron pool (LIP) were determined in digestive gland of freshly collected animals from the North Sea bivalve Mya arenaria. The application of a simple kinetic analysis of these data based on elemental reactions allowed us to estimate the steady state concentrations of superoxide anion, the rate of A· disappearance and the content of unsaturated lipids. This analysis applied to a marine invertebrate opens the possibility of a mechanistic understanding of the complexity of free radical and LIP interactions in a metabolically slow, cold water organism under unstressed conditions. This data can be further used as a basis to assess the cellular response to stress in a simple system as the bivalve M. arenaria that can then be compared to cells of higher organisms.

Serum carotenoids and fat-soluble vitamins in women with type 1 diabetes and preeclampsia: a longitudinal study

OBJECTIVE

Increased oxidative stress and immune dysfunction are implicated in preeclampsia (PE) and may contribute to the two- to fourfold increase in PE prevalence among women with type 1 diabetes. Prospective measures of fat-soluble vitamins in diabetic pregnancy are therefore of interest.

RESEARCH DESIGN AND METHODS

Maternal serum carotenoids (α- and β-carotene, lycopene, and lutein) and vitamins A, D, and E (α- and γ-tocopherols) were measured at first (12.2 ± 1.9 weeks [mean ± SD], visit 1), second (21.6 ± 1.5 weeks, visit 2), and third (31.5 ± 1.7 weeks, visit 3) trimesters of pregnancy in 23 women with type 1 diabetes who subsequently developed PE (DM PE+) and 24 women with type 1 diabetes, matched for age, diabetes duration, HbA(1c), and parity, who did not develop PE (DM PE-). Data were analyzed without and with adjustment for baseline differences in BMI, HDL cholesterol, and prandial status.

RESULTS

In unadjusted analysis, in DM PE+ versus DM PE-, α-carotene and β-carotene were 45 and 53% lower, respectively, at visit 3 (P < 0.05), before PE onset. In adjusted analyses, the difference in β-carotene at visit 3 remained significant. Most participants were vitamin D deficient (<20 ng/mL), and vitamin D levels were lower in DM PE+ versus DM PE- throughout the pregnancy, although this did not reach statistical significance.

CONCLUSIONS

In pregnant women with type 1 diabetes, low serum α- and β-carotene were associated with subsequent development of PE, and vitamin D deficiency may also be implicated.

Combined vitamin C and E supplementation for the prevention of preeclampsia: a systematic review and meta-analysis

OBJECTIVE

To perform a systematic review and meta-analysis of the effectiveness of combined vitamin C and E (vitCE) supplementation for the prevention of preeclampsia.

DATA SOURCES

PubMED, Web of Science, and Cochrane Central Register of Controlled Trials from inception through June 2010, and bibliographies of review articles and eligible studies.

METHODS OF STUDY SELECTION

Fifteen eligible studies that evaluated vitCE supplementation for the prevention of preeclampsia were identified. On the basis of prespecified inclusion and exclusion criteria, 9 were included in the meta-analysis. All were randomized controlled trials. The reporting and methodologic quality of the included studies was assessed with the CONSORT checklist and the Jadad scale.

TABULATION, INTEGRATION, AND RESULTS

The 9 included studies had moderate-to-high CONSORT and Jadad scores. The incidence of preeclampsia was 9.7% (949 of 9833) in the vitCE group and 9.5% (946 of 9842) in the placebo group. A random effects model was used for pooling and no difference was found in the relative risk (RR) of preeclampsia between the vitCE and placebo groups (RR: 0.98; 95% confidence interval [CI]: 0.87-1.10). The incidence of gestational hypertension was 22.6% (1915 of 8491) in the vitCE group and 20.3% (1728 of 8500) in the placebo group (RR: 1.11, 95% CI: 1.05-1.17). The incidence of placental abruption was 0.58% (43 of 7379) in the vitCE group and 0.87% (64 of 7361) in the placebo group (RR: 0.67, 95% CI: 0.46-0.98). No significant differences were observed for other maternal and neonatal outcomes.

CONCLUSION

Combined VitCE supplementation does not decrease the risk of preeclampsia and should not be offered to gravidas for the prevention of preeclampsia or other pregnancy induced hypertensive disorders. Furthermore, combined supplementation with vitCE increased the risk of GH but decreased the risk of placental abruption. However, these latter associations may not be causal, especially since they were the product of multiple statistical comparisons, and the 95% CI around the point estimates almost included one.

LEARNING OBJECTIVES

After completion of this educational activity, the obstetrician/gynecologist should be better able to assess the causes of preeclampsia and related conditions; evaluate and interpret the evidence regarding the use of combined vitamins C and E in prevention of preeclampsia and related conditions; and interpret and understand the effects of the supplementation of vitamins C and E for the prevention of preeclampsia or other pregnancy induced hypertensive disorders.

TARGET AUDIENCE

Obstetricians & Gynecologists, Family Physicians.

Maternal nutrition and perinatal outcomes

Diet and patterns of eating during pregnancy can affect perinatal outcomes through direct physiologic effects or by stressing the fetus in ways that permanently affect phenotype. Supplements are not a magic nutritional remedy, and evidence of profound benefit for most supplements remains inconclusive. However, research supports calcium supplements to decrease preeclampsia. Following a low glycemic, Mediterranean-type diet appears to improve ovulatory infertility, decrease preterm birth, and decrease the risk of gestational diabetes. Although women in the United States have adequate levels of most nutrients, subpopulations are low in vitamin D, folate, and iodine. Vitamin D has increasingly been shown to be important not only for bone health, but also for glucose regulation, immune function, and good uterine contractility in labor. To ensure adequate vitamin and micronutrient intake, especially of folate before conception, all reproductive age women should take a multivitamin daily. In pregnancy, health care providers need to assess women's diets, give them weight gain recommendations based on their body mass index measurement, and advise them to eat a Mediterranean diet rich in omega-3 fatty acids (ingested as low-mercury risk fatty fish or supplements), ingest adequate calcium, and achieve adequate vitamin D levels through sun exposure or supplements. Health care providers should continue to spend time on nutrition assessment and counseling.

