Decreased transferrin and increased transferrin saturation in sera of women with preeclampsia: implications for oxidative stress

Increased ferroptosis in leukocytes from preeclamptic women involving the long non-coding taurine upregulated gene 1 (TUG1)

BACKGROUND

Ferroptosis plays a key role in placental development and physiology, and abnormal ferroptosis has been implicated in trophoblast injury leading to preeclampsia (PE). We hypothesize that leukocytes isolated from PE exhibit increased ferroptosis and that extracellular vesicles contain long non-coding (lnc) RNA/mRNAs that modulate oxidative stress and iron toxicity in vascular endothelial cells.

METHODS

We measured the expression of key regulators of ferroptosis in leukocytes and extracellular vesicles as well as circulating biomarkers of iron homeostasis and oxidative stress in plasma from women with/without PE at different timepoints during pregnancy. For markers that were dysregulated, we assessed their temporal correlation with established markers of disease activity and marker of endothelial activation. For markers dysregulated in early pregnancy, we assessed their ability to predict the development of PE.

RESULTS

We found decreased lncRNA/mRNAs in leukocytes, but not extracellular vesicles, in PE that may modulate oxidative stress and iron toxicity. This decrease in anti-ferroptotic markers does not appear to be related to maternal disease activity or plasma oxidative stress status but rather to attenuated anti-inflammatory expression in these cells. Circulating ferritin was elevated in PE, supporting the hypothesis that PE represents a disbalance in iron homeostasis. Low lncRNA taurine upregulated gene 1 RNA levels in leukocytes at 22-24 weeks were strongly associated with the development of PE.

CONCLUSIONS

Our findings suggest that maternal leukocytes in PE show decreased anti-ferroptotic activity that correlates with anti-inflammatory expression. Moreover, some of these changes in ferroptotic activity appear to precede the development of PE.

Assessing erythroferrone and iron homeostasis in preeclamptic and normotensive pregnancies: A retrospective study

INTRODUCTION

Preeclampsia (PE) is a pregnancy-related disorder associated with maternal hypertension and placental dysfunction. A significant micronutrient during pregnancy is iron, which is important in cellular functions. While iron absorption increases in pregnancy, little is known about the exact mechanisms regulating maternal iron levels and transfer through the placenta in normal and complicated pregnancies.

METHODS

In this retrospective study, we investigated the regulation of maternal and placental iron availability and storage, in normotensive and pregnancies complicated by early- or late-onset PE. Methods used were analysis of clinical records, ELISA analysis on plasma samples, immunofluorescent and Prussian Blue analysis on placenta biopsies.

RESULTS

Focusing on erythroferrone (ERFE) as a new marker and hormonal regulator of iron, our results demonstrated altered maternal ERFE levels in PE. We are the first to report the expression of ERFE in trophoblasts and indicate its lower levels in early-onset PE placentas. These changes were associated with lower placental transferrin receptor 1 (TfR1) in syncytiotrophoblasts in both early- and late-onset PE. In addition, maternal plasma ERFE levels were elevated in both early- and late-onset PE and hepcidin levels reduced in early-onset PE. Unaltered maternal plasma IL-6 levels suggest mechanism other than inflammation being involved in altered iron regulation in PE pregnancy.

DISCUSSION

Our data supports a deregulation in maternal iron bioavailability in early- and late-onset PE vs normotensive pregnancies. The exact role of placental ERFE in regulating maternal-placental-fetal iron transport axis requires further investigation.

Vitamins supplementation affects the onset of preeclampsia

Preeclampsia may affect between 2-8% of all pregnancies. It seriously affects maternal health after pregnancy. This meta-analysis was performed to define the efficacy of vitamins supplementation on the risk of preeclampsia. Potential articles were systematically searched on the databases of Pubmed, Embase and Web of Science up to May 2016. Relative risk (RR) and 95% confidence intervals (95%CIs) were used to analyze the relationship of vitamins supplementation with risk of preeclampsia. Cochran Q test was used to test inter-study heterogeneity. Begg's funnel plot was adopted to assess the potential publication bias. 28 eligible studies were selected. Pooled results indicated that vitamins supplementation could reduce the risk of preeclampsia (RR = 0.74, 95%CI = 0.64-0.86). The studies with non-randomized controlled trial (RCT) analysis also suggested the significant relationship of vitamins supplementation with risk of preeclampsia (RR = 0.60, 95%CI = 0.42-0.85). However, negative results were observed in studies with RCT analysis. Subgroup analysis by vitamin type was performed among the studies with RCT analysis. The results indicated that vitamin D supplementation could significantly reduce the risk of preeclampsia (RR = 0.41, 95%CI = 0.22-0.78). Similar results were observed in the studies with multivitamins supplementation (RR = 0.69, 95%CI = 0.51-0.93). Vitamins supplementation could reduce the onset of preeclampsia.

Metformin, the aspirin of the 21st century: its role in gestational diabetes mellitus, prevention of preeclampsia and cancer, and the promotion of longevity

Metformin is everywhere. Originally introduced in clinical practice as an antidiabetic agent, its role as a therapeutic agent is expanding to include treatment of prediabetes mellitus, gestational diabetes mellitus, and polycystic ovarian disease; more recently, experimental studies and observations in randomized clinical trials suggest that metformin could have a place in the treatment or prevention of preeclampsia. This article provides a brief overview of the history of metformin in the treatment of diabetes mellitus and reviews the results of metaanalyses of metformin in gestational diabetes mellitus as well as the treatment of obese, non-diabetic, pregnant women to prevent macrosomia. We highlight the results of a randomized clinical trial in which metformin administration in early pregnancy did not reduce the frequency of large-for-gestational-age infants (the primary endpoint) but did decrease the frequency of preeclampsia (a secondary endpoint). The mechanisms by which metformin may prevent preeclampsia include a reduction in the production of antiangiogenic factors (soluble vascular endothelial growth factor receptor-1 and soluble endoglin) and the improvement of endothelial dysfunction, probably through an effect on the mitochondria. Another potential mechanism whereby metformin may play a role in the prevention of preeclampsia is its ability to modify cellular homeostasis and energy disposition, mediated by rapamycin, a mechanistic target. Metformin has a molecular weight of 129 Daltons and therefore readily crosses the placenta. There is considerable evidence to suggest that this agent is safe during pregnancy. New literature on the role of metformin as a chemotherapeutic adjuvant in the prevention of cancer and in prolonging life and protecting against aging is reviewed briefly. Herein, we discuss the mechanisms of action and potential benefits of metformin.

Reduced Cellular Glutathione Reductase Activity and Increased Adhesion Molecule Expression in Endothelial Cells Cultured With Maternal Plasma From Women With Preeclampsia

OBJECTIVE

The purpose of the current study was to determine whether maternal circulating components could regulate oxidative status of glutathione redox cycle and adhesion molecule expression in endothelial cells (ECs).

METHODS

Maternal plasma was extracted from venous blood obtained from normal term pregnant women and from women with preeclampsia (PE). Normal and PE pregnancies were defined as American College of Obstetricians and Gynecologists criteria. Confluent ECs were incubated with EC growth medium (EGM) containing 20% plasma from women with normal (n = 8) and PE (n = 8) pregnancies for 4 hours. ECs incubated with EGM only were used as control. EC oxidative status was assessed by measuring cellular glutathione reductase (GR) and glutathione peroxidase (GPx) activities. Adhesion molecule expressions for intercellular adhesion molecule (ICAM), vascular cell adhesion molecule (VCAM), P-selectin, and E-selectin were determined by colorimetric assays detected on EC surface by UV spectrophotometer at OD 450 nm. Data are presented as mean +/- SE and analyzed by analysis of variance (ANOVA). A P value < .05 was set as statistically significant.

