No evidence for lipid peroxidation in severe preeclampsia

Repeated measures of inflammation and oxidative stress biomarkers in preeclamptic and normotensive pregnancies

BACKGROUND

Preeclampsia is a prevalent and enigmatic disease, in part characterized by poor remodeling of the spiral arteries. However, preeclampsia does not always clinically present when remodeling has failed to occur. Hypotheses surrounding the "second hit" that is necessary for the clinical presentation of the disease focus on maternal inflammation and oxidative stress. Yet, the studies to date that have investigated these factors have used cross-sectional study designs or small study populations.

OBJECTIVE

In the present study, we sought to explore longitudinal trajectories, beginning early in gestation, of a panel of inflammation and oxidative stress markers in women who went on to have preeclamptic or normotensive pregnancies.

STUDY DESIGN

We examined 441 subjects from the ongoing LIFECODES prospective birth cohort, which included 50 mothers who experienced preeclampsia and 391 mothers with normotensive pregnancies. Participants provided urine and plasma samples at 4 time points during gestation (median, 10, 18, 26, and 35 weeks) that were analyzed for a panel of oxidative stress and inflammation markers. Oxidative stress biomarkers included 8-isoprostane and 8-hydroxydeoxyguanosine. Inflammation biomarkers included C-reactive protein, the cytokines interleukin-1β, -6, and -10, and tumor necrosis factor-α. We created Cox proportional hazard models to calculate hazard ratios based on time of preeclampsia diagnosis in association with biomarker concentrations at each of the 4 study visits.

RESULTS

In adjusted models, hazard ratios of preeclampsia were significantly (P<.01) elevated in association with all inflammation biomarkers that were measured at visit 2 (median, 18 weeks; hazard ratios, 1.31-1.83, in association with an interquartile range increase in biomarker). Hazard ratios at this time point were the most elevated for C-reactive protein, for interleukin-1β, -6, and -10, and for the oxidative stress biomarker 8-isoprostane (hazard ratio, 1.68; 95% confidence interval, 1.14-2.48) compared to other time points. Hazard ratios for tumor necrosis factor-α were consistently elevated at all 4 of the study visits (hazard ratios, 1.49-1.63; P<.01). In sensitivity analyses, we observed that these associations were attenuated within groups typically at higher risk of experiencing preeclampsia, which include African American mothers, mothers with higher body mass index at the beginning of gestation, and pregnancies that ended preterm.

CONCLUSIONS

This study provides the most robust data to date on repeated measures of inflammation and oxidative stress in preeclamptic compared with normotensive pregnancies. Within these groups, inflammation and oxidative stress biomarkers show different patterns across gestation, beginning as early as 10 weeks. The start of the second trimester appears to be a particularly important time point for the measurement of these biomarkers. Although biomarkers alone do not appear to be useful in the prediction of preeclampsia, these data are useful in understanding the maternal inflammatory profile in pregnancy before the development of the disease and may be used to further develop an understanding of potentially preventative measures.

The enigma ofin vivooxidative stress assessment: isoprostanes as an emerging target

Oxidative stress is believed to be one of the major factors behind several acute and chronic diseases, and may also be associated with ageing. Excess formation of free radicals in miscellaneous body environment may originate from endogenous response to cell injury, but also from exposure to a number of exogenous toxins. When the antioxidant defence system is overwhelmed, this leads to cell damage. However, the measurement of free radicals or their endproducts is tricky, since these compounds are reactive and short lived, and have diverse characteristics. Specific evidence for the involvement of free radicals in pathological situations has been difficult to obtain, partly owing to shortcomings in earlier described methods for the measurement of oxidative stress. Isoprostanes, which are prostaglandin-like bioactive compounds synthesized in vivo from oxidation of arachidonic acid, independently of cyclooxygenases, are involved in many human diseases, and their measurement therefore offers a way to assess oxidative stress. Elevated levels of F₂-isoprostanes have also been seen in the normal human pregnancy, but their physiological role has not yet been defined. Large amounts of bioactive F₂-isoprostanes are excreted in the urine in normal basal situations, with a wide interindividual variation. Their exact role in the regulation of normal physiological functions, however, needs to be explored further. Current understanding suggests that measurement of F₂-isoprostanes in body fluids provides a reliable analytical tool to study oxidative stress-related diseases and experimental inflammatory conditions, and also in the evaluation of various dietary antioxidants, as well as drugs with radical-scavenging properties. However, assessment of isoprostanes in plasma or urine does not necessarily reflect any specific tissue damage, nor does it provide information on the oxidation of lipids other than arachidonic acid.

Serum FRAP Levels and Pre-eclampsia among Pregnant Women in a Rural Community of Northern India

INTRODUCTION

There is a balance between the oxidative and the anti-oxidative forces in human body. Some studies document decreased level of anti-oxidant in pre-eclampsia while other studies showed normal level of anti-oxidant in pre-eclampsia and the evidence is equivocal.

AIM

The aim of the present study was to assess enzymatic anti-oxidant activities in pre-eclamptic women and compare it with normotensive pregnant women with period of gestation between 28 to 36 weeks.

MATERIALS AND METHODS

A community-based cross-sectional survey was conducted (from November 2012-December 2013) at the Ballabgarh Health and Demographic Surveillance System (HDSS) site which was managed by Centre for Community Medicine, All India Institute of Medical Sciences, New Delhi, India. All registered pregnant women with period of gestation between 28 weeks - 36 weeks were eligible for inclusion in the study. All eligible pregnant women were contacted through home visit. A total of 217 pregnant women were enrolled out of which 209 blood samples were collected from pregnant women. About three ml of blood from antecubital vein was drawn without use of tourniquet, under aseptic conditions. It was later analysed for the serum anti-oxidative measures {Malanoaldehyde, Vitamin C, Ferric Reducing Ability of Plasma (FRAP) levels}. Data were entered on Epi-Info version 3.5.4. Data management and analysis was carried out in Stata 11. The means were compared using t-test and p-value stated. Categorical data was analysed using chi-square test. Logistic regression was used and adjusted p-value was stated.

RESULTS

A total of 217 pregnant women were eligible for the study and all were enrolled. Out of the 217 blood samples collected, eight samples accidently got destroyed. A total of 28 out of remaining 209 pregnant women (13.4%) had pre-eclampsia. Mean age (SD) was 22.4 (2.3) years, mean height (SD) was 156.6 (6.9) cm, mean weight (SD) was 65.1 (9.7) kg in pre-eclampsia group. In pre-eclampsia group mean serum levels of malanoaldehyde, vitamin C and FRAP was 4.2 (0.26) ng/dl, 0.83 (0.11) mg/dl, 678.0 (35.6) μmol/L. It was 4.5 (0.09) ng/dl,0.88 (0.03) mg/dl, 599.3 (13.3) μmol/L in normotensive pregnant women group respectively. The difference was statistically significant for FRAP levels only.