The role of EPR spectroscopy in studies of the oxidative status of biological systems and the antioxidative properties of various compounds

In this era of intense study of free radicals and antioxidants, electron paramagnetic resonance (EPR) is arguably the best-suited technique for such research, particularly when considering biochemical and biological systems. No attempt was made to cover all the topics of EPR application but instead attention was restricted to two areas that are both novel and received less attention in previous reviews. In the first section, the application of EPR in assessing the oxidative status of various biological systems, using endogenous stabile paramagnetic species, such as the ascorbyl radical, semiquinone, melanin, and oxidized pigments, is addressed. The second section covers the use of EPR in the emerging field of antioxidant development, using EPR spin-trapping and spin-probing techniques. In both sections, in addition to giving an overview of the available literature, examples (mostly from the authors? recent work) are also presented in sufficient detail to illustrate how to explore the full potential of EPR. This review aims at encouraging biologists, chemists and pharmacologists interested in the redox metabolism of living systems, free radical chemistry or antioxidative properties of new drugs and natural products to take advantage of this technique for their investigations.

Electron Paramagnetic Resonance - A Powerful Tool of Medical Biochemistry in Discovering Mechanisms of Disease and Treatment Prospects

In pathophysiological conditions related to oxidative stress, the application of selected antioxidants could have beneficial effects on human health. Electron paramagnetic resonance (EPR) spectroscopy is a technique that provides unique insight into the redox biochemistry, due to its ability to: (i) distinguish and quantify different reactive species, such as hydroxyl radical, superoxide, carbon centered radicals, hydrogen atom, nitric oxide, ascorbyl radical, melanin, and others; (ii) evaluate the antioxidative capacity of various compounds, extracts and foods; (iii) provide information on other important parameters of biological systems. A combination of EPR spectroscopy and traditional biochemical methods represents an efficient tool in the studies of disease mechanisms and antioxidative therapy prospects, providing a more complete view into the redox processes in the human organism.

Evidence of increased oxidative stress and a change in the plasminogen activator inhibitor (PAI)-1 to PAI-2 ratio in early-onset but not late-onset preeclampsia

OBJECTIVE

The aims of this study were to measure the degree of oxidative stress and alterations in plasminogen activator inhibitor (PAI) type 1 and PAI-2 ratio in women with early-onset and late-onset preeclampsia.

STUDY DESIGN

A case-control study was conducted in women with early-onset (24-32 weeks' gestation; n=18) and late-onset (35-42 weeks' gestation; n=20) preeclampsia and in control pregnant women at corresponding gestational weeks. Placenta, urine, and serum samples were collected.

RESULTS

In early-onset preeclampsia, the median placental concentration of 8-iso-prostaglandin (PG)-F2alpha was higher and the PAI-1 to PAI-2 ratio higher than in early controls. These values did not differ between women with late-onset preeclampsia and their corresponding controls. Serum concentrations of 8-iso-PGF2alpha and vitamins C and E did not differ between cases and controls.

CONCLUSION

Early-onset but not late-onset preeclampsia is associated with increased placental oxidative stress and increased PAI-1 to PAI-2 ratio.

Peroxidase activity of hemoglobin-haptoglobin complexes: covalent aggregation and oxidative stress in plasma and macrophages

As a hemoprotein, hemoglobin (Hb) can, in the presence of H(2)O(2), act as a peroxidase. In red blood cells, this activity is regulated by the reducing environment. For stroma-free Hb this regulation is lost, and the potential for Hb to become a peroxidase is high and further increased by inflammatory cells generating superoxide. The latter can be converted into H(2)O(2) and feed Hb peroxidase activity. Haptoglobins (Hp) bind with extracellular Hb and reportedly weaken Hb peroxidase activity. Here we demonstrate that: (i) Hb peroxidase activity is retained upon binding with Hp; (ii) in the presence of H(2)O(2), Hb-Hp peroxidase complexes undergo covalent cross-linking; (iii) peroxidase activity of Hb-Hp complexes and aggregates consumes reductants such as ascorbate and nitric oxide; (iv) cross-linked Hb-Hp aggregates are taken up by macrophages at rates exceeding those for noncovalently cross-linked Hb-Hp complexes; (v) the engulfed Hb-Hp aggregates activate superoxide production and induce intracellular oxidative stress (deplete endogenous glutathione and stimulate lipid peroxidation); (vi) Hb-Hp aggregates cause cytotoxicity to macrophages; and (vii) Hb-Hp aggregates are present in septic plasma. Overall, our data suggest that under conditions of severe inflammation and oxidative stress, peroxidase activity of Hb-Hp covalent aggregates may cause macrophage dysfunction and microvascular vasoconstriction, which are commonly seen in severe sepsis and hemolytic diseases.

Ferritin-dependent radical generation in rat liver homogenates

The hypothesis of this study was that mammalian ferritin (FER) has the ability of releasing Fe in the tissue to catalyze the generation of free radicals, such as ascorbyl (A) and hydroxyl radical (OH), that might lead to the damage of FER itself. The rat liver homogenates exhibited an electron paramagnetic resonance (EPR) signal with the spectral features (a(H)=1.88 G, g=2.0054) of A. The addition to the reaction medium of isolated rat liver FER increased by 3-fold the EPR signal, as compared to the recorded value in its absence. Isolated microsomes from rat liver incubated during 10 min showed a signal with the spectral features (a(H)=15G, g=2.0062) of OH. The addition of FER in the presence of either ethylenediamine-tetraacetic acid (EDTA) or adenosine-5'-triphosphate (ATP) significantly increased the recorded spectra. The labile Fe pool (LIP) in the homogenate was assessed by EPR. The rat liver homogenates exhibited an EPR signal with the spectral features (g=4.3) of the Fe(2+) and was significantly increased by the addition of FER (3-fold). The oxidation profile of the isolated FER from rat liver was analyzed after incubation with 10 mM ascorbate (AH(-)). A drastic increase in the width of the band suggested alterations to the protein structure. The FER content of tryptophan (Trp) and thiols was significantly lower when the incubation was performed in the presence of AH(-) as compared to the recorded effect in its absence. The data in tissue homogenates presented here showed that radical generation is associated to FER Fe release, and moreover that the FER protein itself was affected during this process.