RESULTS

Cellular GR activity was reduced approximately 35% in ECs treated with normal plasma and 70% in ECs treated with PE plasma compared to that in untreated control cells: 0.072 +/- 0.014 (P < .05), 0.039 +/- 0.006 (P < .01), versus 0.117 +/- 0.010 U/mg cellular protein, respectively. In contrast, GPx activity was slightly increased in ECs treated with normal plasma and significantly increased in ECs treated with PE plasma compared to that in untreated control cells: 0.059 +/- 0.005, 0.075 +/- 0.012 (P < .05) versus 0.044 +/- 0.002 U/mg cellular protein, respectively. P-selectin, E-selectin, and VCAM expressions were elevated in cells treated with normal plasma but significantly increased in cells treated with PE plasma compared to those of untreated controls: P-selectin--0.18 +/- 0.03, 0.35 +/- 0.04 versus 0.04 +/- 0.01 OD 450 nm, P < .01; E--selectin-0.06 +/- 0.02, 0.10 +/- 0.02 (P < .05) versus 0.03 +/- 0.01 OD 450 nm; VCAM--0.12 +/- 0.02, 0.16 +/- 0.03 (P < .01) versus 0.08 +/- 0.02 OD 450 nm, respectively. There was no difference for ICAM expression in cells treated with normal or PE plasma compared to controls.

CONCLUSIONS

These data suggest that endothelial pro- and anti-oxidative status could be directly affected by circulating components during pregnancy. Reduced cellular GR activity and increased GPx activity accompany increased inflammatory reactions in ECs responding to circulating "toxic" factors in preeclampsia.

Transferrin Saturation: A Body Iron Biomarker

Iron is an essential element for several metabolic pathways and physiological processes. The maintenance of iron homeostasis within the human body requires a dynamic and highly sophisticated interplay of several proteins, as states of iron deficiency or excess are both potentially deleterious to health. Among these is plasma transferrin, which is central to iron metabolism not only through iron transport between body tissues in a soluble nontoxic form but also through its protective scavenger role in sequestering free toxic iron. The transferrin saturation (TSAT), an index that takes into account both plasma iron and its main transport protein, is considered an important biochemical marker of body iron status. Its increasing use in many health systems is due to the increased availability of measurement methods, such as calorimetry, turbidimetry, nephelometry, and immunochemistry to estimate its value. However, despite its frequent use in clinical practice to detect states of iron deficiency or iron overload, careful attention should be paid to the inherent limitations of the test especially in certain settings such as inflammation in order to avoid misinterpretation and erroneous conclusions. Beyond its usual clinical use, an emerging body of evidence has linked TSAT levels to major clinical outcomes such as cardiovascular mortality. This has the potential to extend the utility of TSAT index to risk stratification and prognostication. However, most of the current evidence is mainly driven by observational studies where the risk of residual confounding cannot be fully eliminated. Indeed, future efforts are required to fully explore this capability in well-designed clinical trials or prospective large-scale cohorts.

A Dormant Microbial Component in the Development of Preeclampsia

Preeclampsia (PE) is a complex, multisystem disorder that remains a leading cause of morbidity and mortality in pregnancy. Four main classes of dysregulation accompany PE and are widely considered to contribute to its severity. These are abnormal trophoblast invasion of the placenta, anti-angiogenic responses, oxidative stress, and inflammation. What is lacking, however, is an explanation of how these themselves are caused. We here develop the unifying idea, and the considerable evidence for it, that the originating cause of PE (and of the four classes of dysregulation) is, in fact, microbial infection, that most such microbes are dormant and hence resist detection by conventional (replication-dependent) microbiology, and that by occasional resuscitation and growth it is they that are responsible for all the observable sequelae, including the continuing, chronic inflammation. In particular, bacterial products such as lipopolysaccharide (LPS), also known as endotoxin, are well known as highly inflammagenic and stimulate an innate (and possibly trained) immune response that exacerbates the inflammation further. The known need of microbes for free iron can explain the iron dysregulation that accompanies PE. We describe the main routes of infection (gut, oral, and urinary tract infection) and the regularly observed presence of microbes in placental and other tissues in PE. Every known proteomic biomarker of "preeclampsia" that we assessed has, in fact, also been shown to be raised in response to infection. An infectious component to PE fulfills the Bradford Hill criteria for ascribing a disease to an environmental cause and suggests a number of treatments, some of which have, in fact, been shown to be successful. PE was classically referred to as endotoxemia or toxemia of pregnancy, and it is ironic that it seems that LPS and other microbial endotoxins really are involved. Overall, the recognition of an infectious component in the etiology of PE mirrors that for ulcers and other diseases that were previously considered to lack one.

Is the level of maternal serum prohepcidin associated with preeclampsia?

OBJECTIVE

The objective of the study was to compare pro-hepcidin, hemoglobin (Hb) concentration, hematocrit (Hct), C-reactive protein (CRP), IL-6 and iron status parameters in preeclamptic (PE) and healthy pregnant women, and to examine the relationship between serum pro-hepcidin levels and iron parameters of preeclampsia (PE).

METHODS

In a prospective controlled study, we collected serum from women with normal pregnancy (n = 37) and from women with PE (n = 30) at the Department of Obstetrics and Gynecology at Turgut Ozal University between February 2010 and January 2013. Pro-hepcidin, hemoglobin (Hb) concentration, hematocrit (Hct), CRP, IL-6 and iron status parameters were measured in all patients and compared between groups.

RESULTS

Levels of serum prohepcidin in PE and control groups were similar and amount 69.4 ± 19.7 and 71.9 ± 22.1 ng/ml, respectively. The difference was not statistically significant (p: 0.694). On the other hand, the study group had a statistically lower iron binding capacity (IBC), total iron binding capacity, transferin, total protein, albumin levels (p < 0.05). No significant differences were found among prohepcidin, Hb concentration, Hct, iron, ferritin, IL-6, urea and creatine in both the groups.

CONCLUSION

In pregnancies complicated by PE with normal values of hemoglobin and hematocrit, serum prohepcidin concentrations are similar to those observed in healthy pregnant women. The analysis revealed no significant correlations between prohepcidin level and serum iron, serum ferritin or transferrin in the PE.

Newborn LpL (Ser447Stop, Asn291Ser) genotypes and the interaction with maternal genotypes influence the risk for different types of preeclampsia: modulating effect on lipid profile and pregnancy outcome

AIM

To establish that newborn Ser447Stop and Asn291Ser may have interactive effects with maternal genotypes on the plasma lipoprotein levels, risk of preeclampsia as well as on the prognosis of preeclampsia.

MATERIALS AND METHODS

Seventy preeclamptic women and 94 normotensive pregnant women, and their newborns were genotyped using PCR-RFLP methods.

RESULTS

The risk of mild and severe preeclampsia was 4 (p = 0.004) and 5.18 (p = 0.001), respectively, if both the mother and newborn were carriers of the Ser447/Ser477 genotype. If both the mother and newborn were carriers of the Asn291Ser variant, the risk to develop severe preeclampsia was 6.07 (p = 0.03). Women with mild and severe preeclampsia had higher TG (p < 0.001; p < 0.001) and LDL-C levels (p = 0.008; p < 0.001) if both the mother and newborn were carriers of the Ser447/Ser447 genotype. Women with severe preeclampsia had significantly higher TG (p = 0.03) and LDL-C levels (p = 0.037) if both the mother and newborn were carriers of Asn291Ser. Newborn/maternal LpL interaction had no statistically significant influence on pregnancy outcome.

CONCLUSIONS

The newborn/maternal LpL interaction influences the severity of preeclampsia and modulates the lipid profile particularly in severe preeclampsia.

Influence of several sources and amounts of iron on DNA, lipid and protein oxidative damage during anaemia recovery

The study was designed to assess the effect of several Fe amounts and sources on haematological parameters, DNA, lipid and protein oxidative damage during the course of Fe-deficiency anaemia recovery. Peripheral DNA damage was assessed using an alkaline comet assay. The brain, liver, erythrocyte and duodenal mucosa lipid peroxidation and protein damage were assessed in control and anaemic rats after Fe repletion with three different sources (FeSO4, haem Fe, and FeSO4 + haem Fe) and amounts (45, 12, and 31 mg Fe/kg diet) of Fe: F diet, H diet or C diet, respectively. After supplying the diets, the haematological parameters studied were recovered; being remarkable is the haemoglobin increase. The DNA damage was lower in rats with the H diet, as revealed by the percentage of DNA in head, tail and Olive tail moment compared in rats with the F (P < 0.001) and C (P < 0.05) diets. Lipid peroxidation was similar in all the tissues, except in the duodenal mucosa which was lower with H and C diets (P < 0.001). The animals fed with C diet showed lower oxidative protein damage in the duodenal mucosa (P < 0.001) and was also lower in the liver and erythrocytes for H and C diets (P < 0.001). No differences were found in the brain under our experimental conditions. In conclusion, Fe supplementation with low doses of haem Fe or combined forms of non-haem and haem Fe (FeSO4 + haem) are efficient in restoring the impaired haematological parameters and prevent the evoked oxidative stress associated with Fe supplements.

