Total peroxyl radical-trapping ability and anti-oxidant vitamins of the umbilical venous plasma and the placenta in pre-eclampsia

Oxidative stress markers in preeclamptic placentas: A systematic review with meta-analysis

INTRODUCTION

Oxidative stress (OS) is the basis of several diseases. Preeclampsia (PE) is a multisystemic syndrome, considered one of the major causes of maternal and fetal mortality. The placenta is considered the main anatomical pathogenetic substrate for the disease, being the placental OS a likely critical pathway in the pathogenesis of PE. This meta-analysis aimed to verify whether there is OS in the preeclamptic placenta and which markers are altered in this condition.

METHODS

The search was conducted in the following databases: MEDLINE (via PubMed), Lilacs and Scopus. Relevant studies were identified until May 2020. The quality of the studies was evaluated according to the Newcastle-Ottawa scale.

RESULTS

From the 3998 screened records, 43 were finally included in the systematic review, and 23 in the meta-analysis. The biomarkers evaluated were related to cell and macromolecules' damage, such as malondialdehyde (MDA), 8-hydroxy-2'-deoxyguanosine (8-OH-dG), lipid peroxides, isoprostane, total oxidant status (TOS), carbonylated proteins and some of the reactive oxygen and nitrogen species (RONS), like hydrogen peroxide and nitric oxide. It was also related to antioxidant activity, both enzymatic, including superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx), glutathione S-transferase and total antioxidant status, and non-enzymatic, through quantification of reduced glutathione, vitamin C and E, zinc and copper.

CONCLUSION

It was observed that there was OS in the preeclamptic placentas, based on results, like lower activity of some of the enzymes of the antioxidant system (SOD and GPx) as well as the increase in oxidative damage markers (MDA and lipid peroxide), corroborating literature data.

Ascorbic acid inhibits TPA-induced HL-60 cell differentiation by decreasing cellular H₂O₂ and ERK phosphorylation

Retinoic acid (RA), vitamin D and 12-O‑tetradecanoyl phorbol-13-acetate (TPA) can induce HL-60 cells to differentiate into granulocytes, monocytes and macrophages, respectively. Similar to RA and vitamin D, ascorbic acid also belongs to the vitamin family. High‑dose ascorbic acid (>100 µM) induces HL‑60 cell apoptosis and induces a small fraction of HL‑60 cells to express the granulocyte marker, CD66b. In addition, ascorbic acid exerts an anti‑oxidative stress function. Oxidative stress is required for HL‑60 cell differentiation following treatment with TPA, however, the effect of ascorbic acid on HL‑60 cell differentiation in combination with TPA treatment remains to be fully elucidated. The aim of the present study was to investigate the cellular effects of ascorbic acid treatment on TPA-differentiated HL-60 cells. TPA-differentiated HL-60 cells were used for this investigation, this study and the levels of cellular hydrogen peroxide (H2O2), caspase activity and ERK phosphorylation were determined following combined treatment with TPA and ascorbic acid. The results demonstrated that low‑dose ascorbic acid (5 µM) reduced the cellular levels of H2O2 and inhibited the differentiation of HL‑60 cells into macrophages following treatment with TPA. In addition, the results of the present study further demonstrated that low‑dose ascorbic acid inactivates the ERK phosphorylation pathway, which inhibited HL‑60 cell differentiation following treatment with TPA.

New evaluation of fetal oxidative stress: measurement of the umbilical cord blood dimethyl sulfate-induced ascorbyl-free radical by an electron spin resonance method

OBJECTIVE

The aim is to evaluate intrapartum fetal oxidative stress in real-time by umbilical cord blood dimethyl sulfate (DMSO)-induced ascorbyl-free radical (AFR) measured by an electron spin resonance (ESR) method.

METHODS

Seventy-five mothers delivering at gestational age after 37 weeks were recruited. They were divided into three groups: spontaneous vaginal birth (n = 27), elective cesarean section (CS) (n = 34), and emergency CS due to non-reassuring fetal status (n = 14). Umbilical artery (UA) and venous (UV) cord blood gas analysis was performed. Serum levels of DMSO-induced AFR (AFR/DMSO) that reflect vitamin C concentrations were measured by ESR spectroscopy.

RESULTS

Blood gas analysis showed no significant differences among the groups. UA-AFR/DMSO level of elective CS group was significantly lower compared with spontaneous delivery group (0.32 ± 0.12 versus 0.46 ± 0.14, p < 0.005). Emergency CS group showed significantly lower levels of UA-AFR/DMSO compared with elective CS group (0.25 ± 0.11 versus 0.32 ± 0.12, p < 0.005). UV-AFR/DMSO levels had no significant difference among the groups.