Reducing stillbirths: prevention and management of medical disorders and infections during pregnancy

BACKGROUND

An estimated two-thirds of the world's 3.2 million stillbirths occur antenatally, prior to labour, and are often overlooked in policy and programs. Poorly recognised, untreated or inadequately treated maternal infections such as syphilis and malaria, and maternal conditions including hypertensive disorders, are known risk factors for stillbirth.

METHODS

We undertook a systematic review of the evidence for 16 antenatal interventions with the potential to prevent stillbirths. We searched a range of sources including PubMed and the Cochrane Library. For interventions with prior Cochrane reviews, we conducted additional meta-analyses including eligible newer randomised controlled trials following the Cochrane protocol. We focused on interventions deliverable at the community level in low-/middle-income countries, where the burden of stillbirths is greatest.

RESULTS

Few of the studies we included reported stillbirth as an outcome; most that did were underpowered to assess this outcome. While Cochrane reviews or meta-analyses were available for many interventions, few focused on stillbirth or perinatal mortality as outcomes, and evidence was frequently conflicting. Several interventions showed clear evidence of impact on stillbirths, including heparin therapy for certain maternal indications; syphilis screening and treatment; and insecticide-treated bed nets for prevention of malaria. Other interventions, such as management of obstetric intrahepatic cholestasis, maternal anti-helminthic treatment, and intermittent preventive treatment of malaria, showed promising impact on stillbirth rates but require confirmatory studies. Several interventions reduced known risk factors for stillbirth (e.g., anti-hypertensive drugs for chronic hypertension), yet failed to show statistically significant impact on stillbirth or perinatal mortality rates. Periodontal disease emerged as a clear risk factor for stillbirth but no interventions have reduced stillbirth rates.

CONCLUSION

Evidence for some newly recognised risk factors for stillbirth, including periodontal disease, suggests the need for large, appropriately designed randomised trials to test whether intervention can minimise these risks and prevent stillbirths. Existing evidence strongly supports infection control measures, including syphilis screening and treatment and malaria prophylaxis in endemic areas, for preventing antepartum stillbirths. These interventions should be incorporated into antenatal care programs based on attributable risks and burden of disease.

Increased lectin-like oxidized low-density lipoprotein receptor-1 expression in the maternal vasculature of women with preeclampsia: role for peroxynitrite

Preeclampsia is a hypertensive disorder unique to pregnancy, in which the placenta may release factors into the maternal circulation resulting in systemic effects. Small dense low-density lipoprotein (LDL; which is susceptible for oxidation) is increased in preeclampsia. Lectin-like oxidized LDL receptor-1 (LOX-1) is a receptor for oxidized LDL. However, the expression levels and the regulation of LOX-1 in the maternal vasculature of women with preeclampsia are unknown. We hypothesized that there is an increased LOX-1 expression in arteries from women with preeclampsia. We further hypothesized that circulating factors in the plasma of women with preeclampsia would upregulate the LOX-1 expression in vascular endothelial cells and contribute to vascular endothelial oxidative stress. We observed abundant LOX-1 expression and the presence of oxidized LDL in arteries from women with preeclampsia, which was negligible in arteries from normotensive pregnant women. Human umbilical vein endothelial cells treated for 24 hours with 2% plasma from preeclamptic women increased LOX-1 expression and oxidized LDL uptake, as well as induced oxidative stress, as evidenced by increased NADPH oxidase activity and superoxide and peroxynitrite levels. These effects were significantly reduced by pretreatment with blocking antibody or small interfering RNA to LOX-1, as well as 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrinato iron (III), chloride (FeTPPS), a peroxynitrite scavenger. Exogenous peroxynitrite and 3-morpholino sydnonimine (SIN-1) increased LOX-1 protein and mRNA expression. In conclusion, increased LOX-1 expression in the systemic vasculature of preeclampsia women provides a fundamental insight into the pathology of preeclampsia and likely contributes to the induction and maintenance of vascular oxidative stress.

Uric acid inhibits placental system A amino acid uptake

Hyperuricemia, a common clinical characteristic of preeclamptic pregnancies, has historically been considered a marker of reduced renal function in preeclamptic women. More recently it has been suggested that uric acid may directly contribute to pathological cell signaling events involved in disease progression as well as maternal and fetal pregnancy outcomes including fetal growth restriction. We hypothesize that the increased frequency of restricted fetal growth seen in relation to increasing uric acid concentrations in preeclamptic women is in part the result of uric acid-induced reductions in amino acid transport across the placenta. The objective of the current study was to examine the effects of uric acid on human placental System A amino acid transport using a primary placental villous explant model. Further, we examined the necessity of uric acid uptake and the role of redox signaling as a potential mechanism through which uric acid may attenuate System A activity. Placental uptake of a radiolabeled amino acid analogue, specific to the System A transporter, was reduced in a concentration-dependent fashion with increasing uric acid (0-7 mg/dL), corresponding to uric acid concentrations measured in healthy pregnant and preeclamptic women in the third trimester. Uric acid-induced reduction in System A activity was partially reversed by NADPH oxidase inhibition and completely eliminated by antioxidant treatment. This study demonstrates inhibition of placental System A amino acid transport with uric acid treatment, as a result of uric acid-induced stimulation of intracellular redox signaling cascades. These findings may be relevant to the increased frequency of fetal growth restriction observed in hyperuricemic preeclampsia. Additionally the results of this study, indicating a detrimental effect of hyperuricemia on amino acid transport in the placenta, at concentrations present in women with preeclampsia, also suggest a role for uric acid in the pathophysiology of preeclampsia.