Effects of hemochromatosis and transferrin gene mutations on peripheral iron dyshomeostasis in mild cognitive impairment and Alzheimer's and Parkinson's diseases

Deregulation of iron metabolism has been observed in patients with neurodegenerative diseases. We have carried out a molecular analysis investigating the interaction between iron specific gene variants [transferrin (TF, P589S), hemochromatosis (HFE) C282Y and (H63D)], iron biochemical variables [iron, Tf, ceruloplasmin (Cp), Cp:Tf ratio and % of Tf saturation (% Tf-sat)] and apolipoprotein E (APOE) gene variants in 139 Alzheimer's disease (AD), 27 Mild Cognitive Impairment (MCI), 78 Parkinson's disease (PD) patients and 139 healthy controls to investigate mechanisms of iron regulation or toxicity. No difference in genetic variant distributions between patients and controls was found in our Italian sample, but the stratification for the APOEε4 allele revealed that among the APOEε4 carriers was higher the frequency of those carriers of at least a mutated TF P589S allele. Decreased Tf in both AD and MCI and increased Cp:Tf ratio in AD vs. controls were detected. A multinomial logistic regression model revealed that increased iron and Cp:Tf ratio and being man instead of woman increased the risk of having PD, that increased values of Cp:Tf ratio corresponded to a 4-fold increase of the relative risk of having MCI, while higher Cp levels were protective for PD and MCI. Our study has some limitations: the small size of the samples, one ethnic group considered, the rarity of some alleles which prevent the statistical power of some genetic analysis. Even though they need confirmation in larger cohorts, our data suggest the hypothesis that deregulation of iron metabolism, in addition to other factors, has some effect on the PD disease risk.

Comparative study of serum zinc, copper, manganese, and iron in preeclamptic pregnant women

Preeclampsia complicates 2-8 % of all pregnancies and it is one of the leading causes of maternal mortality and pre-term delivery in the world. Unfortunately, there is scarcity of document discussing the circulating level of several essential trace elements in preeclampsia patients in Bangladesh. The present study was designed to evaluate the serum concentration of four trace elements, namely zinc, copper, manganese, and iron, in preeclamptic pregnant women. The study was conducted as a case-control study with 50 preeclamptic pregnant women as cases and 58 normotensive pregnant women as controls. Obstetric, anthropometric, and clinical data were collected at routine obstetric visits. Serum trace elements were determined by flame atomic absorption spectroscopy. Independent sample t test and Pearson's correlation test were done for the statistical analysis using the statistical software package SPSS, version 16.0 (SPSS Inc., Chicago, IL). We observed significant differences for gestational age, body mass index, and systolic and diastolic blood pressure between patient and control groups (p < 0.05). Analysis of serum trace elements explored significantly lower level of all the four elements in preeclampsia patients in comparison to the control group (p < 0.05). Pearson's correlation analysis explored that the correlation between serum level of different trace elements was statistically insignificant (p > 0.05) except the correlation between zinc and iron in preeclampsia patients (p < 0.05). Establishment of inter-element relationship strongly supports that there was a disturbance in the element homeostasis in patient with preeclampsia. In conclusion, our study suggests that preeclampsia patients have considerably lower level of serum zinc, copper, manganese, and iron compared to the healthy pregnant women.

Impact of exercise training on preeclampsia: potential preventive mechanisms

Preeclampsia is characterized by hypertension and de novo proteinuria after 20 weeks of pregnancy. It is the leading cause of perinatal morbidity and mortality in the developed world, and to date, the only means of treating the disease is by inducing delivery. Many studies have shown the benefits of exercise training on normal pregnancy. Conversely, because the impact of exercise on reducing the risk of preeclampsia has long been debated, the American College of Obstetricians and Gynecologists has yet to support the prescription of exercise training to women at risk of developing the disease. There is, however, a significant body of evidence in support of the protective role of exercise training against preeclampsia. A recent animal study demonstrated that many preeclampsia features can be eliminated with prenatal followed by gestational exercise training. Hence, the present article reviews the literature on the impact of exercise training on preeclampsia risk, as well as the mechanisms that may be involved.

Oxidative stress and antioxidant defenses in pregnant women

OBJECTIVES

Oxidative stress (OS) is defined as an imbalance in the production of reactive oxygen species and the capacity of antioxidant defenses. The objective of this work was to investigate OS and antioxidant capacity in pregnant women.

METHODS

Parameters of the oxidative status and antioxidant capacity in serum and whole blood were evaluated in thirty-nine women with normal pregnancy.

RESULTS

The assessment of antioxidants indicated an increase in superoxide dismutase and catalase activities (P<0.05 and P<0.01) and a decrease in ascorbic acid levels and the total content of sulfhydryl (P<0.05 and P<0.001). Additionally, when the pro-oxidant system was investigated we found an increase (P<0.01) in malondialdehyde and no significant change (P>0.05) in protein carbonylation.

DISCUSSION

This study demonstrates that there is a change in the pro-oxidant and antioxidant defenses associated with body and circulation changes that are inherent to the pregnancy process.

Serum level and antioxidant activity of ceruloplasmin in preeclampsia

The antioxidants activities are decreased in the serum of women with preeclampsia. This study was aimed to determine the serum level and antioxidant activity of ceruloplasmin in preeclamptic women with gestational age over than 28 weeks. In a cross-sectional and descriptive-analytic study performed on 60 patients with preeclampsia (30 with mild and 30 with severe preeclampsia) and 30 women with normal pregnancy (control) in Tabriz al-Zahra Hospital, serum level and antioxidant activity of ceruloplasmin was evaluated. The mean gestational age was 32.94+/-2.79 week in mild preeclampsia group, 32.17+/-3.00 week in severe preeclampsia group and 32.46+/-4.04 week in control group (p = 0.821). The mean serum level of ceruloplasmin was 0.62+/-0.16 g L-1 in mild preeclampsia group, 0.61+/-0.23 g L-1 in severe preeclampsia group and 0.47+/-0.16 g L-1 in control group. The serum ceruloplasmin in control group was significantly lower (p = 0.006). The mean antioxidant activity of ceruloplasmin was 562.54+/-139.79 in mild preeclampsia group, 556.21+/-190.94 in severe preeclampsia group and 427.62+/-162.14 in control group. The antioxidant activity was measured as production of mg dL-1 of a colored product. The antioxidant activity of ceruloplasmin in control group patients was significantly lower (p = 0.002). Significant linear positive correlation was found between serum level of ceruloplasmin and antioxidant activity of ceruloplasmin (p<0.001 and r = 0.910). Serum level of ceruloplasmin is significantly lower in normal pregnancy than mild and severe preeclampsia. Antioxidant activity of ceruloplasmin is significantly lower in normal pregnancy than mild and severe preeclampsia.