CONCLUSIONS

It is suggested that fetal cord blood AFR/DMSO is a sensitive marker to assess fetal oxidative stress during delivery.

New evaluation of fetal oxidative stress: measurement of the umbilical cord blood dimethyl sulfate-induced ascorbyl free radical by an electron spin resonance method

OBJECTIVE

The aim is to evaluate intrapartum fetal oxidative stress in real-time by umbilical cord blood dimethyl sulfate (DMSO)-induced ascorbyl free radical (AFR) measured by an electron spin resonance (ESR) method.

METHODS

75 mothers delivering at gestational age after 37 weeks were recruited. They were divided into three groups: spontaneous vaginal birth (n = 27), elective cesarean section (CS) (n = 34), and emergency CS due to non-reassuring fetal status (n = 14). Umbilical artery (UA) and venous (UV) cord blood gas analysis was performed. Serum levels of DMSO-induced AFR (AFR/DMSO) that reflect vitamin C concentrations, was measured by ESR spectroscopy.

RESULTS

Blood gas analysis showed no significant differences among the groups. UA-AFR/DMSO level of elective CS group was significantly lower compared with spontaneous delivery group (0.32 ± 0.12 vs. 0.46 ± 0.14, p < 0.005). Emergency CS group showed significantly lower levels of UA-AFR/DMSO compared with elective CS group (0.25 ± 0.11 vs. 0.32 ± 0.12, p < 0.005). UV-AFR/DMSO levels had no significant difference among the groups.

CONCLUSIONS

It is suggested that fetal cord blood AFR/DMSO is a sensitive marker to assess fetal oxidative stress during delivery.

Effects of antioxidant vitamins on newborn and placental traits in gestations at high altitude: comparative study in high and low altitude native sheep

The present study evaluated the hypothesis that the effects of hypoxia on sheep pregnancies at high altitude (HA) are mediated by oxidative stress and that antioxidant vitamins may prevent these effects. Both HA native and newcomer ewes were maintained at an altitude of 3,589 m during mating and pregnancy. Control low altitude (LA) native ewes were maintained at sea level. Half of each group received daily oral supplements of vitamins C (500 mg) and E (350 IU) during mating and gestation. Near term, maternal plasma vitamin levels and oxidative stress biomarkers were measured. At delivery, lambs were weighed and measured, and placentas were recovered for macroscopic and microscopic evaluation. Vitamin concentrations in supplemented ewes were two- or threefold greater than in non-supplemented ewes. Plasma carbonyls and malondialdehyde in non-supplemented ewes were consistent with a state of oxidative stress, which was prevented by vitamin supplementation. Vitamin supplementation increased lamb birthweight and cotyledon number in both HA native and newcomer ewes, although placental weight and cotyledon surface were diminished. Placentas from vitamin-supplemented HA ewes were similar to those from ewes at sea level, making these placental traits (weight, number and diameter of cotyledons) similar to those from ewes at sea level. Vitamin supplementation had no effect on LA pregnancies. In conclusion, supplementation with vitamins C and E during pregnancy at HA prevents oxidative stress, improving pregnancy outcomes.

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.

Melatonin enhances antioxidant action of alpha-tocopherol and ascorbate against NADPH- and iron-dependent lipid peroxidation in human placental mitochondria

Human placental mitochondria might be a significant source of NADPH- and iron-dependent production of reactive oxygen species (ROS). Preeclampsia is believed to be a consequence of overproduction of ROS in human placenta. The experimental results presented here show that melatonin inhibits NADPH- and iron-dependent lipid peroxidation of human placental mitochondria in a concentration-dependent manner. At 1.5 mm concentration, melatonin suppressed this process nearly completely. Melatonin does not influence significantly the iron oxidation at this conditions, indicating that free radical scavenging rather than metal-chelating phenomenon is the basis of its antioxidant action. The fact of inhibition of lipid peroxidation by melatonin at conditions excluding iron participation also supports this hypothesis. Elucidation of the nature of common interaction among melatonin, ascorbate, and alpha-tocopherol in human placental mitochondria was the main aim of this study. In presence of 90 mum ascorbate, the inhibition of lipid peroxidation by melatonin was strong and had a feature of synergistic interaction. At presence of 30 mum ascorbate, which stimulated lipid peroxidation, melatonin caused a loss of pro-oxidant effect of ascorbate. While the interaction of melatonin with ascorbate indicated synergism, the joint action of melatonin and alpha-tocopherol was additive. When all three antioxidants were applied together, the strongest inhibition of lipid peroxidation was observed. The experimental results presented here indicated that melatonin could be considered as an effective component of antioxidant treatment of preeclampsia, allowing the use of reduced doses of vitamin C and E owing to elevated efficiency of their antioxidant activity in placenta when used in combination.