CONCLUSION

Serum anti-oxidant levels are not raised among women with pre-eclampsia.

Evaluation of maternal systemic inflammatory response in preeclampsia

OBJECTIVE

To evaluate the systemic inflammatory response in preeclampsia compared to normal pregnancy.

MATERIALS AND METHODS

The following serum parameters were determined in three groups of patients: leukocytes, neutrophils, tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), C-reactive protein (CRP), and certain markers of oxidative stress. Fetal status was assessed based on the gestational age at which birth occurred, on the Apgar score, and on fetal weight.

RESULTS

In preeclampsia, a higher systemic inflammatory status was found compared to normal pregnancy. Gestational age at birth, fetal weight, and Apgar score were significantly lower in the group with preeclampsia compared to normal pregnancy.

CONCLUSION

In preeclampsia, there is an increased systemic inflammatory response compared to normal pregnancy, which can influence fetal status at birth.

Placental antioxidant enzyme status and lipid peroxidation in pregnant women with type 1 diabetes: The effect of vitamin C and E supplementation

AIM

In view of the increased rates of pre-eclampsia observed in diabetic pregnancy and the lack of ex vivo data on placental biomarkers of oxidative stress in T1 diabetic pregnancy, the aim of the current investigation was to examine placental antioxidant enzyme status and lipid peroxidation in pregnant women with type 1 diabetes. A further objective of the study was to investigate the putative impact of vitamin C and E supplementation on antioxidant enzyme activity and lipid peroxidation in type 1 diabetic placentae.

METHODS

The current study measured levels of antioxidant enzyme [glutathione peroxidase (Gpx), glutathione reductase (Gred), superoxide dismutase (SOD) and catalase] activity and degree of lipid peroxidation (aqueous phase hydroperoxides and 8-iso-prostaglandin F2α) in matched central and peripheral samples from placentae of DAPIT (n=57) participants. Levels of vitamin C and E were assessed in placentae and cord blood.

RESULTS

Peripheral placentae demonstrated significant increases in Gpx and Gred activities in pre-eclamptic in comparison to non-pre-eclamptic women. Vitamin C and E supplementation had no significant effect on cord blood or placental levels of these vitamins, nor on placental antioxidant enzyme activity or degree of lipid peroxidation in comparison to placebo-supplementation.

CONCLUSION

The finding that maternal supplementation with vitamin C/E does not augment cord or placental levels of these vitamins is likely to explain the lack of effect of such supplementation on placental indices including antioxidant enzymes or markers of lipid peroxidation.

The cellular immunity and oxidative stress markers in early pregnancy loss

OBJECTIVE

We investigated whether changes in cellular immunity and oxidative stress in pregnancy have any association with spontaneous miscarriage.

MATERIAL AND METHODS

Circulating adenosine deaminase (ADA) activity as a marker of cellular immunity and malondialdehyde (MDA) and catalase (CAT), glutathione peroxidase (GPx) as markers of T lymphocyte activation and parameters of oxidative stress and antioxidant defense were compared between 40 women with early pregnancy loss and another 40 women with ungoing healthy pregnancy.

RESULTS

Women with miscarriage had higher serum ADA and GPx levels when compared with women with normal pregnancy (p = 0.034 and p < 0.001, respectively). Although serum MDA level was slightly higher in women with miscarriage, the difference was not significant (p = 0.083). CAT levels were alike in both groups.

CONCLUSION

We have demonstrated an increased cellular immunity and perhaps a compensated oxidative stress related to increased antioxidant activation in women with early spontaneous pregnancy loss.

A Proposed Molecular Mechanism of High-Dose Vitamin D3 Supplementation in Prevention and Treatment of Preeclampsia

A randomized prospective clinical study performed on a group of 74 pregnant women (43 presenting with severe preeclampsia) proved that urinary levels of 15-F(2t)-isoprostane were significantly higher in preeclamptic patients relative to the control (3.05 vs. 2.00 ng/mg creatinine). Surprisingly enough, plasma levels of 25-hydroxyvitamin D3 in both study groups were below the clinical reference range with no significant difference between the groups. In vitro study performed on isolated placental mitochondria and placental cell line showed that suicidal self-oxidation of cytochrome P450scc may lead to structural disintegration of heme, potentially contributing to enhancement of oxidative stress phenomena in the course of preeclampsia. As placental cytochrome P450scc pleiotropic activity is implicated in the metabolism of free radical mediated arachidonic acid derivatives as well as multiple Vitamin D3 hydroxylations and progesterone synthesis, we propose that Vitamin D3 might act as a competitive inhibitor of placental cytochrome P450scc preventing the production of lipid peroxides or excess progesterone synthesis, both of which may contribute to the etiopathogenesis of preeclampsia. The proposed molecular mechanism is in accord with the preliminary clinical observations on the surprisingly high efficacy of high-dose Vitamin D3 supplementation in prevention and treatment of preeclampsia.

The timing of cord clamping and oxidative stress in term newborns

BACKGROUND

Clamping and cutting of the umbilical cord is the most prevalent of all operations, but the optimal timing of cord clamping is controversial, with different timings offering advantages and disadvantages. This study, for the first time, compares the influence of early and late cord clamping in correlation with oxidative stress and inflammation signaling, Because cord clamping timing may have a significant influence on placenta-to-infant blood transfer, thereby modifying oxygenation of maternal and fetal tissues, and on the transfer of inflammatory mediators throughout the placenta.

METHODS

Sixty-four pregnant subjects were selected at the Gynecology and Obstetrics Services Department of the Clinico San Cecilio Hospital, Granada, Spain, based on disease-free women who experienced a normal course of pregnancy and a spontaneous, vaginal, single delivery. Half of the subjects had deliveries with early-clamped newborn infants (at 10 s), and the other half had late-clamped deliveries (at 2 min).

RESULTS

Erythrocyte catalase activity was significantly greater in the late-clamped group than in the early-clamped group (P < .01 for the umbilical vein and P < .001 for the artery). The values for superoxide dismutase, total antioxidant status, and soluble tumor necrosis factor receptor II were all significantly higher in the late-clamped group compared with the early-clamped group (P < .01, P < .001, and P < .001, respectively).

CONCLUSIONS

The results suggest a beneficial effect of late cord clamping, produced by an increase in antioxidant capacity and moderation of the inflammatory-mediated effects induced during delivery of term neonates.