Effects of hemochromatosis and transferrin gene mutations on iron dyshomeostasis, liver dysfunction and on the risk of Alzheimer's disease

It is now accepted that transition metals, such as iron and copper, are involved in the pathogenesis of the Alzheimer's disease (AD) through their participation in toxic oxidative phenomena. In this context, hemochromatosis (Hfe) and transferrin (Tf) genes are of particular importance, since they play a key role in iron homeostasis. Also, signs of liver distress which accompany metal dysmetabolisms have been shown to be linked to AD. In order to investigate whether and how all these factors are interconnected, in this study we have explored the relationship of the gene variants of Hfe H63D and C282Y and of Tf C2 with serum markers of iron status (iron, ferritin, TF, TF-saturation, ceruloplasmin -CP-, CP and TF serum concentrations (CP/TF) ratio), and of liver function (albumin, transaminases, prothrombin time-prothrombin time (PT)) in a sample of 160 AD patients and 79 healthy elderly controls. Albumin resulted in lower, PT longer and AST/ALT higher ratios in AD patients than in controls, indicating a distress of the liver. Also TF was lower and ferritin higher in AD. Multiple logistic regression backward analyses, performed to evaluate the effects of our biochemical variables upon the probability of developing AD, revealed that a one-unit TF serum-decrease increases the probability of AD by 80%, a one-unit albumin serum-decrease reduces this probability by 20%, and a one-unit increase of AST/ALT ratio generates a 4-fold probability increase. Patients who were carriers of the H63D mutation showed higher levels of iron, lower levels of TF and CP and higher CP/TF ratios, a panel resembling hemochromatosis. This picture was found neither in H63D non-carrier patients, nor in healthy controls. Our results suggest the existence of a link between Hfe mutations and iron abnormalities that increases the probability of developing AD when accompanied by a distress of the liver.

Vitamin C and E supplementation does not reduce the risk of superimposed PE in pregnancy

BACKGROUND

Oxidative stress could play a role in the development of preeclampsia. There is some evidence to suggest that vitamin C and E supplements can reduce the risk of the disorder. We hypothesized its beneficial role in a group of pregnant women with essential hypertension.

METHODS

In this randomized controlled trial, we enrolled 50 pregnant women with essential hypertension. We assigned the women 1000 mg vitamin C and 400 IU natural vitamin E (RRR α tocopherol; n = 25), daily from the second trimester of pregnancy until delivery or no supplementation (n = 25). Our primary endpoint was development of superimposed preeclampsia, and main secondary endpoints were aggravation of hypertension, need for admission, need to increase antihypertensive drugs, and small size for gestational age (<fifth customized birthweight centile).

RESULTS

We analyzed 50 women who completed the study. The incidence of superimposed preeclampsia was similar in vitamin and control groups (8% [n = 2] vs 12% [n = 3], p = 1.000). Vitamin C and E supplementation also did not prevent aggravation of hypertension in group of women who took it (12% [n = 3] vs 32% [n = 8], p = 0.172). Small size for gestational age babies did not differ between groups (4% [n = 2] vs 6% [n = 3], p = 1.000).

CONCLUSION

Vitamin C and E supplementation does not prevent development of superimposed preeclampsia in women with essential hypertension. Our results did not show any significant benefit of vitamin supplementation. There was some trend in lessening of hypertensive complications of pregnancy. Our results failed to find any correlation between development of superimposed preeclampsia and oxidative stress.

Variable effects of maternal and paternal-fetal contribution to the risk for preeclampsia combining GSTP1, eNOS, and LPL gene polymorphisms

Objective

To evaluate the maternal, paternal, and fetal genotype contribution to preeclampsia.

Study design, materials, and methods

We combined the analysis of polymorphisms of the GSTP1, eNOS, and LPL genes – affecting biotransformation enzymes and endothelial function – in a cohort of 167 preeclamptic and normal control trios (mother, father, and child) comprising a total of 501 samples in the Greek population, never analyzed before by this approach.

Results

For the frequency of the GSTP1 Ile¹⁰⁵/Val¹⁰⁵, the eNOS Glu298Asp and the LPL-93 polymorphisms, statistically significant differences were found between the two groups. However, the transmission rates of the parental alleles to neonates studied by the transmission disequilibrium test, disclosed no increased rate of transmission to preeclampsia children for the variant alleles of Val¹⁰⁵ GSTP1, 298Asp eNOS, and -93G LPL.

Conclusions

These novel data, suggest that interaction of all three types of genotypes (mother, father and neonate), reveals no effects on the development of preeclampsia, but provide the impetus for further studies to decipher the individual contribution of each genetic parameter of preeclampsia.

Depressed antioxidant status in pregnant women on iron supplements: pathologic and clinical correlates

Iron (Fe) remains a commonly prescribed supplement in pregnancy. Its possible pathologic potential is either uncommonly considered or ignored. We determined the antioxidant status in pregnant women with and without Fe supplements. Fifty-eight apparently healthy pregnant women on Fe supplements were selected for the study from the antenatal clinic of the University College Hospital, Ibadan, Nigeria. Fifty-five aged matched pregnant women who were not on Fe from various parishes of the Christ Apostolic Church, Ibadan (non-drug using Christian sect) were randomly selected as controls. Both groups were classified according to the trimesters of pregnancy. The gestational age in both pregnant women on Fe supplements and non-supplement pregnant women was similar. Fruit and vegetables consumption was higher in the supplement than in the non-supplement group (57.2% vs. 37.3%). Anthropometric indices, weight, height, and BMI, were also similar. But while the weight of the Fe supplement group decreased by nearly 3% in the third trimester, it increased by over 10% (p < 0.00) in the non-supplement group in the same period. Serum Fe level was significantly higher in the supplement than the non-supplement group (p < 0.001). In contrast, the levels of the antioxidants, ascorbic acid, copper (Cu), zinc (Zn), and bilirubin were all significantly decreased (p < 0.05, p < 0.001, p < 0.05, and p < 0.05, respectively). Uric acid level though also lower in the supplement group did not reach statistical significance (p > 0.05), while vitamin E was similar in both groups. There was relative stability of all antioxidants except uric acid, which declined from the first to the last trimester in the non-supplement group. The significantly higher Fe level in the second trimester was sustained in the third trimester though to a lesser degree (p < 0.05) and associated with significant decreases in the following antioxidant levels in the supplement group, ascorbic acid, bilirubin, Cu, and Zn (p < 0.02, p < 0.02, p < 0.02, and p < 0.001, respectively). Uric acid and vitamin E though lower in the supplement group were not significantly different. Remarkably, percentage changes between the first and third trimesters revealed that serum Fe increased by over 116% in the Fe supplement group, while it only increased by over 50% in the non-supplement group. This was associated with 23.50% decrease in ascorbate level (p < 0.003) in the supplement group, while it decreased by only 3.70% in the non-supplement group (p > 0.05). Again vitamin E decreased by 17.22% in the supplement group, while it decreased by only 7.30% in the non-supplement group during the period. Uric acid and bilirubin levels decreased by similar proportions during the period, while Zn decreased by 18.55% in the supplement group and by 14.86% in the non-supplement group. In contrast Cu increased by 7.20% in the supplement group, while it increased by only 2.96 in the non-supplement group. Additionally, all the antioxidants in the supplement group except vitamin E, viz, ascorbic acid, bilirubin, Cu, uric acid, and Zn, were significantly inversely correlated with serum Fe level (r - 0.299, p < 0.05, r - 0.278, p < 0.05, r - 0.383, p < 0.05, and r - 0.0369, p < 0.05). These data imply markedly depressed antioxidant status in the Fe supplement pregnant group with attendant oxidative stress (most probably pro-oxidant Fe-induced). This is associated with molecular and cellular damage as well as a number of pathologic and clinical correlates that underlie the exacerbation of morbidity and mortality in maternal and child populations, particularly in the developing countries. This appears to call for serious caution and prior evaluation of antioxidant and Fe status and during the use of Fe supplements in pregnancy for monitoring and prognostic purposes and to avert or ameliorate oxidative stress-induced pathologies in maternal and fetal systems.

