Assessment of placental oxidative stress in pre-eclampsia

The Trace Element Concentrations and Oxidative Stress Parameters in Afterbirths from Women with Multiple Pregnancies

The aim of this study was to evaluate the intensity of oxidative stress by measuring the concentrations of lipid peroxidation products (LPO) in fetal membrane, umbilical cord, and placenta samples obtained from women with multiple pregnancies. Additionally, the effectiveness of protection against oxidative stress was assessed by measuring the activity of antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), and glutathione reductase (GR). Due to the role of iron (Fe), copper (Cu), and zinc (Zn) as cofactors for antioxidant enzymes, the concentrations of these elements were also analyzed in the studied afterbirths. The obtained data were compared with newborn parameters, selected environmental factors, and the health status of women during pregnancy to determine the relationship between oxidative stress and the health of women and their offspring during pregnancy. The study involved women (n = 22) with multiple pregnancies and their newborns (n = 45). The Fe, Zn, and Cu levels in the placenta, umbilical cord, and fetal membrane were determined using inductively coupled plasma atomic emission spectroscopy (ICP-OES) using an ICAP 7400 Duo system. Commercial assays were used to determine SOD, GPx, GR, CAT, and LPO activity levels. The determinations were made spectrophotometrically. The present study also investigated the relationships between trace element concentrations in fetal membrane, placenta, and umbilical cord samples and various maternal and infant parameters in women. Notably, a strong positive correlation was observed between Cu and Zn concentrations in the fetal membrane (p = 0.66) and between Zn and Fe concentrations in the placenta (p = 0.61). The fetal membrane Zn concentration exhibited a negative correlation with shoulder width (p = -0.35), while the placenta Cu concentration was positively correlated with placenta weight (p = 0.46) and shoulder width (p = 0.36). The umbilical cord Cu level was positively correlated with head circumference (p = 0.36) and birth weight (p = 0.35), while the placenta Fe concentration was positively correlated with placenta weight (p = 0.33). Furthermore, correlations were determined between the parameters of antioxidative stress (GPx, GR, CAT, SOD) and oxidative stress (LPO) and the parameters of infants and maternal characteristics. A negative correlation was observed between Fe and LPO product concentrations in the fetal membrane (p = -0.50) and placenta (p = -0.58), while the Cu concentration positively correlated with SOD activity in the umbilical cord (p = 0.55). Given that multiple pregnancies are associated with various complications, such as preterm birth, gestational hypertension, gestational diabetes, and placental and umbilical cord abnormalities, research in this area is crucial for preventing obstetric failures. Our results could serve as comparative data for future studies. However, we advise caution when interpreting our results, despite achieving statistical significance.

Plasma Levels of Vitamin A in Early Pregnancy and Correlationship with Hypertensive Disorder

Objective. Analyzing the vitamin A content in early pregnancy and finding out the relationship between the serum levels of vitamin A of pregnant women and hypertensive disorder. Method. A total of 4,188 pregnant women who had took part in vitamin A testing in Miyun District Hospital from November 2016 to March 2020 were collected. The serum levels of vitamin A were determined by high performance liquid chromatography, and clinical and testing data were collected for statistical analysis. The original data outcome was finally analyzed with the SPSS. Results. 266 Hypertensive disorder cases and 2836 normal pregnancy cases were analyzed with 27 cases of twin pregnancy, 315 cases without follow-up and 744 of diabetic pregnancies excluded. The 266 women were divided into four groups: 110 women were diagnosed gestational hypertension, 65 women were diagnosed preeclampsia, 78 women were diagnosed pregnancy with chronic hypertension, and 13 women were diagnosed chronic hypertension with preeclampsia. The results shows that vitamin A level of the hypertensive group was 0.46(±0.08) mg/L, 0.47 (±0.012) mg/L, 0.47 (±0.09) mg/L, and 0.52 (±0.012) mg/L, respectively, while the level of normal group was 0.44 (±0.09) mg/L. We found that there were differences between the normal pregnant group and the preeclampsia group with statistical significance (P < 0.05). The difference between the pregnancy with chronic hypertension group and the normal group was statistically significant (P < 0.05). The difference between the chronic hypertension with preeclampsia group and the normal group was also statistically significant (P < 0.05). Conclusion. Serum levels of vitamin A in early pregnant women have a certain correlation with the hypertensive disorder.