Redox considerations in female reproductive function and assisted reproduction: from molecular mechanisms to health implications

Physiological levels of reactive oxygen species (ROS) play an important regulatory role through various signaling transduction pathways in folliculogenesis, oocyte maturation, endometrial cycle, luteolysis, implantation, embryogenesis, and pregnancy. Persistent and elevated generation of ROS leads to a disturbance of redox potential that in turn causes oxidative stress (OS). Our literature review captures the role of ROS in modulating a range of physiological functions and pathological processes affecting the female reproductive life span and even thereafter (i.e., menopause). The role of OS in female reproduction is becoming increasingly important, as recent evidence suggest that it plays a part in conditions such as polycystic ovarian disease, endometriosis, spontaneous abortions, preeclampsia, hydatidiform mole, embryopathies, preterm labor, and intrauterine growth retardation. OS has been implicated in different reproductive scenarios and is detrimental to both natural and assisted fertility. Many extrinsic and intrinsic conditions exist in assisted reproduction settings that can be tailored to reduce the toxic effects of ROS. Laboratory personnel should avoid procedures that are known to be deleterious, especially when safer procedures that can prevent OS are available. Although antioxidants such as folate, zinc, and thiols may help enhance fertility, the available data are contentious and must be evaluated in controlled studies with larger populations.

Preeclampsia and future cardiovascular risk: formal risk factor or failed stress test?

It is estimated that 10% of pregnancies are affected by hypertension worldwide. Approximately one-half of all hypertensive pregnancy disorders are due to preeclampsia, a pregnancy-specific disorder, its distinctive feature being either sudden onset, or worsening of pre-existing proteinuria. It has become increasingly recognized that women with a history of preeclampsia are at increased risk for future cardiovascular disease (CVD), but the mechanisms of this increase in risk are unclear. One possible explanation is that these two conditions share several common metabolic abnormalities as risk factors, including obesity, insulin resistance, and lipid abnormalities that may lead to preeclampsia and CVD at different times of a woman's life. Recent studies have revealed that, similar to CVD, several mediators of endothelial cell dysfunction are up-regulated in preeclampsia. Free radical derived oxidative stress, various inflammatory markers, including neutrophil response, C-reactive protein, and leukocyte adhesion, may contribute to endothelial dysfunction in both preeclampsia and coronary atherosclerosis. Alternatively, preeclampsia itself may induce metabolic and vascular changes that may increase the overall future risk for CVD in affected women. Therefore, at present, it remains unclear whether preeclampsia is a formal risk factor for CVD, or identifies women at increased risk for CVD later in life. Pending large-scale studies aiming to examine the causality of this association, women with a history of preeclampsia should be counseled regarding their increased risks for hypertension and other cardiovascular sequelae later in life, followed closely and treated aggressively for modifiable CVD risk factors.

The planetary biology of ascorbate and uric acid and their relationship with the epidemic of obesity and cardiovascular disease

Humans have relatively low plasma ascorbate levels and high serum uric acid levels compared to most mammals due to the presence of genetic mutations in l-gulonolactone oxidase and uricase, respectively. We review the major hypotheses for why these mutations may have occurred. In particular, we suggest that both mutations may have provided a survival advantage to early primates by helping maintain blood pressure during periods of dietary change and environmental stress. We further propose that these mutations have the inadvertent disadvantage of increasing our risk for hypertension and cardiovascular disease in today's society characterized by Western diet and increasing physical inactivity. Finally, we suggest that a "planetary biology" approach in which genetic changes are analyzed in relation to their biological action and historical context may provide the ideal approach towards understanding the biology of the past, present and future.

Uric acid as a pathogenic factor in preeclampsia

Hyperuricemia is a common finding in preeclamptic pregnancies evident from early pregnancy. Despite the fact that elevated uric acid often pre-dates the onset of clinical manifestations of preeclampsia, hyperuricemia is usually considered secondary to altered kidney function. Increased serum uric acid is associated with hypertension, renal disease and adverse cardiovascular events in the non-pregnant population and with adverse fetal outcomes in hypertensive pregnancies. We hypothesize that an elevated concentration of uric acid in preeclamptic women is not simply a marker of disease severity but rather contributes directly to the pathogenesis of the disorder. Using epidemiological and experimental evidence, gained largely outside of pregnancy, we will propose pathogenic roles for uric acid in preeclamptic pregnancies. Uric acid's ability to promote inflammation, oxidative stress and endothelial dysfunction will be highlighted with discussions of the potential impact on placental development and function and maternal vascular health.

Oxidative lipidomics of gamma-irradiation-induced intestinal injury

Although gamma-irradiation-induced tissue injury has been associated with lipid peroxidation, the individual phospholipid molecular targets have not been identified. We employed oxidative lipidomics to qualitatively and quantitatively characterize phospholipid peroxidation in a radiosensitive tissue, the small intestine, of mice exposed to total body irradiation (TBI) (10 and 15 Gy). Using electrospray ionization mass spectrometry we found that the major classes of intestine phospholipids-phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, and phosphatidylinositol-included clusters with highly oxidizable molecular species containing docosahexaenoic fatty acid. Molecular species of cardiolipin were represented by only two major less oxidizable individual molecular species-tetralinoleoylcardiolipin and trilinoleoyl-mono-oleoylcardiolipin. Selective and robust oxidation of two anionic phospholipids-cardiolipin in mitochondria and phosphatidylserine outside of mitochondria-was observed 24 h after gamma-irradiation. MS analysis detected several TBI-induced molecular species of oxidized cardiolipin: (C(18:2))(3)(C(18:2)-OOH), (C(18:2))(2)(C(18:2)-OOH)(2), (C(18:2))(1)(C(18:2)-OOH)(3), and (C(18:2)-OOH)(4). The major molecular species involved in TBI-triggered peroxidation of phosphatidylserine included C(18:0)/C(22:6)-OOH, C(18:0)/C(22:5)-OOH, and C(18:0)/C(22:4)-OOH. More abundant phospholipids-phosphatidylcholine and phosphatidylethanolamine-did not reveal any oxidative stress responses despite the presence of highly oxidizable docosahexaenoic fatty acid residues in their molecular species. A marked activation of caspases 3/7 that was detected in the intestine of gamma-irradiated mice indicates the involvement of apoptotic cell death in the TBI injury. Given that oxidized molecular species of cardiolipin and phosphatidylserine accumulate during apoptosis of different cells in vitro we speculate that cardiolipin and phosphatidylserine oxidation products may be useful as potential biomarkers of gamma-irradiation-induced intestinal apoptosis in vivo and may represent a promising target for the discovery of new radioprotectors and radiosensitizers.

