The role of antioxidant vitamins in hypertensive disorders of pregnancy

The Influence of Vitamin D on Pregnancy and Outcomes: Current Knowledge and Future Perspectives

INTRODUCTION

The purpose of the research was to explore the relationship between pathology and pregnancy outcomes with serum 25-hydroxycholecalciferol levels and vitamin D supplementation.

METHODS

A literature search was performed for systematic literature reviews published between January 2018 and February 2023. Forty-two publications were selected for further analysis.

RESULTS

This study demonstrates that elevated maternal serum 25(OH)D levels are associated with a decreased risk of preterm labour and various pregnancy-related health issues, highlighting the protective benefits of adequate vitamin D during pregnancy.

CONCLUSION

Vitamin D supplementation during pregnancy at a dose of 2,000 IU or higher is preventive for pre-eclampsia, insulin resistance, and the development of bronchial asthma in early childhood. Vitamin D screening is indicated for all pregnant women. Dosages of vitamin D preparations should be determined individually, considering laboratory tests and risk factors.

DNA damage in Wistar Kyoto rats exercised during pregnancy

Purpose:

To evaluate DNA damage levels in pregnant rats undergoing a treadmill exercise program.

Methods:

Wistar Kyoto rats were allocated into two groups (n= 5 animals/group): non-exercise and exercise. The pregnant rats were underwent an exercise protocol on a treadmill throughout pregnancy. Exercise intensity was set at 50% of maximal capacity during maximal exercise testing performed before mating. Body weight, blood pressure and glucose levels, and triglyceride concentration were measured during pregnancy. At day 10 post-natal, the animals were euthanized and maternal blood samples were collected for DNA damage.

Results:

Blood pressure and glucose levels and biochemical measurements showed no significant differences. Increased DNA damage levels were found in exercise group compared to those of non-exercise group (p<0.05).

Conclusion:

The exercise intensity protocol used in the study might have been exhaustive leading to maternal increased DNA damage levels, demonstrating the relevance of an adequate protocol of physical exercise.

Low Serum Vitamin C Status Among Pregnant Women Attending Antenatal Care at General Hospital Dawakin Kudu, Northwest Nigeria

Background:

Vitamin C levels are low in pregnancy. The purpose of this study was to determine serum Vitamins C levels among pregnant women attending antenatal care at a General Hospital in Dawakin Kudu, Kano, and this can help further research to determine the place of Vitamin C supplementation in pregnancy.

Methods:

This was a prospective study of 400 pregnant women who presented for antenatal care in General Hospital Dawakin Kudu, Kano, Nigeria. Research structured questionnaire was administered to 400 respondents. Determination of serum Vitamin C was done using appropriate biochemical methods.

Results:

Vitamin C deficiency was found in 79.5% of the participants. The values for Vitamin C were 0.20 ± 0.18 mg/dl during the first trimester, 0.50 ± 0.99 mg/dl in the second trimester, and 0.35 ± 0.36 mg/dl in the third trimester and P = 0.001.

Conclusions:

There is a significant reduction in the serum Vitamins C concentration throughout the period of pregnancy with the highest levels in the second trimester. Therefore, Vitamin C supplementation is suggested during pregnancy, especially for those whose fruit and vegetable consumption is inadequate.

Evaluation of oxidative stress in placenta of fetal cardiac dysfunction rat model and antioxidant defenses of maternal vitamin C supplementation with the impacts on P-glycoprotein

AIM

The oxidative stress of placenta during fetal heart dysfunction (FHD) is lack of evaluation. So, we carried out an experiment to explore whether vitamin C (VitC) can be supplied for placental protection under FHD and its impacts on P-glycoprotein expression.