Impaired renal function and increased urinary isoprostane excretion in Ghanaian women with pre-eclampsia

Background

The cause of pre-eclampsia remains largely unknown, but oxidative stress (an imbalance favoring oxidant over antioxidant forces) has been implicated in contributing to the clinical symptoms of hypertension and proteinuria. Assessment of oxidative stress in pre-eclampsia using urinary isoprostane has produced conflicting results, and it is likely that renal function may affect isoprostane excretion. The aim of this study was to determine the role of oxidative stress in the pathophysiology of pre-eclampsia and to assess the effect of renal function on isoprostane excretion in pre-eclampsia in the Ghanaian population.

Methods

This was a case-controlled study, comprising 103 pre-eclamptic women and 107 normal pregnant controls and conducted at the Korle-Bu Teaching Hospital between December 2006 and May 2007. The study participants were enrolled in the study after meeting the inclusion criteria and signing their written informed consent. Oxidative stress was determined by measuring urinary excretion of isoprostane and total antioxidant capacity using an enzyme-linked immunosorbent assay technique. Renal function was assessed by calculating the estimated glomerular filtration rate using the Modification of Diet in Renal Disease formula.

Results

The pre-eclampsia group had significantly (P = 0.0006) higher urinary isoprostane excretion (2.81 ± 0.14 ng/mg creatinine) than the control group (2.01 ± 0.18 ng/mg creatinine) and a significantly (P = 0.0008) lower total antioxidant power (1.68 ± 0.05 mM) than the control group (1.89 ± 0.04 mM). Urinary isoprostane excretion showed a positive correlation with both mean arterial pressure (r = 0.261) and microalbuminuria (r = 0.510) in the pre-eclampsia cases. The pre-eclampsia group had a significantly lower estimated glomerular filtration rate than the control group (P < 0.001), indicating more renal impairment.

Conclusion

The increased urinary excretion of isoprostanes and decreased total antioxidant power in the in pre-eclampsia group suggest increased production of oxidants and depletion and/or reduction of maternal antioxidants. Increased oxidative stress may be important in the pathophysiology of pre-eclampsia by contributing to endothelial dysfunction, proteinuria, and hypertension.

Assessment of oxidative status markers and NO bioavailability in hypertensive disorders of pregnancy

The systemic oxidative status in hypertensives disorders of pregnancy (HDP) and its association with endothelial dysfunction is controversial. In the present study, we evaluated systemic plasma levels of oxidative stress markers (TBARS (thiobarbituric acid-reactive substances) and carbonyl) and total antioxidant status (FRAP (ferric reducing ability of plasma (ferric reducing/antioxidant power) and reduction of MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide))), as well as assessed the impact these markers have on nitric oxide (NO) status in healthy pregnant (HP, n=38), gestational hypertensive (GH, n=33) and preeclamptic pregnant women (PE, n=28). We found similar values of TBARS among all groups, and reduced carbonyl levels in HDP between the PE and GH. Conversely, significant increases in plasma activity of antioxidant status were observed in the GH and PE groups compared to the HP group (using both MTT or FRAP method). Importantly, HDP present significantly lower nitrite levels compared to HP women. In Conclusion, our findings show a compensatory antioxidant mechanism against reactive oxygen species (ROS) generation in HDP, which is not associated with nitrite levels restoration.

Evaluation of oxidative stress in pregnancy induced hypertension

This work was undertaken to investigate correlation between oxidative stress and initiation of pathogenesis of pregnancy induced hypertension (PIH). Fifty primigravidae in age group of 20-35 years and gestational age 28-42 weeks with PIH were taken as cases. Twenty healthy primigravidae with no medical and surgical complications of pregnancy and with blood pressure ≤140/90 mm Hg served as controls. The cases were again subgrouped as severe preeclampsia (12 in number) and mild pre-eclampsia (38 in number). All of them were evaluated for serum malondialdehyde (MDA), Serum vitamin E and plasma vitamin C levels. The serum MDA levels were raised significantly in women with mild preeclampsia (P<0.01) and in women with severe preeclampsia (P<0.01) in comparison to normal primi gravida. The serum vitamin E levels were decreased in primi gravida with mild preeclampsia (p<0.1) and in primi with severe pre eclampsia (P<0.1) in comparison to normal primi gravida but the fall was not statistically significant. There was a significant fall (P<0.05) in the vitamin C levels in primi with mild preeclampsia than in the normal primi. The vitamin C levels in severe preeclamptic patients were lower than the normal primi but the fall was not statistically significant (P=0.10). The serum MDA and vitamin E showed a negative correlation in all the cases. The serum MDA and plasma vitamin C also showed a negative correlation in the control and study group. This observation suggests that in hypertensive disorders of pregnancy there is an imbalance between lipid peroxidation and antioxidant vitamin status because of oxidative stress. The decreased serum concentrations of the antioxidant vitamins supports the hypothesis that lipid peroxidation is an important causative factor in the pathogenesis of preeclampsia. The rise in antioxidants is probably to compensate the increased peroxide load in severe preeclampsia.

Inflammatory disturbances in preeclampsia: relationship between maternal and umbilical cord blood

Preeclampsia (PE) is one of the main causes of maternal and fetal mortality and morbidity. PE is associated with an inflammatory state and with oxidative stress, in maternal circulation. Our aim was to evaluate and compare the levels of oxidative stress and inflammatory markers in maternal and umbilical cord blood (UCB), in normal and PE pregnancies. We measured acute-phase proteins (CRP and α1-antitrypsin), proinflammatory cytokines (IL-6 and TNF-α), leukocyte activation (elastase, lactoferrin, sL-selectin, sVCAM, sPECAM), total antioxidant status (TAS), thiobarbituric acid reactive substances (TBARS), and uric acid levels. We studied 42 healthy pregnant women, 46 PE women, and their neonates. The concentrations of IL-6, TNF-α, α1-antitrypsin, CRP, sVCAM, uric acid, and TBARS were significantly higher, and sL-selectin was significantly lower in PE pregnant women as compared with normotensive pregnant women. In newborns uric acid, α1-antitrypsin, and CRP values were significantly higher in PE; leukocyte count, sL-selectin, lactoferrin, and the ratio elastase/α1-antitrypsin were significantly lower. Our data suggest that PE pregnancy is associated with an enhanced maternal inflammatory condition, which is reflected in fetal circulation. This enhanced inflammatory state seems to be related to endothelial dysfunction and increased cytokine synthesis, rather than with neutrophil activation.