Antioxidants for preventing pre-eclampsia

BACKGROUND

Oxidative stress has been proposed as a key factor involved in the development of pre-eclampsia. Supplementing women with antioxidants during pregnancy may help to counteract oxidative stress and thereby prevent or delay the onset of pre-eclampsia.

OBJECTIVES

To determine the effectiveness and safety of any antioxidant supplementation during pregnancy and the risk of developing pre-eclampsia and its related complications.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (May 2007), the Cochrane Central Register of Controlled Trials (The Cochrane Library 2006, Issue 3), MEDLINE (1950 to October 2007) and Current Contents (1998 to August 2004).

SELECTION CRITERIA

All randomised trials comparing one or more antioxidants with either placebo or no antioxidants during pregnancy for the prevention of pre-eclampsia, and trials comparing one or more antioxidants with another, or with other interventions.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and trial quality and extracted data.

MAIN RESULTS

Ten trials, involving 6533 women, were included in this review, five trials were rated high quality. For the majority of trials, the antioxidant assessed was combined vitamin C and E therapy. There was no significant difference between antioxidant and control groups for the relative risk (RR) of pre-eclampsia (RR 0.73, 95% confidence intervals (CI) 0.51 to 1.06; nine trials, 5446 women) or any other primary outcome: severe pre-eclampsia (RR 1.25, 95% CI 0.89 to 1.76; two trials, 2495 women), preterm birth (before 37 weeks) (RR 1.10, 95% CI 0.99 to 1.22; five trials, 5198 women), small-for-gestational-age infants (RR 0.83, 95% CI 0.62 to 1.11; five trials, 5271 babies) or any baby death (RR 1.12, 95% CI 0.81 to 1.53; four trials, 5144 babies). Women allocated antioxidants were more likely to self-report abdominal pain late in pregnancy (RR 1.61, 95% CI 1.11 to 2.34; one trial, 1745 women), require antihypertensive therapy (RR 1.77, 95% CI 1.22 to 2.57; two trials, 4272 women) and require an antenatal hospital admission for hypertension (RR 1.54, 95% CI 1.00 to 2.39; one trial, 1877 women). However, for the latter two outcomes, this was not clearly reflected in an increase in any other hypertensive complications.

AUTHORS' CONCLUSIONS

Evidence from this review does not support routine antioxidant supplementation during pregnancy to reduce the risk of pre-eclampsia and other serious complications in pregnancy.

Nitric oxide for preventing pre-eclampsia and its complications

BACKGROUND

Pre-eclampsia, a multisystem disorder of pregnancy characterised by high blood pressure and protein in the urine, is associated with endothelial dysfunction. Nitric oxide mediates many functions of the endothelium, including vasodilatation and inhibition of platelet aggregation. Pre-eclampsia may be associated with nitric oxide deficiency, but the evidence to support this suggestion is contradictory. Nevertheless, it has been hypothesised that agents which increase nitric oxide may prevent pre-eclampsia.

OBJECTIVES

To assess the effectiveness and safety of nitric oxide donors and precursors for preventing pre-eclampsia and its complications.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (November 2006), CENTRAL (The Cochrane Library 2006, Issue 3), and EMBASE (2002 to December 2004).

SELECTION CRITERIA

Studies were included if they were randomised trials evaluating nitric oxide donors or precursors for preventing pre-eclampsia and its complications.

DATA COLLECTION AND ANALYSIS

Both review authors independently assessed studies for inclusion. Data were extracted and double checked for accuracy.

MAIN RESULTS

Six trials (310 women) were included. Four were of good quality and two were of uncertain quality. Four trials (170 women) compared nitric oxide donors (glyceryl trinitrate) or precursors (L-arginine) with either placebo or no intervention. There are insufficient data for reliable conclusions about the effects on pre-eclampsia (four trials, 170 women; relative risk (RR) 0.83, 95% confidence interval (CI) 0.49 to 1.41) or its complications. One trial (36 women) compared a nitric oxide donor with nifedipine, and another (76 women) compared it with antiplatelet agents. Both were too small for reliable conclusions about possible differential effects. Glyceryl trinitrate was associated with an increased risk of headache (two trials, 56 women; RR 6.85, 95% CI 1.42 to 33.04), and of stopping treatment (two trials, 56 women; RR 4.02, 95% CI 1.15 to 14.09) compared to placebo. However, the increase for both outcomes was due to an extreme result in one small trial (7/7 versus 0/9 for both outcomes).

AUTHORS' CONCLUSIONS

There is insufficient evidence to draw reliable conclusions about whether nitric oxide donors and precursors prevent pre-eclampsia or its complications.

Could antioxidant supplementation prevent pre-eclampsia?

Pre-eclampsia is a disorder characterised by pregnancy-induced hypertension and new-onset proteinuria occurring in the second half of pregnancy. Worldwide, approximately 2–3% of all pregnant women develop pre-eclampsia. The condition is a major cause of maternal and fetal morbidity and mortality. Abnormal placentation is an important predisposing factor for pre-eclampsia, while endothelial activation appears to be central to the pathophysiological changes, possibly indicative of a two-stage disorder characterised by reduced placental perfusion and a maternal syndrome. There is increasing evidence that pre-eclampsia is associated with both increased oxidative stress and reduced antioxidant defences, which has led to the hypothesis that oxidative stress may play an important role in the pathogenesis of pre-eclampsia, perhaps acting as the link in a two-stage model of pre-eclampsia. In support of this hypothesis a small, but important, preliminary study has shown a highly significant (P= 0.02) reduction in the incidence of pre-eclampsia in women at risk who were taking a supplement of vitamins C and E from mid-pregnancy. Furthermore, these findings support the hypothesis that oxidative stress is at least partly responsible for the endothelial dysfunction of pre-eclampsia. Several larger multicentre trials are currently underway to evaluate the efficacy, safety and cost benefits of antioxidant supplementation during pregnancy for the prevention of pre-eclampsia in both low- and high-risk women, including women with diabetes. The results of these trials are awaited with interest.