METHODS

Fetal heart dysfunction was induced by two intra-amniotic injections of isoproterenol, then (VitC) was supplied. Hematoxylin-eosin (HE) staining was used to evaluate placental histology, and oxidative stress was measured by total antioxidant capacity, total superoxide dismutase and level of advanced oxidation protein products (AOPP), as well as apoptosis rate. Real-time polymerase chain reaction was adopted to measure the expressions of superoxide dismutase-1 (Sod-1), glutathione peroxidase-1 (Gpx-1) and endothelial nitric oxide synthase (eNOS) in placenta. Finally, western blot was performed to detect P-glycoprotein expression.

RESULTS

All isoproterenol twice-treated fetuses exhibited significant (P < 0.05) contractile dysfunction by fetal echocardiography compared to others. The HE staining showed severe placental hydrops in the FHD group, and that hydrops could be reduced by VitC treatment. Total antioxidant capacity and total Sod-1 decreased in FHD and elevated after VitC supplementation. Also, level of AOPP increased in FHD and dropped after VitC supplementation. Analysis of apoptosis demonstrated that there was a mild increase in apoptosis rate of FHD. Reductions of Sod-1 and eNOS mRNA expression were confirmed in FHD, but these could recovered after VitC supplementation, with the same tendency of the P-glycoprotein.

CONCLUSION

Severe oxidative injuries were identified in placentas of FHD with P-glycoprotein repression. VitC administration can reduce the oxidative stress and rebuild the protective mechanism of placenta.

IL-27 activates human trophoblasts to express IP-10 and IL-6: implications in the immunopathophysiology of preeclampsia

Purpose. To investigate the effects of IL-27 on human trophoblasts and the underlying regulatory signaling mechanisms in preeclampsia. Methods. The expression of IL-27 and IL-27 receptor (WSX-1) was studied in the placenta or sera from patients with preeclampsia. In vitro, we investigated the effects of IL-27 alone or in combination with inflammatory cytokine tumor necrosis factor (TNF-α) on the proinflammatory activation of human trophoblast cells (HTR-8/SVneo) and the underlying intracellular signaling molecules. Results. The expression of IL-27 and IL-27 receptor α (WSX-1) was significantly elevated in the trophoblastic cells from the placenta of patients with preeclampsia compared with control specimens. In vitro, IL-27 could induce the expression of inflammatory factors IFN-γ-inducible protein 10 (CXCL10/IP-10) and IL-6 in trophoblasts, and a synergistic effect was observed in the combined treatment of IL-27 and TNF-α on the release of IP-10 and IL-6. Furthermore, the production of IP-10 and IL-6 stimulated by IL-27 was differentially regulated by intracellular activation of phosphatidylinositol 3-OH kinase-AKT, p38MAPK, and JAK/STAT pathways. Conclusions. These results provide a new insight into the IL-27-activated immunopathological effects mediated by distinct intracellular signal transduction molecules in preeclampsia.

Biomarkers of oxidative stress in women with pre-eclampsia

AIM

The potential role of oxidative stress in the pathophysiology of pre-eclampsia has been reported in the literature. There are only a few studies that have investigated changes in malondialdehyde (MDA), vitamin E and total blood glutathione together in pre-eclampsia. Therefore, the aim of this study was to measure the levels of MDA, vitamin E and total glutathione as putative circulatory markers of oxidative stress for the early detection of pre-eclampsia.

PATIENTS & METHODS

In this case-control study, blood samples were collected from 40 pre-eclamptic and 80 normal pregnant females at the department of obstetrics and gynecology at King Abdulaziz Medical City (Riyadh, Saudi Arabia) between February 2009 and January 2010. Circulating markers of oxidative stress were evaluated, including MDA, total glutathione and vitamin E, by high-performance liquid chromatography.

RESULTS

Markers of oxidative stress including serum MDA, total glutathione and vitamin E were found to be significantly different in both groups.

CONCLUSION

MDA, vitamin E and blood total glutathione are possible candidate markers to predict pre-eclampsia.