Influence of sex and glucocorticoid exposure on preterm placental pro-oxidant-antioxidant balance

Glucocorticoids (GC) are known to influence fetal ROS production and anti-oxidant defences yet little attention has focused on the potential for effects in the placenta. We hypothesised that antenatal GC exposure alters placental pro-oxidant-anti-oxidant balance sex-specifically, based upon the known relationship between male sex and poor pregnancy outcome. Placentae were collected from 60 women who delivered between 24 and 31 completed weeks gestation and placental oxidative and nitrative stress (protein carbonyl, lipid hydroperoxide, and nitrotyrosine concentration) and anti-oxidant enzyme activity (glutathione peroxidase, thioredoxin reductase, and superoxide dismutase) measured. A pro-oxidant state was observed in placentae of male compared to female infants born within 72 h of antenatal GC exposure, with higher levels of protein carbonyl content (p = 0.04), lipid hydroperoxide (p < 0.01) and nitrotyrosine content (p = 0.02), and lower levels of glutathione peroxidase activity (p = 0.01). A pro-oxidant state continued to be observed in placentae of males compared to females born outside of 72 h, with higher protein carbonyl content (p = 0.04) and lower glutathione peroxidase activity (p = 0.01) than females, however no differences in placental lipid hydroperoxide and nitrotyrosine content were observed. These sex-specific alterations in products of placental oxidative stress could not purely be explained by differences in clinical illness severity (CRIB2 score). Therefore, these sex-specific alterations in placental pro-oxidant-antioxidant balance in response to antenatal betamethasone exposure, independent of illness severity, could contribute to the patho-physiologic processes underlying oxygen radical diseases of the newborn, conditions known to exhibit a male excess.

Role of oxidative stress markers and antioxidants in the placenta of preeclamptic patients

AIM

The present study aimed to evaluate and compare the placental variables of oxidative stress markers in preeclamptic women.

METHODS

A total of 60 placentas were collected. Of these, 30 were obtained from normotensive pregnancies, and 30 from pregnancies with preeclampsia as per International Society for the Study of Hypertension in Pregnancy (ISSHP) criteria. Each placental tissue was analyzed for levels of pro-oxidant (malondialdehyde) and antioxidants (glutathione and superoxide dismutase) using the standard enzymatic assays.

RESULTS

Malondialdehyde levels were significantly higher (12.21 ± 4.1 versus 4.7 ± 2.1 nmol/g tissue, P < 0.0001) and glutathione (GSH) levels were significantly lower (0.46 ± 0.37 versus 1.03 ± 0.43 µmol/g tissue, P < 0.0001) in the placentas of preeclamptic women when compared to those of normal pregnancies. Though not statistically significant, decreases in superoxide dismutase levels were observed in placentas of preeclamptic women (4.14 ± 2.25 versus 5.22 ± 2.0 units/mg tissue protein, P < 0.055). Receiver operator characteristic curve analysis of malondialdehyde revealed a sensitivity of 87% and specificity of 87%, at a cutoff value 6.5 nmol/g. Similarly, GSH had a sensitivity of 77% and a specificity of 77% at a cutoff value 0.62 µmol/g.

CONCLUSION

The present study demonstrated that increased placental lipid peroxidation and decreased levels of antioxidants may play an important role in the pathogenesis of preeclampsia. These findings are suggestive of involvement of oxidative stress markers in preeclamptic patients.

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.

A quantitative evaluation of total antioxidant status and oxidative stress markers in preeclampsia and gestational diabetic patients in 24-36 weeks of gestation

OBJECTIVE

To assess the plasma and serum maternal total antioxidant status, circulating levels of lipid peroxidation breakdown products (MDA), protein oxidation markers (AOPPs), myeloperoxidase (MPO) and lipid hydroperoxide (LHP) in preeclampsia, gestational diabetes mellitus (GDM) patients and compare them with noncomplicated normal pregnancies between 24 and 36 weeks of gestation.

STUDY DESIGN

27 GDM, 27 preeclampsia and 29 noncomplicated singleton pregnancies were included. The blood samples were taken at the diagnosis of disease.

RESULTS

TAS was decreased in GDM and preeclampsia when compared to normal pregnancies. MDA levels were higher only in GDM group than normal pregnancies. AOPP levels were increased but MPO and LHP levels were not changed both in GDM and preeclampsia when compared to normal pregnancies.

CONCLUSIONS

We concluded that increased oxidative stress and reduction in antioxidant defense mechanisms may contribute to disease processes both in GDM and preeclampsia.

Vitamins C and E to prevent complications of pregnancy-associated hypertension

BACKGROUND

Oxidative stress has been proposed as a mechanism linking the poor placental perfusion characteristic of preeclampsia with the clinical manifestations of the disorder. We assessed the effects of antioxidant supplementation with vitamins C and E, initiated early in pregnancy, on the risk of serious adverse maternal, fetal, and neonatal outcomes related to pregnancy-associated hypertension.

METHODS

We conducted a multicenter, randomized, double-blind trial involving nulliparous women who were at low risk for preeclampsia. Women were randomly assigned to begin daily supplementation with 1000 mg of vitamin C and 400 IU of vitamin E or matching placebo between the 9th and 16th weeks of pregnancy. The primary outcome was severe pregnancy-associated hypertension alone or severe or mild hypertension with elevated liver-enzyme levels, thrombocytopenia, elevated serum creatinine levels, eclamptic seizure, medically indicated preterm birth, fetal-growth restriction, or perinatal death.

RESULTS

A total of 10,154 women underwent randomization. The two groups were similar with respect to baseline characteristics and adherence to the study drug. Outcome data were available for 9969 women. There was no significant difference between the vitamin and placebo groups in the rates of the primary outcome (6.1% and 5.7%, respectively; relative risk in the vitamin group, 1.07; 95% confidence interval [CI], 0.91 to 1.25) or in the rates of preeclampsia (7.2% and 6.7%, respectively; relative risk, 1.07; 95% CI, 0.93 to 1.24). Rates of adverse perinatal outcomes did not differ significantly between the groups.

CONCLUSIONS

Vitamin C and E supplementation initiated in the 9th to 16th week of pregnancy in an unselected cohort of low-risk, nulliparous women did not reduce the rate of adverse maternal or perinatal outcomes related to pregnancy-associated hypertension (ClinicalTrials.gov number, NCT00135707).

Pathogenesis of preeclampsia

Preeclampsia is a systemic syndrome that occurs in 3 to 5% of pregnant women and classically manifests as new-onset hypertension and proteinuria after 20 weeks of gestation. Preeclampsia is a leading cause of maternal and neonatal morbidity and mortality. The only known cure is delivery of the placenta. Recent discoveries, however, have led to important advances in understanding the pathogenesis of the condition. Placental antiangiogenic factors are upregulated and disrupt the maternal endothelium. This change in the normal angiogenic balance toward an antiangiogenic state can result in hypertension, proteinuria, glomerular endotheliosis, HELLP (hemolysis, elevated liver enzymes, and low platelets) syndrome, and cerebral edema-the clinical signs of preeclampsia and eclampsia. The regulation of these antiangiogenic factors in the placenta is unknown. The recent discoveries of upregulated antiangiogenic factors provide promise for future testing to predict and diagnose preeclampsia as well as therapeutic targets for amelioration of the clinical disease.