Thromboxane mediates neutrophil superoxide production in pregnancy

OBJECTIVE

We recently reported that activation of neutrophils obtained from pregnant women resulted in production of tumor necrosis factor-alpha by a thromboxane- and cyclooxygenase-2- dependent mechanism. Activated neutrophils also generate reactive oxygen species such as the superoxide anion, which can lead to oxidative damage of biomolecules. In this study, we tested the possibility that thromboxane plays a role in neutrophil superoxide generation in pregnancy via cyclooxygenase-2 by inhibiting key enzymes in the pathway leading to its synthesis.

STUDY DESIGN

Neutrophils were isolated from normal pregnant women and incubated for 2 hours in phosphate-buffered saline with glucose alone or with treatments. Experiment 1 treatments were: (1) indomethacin at a dose sufficient to inhibit phospholipase A2 (100 microM); (2) aspirin (100 microM), a cyclooxygenase-1 and cyclooxygenase-2 inhibitor; (3) NS-398 (10 microM), a specific cyclooxygenase-2 inhibitor; (4) nordihydroguaiaretic acid (10 microM), a lipoxygenase inhibitor; and (5) pinane thromboxane, a thromboxane synthase inhibitor. Experiment 2 treatments were arachidonic acid (50 microM and 100 microM) and arachidonic acid (100 microM) alone or in combination with phorbol myristic acid plus varying doses of pinane thromboxane (5 microM to 100 microM).

RESULTS

Indomethacin inhibited superoxide production to one fourth of control. Aspirin, NS-398, and pinane thromboxane also significantly decreased neutrophil superoxide production. Nordihydroguaiaretic acid had no significant affect on neutrophil superoxide generation. Arachidonic acid stimulated superoxide generation by neutrophils, and this was inhibited by pinane thromboxane in a dose-dependent manner. Pinane thromboxane also significantly inhibited superoxide production by neutrophils exposed to arachidonic acid plus phorbol myristic acid, a known activator of neutrophils.

CONCLUSION

These data demonstrate that thromboxane is involved in the production of superoxide by neutrophils obtained from pregnant women. Neutrophil superoxide generation is significantly decreased by inhibition of thromboxane synthase, cyclooxygenase-2, or phospholipase A2. NS-398 inhibits neutrophil superoxide generation as effectively as aspirin, suggesting that cyclooxygenase-2 plays an important role in neutrophil superoxide production mediated by thromboxane.

Oxidative stress markers and antioxidant levels in normal pregnancy and pre-eclampsia

OBJECTIVE

To compare the levels of 3 oxidative stress markers (glutathione peroxidase [GPX], superoxide dismutase [SOD], and malondialdehyde [MDA]) and 2 antioxidants (vitamin C and lycopene) in healthy and pre-eclamptic pregnant women.

METHODS

Circulating levels of GPX, SOD, MDA, vitamin C and lycopene were measured in 50 healthy pregnant women and 50 women with pre-eclampsia (PE) (41 with mild PE and 9 with severe PE) attending the antenatal clinic or admitted to the maternity ward of the All-India Institute of Medical Sciences, New Delhi, India.

RESULTS

The levels of GPX, SOD and MDA were significantly higher in women with PE than in controls, and the increase was higher in women with severe PE (P<0.001 using analysis of variance and the Kruskal Wallis test). The levels of vitamin C and lycopene were significantly lower in women with PE than in controls, with a greater decrease in women with severe PE.

CONCLUSION

Increased levels of oxidative stress markers and decreased levels of antioxidants in pre-eclamptic women suggest that oxidative stress markers play a significant role in the pathophysiology of pre-eclampsia, and that supplemental dietary antioxidants may have a beneficial role in the prevention of pre-eclampsia in women at high-risk for this condition.

Breast milk provides better antioxidant power than does formula

OBJECTIVE

We examined the effect of breast milk on plasma total antioxidant capacity (TAC), total peroxide (TP), and oxidative stress index (OSI), which are biomarkers of oxidative status.

METHODS

Fifty-four healthy term infants 3 to 6 mo of age were fed breast milk or a cow's milk modified formula. Plasma TAC, vitamin C, albumin, bilirubin, and uric acid levels were measured as indexes of antioxidative markers. Plasma TP levels were measured as an oxidative stress marker. The OSI was calculated to assess oxidative status.

RESULTS

No significant differences were observed between groups with respect to growth or anthropometric measurements. Plasma uric acid, total protein, and albumin concentrations were slightly higher in the breast-fed group than in the formula-fed group. There was a positive correlation between infant's age and serum albumin levels; between TAC and plasma uric acid, albumin, and total bilirubin; and between plasma iron and TP levels in both groups (r > 0.256, P < 0.05). In addition, there was a negative correlation between plasma iron and TAC (r = -0.267, P = 0.01). Plasma TAC and vitamin C levels were significantly higher in the breast-fed group than in the formula-fed group (P < 0.05). Plasma TP levels and the OSI were higher in the formula-fed group than those in the breast-fed group (P < 0.05).

CONCLUSIONS

Our data suggest that breast milk provides better antioxidant power than does formula.

Moderate Ascorbate Deficiency Increases Myogenic Tone of Arteries From Pregnant but Not Virgin Ascorbate–Dependent Rats

Plasma ascorbic acid is decreased in women with the pregnancy disorder preeclampsia. We used a mutant strain of rats (Osteogenic Disorder Shionogi), dependent on dietary sources of vitamin C, to investigate whether reduced intake of the vitamin would differentially affect vascular function in late-pregnant (day 19) and age-matched virgin rats. The animals were given either 1 mg/mL of ascorbic acid ad libitum in drinking water [fully supplemented (FS)] or 0.25 mg/mL [marginally supplemented (MS)]. Fetal weights were 21% lower in MS than FS rats, whereas mean maternal weights and pup numbers did not differ. Small mesenteric arteries (diameter, 268±7 μm) were mounted in a pressurized arteriograph. Myogenic reactivity (contractile response to step increases in intraluminal pressure) was increased in arteries from MS pregnant compared with FS pregnant rats to levels observed in virgin rats. Ascorbic acid intake did not affect myogenic responses of arteries from virgin rats. Hence, the normal pregnancy-induced reduction in myogenic reactivity was abrogated in MS pregnant animals. Inhibition of nitric oxide synthase had no effect on the myogenicity of arteries from virgin or MS pregnant rats but increased myogenicity of FS pregnant rats to the level of MS pregnant rats. Free radical scavengers reversed the accentuated myogenicity of MS pregnant rats without affecting FS pregnant or virgin rat arteries. These data indicate that moderate ascorbate deprivation increases mesenteric artery myogenic responsiveness during pregnancy. This increase may result from a decrease in nitric oxide–mediated modulation of the myogenic contractile response.

