A prospective study of early-pregnancy plasma malondialdehyde concentration and risk of preeclampsia

Oxidative Stress in Pregnancy

Recent years have seen an increased interest in the role of oxidative stress (OS) in pregnancy. Pregnancy inherently heightens susceptibility to OS, a condition fueled by a systemic inflammatory response that culminates in an elevated presence of reactive oxygen species (ROS) and reactive nitrogen species (RNS) in the circulatory system. The amplified OS in pregnancy can trigger a series of detrimental outcomes such as underdevelopment, abnormal placental function, and a host of pregnancy complications, including pre-eclampsia, embryonic resorption, recurrent pregnancy loss, fetal developmental anomalies, intrauterine growth restriction, and, in extreme instances, fetal death. The body's response to mitigate the uncontrolled increase in RNS/ROS levels requires trace elements that take part in non-enzymatic and enzymatic defense processes, namely, copper (Cu), zinc (Zn), manganese (Mn), and selenium (Se). Determination of ROS concentrations poses a challenge due to their short half-lives, prompting the use of marker proteins, including malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR), catalase (CAT), and glutathione (GSH). These markers, indicative of oxidative stress intensity, can offer indirect assessments of pregnancy complications. Given the limitations of conducting experimental studies on pregnant women, animal models serve as valuable substitutes for in-depth research. This review of such models delves into the mechanism of OS in pregnancy and underscores the pivotal role of OS markers in their evaluation.

Effect of Preconception Selenium Intake on the Risk for Gestational Diabetes: The Japan Environment and Children's Study

Selenium (Se) acts as a cofactor of antioxidant enzymes. Preconception care may reduce the risk of gestational diabetes mellitus (GDM). We examined the association between preconception Se intake and the risk of GDM in Japanese women. Using the Japan Environment and Children’s Study database, we identified 92,764 Japanese women recruited between January 2011 and March 2014. Participants were categorized into five groups according to preconception Se intake quintiles (Q1 and Q5 were the lowest and highest Se intake groups, respectively). GDM was categorized as early-onset (Eo-GDM) or late-onset (Lo-GDM) diagnosed before or after 24 weeks, respectively. Multiple logistic regressions were performed to identify the effect of preconception Se intake on GDM, Eo-GDM, and Lo-GDM. Using Q3 (the middle Se intake group) as the reference, a multiple logistic regression analysis showed that the highest (Q5) Se intake group demonstrated increased risks of GDM (adjusted odds ratio (aOR): 1.15, 95% confidence interval (CI): 1.01–1.30) and the lowest (Q1) Se intake group had increased risks of Lo-GDM (aOR: 1.19, 95% CI: 1.01–1.41). Thus, both high and low preconception Se intakes increase risks of glucose intolerance during pregnancy. This finding may indicate new recommendations for preconception Se intake to prevent GDM.

Oxidative stress in early pregnancy and the risk of preeclampsia

INTRODUCTION

Preeclampsia (PE), one of the most serious complications of pregnancy, is characterized by endothelial dysfunction and hypertension. The pathophysiology of the disease is still unknown; however, evidence suggests that placental and maternal oxidative stress promote the disease process. Several studies have assessed levels of oxidative stress during pregnancy, but after diagnosis of PE. However, few studies have examined oxidative stress before PE diagnosis. Thus, the present work was aimed to gain further insight into the role of oxidative stress prior to diagnosis of PE (i.e. 12-20 weeks of gestation) and to further understand and predict PE incidence.

METHODS

Blood levels of superoxide (O₂^-) and erythrocyte antioxidants such as superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH) and oxidized glutathione (GSSG) levels were measured in 23 preeclamptic pregnant women and 91 women with normal pregnancies. We further used logistic regression of O₂^- and each antioxidant level as the main predictor variable for PE risk.

RESULTS

CAT activity, GSH, and Total glutathione (TGSH) were significantly lower with All PE pregnant groups, whereas O₂^- levels were modestly, but significantly, higher in women with mild PE. Logistic regression analysis suggests increased CAT activity in pregnant women is associated with a decreased odds of being preeclamptic.

CONCLUSION

CAT is the only antioxidant as shown in our study to be related to the severity of the disease and may be a promising predictor for PE. Further studies are warranted to investigate the use of CAT as a novel therapeutic for PE.