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.

Comparison of effect of daily versus weekly iron supplementation during pregnancy on lipid peroxidation

OBJECTIVES

To compare the effect of daily versus weekly iron supplementation on lipid peroxidation, hemoglobin levels and maternal and perinatal outcome in non-anemic pregnant women.

METHODS

Of 109 women randomly allocated into three groups, 90 completed the study. Group I (n = 30) received daily iron folic acid; Group II (n = 30) received weekly iron folic acid; Group III (n = 30) received daily iron (III)-hydroxide polymaltose complex. Hemoglobin levels, hematological indices, thiobarbituric acid reactive substances (TBARS) and glutathione levels were measured at baseline (14-16 weeks) and at 30-34 weeks. Statistical analysis was done using the anova test.

RESULTS

Group I had a highly significant increase in TBARS level (0.61 +/- 0.26 micromol/L, P = 0.000) compared to groups II and III in which the change in TBARS was not significant (0.02 +/- 0.06 and 0.007 +/- 0.06 micromol/L, respectively). There was an insignificant fall in glutathione levels in all groups. There was no significant difference in the mean period of gestation, pregnancy complications and neonatal outcome between the three groups. Among 22.2% of women who were non-compliant, Group I had significantly higher incidence of non-compliance (P = 0.016) and side-effects (P = 0.001). Final hemoglobin was higher in Group I than II (11.9 +/- 1.2, 11.3 +/- 0.9, respectively, P = 0.041). The TBARS level was not statistically different between preterm and term deliveries. Nine out of 11 patients who developed hypertension during pregnancy had preeclampsia. The final TBARS level was significantly higher in these women (P = 0.000).

CONCLUSIONS

Daily supplementation with ferrous sulphate results in greater lipid peroxidation than weekly supplementation, the latter is comparable with daily iron (III)-hydroxide polymaltose complex. Lipid peroxidation levels are significantly higher in preeclampsia.

Redox modulation of Ca2+ signaling in human endothelial and smooth muscle cells in pre-eclampsia

Pre-eclampsia (PE) is a leading cause of maternal hypertension in pregnancy and is associated with fetal growth restriction, premature birth, and fetal and maternal mortality. Activation and dysfunction of the maternal and fetal endothelium in PE appears to be a consequence of increased oxidative stress, resulting from elevated levels of circulating lipid peroxides. Accumulating evidence implicates reactive oxygen species (ROS) in the pathogenesis of vascular dysfunction in PE, perhaps involving a disturbance in intracellular Ca(2+) signaling. Several ion-transport pathways are highly sensitive to oxidative stress, and the resulting modulation of ion transport by ROS will affect intracellular Ca(2+) homeostasis. We review the evidence that changes in ion transport induced by ROS may be linked with abnormalities in Ca(2+)-mediated signal transduction, leading to endothelial and smooth muscle dysfunction in maternal and fetal circulations in PE. As dysregulation of Ca(2+) signaling in fetal umbilical endothelial cells is maintained in culture and embryonic, fetal, and postnatal development is affected by the cellular redox state, we hypothesize that impaired redox signaling in PE may influence "programming" of the fetal cardiovascular system and endothelial function in adulthood.

Post-delivery oxidative stress in women with preeclampsia or IUGR

AIM

To compare oxidative stress in patients with preeclampsia (PE) or intrauterine growth restriction (IUGR) vs. normal pregnancy (controls) during 48 h after delivery.

STUDY DESIGN

Women with singleton pregnancies were recruited immediately after delivery (gestational age >26.0 weeks). Women with PE or IUGR were matched with healthy controls by age, BMI, gestational age and delivery mode. Venous blood samples and urine samples were tested for oxidative stress products 24 h and 48 h after delivery.

RESULTS

Plasma malondialdehyde (MDA) concentration 24 h after delivery was significantly higher in subjects with PE or IUGR (3.41+/-1.14 micromol/L, n=20) than in controls (2.91+/-0.82 micromol/L, n=38) (P=0.04). Urine iPF(2alpha)-VI declined from 24 to 48 h after delivery significantly in controls (P=0.006) and not in subjects with PE or IUGR (P=0.71).

CONCLUSION

Of the markers tested only MDA is indicating higher oxidative stress in women with PE/IUGR than in normal pregnancy and only at 24 h after delivery. No consistent pattern of change in the oxidative stress markers exists between 24-48 h after delivery.

F2-isoprostanes in human health and diseases: from molecular mechanisms to clinical implications

Oxidative stress is implicated as one of the major underlying mechanisms behind many acute and chronic diseases, and involved in normal aging. However, the measurement of free radicals or their end products is complicated. Thus, proof of association of free radicals in pathologic conditions has been absent. Isoprostanes are prostaglandin-like bioactive compounds that are biosynthesized in vivo independent of cyclooxygenases, principally through free-radical catalyzation of arachidonic acid. Isoprostanes are now considered to be reliable biomarkers of oxidative stress, as evidenced by an autonomous study organized recently by the National Institutes of Health (NIH) in the United States. A number of these compounds have potent biologic activities such as vasoconstrictive and certain inflammatory properties. Isoprostanes are involved in many human diseases. Additionally, elevated levels of F(2)-isoprostanes have been seen in normal human pregnancy and after intake of some fatty acids, but their physiologic assignments have not yet been distinctive. This evidence indicates that measurement of bioactive F(2)-isoprostanes in body fluids offers a unique noninvasive analytic utensil to study the role of free radicals in physiology, oxidative stress-related diseases, experimental acute or chronic inflammatory conditions, and also in the assessment of various antioxidants, radical scavengers, and drugs.

Metabolic changes, hypothalamo-pituitary-adrenal axis and oxidative stress after short-term starvation in healthy pregnant women

AIM

To compare metabolic effects and oxidative stress in pregnant and non-pregnant women after 12 h of fasting.

METHODS

Twenty-six healthy women with uncomplicated singleton pregnancies between the 24(th) and 28(th) gestational week were recruited. After an overnight fast, venous blood samples and urine samples were tested for metabolic parameters characteristic for starvation, cortisol and oxidative stress products. Healthy non-pregnant women matched by age, body mass index and length of fasting comprised the control group.

RESULTS

The metabolic parameters beta-hydroxybutyrate and free fatty acids in blood and ketones in urine showed no differences in pregnant and non-pregnant women. However, the oxidative stress parameters, 8,12-iso-iPF(2alpha)-VI, isoprostanes and malondialdehyde were significantly higher in pregnant subjects, as was cortisol.