Neuroprotective effects of TEMPOL in central and peripheral nervous system models of Parkinson's disease

TEMPOL (4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl) is a stable nitroxyl antioxidant. Previous studies have suggested that TEMPOL is protective in acute disorders thought to involve reactive oxygen species (ROS), such as ischemic stroke and cardiac reperfusion injury. Oxidized TEMPOL can be recycled to its redox-active reducing form by co-administration with polynitroxylated albumin, making it a candidate as a pharmacological "reservoir" for reducing potential of use in chronic disorders involving ROS. The present studies examine the efficacy of TEMPOL in cell culture and animal models of the central and peripheral dysfunction associated with Parkinson's disease, a disorder in the pathogenesis of which ROS generated from dopamine have been implicated. Antioxidants have been proposed as both preventive and symptomatic therapy for Parkinson's disease. TEMPOL protects MN9D dopaminergic mesencephalic cells in culture from 6-hydroxydopamine (6-OHDA)-induced apoptosis. Translocation of the p65 component of NF-kappaB to the nucleus accompanies protection by TEMPOL. In vivo, intraperitoneal TEMPOL protects mice from intrastriatal 6-OHDA-induced cell and dopamine metabolite loss in the striatum. TEMPOL also protects mice against the 6-OHDA-induced rotational behavior elicited by intrastriatal administration of d-amphetamine. In addition, TEMPOL protects mice from the ptosis, activity level decrement, and mortality induced by intraperitoneal administration of 6-OHDA, a model of autonomic dysfunction in Parkinson's disease. Adjunctive use of polynitroxylated albumin enhances the in vitro and in vivo effects of TEMPOL.

Plasmatic antioxidant capacity due to ascorbate using TEMPO scavenging and electron spin resonance

BACKGROUND

Ascorbate is the most effective water-soluble antioxidant and its plasma concentration is usually measured by different methods including colorimetric assays, HPLC or capillary electrophoresis. Plasma antioxidant capacity is determined by indexes such as total reactive antioxidant potential, total antioxidant reactivity, oxygen radical absorbance capacity, etc. We developed an alternative method for the evaluation of the plasma antioxidant status due to ascorbate.

METHODS

TEMPO kinetics scavenging analyzed by ESR spectroscopy was performed on plasma samples in different antioxidant situations. Plasma ascorbate concentrations were determined by capillary electrophoresis. Ascorbyl radical levels were measured by ESR.

RESULTS

Plasma reactivity with TEMPO (PR-T) reflected plasma ascorbate levels. Average PR-T for normal plasmas resulted 85+/-27 micromol/l (n=43). PR-T during ascorbic acid intake (1 g/day) increased to an average value of 130+/-20 micromol/l (p<0.001, n=20). PR-T correlated with the plasmatic ascorbate levels determined by capillary electrophoresis (r=0.92), presenting as an advantage the avoiding of the deproteination step. Plasma ascorbyl radical levels increase from 16+/-2 to 24+/-3 nmol/l (p<0.005, n=14) after ascorbate intake.

CONCLUSIONS

PR-T could be considered as a measure of the plasmatic antioxidant capacity due to the plasma ascorbate levels and could be useful to investigate different antioxidant situations.

Antioxidants for preventing pre-eclampsia

BACKGROUND

Oxidative stress has been proposed as a key factor involved in the development of pre-eclampsia. Supplementing women with antioxidants during pregnancy may help to counteract oxidative stress and thereby prevent or delay the onset of pre-eclampsia.

OBJECTIVES

To determine the effectiveness and safety of any antioxidant supplementation during pregnancy and the risk of developing pre-eclampsia and its related complications.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group Trials Register (June 2004) and the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 3, 2004).

SELECTION CRITERIA

All randomised and quasi-randomised trials comparing one or more antioxidants with either placebo or no antioxidants during pregnancy for the prevention of pre-eclampsia, and trials comparing one or more antioxidants with another, or with other interventions.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion, data extraction and trial quality. Data were double-entered into the Review Manager software.

MAIN RESULTS

Seven trials involving 6082 women are included in this review. The largest trial (5021 women) was quasi-random and only three of the seven included trials were rated high quality. Supplementing women with any antioxidants during pregnancy compared with control or placebo was associated with a 39% reduction in the risk of pre-eclampsia (relative risk (RR) 0.61, 95% confidence intervals (CI) 0.50 to 0.75, seven trials, 6082 women). Women receiving antioxidants compared with control or placebo also had a reduced risk of having a small-for-gestational-age infant (RR 0.64, 95% CI 0.47 to 0.87, three trials, 634 women), their infants had a greater mean birthweight (weighted mean difference 91.83 g, 95% CI 11.55 to 172.11, three trials, 451 women), but they were more likely to give birth preterm (RR 1.38, 95% CI 1.04 to 1.82, three trials, 583 women). There were insufficient data for reliable conclusions about possible effects on any other outcomes.

AUTHORS' CONCLUSIONS

These results should be interpreted with caution, as most of the data come from poor quality studies. Nevertheless, antioxidant supplementation seems to reduce the risk of pre-eclampsia. There also appears to be a reduction in the risk of having a small-for-gestational-age baby associated with antioxidants, although there is an increase in the risk of preterm birth. Several large trials are ongoing, and the results of these are needed before antioxidants can be recommended for clinical practice.