Biomarkers of placental redox imbalance in pregnancies with preeclampsia and consequent perinatal outcomes

OBJECTIVE

To compare redox and inflammatory markers between normal and PE-derived placentas and to evaluate the relationship between placental redox imbalance markers and perinatal outcomes in pregnancies with PE.

METHODS

This was a cross-sectional study conducted at the maternity hospital of a university hospital in Maceio-Alagoas, Brazil, in 2017, including women diagnosed with PE and healthy pregnant women and their conceptuses. After screening, standardized questionnaires containing socioeconomic, clinical, obstetric and anthropometric data were applied. After delivery, placental samples were collected for quantification of biomarkers of redox imbalance (catalase - CAT; malondialdehyde - MDA; hydrogen peroxide - H₂O₂; superoxide dismutase - SOD; reduced glutathione - GSH; oxidized glutathione - GSSG; and their ratio - GSH/GSSG) and inflammation (myeloperoxidase - MPO; interleukin (IL)-6; IL-8; IL-10; and tumor necrosis factor-alpha - TNF-α). All biomarkers were evaluated via linear regression with adjustments of variables with measures of weight, length, head circumference (HC), chest circumference (CC) and gestational age of newborns at birth, considering p < 0.05 as significant.

RESULTS

A total of 100 pregnant women with PE and 50 healthy pregnant women were studied. Higher placental levels of catalase (p = 0.018), SOD (p = 0.031), the GSH/GSSG ratio (p = 0.019) and IL-6 (p = 0.010) and lower GSSG (p = 0.001) were observed in pregnant women with PE than in the control group. Positive associations between placental GSH levels and body weight, HC, CC and gestational age at birth (p < 0.05) were identified.

CONCLUSION

PE-derived placentas had high concentrations of some antioxidants (enzymes and thiols), which might be a compensation mechanism against oxidative stress. Placental GSH levels were the only biomarker, among the studied ones, related positively with beneficial perinatal outcomes, suggesting that this endogenous antioxidant plays an important role in maintaining the health of the conceptus and women with PE.

What is precise pathophysiology in development of hypertension in pregnancy? Precision medicine requires precise physiology and pathophysiology

It is widely accepted that placental ischemia is central in the evolution of hypertension in pregnancy. Many studies and reviews have targeted placental ischemia to explain mechanisms for initiating pregnancy hypertension. The placenta is rich in blood vessels, which are the basis for developing placental ischemia. However, is the physiology of placental vessels the same as that of nonplacental vessels? What is the pathophysiology of placental vessels in development of pregnancy hypertension? This review aims to provide a comprehensive summary of special features of placental vascular regulations and the pathophysiological changes linked to preeclamptic conditions. Interestingly, some popular theories or accepted concepts could be based on our limited knowledge and evidence regarding placental vascular physiology, pharmacology and pathophysiology. New views raised could offer interesting ideas for future investigation of mechanisms as well as targets for pregnancy hypertension.

Combined use of serum gamma glutamyl transferase level and ultrasonography improves prediction of perinatal outcomes associated with preeclamptic pregnancy

INTRODUCTION

Serum gamma glutamyl transferase (GGT), produced and released mostly from the liver and bile duct, is an enzyme involved in response to oxidative stress, and has been used as a maker for prediction of cardiovascular events. Umbilical artery blood flow resistance index, e.g., the systolic/diastolic ratio (S/D ratio) as determined by ultrasound, has been used to assess the fetal intrauterine conditions. While changes of GGT and S/D ratio in preeclampsia are found to be associated with the risk for adverse perinatal outcome, the potential value of combined use of the two measurements for the prediction of adverse perinatal outcome has not been determined.

MATERIALS AND METHODS

This study included severe preeclampsia patients in late pregnancy and determined their serum GGT levels and ultrasonic flow resistance index of umbilical artery within a week before delivery. Demographic data and perinatal outcomes including perinatal death, five-minute Apgar score, admission to neonatal intensive care unit, respiratory distress syndrome, and intrauterine growth restriction, are documented and analyzed.

RESULTS

It was found that serum GGT combined with umbilical artery S/D ratio predicted perinatal adverse outcomes in severe preeclampsia patients with a sensitivity of 94.30% and a specificity of 80.00%. Moreover, absent or reversed UA diastolic blood flow was found to be an independent risk factor for intrauterine growth restriction.