CONCLUSION

Healthy pregnant women are exposed to oxidative stress and activation of the hypothalamo-pituitary-adrenal axis, but not to metabolic changes resembling starvation during short fasting periods in comparison to non-pregnant healthy women.

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.

Serum advanced oxidation protein products, myeloperoxidase and ascorbic acid in pre-eclampsia and eclampsia

BACKGROUND

Activation products from neutrophils and the complement system might cause endothelial dysfunction, which is central to the aetiology of pre-eclampsia. This study aimed to investigate the activity of myeloperoxidase (MPO), and its association with advanced oxidation protein products (AOPP), in women with pre-eclampsia and eclampsia.

MATERIALS AND METHOD

Twenty-one pregnant women with pre-eclampsia, 11 pregnant women with eclampsia and 19 healthy pregnant women were studied. Serum levels of malondialdehyde (MDA), AOPP, ascorbic acid (AA) and activities of MPO and catalase (CAT) were measured using a colorimetric method.

RESULTS

The MDA level was significantly higher in the pre-eclampsia (3.15+/-0.28 nmol/mL) and eclampsia (4.01+/-0.66 nmol/mL) groups than in controls (1.85+/-0.18 nmol/mL); the difference between MDA levels in the pre-eclampsia and eclampsia groups was not statistically significant. MPO activity was significantly higher in the eclampsia (347.59+/-88.06 U/L) group than in the pre-eclampsia (196.17+/-30.8) and control (93.22+/-9.52) groups, and there was also no significant difference in these levels between the pre-eclampsia and control groups. CAT activity was significantly higher in the pre-eclampsia (166.35+/-31.75 U/L) and eclampsia (166.98+/-40.31 U/L) groups than in controls (81.28+/-7.41 U/L), and AA level was significantly higher in the pre-eclampsia (0.54+/-0.15 mg/dL) group than in controls (0.18+/-0.01 mg/dL); the differences in AA and CAT activity between the pre-eclampsia and eclampsia groups were not statistically significant. AOPP levels did not change significantly among the control, pre-eclampsia and eclampsia groups (106.88+/-5.62, 98.89+/-6.47, 111.89+/-6.8 micromol/L, respectively).

CONCLUSIONS

We suggest that increased oxidative stress might contribute to the pathophysiological mechanisms of pre-eclampsia and eclampsia, and that AA and CAT might have a protective role via free radical-scavenging properties. However, further study is needed.

Lipid peroxidation in cord blood and neonatal outcome

BACKGROUND

Periventricular-intraventricular hemorrhage, necrotizing enterocolitis, chronic lung disease and retinopathy of prematurity have been referred to as oxygen radical diseases (ORD) because they are thought to be related to excess oxidant stress relative to anti-oxidant defenses in premature infants. 8-Isoprostane is a product of lipid peroxidation that can be used as a measure of free radical exposure or injury. The aim of the present study was to determine whether fetal oxidant stress is associated with adverse effects in preterm infants.

METHODS

Mothers delivering at gestational age <37 weeks were recruited. Umbilical arterial and venous cord blood samples were collected and 8-isoprostane levels measured. Levels of 8-isoprostane in cord blood were correlated with maternal and perinatal variables, neonatal mortality, and the development of one or more ORD.

RESULTS

Umbilical cord venous, but not arterial, 8-isoprostane levels were associated with mortality and the development of one or more of the ORD. After controlling for gestational age, for each unit change in the log value of 8-isoprostane in venous cord blood the odds of mortality were 12 (95% confidence interval [CI]: 1-223) and oxygen radical disease were 2.7 (95%CI: 1-7.2). Isoprostane levels were not related to gender, method of delivery, use of maternal magnesium or steroids, pregnancy-induced hypertension, or delivery room resuscitation.

CONCLUSION

Oxidant stress in utero may be an important determinant of mortality and morbidity in preterm infants. Elevated umbilical venous isoprostane levels suggest that oxidative injury to maternal and placental tissues predispose to adverse neonatal outcomes.

Cardiovascular pharmacology and physiology of the isoprostanes

F(2)-isoprostanes are a complex family of compounds produced from arachidonic acid via a free radical-catalyzed mechanism. Their quantification as a pathophysiological biomarker provides a unique opportunity to investigate lipid peroxidation in vascular diseases. Their measurement also provides an interesting biomarker for the rational dose selection of antioxidants in vascular diseases where oxidative stress might be involved. In addition to their use as biomarkers, some isoprostanes possess a biological activity. The 15-series F(2)- and E(2)-isoprostanes mediate vasoconstriction in different vascular beds and species. In addition, 15-F(2t)-IsoP induces smooth muscle cells mitogenesis and monocyte adhesion to endothelial cells. The data available supports but does not prove the hypothesis that isoprostanes are involved in vascular physiology and pathogenesis.

Oxidative stress in midpregnancy as a predictor of gestational hypertension and pre-eclampsia

OBJECTIVES

To explore the relationship between the levels of maternal oxidative stress and glycaemia during pregnancy and to compare the predictive values of 8-epimer of prostaglandin F(2alpha) (8-isoPGF(2alpha)) and mean arterial pressure (MAP) in midpregnancy for the development of hypertensive complications in later pregnancy.

DESIGN

Prospective observational study as an ancillary study to the Hyperglycaemia and Adverse Pregnancy Outcome (HAPO) study.

SETTING

Obstetric clinics and wards of a university teaching hospital in Hong Kong.

POPULATION

Selected women with singleton pregnancies attending the antenatal clinic.

METHODS

Pregnant women who met HAPO inclusion criteria were recruited for the study. Glucose tolerance was assessed by a 75-g 2-hour oral glucose tolerance test (OGTT) at 24-32 weeks of gestation. Fasting plasma samples for 8-isoPGF(2alpha) estimation and urine samples for 8-isoPGF(2alpha) and 2,3-dinor 8-isoPGF(2alpha) assays were collected and blood pressures measured during the OGTT visit. Random plasma and urine samples were also obtained at 34-37 weeks. Glucose results were unblinded to the attending obstetrician if limits preset under the HAPO protocol were met.

MAIN OUTCOME MEASURES

Maternal plasma 8-isoPGF(2alpha) and urinary 8-isoPGF(2alpha) and 2,3-dinor 8-isoPGF(2alpha) both at the time of OGTT (24-32 weeks) and at 34-37 weeks of gestation. Incidence of pre-eclampsia and gestational hypertension.