FOLATE METABOLISM AND PREECLAMPSIA

Preeclampsia (PE) is a multisystem disorder of human pregnancy, affecting about 6% of all pregnancies worldwide, and is one of the leading causes of maternal and infant morbidity and mortality. Despite decades of research into the pathogenesis of this complex disease, the underlying mechanisms remain unclear. As a result, the options for prevention and management of PE are limited. In recent years, there has been a growing body of evidence suggesting that folate deficiency is associated with PE, and folic acid supplementation may reduce the risk of developing PE in certain populations. Folate contributes to cell division and growth, and folate metabolism is involved in a large number of physiological and pathophysiological processes in human development. Sufficient supply of folate is therefore particularly important during pregnancy. Nevertheless, the exact mechanisms of folic acid deficiency increasing the risk of developing PE are still unclear. This article reviews what is understood about the aetiology of PE and the relationship between folate metabolism and PE so as to enhance further discussions on the subject.

Ascorbate prevents placental oxidative stress and enhances birth weight in hypoxic pregnancy in rats

This study isolated the effects of maternal hypoxia independent of changes in maternal nutrition on maternal circulatory and placental molecular indices of oxidative stress and determined whether maternal antioxidant treatment conferred protection. Pregnant rats were subjected to normoxic pregnancy or 13% O2 chronic hypoxia for most of gestation with and without maternal treatment with vitamin C in the drinking water. Maternal hypoxia with and without vitamin C did not affect maternal food or water intake and led to a significant increase in maternal and fetal haematocrit. At gestational day 20, maternal plasma urate and L-cysteine concentrations, and placental levels of 4-hydroxynonenal and heat shock protein 70 were increased while placental heat shock protein 90 levels were decreased in hypoxic pregnancy. The induction of maternal circulatory and placental molecular indices of oxidative stress in hypoxic pregnancies was prevented by maternal treatment with vitamin C. Maternal hypoxia during pregnancy with or without vitamin C increased placental weight, but not total or compartmental volumes. Maternal treatment with vitamin C increased birth weight in both hypoxic and normoxic pregnancies. The data show that maternal hypoxia independent of maternal undernutrition promotes maternal and placental indices of oxidative stress, effects that can be prevented by maternal treatment with vitamin C in hypoxic pregnancy. While vitamin C may not be the ideal candidate of choice for therapy in pregnant women, and taking into consideration differences in ascorbic acid metabolism between rats and humans, the data do underlie that antioxidant treatment may provide a useful intervention to improve placental function and protect fetal growth in pregnancy complicated by fetal hypoxia.

Developmental programming of cardiovascular dysfunction by prenatal hypoxia and oxidative stress

Fetal hypoxia is a common complication of pregnancy. It has been shown to programme cardiac and endothelial dysfunction in the offspring in adult life. However, the mechanisms via which this occurs remain elusive, precluding the identification of potential therapy. Using an integrative approach at the isolated organ, cellular and molecular levels, we tested the hypothesis that oxidative stress in the fetal heart and vasculature underlies the molecular basis via which prenatal hypoxia programmes cardiovascular dysfunction in later life. In a longitudinal study, the effects of maternal treatment of hypoxic (13% O(2)) pregnancy with an antioxidant on the cardiovascular system of the offspring at the end of gestation and at adulthood were studied. On day 6 of pregnancy, rats (n = 20 per group) were exposed to normoxia or hypoxia ± vitamin C. At gestational day 20, tissues were collected from 1 male fetus per litter per group (n = 10). The remaining 10 litters per group were allowed to deliver. At 4 months, tissues from 1 male adult offspring per litter per group were either perfusion fixed, frozen, or dissected for isolated organ preparations. In the fetus, hypoxic pregnancy promoted aortic thickening with enhanced nitrotyrosine staining and an increase in cardiac HSP70 expression. By adulthood, offspring of hypoxic pregnancy had markedly impaired NO-dependent relaxation in femoral resistance arteries, and increased myocardial contractility with sympathetic dominance. Maternal vitamin C prevented these effects in fetal and adult offspring of hypoxic pregnancy. The data offer insight to mechanism and thereby possible targets for intervention against developmental origins of cardiac and peripheral vascular dysfunction in offspring of risky pregnancy.