Intra-arterial tert-Butyl-hydroperoxide infusion induces an exacerbated sensory response in the rat hind limb and is associated with an impaired tissue oxygen uptake

The objective of this study was to investigate oxidative stress and oxygen extraction mechanisms in an animal model of continuous intra-arterial infusion of a free radical donor and in an in vitro model using isolated mitochondria. tert-Butyl-hydroperoxide (tert-BuOOH, 25 mM) was infused for 24 h in the left hind limb of rats to induce soft tissue damage (n = 8). After 7 days, we assessed local sensory response, tissue oxygen consumption, oxygen radicals, and antioxidant levels. In vitro mitochondrial function was measured after stimulation of isolated mitochondria of skeletal muscle cells with increasing doses of tert-BuOOH. tert-BuOOH infusion resulted in an increased skin temperature (p = 0.04), impaired function, and a significantly increased pain sensation (p = 0.03). Venous oxygen saturation levels (p = 0.01) and the antioxidant ceruloplasmin (p = 0.04) were increased. tert-BuOOH inhibited mitochondrial function in vitro. Induction of free radical formation in the rat hind limb results in an exacerbated sensory response and is associated with impaired oxygen extraction, which likely results from mitochondrial dysfunction caused by free radicals.

Iron behaving badly: inappropriate iron chelation as a major contributor to the aetiology of vascular and other progressive inflammatory and degenerative diseases

BACKGROUND

The production of peroxide and superoxide is an inevitable consequence of aerobic metabolism, and while these particular 'reactive oxygen species' (ROSs) can exhibit a number of biological effects, they are not of themselves excessively reactive and thus they are not especially damaging at physiological concentrations. However, their reactions with poorly liganded iron species can lead to the catalytic production of the very reactive and dangerous hydroxyl radical, which is exceptionally damaging, and a major cause of chronic inflammation.

REVIEW

We review the considerable and wide-ranging evidence for the involvement of this combination of (su)peroxide and poorly liganded iron in a large number of physiological and indeed pathological processes and inflammatory disorders, especially those involving the progressive degradation of cellular and organismal performance. These diseases share a great many similarities and thus might be considered to have a common cause (i.e. iron-catalysed free radical and especially hydroxyl radical generation).The studies reviewed include those focused on a series of cardiovascular, metabolic and neurological diseases, where iron can be found at the sites of plaques and lesions, as well as studies showing the significance of iron to aging and longevity. The effective chelation of iron by natural or synthetic ligands is thus of major physiological (and potentially therapeutic) importance. As systems properties, we need to recognise that physiological observables have multiple molecular causes, and studying them in isolation leads to inconsistent patterns of apparent causality when it is the simultaneous combination of multiple factors that is responsible.This explains, for instance, the decidedly mixed effects of antioxidants that have been observed, since in some circumstances (especially the presence of poorly liganded iron) molecules that are nominally antioxidants can actually act as pro-oxidants. The reduction of redox stress thus requires suitable levels of both antioxidants and effective iron chelators. Some polyphenolic antioxidants may serve both roles.Understanding the exact speciation and liganding of iron in all its states is thus crucial to separating its various pro- and anti-inflammatory activities. Redox stress, innate immunity and pro- (and some anti-)inflammatory cytokines are linked in particular via signalling pathways involving NF-kappaB and p38, with the oxidative roles of iron here seemingly involved upstream of the IkappaB kinase (IKK) reaction. In a number of cases it is possible to identify mechanisms by which ROSs and poorly liganded iron act synergistically and autocatalytically, leading to 'runaway' reactions that are hard to control unless one tackles multiple sites of action simultaneously. Some molecules such as statins and erythropoietin, not traditionally associated with anti-inflammatory activity, do indeed have 'pleiotropic' anti-inflammatory effects that may be of benefit here.

CONCLUSION

Overall we argue, by synthesising a widely dispersed literature, that the role of poorly liganded iron has been rather underappreciated in the past, and that in combination with peroxide and superoxide its activity underpins the behaviour of a great many physiological processes that degrade over time. Understanding these requires an integrative, systems-level approach that may lead to novel therapeutic targets.

Catalase Activity, Serum Trace Element and Heavy Metal Concentrations, and Vitamin A, D and E Levels in Pre-Eclampsia

Catalase (antioxidant enzyme) activity in erythrocytes and serum levels of trace elements (copper, iron, zinc), heavy metals (cadmium, cobalt) and vitamins A (retinol), D (cholecalciferol) and E (α-tocopherol) were measured in 145 subjects comprising 47 pre-eclamptic pregnant women (PE), 48 healthy pregnant women (HP) and 50 healthy non-pregnant controls (NP). Catalase, vitamins A, D and E and levels of cobalt were significantly lower in the PE group compared with the HP and NP groups, whereas levels of copper, iron and cadmium were significantly higher in the PE group than in the HP and NP groups. Levels of zinc were significantly lower in both the PE and HP groups compared with the NP group. This assessment of oxidant/antioxidant imbalance in pregnant women could be useful in the early identification of pre-eclampsia and antioxidant supplementation in the early weeks of gestation might be useful.

Placental expression profiling in preeclampsia: local overproduction of hemoglobin may drive pathological changes

OBJECTIVE

To create a library enriched in cDNAs from preeclamptic placentas to print onto microarrays for placental profiling of preeclampsia (PE) and high risk pregnancies.

DESIGN

Prospective study.

SETTING

University women's clinic and academic research laboratory.

PATIENT(S)

Ten patients with PE, 5 with PE and bilateral notching, 5 with bilateral notching without PE, and 15 normotensive patients were recruited.

INTERVENTION(S)

Placenta and placenta bed biopsies were collected after delivery.

MAIN OUTCOME MEASURE(S)

Subtracted libraries of PE transcripts were produced, and cDNAs from these libraries were used to make PE-specific cDNA arrays. Results were verified quantitatively using real-time polymerase chain reaction (PCR) and histologically using in situ hybridization and immunohistochemistry.

RESULT(S)

Thirty genes were significantly altered in at least one group comparison. Differences in two candidate genes were confirmed using quantitative real-time PCR. Hemoglobin alpha2 and gamma transcripts were significantly overexpressed in the PE placenta. Scattered cells in the placenta and placental blood vessels were shown to express genes encoding these hemoglobin chains.

CONCLUSION(S)

We demonstrate increased hemoglobin production in the PE placenta. The hemoglobin may be released into the placenta blood vessel lumen. Free heme and hemoglobin are potent toxins that cause endothelial damage and inflammation.

Association of microsomal epoxide hydrolase gene polymorphism and pre-eclampsia in Turkish women

AIM

To assess the association between human epoxide hydrolase exon 3 and 4 polymorphisms and pre-eclampsia by carrying out a case-control study in Turkish women.

METHODS

DNA was extracted from peripheral blood leukocytes, and genotype distribution of exon 3 and exon 4 of epoxide hydrolase gene (EPHX) was carried out in 271 patients and 155 controls.

RESULTS

There was no statistically significant difference in the distribution of genotypes between pre-eclampsia without HELLP and pre-eclampsia plus HELLP cases and controls for the exon 3 and 4 polymorphism of EPHX. However, we found a significant association between the predicted enzyme activity level and pre-eclampsia (P = 0.018). The distribution of subjects with predicted high, intermediate and low microsomal epoxide hydrolase enzyme (EPHX) activity were 23.2, 38.8 and 38% in cases and 12, 47.3 and 40.7% in controls, respectively.

CONCLUSION

Although we could not find any association between genetic variability in exon 3 and 4 of EPHX and pre-eclampsia, genetic variability in these two exons jointly modifies the predicted enzyme activity and may be a risk factor for pre-eclampsia.