RESULTS

Of the 408 women who attended for OGTT at 24-32 weeks, two met the glucose criteria for unblinding and 25 had missing 8-isoPGF(2alpha) values and thus were excluded from analysis. Of the 381 women, 338 (88.7%) attended for random plasma samples at 34-37 weeks. Significant correlations were observed between maternal fasting plasma isoprostane and both fasting (r= 0.20; P < 0.001) and 2-hour (r= 0.39; P < 0.001) plasma glucose levels at the time of OGTT. Gestational hypertension/pre-eclampsia occurred in 17 (4.2%) women, and at the time of OGTT, they had significantly higher fasting plasma 8-isoPGF(2alpha) (P < 0.001), urine 8-isoPGF(2alpha) (P < 0.005) and urine 2,3-dinor 8-isoPGF(2alpha) to creatinine ratios (P < 0.001), as well as higher MAP (P < 0.001) than women who remained normotensive. At 34-37 weeks, only random plasma 8-isoPGF(2alpha) was significantly higher (P < 0.001) among the women with gestational hypertension/pre-eclampsia.

CONCLUSIONS

Plasma markers of oxidative stress were positively correlated with plasma glucose at the time of OGTT (24-32 weeks). Women who subsequently developed gestational hypertension/pre-eclampsia had significantly higher plasma and urine markers of oxidative stress at the time of OGTT but only higher plasma markers at 34-37 weeks. Plasma 8-isoPGF(2alpha) appears to be a very good predictor of subsequent gestational hypertension/pre-eclampsia when measured at the time of OGTT, but its ability to discriminate deteriorates as pregnancy advances.

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.

The role of placental oxidative stress and lipid peroxidation in preeclampsia

Preeclampsia is a complex multisystem disorder exclusively seen in human species that is characterized by hypertension and proteinuria. This disorder has the highest maternal and fetal morbidity and mortality of all pregnancy-related complications. Growing evidence suggests that placental oxidative stress is involved in the etiopathogenesis of preeclampsia. Reduced perfusion as a result of abnormal placentation leads to ischemia reperfusion injury to the placenta. Placental oxidative stress, which results from the ischemia reperfusion injury, is being increasingly reported to be involved in the etiopathogenesis of preeclampsia. It has been proposed as a promoter of lipid peroxidation and the endothelial cell dysfunction that is commonly seen in this condition. Although preeclampsia is characterized by increased lipid peroxidation and diminished antioxidant capacity, there is no consensus regarding causality of lipid peroxidation in preeclampsia. In this article, we address the question of the biologic association of lipid peroxidation and preeclampsia. Lipid peroxidation and leukocyte activation may play a pivotal role in endothelial cell dysfunction. We also review the different factors that have been proposed to cause endothelial cell dysfunction in preeclampsia, trials investigating the role of antioxidant supplementation in preeclampsia, and the lack of consensus among the trials. Additional longitudinal studies are necessary to determine if the various oxidative stress biomarkers estimated early in pregnancy can be narrowed to a single marker for predicting preeclampsia.

TARGET AUDIENCE

Obstetricians & Gynecologists, Family Physicians.

LEARNING OBJECTIVES

After completion of this article, the reader should be able to recall that placental oxidative stress is involved in the etiopathogenesis of preeclampsia, state that placental oxidative stress results from ischemic reperfusion injury, and explain that ischemic reperfusion injury is a promoter of lipid peroxidation and endothelial cell dysfunction seen in preeclampsia.

Oxidative stress in infants born to preeclamptic mothers

BACKGROUND

Oxidative stress may play an important role in the pathophysiology of preeclampsia. An increase in lipid peroxidation products and a decrease in antioxidant activity in preeclamptic women have been reported in many papers. The objective of this study was to evaluate oxidative stress in infants born to preeclamptic mothers.

METHODS

Malondialdehyde (MDA) and glutathione (GSH) levels and glutathione peroxidase (GPx) and superoxide dismutase (SOD) activities were measured in cord plasma of infants born to preeclamptic (n = 18) or normotensive (n = 9) mothers.

RESULTS

Gestational age was similar in both groups. The mean birth weight was significantly lower in the preeclamptic group (P = 0.007). Maternal age, primigravidity, antenatal steroid use, premature rupture of the membranes, clinical chorioamnionitis and adverse neonatal outcomes including sepsis, respiratory distress syndrome and neonatal mortality did not differ between groups. Cesarean delivery was significantly higher in the preeclamptic group. There was no significant difference in cord plasma levels of MDA and GSH, and activity of GPx between the preeclamptic and control groups. SOD was found to be increased in preeclamptic group (P = 0.03).

CONCLUSIONS

We concluded that although cord plasma MDA levels were similar in both the preeclamptic and control groups, increased SOD activity might be an indicator of increased oxidative stress in infants born to preeclamptic mothers.

Preeclampsia

Preeclampsia is a pregnancy complication with serious consequences for mother and infant. The disorder is diagnosed by gestational hypertension and proteinuria but is far more than pregnancy induced hypertension. Preeclampsia is proposed to occur in 2 stages. Stage 1 reduced placental perfusion is postulated as the root cause and to lead to the maternal syndrome, Stage 2. Why perfusion is reduced, how this translates to a maternal disease in some but not all women and what is the linkage of the 2 stages are topics of intense study. In the last decade such studies have provided valuable insights into pathophysiology that now guide ongoing clinical trials.

Isoprostanes, prostaglandins and tocopherols in pre-eclampsia, normal pregnancy and non-pregnancy

This study is designed to evaluate whether oxidative stress and inflammation are involved in severe pre-eclampsia compared to normal pregnancy and non-pregnancy. We have measured plasma and urinary levels of 8-iso-PGF2alpha, a major isoprostane as an indicator of oxidative stress; plasma and urinary 15-keto-dihydro-PGF2alpha, a major metabolite of cyclooxygenase-catalysed PGF2alpha as an indicator of inflammatory response, and plasma -alpha-and -gamma-tocopherol in 18 pre-eclamptic, 19 normal pregnancy and 20 non-pregnant women. Pregnant women had significantly higher levels of 8-iso-PGF2alpha and PGF2alpha metabolite as compared to the non-pregnancy. Levels of 8-iso-PGF2alpha in the pre-eclamptic women did not differ from the normal pregnancy but PGF2alpha metabolite levels were significantly higher in normal pregnancy. On the other hand, gamma-tocopherol levels were significantly lower in pre-eclampsia than normal pregnancy. In contrast, the concentration of alpha-tocopherol was very similar between the groups. alpha-and gamma-tocopherol levels were significantly lower in pregnancy compared to non-pregnancy. Although no direct evidence of oxidative stress and inflammatory response was observed in severe pre-eclampsia, a reduction of gamma-tocopherol suggests the possible precedence of oxidative stress in this condition. Higher levels of isoprostanes and prostaglandin metabolite in late pregnancy suggest the importance of both free radicals and cyclooxygenase-catalysed oxidation products in normal biological processes of pregnancy.