Modification of endothelial nitric oxide synthase by 4-oxo-2(E)-nonenal(ONE) in preeclamptic placentas

Preeclampsia (PE) is a leading cause of pregnancy complications, affecting 3-7% of pregnant women worldwide. The pathophysiology of preeclampsia involves a redox imbalance, oxidative stress and a reduced nitric oxide (NO) bioavailability. The molecular and cellular mechanisms leading to the dysfunction of the placental endothelial NO synthase (eNOS) are not clarified. This study was designed to investigate whether aldehydes generated by lipid peroxidation products (LPP), may contribute to placental eNOS dysfunction in PE. The analysis of placentas from PE-affected patients and normal pregnancies, showed a significant increase in protein carbonyl content, indicative of oxidative stress-induced protein modification, as shown by the accumulation of acrolein, 4-hydroxynonenal (HNE), and 4-oxo-2(E)-nonenal (ONE) adducts in PE placentas. In contrast, the levels of these LPP-adducts were low in placentas from normal pregnancies. Immunofluorescence and confocal experiments pointed out a colocalization of eNOS with ONE-Lys adducts, whereas eNOS was not modified in normal placentas. LC-MS/MS analysis of recombinant eNOS preincubated with ONE, allowed to identify several ONE-modified Lys-containing peptides, confirming that eNOS may undergo post-translational modification by LPP. The preincubation of HTR-8/SVneo human trophoblasts (HTR8) with ONE, resulted in ONE-Lys modification of eNOS and a reduced generation of NO. ONE inhibited the migration of HTR8 trophoblasts in the wound closure model, and this was partly restored by the NO donor, NOC-18, which confirmed the important role of NO in the invasive potential of trophoblasts. In conclusion, placental eNOS is modified by ONE in PE placentas, which emphasizes the sensitivity of this protein to oxidative stress in the disturbed redox environment of preeclamptic pregnancies.

Increased oxidative stress from early pregnancy in women who develop preeclampsia

Preeclampsia (PE) is a pregnancy-specific disorder, defined as new onset of maternal hypertension and proteinuria after 20 weeks of gestation. Our earlier study has shown increased maternal oxidative stress at delivery to be associated with poor birth outcome in PE. However, these results were observed when the pathology had progressed and may have been secondary to the effects of the disorder. To understand the role of antioxidant defense mechanisms in PE right from early pregnancy, in this prospective study, we measured malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione (GSH) concentrations in maternal blood at 3 time-points of gestation [16-20 weeks (T1), 26-30 weeks (T2), at delivery (T3)] and in cord blood. Gene expression of SOD and GPx and protein levels of endothelial nitric oxide synthase (eNOS) enzyme were also analyzed in the placenta. MDA levels were higher at T1 (p < 0.01) and T2 (p < 0.01) in women with PE as compared with control. GPx levels were higher at T3 (p < 0.05) while SOD levels were lower at T2 (p < 0.05), T3 (p < 0.01) and in cord (p < 0.01) in PE. GSH levels at T1 (p < 0.05) and expression of GPx in the placenta were lower in PE as compared with control. In conclusion, this study demonstrates that women who develop PE exhibit increased oxidative stress right from 16 to 20 weeks of gestation. This may alter placental development and lead to fetal programming of adult non-communicable disease in the offspring.

Maternal hyperlipidemia and the risk of preeclampsia: a meta-analysis

Published reports examining lipid levels during pregnancy and preeclampsia have been inconsistent. The objective of this meta-analysis was to test the association between preeclampsia and maternal total cholesterol, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), non-HDL-C, and triglyceride levels measured during pregnancy. We conducted a systematic search for studies published between the index date until July 2013 reporting maternal lipid levels in women with preeclampsia and normotensive pregnant women. Seventy-four studies met all eligibility criteria and were included in the meta-analysis. Weighted mean differences in lipid levels were calculated using a random-effects model. Statistical heterogeneity was investigated using the I(2) statistic. Meta-regression was used to identify sources of heterogeneity. Preeclampsia was associated with elevated total cholesterol, non-HDL-C, and triglyceride levels, regardless of gestational age at the time of blood sampling, and with lower levels of HDL-C in the third trimester. A marginal association was found with LDL-C levels. Statistical heterogeneity was detected in all analyses. Meta-regression analyses suggested that differences in body mass index (weight (kg)/height (m)(2)) across studies may be partially responsible for the heterogeneity in the triglyceride and LDL-C analyses. This systematic review and meta-analysis demonstrates that women who develop preeclampsia have elevated levels of total cholesterol, non-HDL-C, and triglycerides during all trimesters of pregnancy, as well as lower levels of HDL-C during the third trimester.

Oxidative stress increased in pregnant women with iodine deficiency

Iodine is an essential element trace for the synthesis of maternal thyroid hormones needed to support normal fetal development; it also acts as an antioxidant directly or induce antioxidant enzymes indirectly. Iodine deficiency and oxidative stress are associated with pregnancy complications. This study aimed to assess the urinary iodine concentration and its relationship with the antioxidant and oxidative stress status during gestation. Pregnant women were consecutively recruited from an obstetric clinic during all gestation trimesters, and urinary iodine concentration, antioxidant, and oxidative stress were determined. Results showed that 70 % of pregnant women have optimal iodine levels (150-200 μg/L), while approximately 30 % showed mild iodine deficiency (50-99 μg/L). Oxidative stress was significantly higher, and the antioxidant status was also compromised as evidenced by decreased total antioxidant status and superoxide dismutase (SOD) activity in pregnant women with mild iodine deficiency than pregnant women with optimal iodine levels. Significant positive correlations were noted between optimal iodine levels and total antioxidant status. Oxidative stress was significantly correlated with mild iodine deficiency. However, no significant correlation was found between iodine levels and SOD and catalase activities. In conclusion, for the first time, these data suggest a correlation between iodine levels and the antioxidant status during pregnancy.