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.

Specific systemic antioxidant response to preeclampsia in late pregnancy: the study of intracellular glutathione peroxidases in maternal and fetal blood

OBJECTIVE

The physiopathology of preeclampsia is still unclear, but an imbalance between reactive oxygen species (ROS) and antioxidants, also called oxidative stress, appears to be an important contributing factor. The ROS promote lipid oxidation and are known to induce stress proteins, such as hemeoxygenase 1 (HO-1) and heat-shock protein 70 (Hsp-70). We hypothesized that glutathione peroxidases (GPx), a major class of antioxidant enzymes that regulate cell homeostasis by neutralizing lipid peroxides, are altered in the blood of preeclamptic women and neonates (venous cord blood).

METHODS

Thirty-one preeclamptic and 30 normotensive pregnancies were recruited. The blood was fractionated using a discontinuous gradient to separate the different cell types. The messenger ribonucleic acid (mRNA) expression of GPx-1 and -4, HO-1, and Hsp-70 were analyzed by quantitative reverse transcriptase-polymerase chain reaction. GPx-1 and -4 protein level in blood cells was also detected by Western blot. The experiments were analyzed using the Student t test.

RESULTS

The HO-1 and Hsp-70 mRNA expression in whole blood was significantly higher in both fetal and maternal circulations (P < .05). We also discovered that GPx-4 mRNA was 1.6-fold higher in blood of women with preeclampsia than in control pregnancies (P = .04). The latter was associated with an increase of both GPx-1 and GPx-4 protein and mRNA levels in the lymphocyte/monocyte fraction of the blood. Significantly higher GPx-4 mRNA levels in the fetal circulation of the preeclamptic group than the control group were also detected (P < .001).

CONCLUSION

These data indicate that preeclampsia is associated with a specific antioxidant response in both maternal and fetal circulations, likely in response to the deleterious oxidative stress observed in this syndrome.

Decrease and dysfunction of endothelial progenitor cells in umbilical cord blood with maternal pre-eclampsia

BACKGROUND

The pre-eclampsia is characterized by placental defective angiogenesis and maternal vascular/endothelial dysfunction. Recently, the decrease and senescence of endothelial progenitor cells (EPC) has been observed in maternal circulation with pre-eclampsia. Given the essential involvement of EPC in neovascularization and reendothelialization, we investigate whether or not the depletion of EPC is existent in placental/fetal circulation with maternal pre-eclampsia.

METHODS

Samples of venous cord blood were collected during the labor of preeclamptic mothers (n = 14) and normotensive controls (n = 10). Circulating EPC were enumerated as AC133+/KDR+ cells via fluorescence-activated cell sorting (FACS) analysis. Additionally, EPC were expanded in vitro and identified by DiI-acLDL uptake and lectin staining by direct fluorescent staining under a laser scanning confocal microscope. EPC proliferation, migration and vasculogenesis activities were determined by MTT, modified Boyden chamber assay and in vitro vasculogenensis assay.

RESULT

The placental/fetal circulating EPC numbers were significantly decreased in the pre-eclampsia group compared with the control (median, 200; range, 100-440 cells/mL vs 390; 270-440 cells/mL, P < 0.001), and after in vitro cultivation the numbers of EPC also decreased in pre-eclampsia group (19.5; 5.0-32.0 vs 39.5; 31.2-52.0 EPC/x200 field; P < 0.001). Both circulating EPC and cultivated EPC were inversely correlated with cord blood level of soluble fms-like tyrosine kinase 1 (sFlt-1). In addition, the EPC from patients with pre-eclampsia were significantly impaired in their proliferation, migration and vasculogenesis capacities.

CONCLUSION

The present study documented the decrease and dysfunction of placental/fetal circulating EPC in patients with pre-eclampsia. The alteration is probably associated with the increased sFlt-1 levels in the umbilical cord blood.