Strategies for dissecting genetic-environmental interactions in neurodegenerative disorders

Complex genetic and environmental interactions contribute to abnormal aging and neurodegenerative disorders. We present information from a series of 1136 consecutive patients presenting with cognitive disorders and show possible significant contribution of toxic environmental and occupational exposures to pathological aging (21% of patients) and interactions of these exposures with common polymorphisms that affect cell injury and inflammation. Such exposures may lower age of onset to same degree as APOE4/4. Common polymorphisms in apolipoprotein E (APOE), hemochromatosis gene (Hfe) and alpha-1-antitrypsin (AAT) are present in up to 40+% of patients and may partially account for differences in clinical syndrome, age of onset and rate of progression. Strategies for the study of these disorders must also consider the role and treatment of common co-morbid illnesses such as alcohol use, nutritional deficiencies, sleep disorders, and pre-existing affective disorder. APOE, Hfe, and AAT genes are expressed in liver tissue and in macrophages and are involved in the host innate immune response to stress, inflammation and infections. Hfe and AAT are involved in iron metabolism and their polymorphisms may contribute to hepatosteatosis and altered homeostasis of lipids (role of APOE), iron, and trace minerals. Some of these responses may be adaptive. Hfe and AAT modulate the apparent effects of toxic exposures on age of onset and progression rate. C282Y polymorphism paradoxically reverses APOE4/4 effect on age of onset. S and Z AAT polymorphisms may attenuate earlier age of onset in persons with toxic or environmental exposure. AAT S or Z polymorphisms are present in 25% of persons with anxiety disorder and 42% of persons with bipolar disorder compared to 10% of control group without pre-existing affective disorder. Common genetic polymorphisms that affect the response to inflammation and cell injury provide a beginning strategy for dissecting neurodegenerative disorders. The effects of APOE, Hfe, and AAT on glucose, lipid, iron and trace mineral homeostasis may affect normal development and aging of the nervous system in addition to their effects on outcome of toxic environmental and occupational exposures and susceptibility and outcome of neurodegenerative illnesses.

Serum iron and copper status and oxidative stress in severe and mild preeclampsia

Our aim was to investigate parameters of iron and copper status and oxidative stress and antioxidant function in women with healthy pregnancy, mild and severe preeclampsia with a view to exploring the possible contribution of these parameters to the aetiology. Thirty healthy, 30 mild preeclamptic and 30 severe preeclamptic pregnant women were included. Serum and placental lipid peroxides, and serum vitamin E and total carotene levels were measured by colorimetric assay. Cholesterol, copper, iron, total iron binding capacity (TIBC), ceruloplasmin and transferrin concentrations were measured by commercially available procedures. Data were analysed statistically using one-way analysis of variance and Pearson correlation test. Logistic regression procedures were used to calculate odds ratios. Lipid peroxides in serum and placental tissue, and iron, copper and ceruloplasmin levels in serum were significantly increased, and transferrin, TIBC, vitamin E/total cholesterol and total carotene/total cholesterol ratios in serum were significantly decreased especially in women with severe preeclampsia. Significant correlations were detected between serum iron and lipid peroxides in serum and placental tissue and between serum iron and vitamin E/total cholesterol in severe preeclamptic pregnancy. Furthermore, there were significant correlations between serum malondialdehyde and ceruloplasmin and vitamin E/total cholesterol in women with severe preeclampsia, and changes in serum and placental lipid peroxides and serum iron concentrations were significantly associated with preeclampsia. In conclusion, ischaemic placental tissue may be a primary source of potentially toxic iron in preeclampsia and the released iron species may contribute to the aetiology and would exacerbate lipid peroxidation and endothelial cell injury, which may be abated by antioxidant supplementation.

N-acetyl-transferase phenotype and risk for preeclampsia

OBJECTIVE

This study was undertaken to determine whether the N-acetyltransferase (NAT) phenotype contributes to the susceptibility for the development of preeclampsia.

STUDY DESIGN

The NAT acetylator status was determined by measuring urinary caffeine metabolites in 134 nonpregnant women with a history of preeclampsia and in 109 control women with uncomplicated pregnancy. The chi(2) and logistic regression analyses were used for statistical evaluation of differences in acetylator status.

RESULTS

Significantly more fast acetylators were found among the women with a history of preeclampsia (46.3%) than among the controls (25.4%). Fast acetylators showed an odds ratio of 2.5 (95% CI 1.4-4.3) for preeclampsia. No differences in the acetylator status were found between women with a history of preeclampsia only and those with the HELLP syndrome as well.

CONCLUSION

The fast NAT acetylator status, which may result in altered NAT detoxification capacity, is associated with preeclampsia.

No association of polymorphisms in the glutathione S-transferase genes with pre-eclampsia, eclampsia and HELLP syndrome in a Turkish population

AIM

There is substantial evidence that genetic factors play a role in pre-eclampsia. The aim of this study was to determine whether genetic variability in the encoding of genes for glutathione S-transferase M1 (GSTM1) and glutathione S-transferase T1 (GSTT1) contributes to individual differences in susceptibility to pre-eclampsia, eclampsia, or hemolysis, elevated liver enzymes, and low platelets (HELLP syndrome).

METHODS

A total of 221 women with pre-eclampsia, eclampsia and HELLP syndrome and 147 healthy female controls were genotyped for GSTM1 and GSTT1 polymorphisms by polymerase chain reaction (PCR). Statistical evaluation of differences in polymorphic rates was carried out using chi(2) analysis.

RESULTS

This study included 140 pre-eclamptic, 33 eclamptic and 48 HELLP syndrome cases and 147 healthy controls. The frequencies for the GSTM1 null genotype were 58%, 45%, and 60% for pre-eclampsia, eclampsia, and HELLP syndrome, respectively, and in controls it was 55%. The distribution of the GSTT1 null genotype was 22%, 21%, and 27% for pre-eclampsia, eclampsia, and HELLP syndrome, respectively, and in controls it was 22%. There was no significant association between GSTM1 and GSTT1 polymorphisms and pre-eclampsia, eclampsia, and HELLP syndrome.

CONCLUSION

Our data do not support a role for polymorphisms of the GSTM1 and GSTT1 genes in the pathogenesis of pre-eclampsia, eclampsia and HELLP syndrome.

Voltammetric studies of Zn and Fe complexes of EDTA: Evidence for the push mechanism

The 'push' hypothesis for the antioxidant action of Zn2+ is based on its displacement of iron from a low molecular weight pro-oxidant complex. In this study, the chemical plausibility of that proposed function is investigated by cyclic voltammetry. As a model for a pro-oxidative low molecular weight iron complex the Fe(II/III)/EDTA couple was examined. This complex was selected for its well-defined electrochemical, iron stability constants, and similarity to other low molecular weight chelates in physiological fluids in terms of logical binding sites, i.e. amino, and carboxylate groups. Also investigated were iron complexes of nitrilotriacetic acid and DL-glutamic acid. Results demonstrate that approximately 90% of the cyclic voltammetric peak current for Fe(III)EDTA reduction and the EC' current for the mediated reduction of H2O2 by Fe(II/III)EDTA (Fenton Reaction) are lost when Zn2+ is introduced to a 1:1 molar ratio relative to iron. All experiments were conducted in HEPES buffered solutions at pH 7.4. Iron (II/III) complexes of nitrilotriacetic acid and DL-glutamic acid followed the same trends. Cyclic voltammetric experiments indicate that Zn2+ displaces Fe(III) from EDTA despite the much larger stability constant for the iron complex (10(25.1)) versus zinc (10(16.50)). The hydrolysis aided displacement of Fe(III) from EDTA by Zn2+ is considered by the equilibria modeling program, HySS. With Fe(III) hydrolysis products included, Zn2+ is able to achieve 90% displacement of iron from EDTA, a result consistent with cyclic voltammetric observations.

Neutrophil activation and C-reactive protein concentration in preeclampsia

Preeclamptic pregnancies seem to be associated with a higher extent of inflammation compared with normal ones. We intended to test this proposal and also to clarify the contribution of some variables in such inflammatory process. We measured total and differential leukocyte count, serum C-reactive protein (CRP), and plasma levels of lactoferrin, elastase, and granulocyte-macrophage colony-stimulating factor (GM-CSF). Uric acid was also evaluated and used as an indicator of the severity of the disease. A cross-sectional study was performed by evaluating healthy and preeclamptic women in the third trimester of gestation (n = 67 and n = 51, respectively) and 24 to 48 h postpartum (n = 32 and n = 26, respectively). When comparing the third trimester of normal and preeclamptic pregnancies, we found significantly higher levels of uric acid, CRP, and elastase, and a significantly higher elastase to neutrophil ratio in the pathologic group. However, for CRP, statistical significance was lost after adjustment for maternal weight. No significant differences were found in total leukocyte count, plasma levels of GM-CSF, and lactoferrin between groups. In preeclampsia, a significant positive correlation was found between elastase and lactoferrin and these neutrophil activation products correlated positively with uric acid level. Considering the analysis of all variables in the postpartum period, only CRP and uric acid levels were significantly elevated in the pathologic group. However, CRP differences obtained in the puerperium seem to be influenced by the increased number of dystocic deliveries in the preeclamptic group. In conclusion, our data suggest that inflammation is further pronounced in preeclampsia and that the extent of neutrophil activation correlates with the severity of this syndrome.