Oxidative DNA damage in early pregnancy and risk of gestational diabetes mellitus: A pilot study

OBJECTIVES

To examine the association of maternal early pregnancy oxidative stress with risk of gestational diabetes mellitus (GDM).

DESIGN AND METHODS

A pilot prospective, nested case-control study was conducted. Study participants were recruited before 20weeks gestation. Maternal urinary 8-hydroxydeoxyguanosine (8-OHdG), a biomarker of systemic oxidative DNA damage and repair, was measured using competitive immunoassays. Logistic regression was used to calculate odds ratio (OR) and 95% confidence intervals (95%CI).

RESULTS

Elevations in early pregnancy urinary 8-OHdG concentrations were associated with increased GDM risk. After adjusting for confounders, the OR for extreme quartiles (≥8.01 vs. <4.23ng/mg creatinine) of 8-OHdG was 3.79 (95%CI 1.03-14.00). The risk for GDM was highest for overweight women with urine 8-OHdG concentrations ≥8.01ng/mg creatinine (OR=5.36, 95%CI 1.33-21.55) when compared with lean women who had 8-OHdG concentrations <8.01ng/mg creatinine.

CONCLUSIONS

Elevated urine 8-OHdG concentrations in early pregnancy appear to be associated with increased GDM risk.

Evaluation of oxidative stress markers in first trimester for assessment of preeclampsia risk

AIM

The aim of this study is to determine the predictive values of oxidative stress markers and antioxidants in the development of preeclampsia between 10-14 and also at 20-24 weeks of gestation, after the completion of vascular transformation.

MATERIALS AND METHODS

Levels of oxidative stress parameters such as malondialdehyde (MDA), lipidhydroperoxide (LHP) and prostaglandin F(2α) (PGF(2α)), oxidized LDL (oxLDL), and antioxidant status parameters such as paraoxonase 1 (PON1), superoxide dismutase (SOD) and total antioxidant capacity (TAC) levels were measured and compared in 21 preeclamptic and 24 healthy pregnant women.

RESULTS

In preeclamptic women, both between 10-14 and also at 20-24 weeks of gestation the levels of oxLDL, MDA and PGF(2α) were significantly higher (P < 0.001, P < 0.001, respectively), PON1, SOD and TAC were significantly lower (P < 0.01, P < 0.001, P < 0.05, respectively) compared to healthy pregnant women; yet there was no significant difference in LHP levels.

CONCLUSION

Increased levels of serum MDA and PGF(2α), low levels of SOD and PON1 activity, in 10-14 GW may have been associated with preeclampsia etiology. High levels of MDA and PGF(2α) indicate that the oxidative damage is present well before the clinical symptoms occur. A panel of oxidative stress markers such as MDA and PGF(2α) in maternal blood can predict the development of preeclampsia long before clinical onset.

Pathological aspects of lipid peroxidation

Lipid peroxidation (LPO) product accumulation in human tissues is a major cause of tissular and cellular dysfunction that plays a major role in ageing and most age-related and oxidative stress-related diseases. The current evidence for the implication of LPO in pathological processes is discussed in this review. New data and literature review are provided evaluating the role of LPO in the pathophysiology of ageing and classically oxidative stress-linked diseases, such as neurodegenerative diseases, diabetes and atherosclerosis (the main cause of cardiovascular complications). Striking evidences implicating LPO in foetal vascular dysfunction occurring in pre-eclampsia, in renal and liver diseases, as well as their role as cause and consequence to cancer development are addressed.

Association between abnormal uterine artery Doppler flow velocimetry, risk of preeclampsia, and indices of arterial structure and function: a pilot study

Preeclampsia increases the risk of future cardiovascular disease. The association between abnormal uterine artery Doppler flow velocimetry, risk of preeclampsia, and indices of arterial structure and function is investigated in this study. The carotid intima-media thickness of 34 pregnant women with normal uteroplacental flow was compared with 30 women with abnormal uterine artery Doppler analysis during the transvaginal assessment of the uterine arteries at the routine anomaly scan (20-23 weeks of gestation). Women with abnormal uterine artery Doppler results had a greater mean internal (but not common) carotid intima-media thickness (0.58 +/- 0.06 vs 0.53 +/- 0.08, respectively, P = .005) and risk of developing preeclampsia (6 of 30 vs 0 of 34 or 20% vs 0%, respectively, P = .0079) compared with those with normal uteroplacental flow. Women with abnormal uterine artery Doppler results may be at increased risk not only for developing subsequent preeclampsia but also for future cardiovascular disease.