Heat shock protein-70 and 4-hydroxy-2-nonenal adducts in human placental villous tissue of normotensive, preeclamptic and intrauterine growth restricted pregnancies

OBJECTIVE

The purpose of this study was to compare immunohistochemical expression of heat shock protein-70 (hsp70), a marker for oxidative stress, and 4-hydroxy-2-nonenal adducts (HNE), a marker for lipid peroxidation, in placental villous tissue of normotensive, preeclampsia, and intrauterine growth restricted (IUGR) pregnancies.

STUDY DESIGN

Placentas were collected and flash frozen in liquid nitrogen after delivery from normotensive pregnancies (n=5), and pregnancies complicated by preeclampsia (n=5), IUGR (n=5), and preeclampsia plus IUGR (n=4). Cryosections were cut and immunostained with polyclonal anti-hsp70 and monoclonal anti-HNE antibodies using Vectastain Elite ABC kit. Normal rabbit serum or mouse IgG were used as negative controls. Three independent observers, blinded to identity of tissue, examined each slide to identify cellular localization and intensity of the immunostaining. Western blot analysis and scanning densitometry were used to quantify and compare the amount of hsp70 and HNE adducts present in tissue homogenates.

RESULTS

Positive immunostaining for both antibodies was observed in cytoplasm of syncytiotrophoblasts, extravillous trophoblasts, vascular smooth muscle, and endothelial cells for all groups. Expression of hsp70 and HNE adducts was reported as observers' mean stained intensity. Overall, kappa showed good agreement between observers. Immunostaining intensity was similar in all tissue types for each group with the exception that immunostaining was significantly more intense in the vascular endothelium of the preeclamptic group for HNE adducts (P=.02) and significantly less intense in the IUGR group for hsp70 (P=.013). Scanning densitometric analysis of the Western blots showed no significant difference in total hsp70 and HNE adducts expression in all 4 tissue groups.

CONCLUSION

Immunohistochemistry showed local changes for oxidative stress and lipid peroxidation in the vascular endothelium from placentas of preeclamptic and IUGR pregnancies. However, these changes were masked when studying tissue homogenates.

Pathophysiological basis for the prophylaxis of preeclampsia through early supplementation with antioxidant vitamins

Preeclampsia (PE) is a multisystem disorder that remains a major cause of maternal and foetal morbidity and death. To date, no treatment has been found that prevents the development of the disease. Endothelial dysfunction is considered to underlie its clinical manifestations, such as maternal hypertension, proteinuria, and edema; however, the precise biochemical pathways involved remain unclear. A current hypothesis invokes the occurrence of oxidative stress as pathogenically important, as suggested by the fact that in PE, the placental and circulating levels of lipid peroxidation products (F2-isoprostanes and malondialdehyde [MDA]) are increased and endothelial cells are activated. A potential mechanism for endothelial dysfunction may occur via nuclear transcription factor kappa B (NF-kappaB) activation by oxidative stress. Alternatively, the idea that the antiangiogenic placental soluble fms-like tyrosine kinase 1 factor (sFlt1) is involved in the pathogenesis of this disease is just emerging; however, other pathophysiological events seem to precede its increased production. This review is focused on evidence providing a pathophysiological basis for the beneficial effect of early antioxidant therapy in the prevention of PE, mainly supported by the biological effects of vitamins C and E.

Dietary intake of vitamin C and vitamin E and the development of hypertensive disorders of pregnancy

OBJECTIVES

To explore the relationship, if any, between dietary intake of the antioxidant vitamins C and E, and the development of pre-eclampsia and gestational hypertension.

STUDY DESIGN

A prospective cohort study of pregnant women attending the antenatal clinic of the Women's and Children's Hospital in Adelaide, Australia, was carried out between April and July 2001. Women completed a semi-quantitative 116-item food frequency questionnaire (FFQ). Women's medical records were viewed after birth to collect data on pregnancy outcomes. Relationships were explored through cross-tabulations, chi-square analysis, and adjustments were made for potential confounders using binary logistic regression.

RESULTS

A total of 299 women completed the FFQ. Median intake of vitamin C was 188 mg and for vitamin E was 6.74 mg. There was no relationship between the intake of vitamin C and hypertensive disorders of pregnancy. For vitamin E, being in the lowest quartile of intake, was associated with an increased risk of hypertensive disorders (RR 1.75, 95% CI 1.11-2.75, P = 0.02). This relationship was confirmed after adjusting for the confounding factors of maternal age and parity.

CONCLUSIONS

Little support was found for a relationship between dietary intake of vitamin C and the development of hypertensive disorders of pregnancy. Low vitamin E intake was associated with a significant increase in the risk of hypertensive disorders of pregnancy, even after adjustments were made for confounding factors. Further research is required to investigate whether supplementation above dietary intake of antioxidant vitamins influences the risk of hypertensive disorders of pregnancy.

Expression of lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) in human preeclamptic placenta: possible implications in the process of trophoblast apoptosis

Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) was originally identified as a receptor for oxidatively modified low-density lipoprotein. It has been reported that oxidative stress and hyperlipidemia play important roles in the etiology of preeclampsia, and that placental oxidative stress may stimulate syncytiotrophoblast apoptosis in preeclampsia. In this study, we examined the expression of LOX-1 in the human placentas of normal pregnancies and in preeclampsia using immunohistochemistry and Western blot analysis, and proposed that LOX-1 has a role in trophoblast apoptosis. To analyze apoptotic activity, the expression of the specific caspase cleavage site within cytokeratin 18 was assessed immunohistochemically using the monoclonal antibody M30 CytoDeath. Both LOX-1 and M30 immunoreactivity occurred predominantly in syncytiotrophoblasts. A significantly higher number of LOX-1 and M30-positive cells were found in preeclamptic placentas than in normal placentas. The number of M30-positive cells correlated with the apoptotic index of trophoblasts determined by TdT-mediated dUTP nick-end labeling (TUNEL). Syncytiotrophoblasts showing apoptotic activity were immunopositive to LOX-1 by double immunohistochemical fluorescence. We suggest that the functional role of syncytiotrophoblasts in placental dysfunction results from the localization and upregulation of LOX-1 in the preeclamptic placenta, possible implications in upregulation of syncytiotrophoblast apoptotic activity in preeclampsia.