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.

Preeclampsia: a renal perspective

Preeclampsia is a syndrome that affects 5% of all pregnancies, producing substantial maternal and perinatal morbidity and mortality. The aim of this review is to summarize our current understanding of the pathogenesis of preeclampsia with special emphasis on the recent discovery that circulating anti-angiogenic proteins of placental origin may play an important role in the pathogenesis of proteinuria and hypertension of preeclampsia.

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.

Oxidative stress, diet, and the etiology of preeclampsia

BACKGROUND

A current theory holds that oxidative stress, ie, an imbalance between maternal prooxidants and antioxidants, is a component of preeclampsia. It is uncertain whether such an imbalance occurs before clinical recognition of the syndrome or whether it is related to diet.

OBJECTIVE

We measured urinary excretion of the isoprostane 8-iso-prostaglandin F(2alpha), which is an indicator of oxidative damage to lipids, and the total antioxidant power, which is a global measure of antioxidant status, at the entry to prenatal care. We also examined the relation of these indexes to diet during pregnancy.

DESIGN

A cohort of 307 gravidae from Camden, NJ, was studied from entry to prenatal care (at 15.0 +/- 0.49 wk gestation). Measures of the maternal diet were obtained by 24-h recall.

RESULTS

Risk of preeclampsia was increased 5-fold with higher urinary isoprostane excretion and decreased 3-fold with higher total antioxidant power. Over the course of pregnancy, there were significant trends for an association of higher isoprostane excretion with increased consumption of energy-adjusted fat, polyunsaturated fat, and polyunsaturated fatty acids (n-3, n-6, and linoleic and linolenic fatty acids), whereas total antioxidant power was not related to diet.

CONCLUSIONS

Increased urinary excretion of isoprostane and decreased antioxidant production is an imbalance that is consistent with oxidative stress, and it precedes clinical recognition of preeclampsia. The maternal diet is an underlying factor that provides an environment for free radical generation.

Effect of quercetine and glutathione on the level of superoxide dismutase, catalase, malonyldialdehyde, blood pressure and neonatal outcome in a rat model of pre-eclampsia induced by NG-nitro-l-arginine-methyl ester

OBJECTIVE

To anticipate the impact of antioxidant use on lipid peroxidation products, free oxygen radical scavengers, blood pressure (BP), proteinuria and neonatal outcome (as seen in percentage survival, litter birth weight) in a rat model of pre-eclampsia induced by NG-nitro-L-arginine-methyl-ester (L-NAME), an inhibitor of nitric oxide synthase (NOS).

MATERIAL AND METHODS

Female adult non-pregnant Sprague-Dawley rats (n=40) with timed pregnancies were allocated into four groups according to medication they received on day 17 to term. Rats were randomised into a sham-treated group (group I, n=10) and groups treated with L-NAME, 50 mg/day i.p., only (group II, n=10), L-NAME + quercetine, 10mg/kg i.p. (group III, n=10) and L-NAME + glutathione, 60 mg/kg i.p. (group IV, n=10). Blood levels of superoxide dismutase (SOD), catalase (CAT) and malonyldialdehyde (MDA) were assessed on day 22 of gestation. Intracardiac blood sampling and hysterotomy were performed on day 22 of gestation. Mean systolic BP (measured with a tail-cuff device), level of proteinuria, total urine output, pups birth weight and percentages of live and of dead pups were recorded.

RESULTS

Mean systolic BP and SOD, CAT and MDA levels were higher in rats infused with L-NAME than in the sham-treated group. In group IV, SOD levels were lower than in group II (P <0.001). A linear positive correlation between BPs on day 20 and SOD levels (rp=0.39) was recorded, as were negative correlations between level of proteinuria and SOD levels (rp=-0.39) and between CAT and MDA levels (rp=-0.39). Birth weights were higher in the sham-treated group than in the other groups (P <0.001). Pups of hypertensive gravid rats treated with antioxidants had better survival rates than those of rats in group II and the sham-treated group (Chi-square=15.9, d.f.: 3, P <0.01).However, no correlation was detected between higher pup mortality rate and birth weight of pups.

CONCLUSION

In this rat model of pre-eclampsia, adverse outcomes, such as proteinuria and high neonatal death rate, are reversed by exogenous antioxidant use, even though no significant improvement is detected in terms of BP and birth weight of pups.

Plasma antioxidant vitamins and lipid peroxidation products in pregnancy induced hypertension

It has been suggested that antioxidant systems are impaired in pregnancy induced hypertension and hence patients are exposed to oxidative stress. In order to investigate the relationship between lipid peroxidation and certain antioxidant parameters in blood of pregnancy induced hypertension (PIH) cases, 25 normotensive and 23 PIH samples were studied. In the present study, thiobarbituric acid reactive substances showed a tendency to increase, however the increase remained statistically insignificant. Plasma ascorbic acid level remained unaltered and Vitamin E showed a tendency to increase in the study group. The findings implicate oxidative stress in the disease and cite the biochemical rationale for clinical trials of antioxidants to prevent and treat pregnancy induced hypertension.

Isoprostanes: novel bioactive products of lipid peroxidation

Isoprostanes, are a novel group of prostaglandin-like compounds that are biosynthesised from esterified polyunsaturated fatty acid (PUFA) through a non-enzymatic free radical-catalysed reaction. Several of these compounds possess potent biological activity, as evidenced mainly through their pulmonary and renal vasoconstrictive effects, and have short half-lives. It has been shown that isoprostanes act as full or partial agonists through thromboxane receptors. Both human and experimental studies have indicated associations of isoprostanes and severe inflammatory conditions, ischemia-reperfusion, diabetes and atherosclerosis. Reports have shown that F2-isoprostanes are authentic biomarkers of lipid peroxidation and can be used as potential in vivo indicators of oxidant stress in various clinical conditions, as well as in evaluations of antioxidants or drugs for their free radical-scavenging properties. Higher levels of F2-isoprostanes have been found in the normal human pregnancy compared to non-pregnancy, but their physiological role has not been well studied so far. Since bioactive F2-isoprostanes are continuously formed in various tissues and large amounts of these potent compounds are found unmetabolised in their free acid form in the urine in normal basal conditions with a wide inter-individual variation, their role in the regulation of normal physiological functions could be of further biological interest, but has yet to be disclosed. Their potent biological activity has attracted great attention among scientists, since these compounds are found in humans and animals in both physiological and pathological conditions and can be used as reliable biomarkers of lipid peroxidation.