Supplementation with vitamins C and E during pregnancy for the prevention of preeclampsia and other adverse maternal and perinatal outcomes: a systematic review and metaanalysis

OBJECTIVE

To determine whether supplementation with vitamins C and E during pregnancy reduces the risk of preeclampsia and other adverse maternal and perinatal outcomes.

STUDY DESIGN

Systematic review and metaanalysis of randomized controlled trials.

RESULTS

Nine trials involving a total of 19,810 women were included. Overall, there were no significant differences between the vitamin and placebo groups in the risk of preeclampsia (9.6% vs 9.6%; relative risk, 1.00, 95% confidence interval, 0.92-1.09). Similar results were obtained when subgroup analyses were restricted to women at high risk or low/moderate risk for preeclampsia. Women supplemented with vitamins C and E were at increased risk of developing gestational hypertension and premature rupture of membranes, and decreased risk of abruptio placentae. There were no significant differences between the vitamin and placebo groups in the risk of other adverse maternal or fetal/perinatal outcomes.

CONCLUSION

Supplementation with vitamins C and E during pregnancy does not prevent preeclampsia.

DNA damage and health in pregnancy

In healthy pregnancy reactive oxygen species and antioxidants remain in balance and DNA damage is repaired effectively. However, pregnancy is an inflammatory state exhibiting increased susceptibility to oxidative stress such that this balance can be easily disrupted. Increased DNA damage has been shown to be involved in many pathological states including pregnancy complications. Modern lifestyles including exposure to pollutants, poor diet, and lack of exercise cause excess inflammation, oxidative stress, and ultimately DNA damage. There is a growing body of literature providing evidence that these lifestyle changes are increasing our risk of infertility, miscarriage, and late-gestation pregnancy complications. Moreover, baseline DNA damage rises with age and couples in developed societies are delaying childbirth, placing them at further risk. In order to understand the effect of lifestyle and DNA damage on pregnancy health we require large prospective studies, with the collection of samples prior to conception and endpoints of time-to-pregnancy, early pregnancy loss, and late-gestation maternal and fetal health.

Maturation of the antioxidant system and the effects on preterm birth

The study of the interplay of the generation of reactive oxygen and nitrogen species with their related antioxidant enzymes at the maternal-placental-fetal interfaces during normal and abnormal pregnancy is in its 'infancy'. Our understanding of the role of antioxidant systems during fetal and neonatal development is constantly changing with research better defining the biological roles of these highly reactive species and the maintenance of optimal oxidant/antioxidant balance. The antioxidant enzyme system is upregulated during the last 15% of gestation, a timeframe when non-enzymatic antioxidants are also crossing the placenta in increasing concentrations. These developmental changes provide for the transition from the relative hypoxia of intrauterine development to the oxygen-rich extrauterine environment. Preterm birth is associated with an increased oxidant burden which places these infants at much higher risk of injury. This is especially true since studies have failed to reveal significant induction of antioxidants in response to the increased generation of these reactive species. Improved understanding of these relationships will be necessary for the development of rational treatments aimed at improving pregnancy outcomes and reducing the burden of oxidative stress to premature newborns.