CONCLUSION

GGT in combination with umbilical artery S/D ratio is a potentially useful marker for the prediction of adverse outcome in severe preeclampsia patients. Future studies in a larger cohort of patients should be performed to verify the efficacy of the strategy. Early and accurate prediction of adverse perinatal events can facilitate the efforts to improve the perinatal outcomes of neonates associated with preeclamptic pregnancies.

The effects of sildenafil citrate on uterine angiogenic status and serum inflammatory markers in an L-NAME rat model of pre-eclampsia

Pre-eclampsia (PE), a hypertensive disorder of pregnancy, is detrimental to both mother and foetus. There is currently no effective treatment, but we have shown that Sildenafil Citrate (SC) improve various foetal outcomes in N^ω-nitro-L arginine methyl ester (L-NAME) rat model of PE. Therefore, we aimed to investigate the effects of SC on a uterine angiogenic status and serum inflammatory markers in an L-NAME rat model of PE. One hundred and twenty adult nulliparous pregnant female Sprague-Dawley rats were used for the study. These were divided into five equal groups; the pregnant control, early and late onset PE and respective SC treated animals. Hypertension was manifested by considerably increased systolic blood pressure and placental lipid peroxidative marker (thiobarbituric acid reactive substances) and also we assessed the activities of plasma nitric oxide level, serum inflammatory marker (TGF-β and IFN-γ) and uterine angiogenic status (VEGF and sFlt-1) at two stages of PE. The administration of SC decreased systolic blood pressure, placental lipid peroxidation product and altered uterine angiogenic status; increased plasma nitric oxide levels in an early and late onset L-NAME model of PE. In addition, histological findings of SC treated preeclamptic rat placenta support the biochemical findings of this study. Our findings revealed that SC enhanced plasma NO levels and uterine angiogenic status in an L-NAME model of PE at two gestational stages.

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.

A putative role for telocytes in placental barrier impairment during preeclampsia

Preeclampsia (PE) is a major health problem occurring in pregnant women and the principal cause of maternal morbidity and perinatal mortality. It is characterized by alteration of the extravilli trophoblast cell migration toward the endometrial spiral arteries with a concomitant reduction in maternal blood flow in the placenta. This result in a state of ischemia-hypoxia which triggers an oxidative stress stage with production of reactive oxygen species. A cascade of cellular and molecular events leads then to endothelial dysfunction, transduction pathway signal disruption and induction of apoptosis and necrosis mechanisms and therefore a significant reduction in the amount of nutrients required for normal fetal development. Placental anchoring chorionic and stem villi present a skeleton of myofibroblasts arranged in parallel disposition to its longitudinal axis. The intraplacental blood volume is controlled by the contraction/relaxation of these myofibroblasts, promoting the delivery of nutrients and metabolites to the fetus. Recently, a new mesodermal originated cell type has been described in the villous stroma, the so named "telocytes". These cells are strategically located between the smooth muscle cells of the blood vessel wall and the myofibroblasts, and it is reasonable to hypothesize that they may play a pacemaker role, as in the intestine. This study provide new information supporting the notion that the occurrence of oxidative stress in PE is not only related to endothelial dysfunction and apoptosis of the trophoblast cells, but also involves telocytes and its putative role in the regulation of fetal blood flow and the intra-placental blood volume. Some ideas aimed at dilucidating the relationship between placental failure and the behavior of telocytes in pathological organs in adulthood, are also discussed.

Endothelial dysfunction and preeclampsia: role of oxidative stress

Preeclampsia (PE) is an often fatal pathology characterized by hypertension and proteinuria at the 20th week of gestation that affects 5-10% of the pregnancies. The problem is particularly important in developing countries in where the incidence of hypertensive disorders of pregnancy is higher and maternal mortality rates are 20 times higher than those reported in developed countries. Risk factors for the development of PE include obesity, insulin resistance and hyperlipidemia that stimulate inflammatory cytokine release and oxidative stress leading to endothelial dysfunction (ED). However, how all these clinical manifestations concur to develop PE is still not very well understood. The related poor trophoblast invasion and uteroplacental artery remodeling described in PE, increases reactive oxygen species (ROS), hypoxia and ED. Here we aim to review current literature from research showing the interplay between oxidative stress, ED and PE to the outcomes of current clinical trials aiming to prevent PE with antioxidant supplementation.