Antioxidant Potential and Transferrin, Ceruloplasmin, and Lipid Peroxidation Levels in Women with Preeclampsia

Background

The aim of this study was to evaluate lipid peroxidation and antioxidant function in patients with preeclampsia and in normotensive pregnant women and to assess an association with the severity of the disease.

Methods

Twenty-one patients with mild preeclampsia, 15 patients with severe preeclampsia, and 19 normotensive pregnant women were included in the study. Plasma antioxidant potential (AOP) status, ceruloplasmin (Cp) and transferrin (Trf) levels as antioxidants, and malondialdehyde (MDA) levels as an indicator of lipid peroxidation were measured.

Results

Whereas the AOP and Trf levels of the severe and mild preeclampsia groups were found to be reduced, the MDA and Cp levels were increased compared with those of the normotensive pregnant group. There were statistically significant negative correlations between AOP and MDA in all groups. No differences were observed between the groups with severe and mild preeclampsia with respect to these analytes.

Conclusion

Our findings suggest that lipid peroxidation may be an important factor in the pathogenesis of preeclampsia and that plasma antioxidants and oxidants are altered in preeclampsia. However, these findings may not be useful in distinguishing women with severe and mild preeclampsia.

Transferrin microheterogeneity in pregnancies with preeclampsia

BACKGROUND

It has been reported that concentrations of serum transferrin (Tf) and its highly sialylated subfraction increase in normal pregnancy. This study investigated changes in the concentrations of serum transferrin and its subfractions in preeclampsia.

METHODS

The serum concentration of transferrin was determined by a standard turbidimetric assay and microheterogeneous transferrin subgroups (low sialylated, 4-sialo and highly sialylated transferrins) were assessed by crossed immuno-isoelectric focusing.

RESULTS

Compared to normal pregnancy, the concentrations of total, 4-sialo and highly sialylated transferrins decreased by 27%, 16% and 38%, respectively, in severe preeclampsia, while these values did not significantly decrease in mild preeclampsia. The concentration of low sialylated transferrin involving 2-sialo- and 3-sialo-transferrins significantly decreased both in mild and severe preeclampsia, the value in severe preeclampsia was even significantly lower than that in nonpregnant women. The serum concentrations of total and highly sialylated transferrins in preeclampsia were correlated positively with infant birth weights (r=0.587 and r=0.645, respectively).

CONCLUSIONS

The serum concentrations of total and highly sialylated transferrins in severe preeclampsia decrease significantly. This might have a negative impact on intrauterine growth. Additionally, the serum low sialylated transferrin decreases more sensitively in preeclampsia, although the concentration is low even in normal pregnancy.

Nutrient involvement in preeclampsia

Preeclampsia is a pregnancy-specific condition that increases maternal and infant mortality and morbidity. It is diagnosed by new-onset increased blood pressure and proteinuria during gestation; for many years these markers were the sole targets for study. More recently, increased attention to the multisystemic nature of the syndrome with involvement of almost all organs, activation of coagulation and increased sensitivity to pressor agents has expanded understanding of the disorder. The epidemiology of preeclampsia, being more common in poor women, long ago suggested that nutrients might be involved in the disorder. Numerous conflicting hypotheses were advanced but the testing of these hypotheses has either been done poorly or not at all. Review of the available data indicates very few studies that provide useful insights. In many studies the syndrome is poorly defined and in most studies nutritional data (questionnaires or biomarkers) are obtained on women with the clinical syndrome. In overtly preeclamptic women it is impossible to decipher cause from effect. Nonetheless, current concepts of the genesis of preeclampsia that include endothelial dysfunction, inflammatory activation, oxidative stress and predisposing maternal factors provide targets for well-designed nutritional investigation. In this review the current concepts of the pathogenesis of preeclampsia are reviewed and available data are assessed in light of these concepts. Targets for nutritional investigation based on the current knowledge of pathophysiology are suggested.

Oxidative stress reproduces placental abnormalities of preeclampsia

OBJECTIVE

The activities of placental superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), but not catalase, are lower than normal in preeclampsia, which could contribute to the uncontrolled placental production of lipid peroxides and thromboxane (TX). Oxidative stress, hyperlipidemia and increased iron levels in the maternal compartment in preeclampsia could be responsible for these placental changes by causing oxidative stress in the placenta.

METHODS

We tested this possibility in vitro by exposing a trophoblast-like cell line, ED27, to a combination of linoleic acid (LA, 90 microM) and an oxidizing solution composed of hypoxanthine, xanthine oxidase and ferrous sulfate (OxLA) for 6 days. For these studies, the cells were treated with dexamethasone (10-8 M) for the first 72 hr. This was done to differentiate the cells into a phenotype more like syncytiotrophoblast cells as evidenced by production of beta-human chorionic gonadotropin (beta-hCG).

RESULTS

After 6 days of exposure to OxLA, the activities of SOD and GSH-Px were significantly decreased as compared to exposure to LA alone. In contrast, catalase activity was increased by OxLA. The OxLA-induced decreases in SOD and GSH-Px activities were attenuated by deferoxamine, an iron chelator, suggesting a role for Fe2+ in the decreased activities. Compared to LA, OxLA significantly increased TX secretion and lipid peroxidation in cells and media at 2, 4 and 6 days. Deferoxamine inhibited the OxLA-induced increase in lipid peroxidation, but not the increase in TX. Isolation of trophoblast cells and villous core tissue from term placentas verified that antioxidant enzyme activity was localized primarily to the trophoblast cell compartment lending validity to the in vitro findings.

CONCLUSIONS

These data mimic the changes in placental SOD, GSH-Px, catalase, TX and lipid peroxidation that occur in preeclampsia suggesting that maternal hyperlipidemia and increased iron levels may be responsible for placental oxidative stress and abnormalities in antioxidants and thromboxane.

Abnormal iron parameters in the pregnancy syndrome preeclampsia

OBJECTIVE

Our purpose was to investigate iron status parameters in preeclampsia with a view to exploring their possible contribution to the etiology.

STUDY DESIGN

In prepared serum samples from 40 preeclamptic women and matched pregnant control subjects at the John Radcliffe Hospital, Oxford, a number of iron status parameters were measured. Statistical analysis was by the Wilcoxon signed rank test and linear regression.

RESULTS

Serum iron concentration, ferritin, and percent saturation of transferrin were significantly higher in the preeclamptic patients than in control subjects, whereas unsaturated iron-binding capacity and apotransferrin levels were significantly lower. No difference was found in hemopexin concentrations in the two groups. Gestational age at the time of sampling was correlated (positively) with only two parameters, total and unsaturated iron-binding capacity, but only in the preeclampsia group. Eighteen percent of preeclamptic subjects had percent transferrin saturation levels in the region associated with iron overload.

CONCLUSION

Released iron species in preeclampsia may contribute to the etiology and will exacerbate lipid peroxidation and endothelial cell injury. Given the high prevalence of heterozygosity for hemochromatosis with the associated reduced ability to exclude ingested iron, it would seem inadvisable, in the absence of evidence of iron deficiency, to give iron supplements to pregnant women at high risk for preeclampsia.

Mishandling of copper by albumin: role in redox-cycling and oxidative stress in preeclampsia plasma

OBJECTIVE

To test the hypothesis that enhanced oxidative stress during pregnancies complicated by preeclampsia is associated with improper copper (Cu) binding by plasma albumin, resulting in enhanced Cu redox-cycling activity and that altered Cu binding, in turn, is caused by interactions of excessive amounts of free fatty acids with albumin.