Aetiology and physiopathology of preeclampsia and related forms

Preeclampsia, a pregnancy-specific syndrome characterized by hypertension, proteinuria and oedema, resolves on placental delivery. Its pathogenesis is thought to be associated to a hypoxic placenta. Placental hypoxia is responsible for the maternal vascular dysfunction via the increased placental release of anti-angiogenic factors such as soluble flt1 and endoglin. These soluble receptors bind VEGF, PLGF and TGFbeta1 and 3 in the maternal circulation, causing endothelial dysfunction in many maternal tissues. Despite these recent and important new molecular findings, it is important to consider that normal pregnancy is also characterized by systemic inflammation, oxidative stress and alterations in levels of angiogenic factors and vascular reactivity. Both the placenta and maternal vasculatures are major sources of reactive oxygen and nitrogen species which can produce powerful pro-oxidants that covalently modify proteins and alter vascular function in preeclampsia. Finally, the recent demonstration of activating auto-antibodies to the Angiotensin 1 receptor that experimentally play a major pathogenic role in preeclampsia further indicates the pleiotropism of aetiologies of this condition.

HLA antigen sharing between mother and fetus as a risk factor for eclampsia and preeclampsia

Immune maladaption between mother and infant has been suggested to induce preeclampsia/eclampsia. When fetuses share more human leukocyte antigen (HLA) types with their mother, immune differences would be limited and thereby could affect this risk. Data from Danish women (1996-2002) with single live-birth pregnancies complicated by severe preeclampsia/eclampsia were compared to women with term pregnancies uncomplicated by hypertension. HLA A, B, and DR types were resolved at the intermediate-level typing (antigen). A total of 201 cases and 195 control mother-infant pairs had complete HLA types. The odds ratios of preeclampsia/eclampsia in mothers sharing both HLA antigens with their infants were 1.19 (95% confidence interval: 0.81-1.76) for HLA A, 0.91 (0.59-1.42) for HLA B, and 1.05 (0.5-1.59) for HLA DR antigens. No specific HLA antigens in either mother or infant appeared important after Bonferroni correction, except possibly DR01 in mothers (protective). Thus, maladaption mediated by adaptive immunity between mother and infant is not the basis for the mother developing preeclampsia/eclampsia.

Reducing stillbirths: prevention and management of medical disorders and infections during pregnancy

BACKGROUND

An estimated two-thirds of the world's 3.2 million stillbirths occur antenatally, prior to labour, and are often overlooked in policy and programs. Poorly recognised, untreated or inadequately treated maternal infections such as syphilis and malaria, and maternal conditions including hypertensive disorders, are known risk factors for stillbirth.

METHODS

We undertook a systematic review of the evidence for 16 antenatal interventions with the potential to prevent stillbirths. We searched a range of sources including PubMed and the Cochrane Library. For interventions with prior Cochrane reviews, we conducted additional meta-analyses including eligible newer randomised controlled trials following the Cochrane protocol. We focused on interventions deliverable at the community level in low-/middle-income countries, where the burden of stillbirths is greatest.

RESULTS

Few of the studies we included reported stillbirth as an outcome; most that did were underpowered to assess this outcome. While Cochrane reviews or meta-analyses were available for many interventions, few focused on stillbirth or perinatal mortality as outcomes, and evidence was frequently conflicting. Several interventions showed clear evidence of impact on stillbirths, including heparin therapy for certain maternal indications; syphilis screening and treatment; and insecticide-treated bed nets for prevention of malaria. Other interventions, such as management of obstetric intrahepatic cholestasis, maternal anti-helminthic treatment, and intermittent preventive treatment of malaria, showed promising impact on stillbirth rates but require confirmatory studies. Several interventions reduced known risk factors for stillbirth (e.g., anti-hypertensive drugs for chronic hypertension), yet failed to show statistically significant impact on stillbirth or perinatal mortality rates. Periodontal disease emerged as a clear risk factor for stillbirth but no interventions have reduced stillbirth rates.

CONCLUSION

Evidence for some newly recognised risk factors for stillbirth, including periodontal disease, suggests the need for large, appropriately designed randomised trials to test whether intervention can minimise these risks and prevent stillbirths. Existing evidence strongly supports infection control measures, including syphilis screening and treatment and malaria prophylaxis in endemic areas, for preventing antepartum stillbirths. These interventions should be incorporated into antenatal care programs based on attributable risks and burden of disease.