Dual In Vitro Perfusion of an Isolated Cotyledon as a Model to Study the Implication of Changes in the Third Trimester Placenta on Preeclampsia

In the current study perfusions of an isolated cotyledon of term placenta using standard medium were compared to medium containing xanthine plus xanthine oxidase (X+XO), which generates reactive oxygen species (ROS). A time-dependant increase in the levels of different cytokines (TNF-alpha, IL-1ss, IL-6, IL-8 and IL-10) was observed between 1 and 7h with more than 90% of the total recovered from the maternal compartment with no significant difference between the 2 groups. For 8-iso-PGF2alpha 90% of the total was found in the fetal compartment and a significantly higher total release was seen in the X+XO group. Microparticles (MPs) isolated from the maternal circuit were identified by flow cytometry as trophoblastic sheddings, whereas MPs from the fetal circuit were predominantly derived from endothelial cells. More than 90% of the total of MPs was found in the maternal circuit. The absolute amount of the total as well as the maternal fraction were significantly higher in the X+XO group. Immunohistochemistry (IHC) of the perfused tissue revealed staining for IL-1beta of villous stroma cells, which became clearly more pronounced in experiments with X+XO. Western blot of tissue homogenate revealed 2 isoforms of IL-1beta at 17 and 31kD. In X+XO experiments there was a tendency for increased expression of antioxidant enzymes in the tissue. Western blot of MPs from the maternal circuit showed increased expression of antioxidant enzymes in the X+XO group and for IL-1beta only the 17kD band was detected. In vitro reperfusion of human placental tissue results in mild tissue injury suggestive of oxidative stress. In view of the increased generation of ROS in perfused tissue with further increase under the influence of X+XO, the overall manifestation of oxidative stress remained rather mild. Preservation of antioxidant capacity of human placental tissue could be a sign of integrity of structure and function being maintained in vitro by dual perfusion of an isolated cotyledon. The observed changes resemble findings seen in placentae from preeclampsia.

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.

Vitamin E During Pre‐ and Postnatal Periods

Vitamin E is a fat-soluble nutrient that is extremely important during the early stages of life, from the time of conception to the postnatal development of the infant. The mechanisms involved in its placental and mammary uptake appear to be allowed by the presence of lipoprotein receptors (LDL-receptor, VLDL-receptor, scavenger receptor class B type I) together with lipoprotein lipase at the placental and mammary barriers. In addition, alpha-tocopherol transfer protein has been described as playing an essential role in the selective transfer of RRR-alpha-tocopherol across the placenta. Lower alpha-tocopherol concentrations are found in cord blood as compared to maternal circulation. The ingestion of colostrum which contains very high levels of vitamin E is therefore of utmost importance to supply the newborn with an essential defense against oxygen toxicity. Pregnancy is sometimes associated with complications that may lead to a premature delivery of the baby. Preterm infants are usually facing an oxidative stress that is among others related to a deficiency in alpha-tocopherol, as it accumulates mainly during the third trimester of pregnancy. Despite vitamin E supplementation, preterm infants usually require significantly longer to replenish their serum alpha-tocopherol levels than full-term infants. The use of vitamin E as a therapeutic agent in preeclampsia, which induces high maternal and fetal morbidity and mortality, has been discussed in numerous papers. This disorder is indeed associated with an important oxidative stress in the placenta and maternal circulation. However, the most recent studies did not show a beneficial effect of vitamin E administration in this pathology.

Nutritional supplements in pregnancy: commercial push or evidence based?

PURPOSE OF REVIEW

This review examines whether nutritional supplements during pregnancy have a role to play in the health of the mother, outcome of pregnancy or health of the baby. It will put into context the increased use of nutritional supplements in pregnancy and whether there is an evidence base for this supplementation.

RECENT FINDINGS

Women are not consuming enough nutrients from their diet alone and food is depleted in many important minerals. There is increasing support that supplementation of specific vitamins, minerals and omega-3 fatty acids can have a positive impact on maternal health in terms of prevention of preeclampsia, miscarriage, preterm birth, low birthweight, gestational diabetes and also on the long-term health of the baby. There are some contradictory findings with antioxidants and prevention of preeclampsia, and these are discussed.

SUMMARY

With soil depletion, overfarming and transportation of foods over hundreds of miles with loss of nutrients en route, together with the increased use of convenience and fast foods, women can be over-fed, but under-nourished in our modern society. These can lead to nutrient deficiencies which can have an impact on the outcome of pregnancy. Evidence shows that supplementation can play a valuable role in the health of the pregnant mother and her baby. Emphasis must always be on eating a good diet, but given the limitations of the 21st century lifestyle and the nutritional content of food, good quality nutritional supplements should be used during pregnancy in combinations rather than isolated single nutrients.