STUDY DESIGN

We studied binding and redox-cycling activity of Cu in 17 normal pregnancy and 17 preeclampsia plasma samples. Binding of exogenous Cu in plasma samples was quantified indirectly using spectrophotometric measurements of its complex with a specific chelator of Cu(I), bathocuproine disulfonate. Redox-cycling activity of Cu in plasma samples was estimated by electron paramagnetic resonance (EPR) spectroscopy of ascorbate radicals formed during one-electron oxidation of ascorbate by redox-active catalytic Cu. Formation of Cu/albumin complexes in model systems in the presence and absence of fatty acids was studied using EPR spectroscopy of Cu(II)/albumin.

RESULTS

We found that preeclampsia plasma (as compared to normal pregnancy plasma) (1) displays elevated endogenous ascorbate redox-cycling that is normalized by a Cu(II) chelator, cuprizone I, (2) has lowered capacity to bind and redox-regulate exogenously added Cu, and (3) responds to treatment with fatty-acid-free albumin by diminished ascorbate oxidizing activity. Conversely, addition of free fatty acid (oleic acid) to normal pregnancy plasma sample yields increased ascorbate redox-cycling activity. Our model experiments showed that Cu-dependent redox-cycling activity of purified human serum albumin is significantly increased by excess free fatty acids.

CONCLUSION

Mishandling of Cu by albumin contributes to oxidative stress in preeclampsia. Cu chelators may represent promising mechanism-based antioxidants to attenuate oxidative stress in preeclampsia.

Effect of concentration and biochemical assay on the accuracy of urine dipsticks in hypertensive pregnancies

OBJECTIVE

To assess how urine concentration and biochemical assay influence the assessment of proteinuria.

METHODS

This was a prospective study to assess the accuracy of detection and quantification of proteinuria within the day assessment unit and antenatal ward of a teaching hospital in Leicester, United Kingdom. We studied hypertensive pregnancies (of mixed parity) referred to day care assessment or attending the antenatal hypertension clinic after 20 completed weeks of gestation (n = 197). Aliquots of a well-mixed 24-h urine collection were tested by routine dipstick urinalysis and then assayed for protein using the Benzethonium Chloride and the Bradford assays (n = 197).

MAIN OUTCOME MEASURES

Total protein excretion in 24 h and protein concentration per liter of urine for both biochemical assays were compared to semiquantitative dipstick protein measurement.

RESULTS

The prevalence of proteinuria in the study group varied according to the method used for testing. Dipstick urinalysis recorded the lowest prevalence (16.2%) and the Benzethonium Chloride assay measuring total protein excretion in 24 h recorded the highest (70.1%). When the positive and negative predictive values for dipstick urinalysis were calculated, performance was found to be dependent on both the units of measurement compared and the type of assay used as the "gold standard." Positive predictive values ranged from 87.5% to 96.9% and negative predictive values ranged from 35.2% to 92.1%.

CONCLUSIONS

The prevalence of proteinuria in hypertensive pregnancies is dependent on the method used to detect it. The amount of protein assessed quantitatively is further dependent on the biochemical assay employed. However, regardless of the quantitative assessment, dipstick urinalysis has a significant false-negative rate. This first reporting of a variation in performance between dipstick urinalysis and two different biochemical assays in pregnancy may be explained in relation to protein assay specificity and the observed protein compositions of the samples on electrophoretic analysis. The significance of proteinuria should be considered in light of the method used to detect it, but, ultimately, it must be related to clinical outcome.

Possible beneficial effect of exercise, by reducing oxidative stress, on the incidence of preeclampsia

We hypothesize that regular exercise enhances antioxidative enzymes in pregnant women, which reduce oxidative stress and, thus, the incidence of preeclampsia. Oxidative stress with enhanced lipid peroxide formation could lead to endothelial dysfunction in preeclampsia. Other conditions, such as increased transferrin saturation and decreased iron-binding capacity, directly and indirectly promote the process of oxidative stress and subsequent endothelial dysfunction. Exercise increases oxidative metabolism and produces a prooxidant environment. This acidic environment during exercise (at or beyond anaerobic threshold) promotes oxygen release from hemoglobin and increases in PO(2) in tissues, as well as releases iron from transferrin. When exercise is repeated regularly, the body promptly adjusts so that oxidative stress is eliminated or reduced. The body's adaptations to a regular exercise habit seem to have an antioxidant effect. In humans, training effects have been identified with an enhanced activity of antioxidative enzymes. Another concerted adaptation that regular exercise brings to women's bodies is resistance against production of prooxidants by increasing the number of mitochondria. Equally important is a training effect that decreases susceptibility to lipid peroxidation. Evidence suggests that physically active women are less likely to develop preeclampsia. In theory, intracellular and extracellular conditions resulting from regular exercise should counteract the enhancement of oxidative stress, thus interfering with the process leading to endothelial dysfunction. This position paper describes a hypothesis and includes a brief review of exercise physiology and biochemical research in preeclampsia. Unlike other preventive treatments, such as aspirin or calcium supplements, a regular exercise habit leads to a positive and healthy lifestyle without concern of side effects.

Study of plasma factors associated with neutrophil activation and lipid peroxidation in preeclampsia

Neutrophil activation occurs in women with preeclampsia and is resolved after delivery. The present study examined whether circulating factors in plasma of women with preeclampsia caused neutrophil activation and lipid peroxidation. Twenty-one women with proteinuric preeclampsia were matched for age and gestational age with 19 normal pregnant women. Plasma was collected from all subjects before delivery and at 6 weeks postpartum and incubated with autologous white-cell buffy coat collected at the postpartum visit. Neutrophil activation was assessed by level of CD11b and CD18 expression after incubation with autologous antepartum or postpartum plasma. Lipid peroxidation was assessed by measurement of F(2)-isoprostanes in plasma, plasma-white cell incubates, and urine. Neutrophil CD11b and CD18 expression was not differentially altered by incubation with plasma from either women with preeclampsia or normal pregnant women and was similar between groups when incubation was performed with plasma collected after delivery. In preeclampsia, plasma F(2)-isoprostanes were significantly increased before and after delivery compared with controls. Plasma F(2)-isoprostanes were increased 2-fold after incubation of plasma with buffy coat, but preeclamptic women had higher levels compared with those of controls when either pregnant or postpartum plasma was used. In pregnant preeclamptics, plasma F(2)-isoprostanes were positively correlated with lymphocyte count. Six weeks after delivery, plasma F(2)-isoprostanes in the preeclamptic women were significantly positively associated with lymphocyte count and cholesterol and negatively associated with albumin. In conclusion, the present study does not suggest that a stable circulating factor causes neutrophil activation in preeclampsia. However, lipid peroxidation is elevated before and after delivery in women with preeclampsia, which suggests that these women may have an underlying predisposition to increased oxidative stress that may be driven by or contribute to a persistent low-grade inflammatory response.

Blood glutathione redox status in gestational hypertension

Gestational hypertension during the third trimester reflects an exaggerated maternal inflammatory response to pregnancy. We hypothesized that oxidative stress present even in normal pregnancy becomes uncompensated in hypertensive patients. A glucose-6-phosphate dehydrogenase (G6PD) activity sufficient to meet the increased reductive equivalent need of the cells is indispensable for defense against oxidative stress. The erythrocyte glutathione redox system was studied, where G6PD is the only NADPH source. The glutathione (GSH) redox status was measured both in vivo and after an in vitro oxidative challenge in pregnant women with gestational hypertension (n = 19) vs. normotensive pregnant subjects (n = 18) and controls (n = 20). An erythrocyte GSH depletion with an increase in the oxidized form (GSSG) resulted in an elevated ratio GSSG/GSH (0.305 +/- 0.057; mean +/- SD) in hypertensive pregnant women vs. normotensive pregnant or control subjects (0.154 +/- 0.025; 0.168 +/- 0.073; p <.001). In hypertensive pregnant patients, a "GSH stability" decrease after an in vitro oxidative challenge suggested a reduced GSH recycling capacity resulting from an insufficient NADPH supply. The erythrocyte GSSG/GSH ratio may serve as an early and sensitive parameter of the oxidative imbalance and a relevant target for future clinical trials to control the effects of antioxidant treatment in women at increased risk of the pre-eclampsia syndrome.