Aspirin inhibits expression of sFLT1 from human cytotrophoblasts induced by hypoxia, via cyclo-oxygenase 1

Steroid Profiles and Precursor-to-Product Ratios Are Altered in Pregnant Women with Preeclampsia

Steroid hormone imbalance is associated with the pathogenesis of preeclampsia. However, affected enzymes of steroid metabolism and gene and protein expression in serum and placenta have not been elucidated yet. We aimed to investigate steroid hormone profiles and precursor-to-product ratios in preeclamptic women compared to women with healthy pregnancy (controls) to identify potentially affected steroid hormones and their metabolizing enzymes. Also, we aimed to investigate whether the mRNA expression of these enzymes is different between the study groups and whether levels of serum mRNA expression reflect postnatal placental protein expression. Serum levels of 14 steroid hormones were measured at eight time points throughout pregnancy in nine preeclamptic women and 36 controls. Serum mRNA expression of selected steroid-metabolizing enzymes was assessed, and their protein expression was analyzed in additional nine preeclamptic women. Mean levels of sex steroid and corticosteroid hormones were significantly altered in preeclamptic women. Precursor-to-product ratios of 5α-reductase, aromatase and 11β-hydroxysteroid dehydrogenase 1 were significantly increased, those of steroid 17α-hydroxylase, 17β-hydroxysteroid-dehydrogenase, steroid 11β-hydroxylase and 11β-hydroxysteroid dehydrogenase 2 were significantly decreased. Serum mRNA expression and placenta protein expression were comparable between the groups. Results contribute to understanding the heterogeneity of preeclampsia and can thus promote future research in personalized medicine.

Effect of aspirin on biomarker profile in women at high risk for preeclampsia

BACKGROUND

There is limited evidence in the literature regarding the temporal changes of preeclampsia-related biomarkers during pregnancy in high-risk women who develop preeclampsia despite the administration of aspirin prophylaxis.

OBJECTIVE

This study aimed to compare the temporal changes in mean arterial pressure, uterine artery pulsatility index, placental growth factor, and soluble fms-like tyrosine kinase-1 across gestation in women identified as having high risk for preterm preeclampsia receiving aspirin prophylaxis and low-risk women without aspirin treatment.

STUDY DESIGN

This was a prospective longitudinal nested case-control study of 2007 women with singleton pregnancies who participated in the first-trimester screen-and-prevent program for preeclampsia at the Prince of Wales Hospital, Hong Kong Special Administrative Region, China, between January 2020 and May 2023. The risk of developing preterm preeclampsia was determined using the Fetal Medicine Foundation triple test (maternal factors, mean arterial pressure, uterine artery pulsatility index, and placental growth factor). High-risk women (adjusted risk ≥1:100) were administered a daily dose of aspirin at either 100 or 160 mg according to maternal weight, starting before 16 weeks until 36 weeks or until delivery or the onset of preeclampsia before 36 weeks. Low-risk women were matched according to maternal age, weight, and the date of the scan. The participants were followed up at 12 to 15+6, 20 to 24+6, and 30 to 37+6 weeks to measure mean arterial pressure, uterine artery pulsatility index, placental growth factor, and soluble fms-like tyrosine kinase-1 at each visit. The level of biomarker was expressed as multiple of the median. Log10 transformation was applied to fit the data to a Gaussian distribution before statistical analysis. A linear mixed-effects analysis was performed to compare the longitudinal changes of these biomarkers across gestation between the study groups.

RESULTS

Our study involved 403 low-risk women without preeclampsia, 1471 high-risk women without preeclampsia, and 133 high-risk women who developed preeclampsia. The low-risk group had significantly lower estimated marginal mean log10 mean arterial pressure multiple of the median, log10 uterine artery pulsatility index multiple of the median, and log10 soluble fms-like tyrosine kinase-1 multiple of the median, and higher estimated marginal mean log10 placental growth factor multiple of the median across gestation compared with the high-risk groups (P<.001). Among high-risk women, those who developed preeclampsia exhibited a significantly higher estimated marginal mean log10 mean arterial pressure multiple of the median (0.06378 vs 0.02985; P<.001), log10 uterine artery pulsatility index multiple of the median (0.08651 vs 0.02226; P<.001), and log10 soluble fms-like tyrosine kinase-1 multiple of the median (0.13204 vs 0.01234; P<.001), and lower estimated marginal mean log10 placental growth factor multiple of the median (-0.33504 vs -0.16388; P<.001) across gestation compared with those without preeclampsia. In the individual gestational time point analysis, compared with high-risk women without preeclampsia, those who developed preeclampsia exhibited higher log10 mean arterial pressure multiple of the median in all 3 trimesters, higher log10 uterine artery pulsatility index multiple of the median and lower log10 placental growth factor multiple of the median in the second and third trimesters, and higher log10 soluble fms-like tyrosine kinase-1 multiple of the median in the third trimester.

CONCLUSION

This study demonstrated that high-risk women who developed preeclampsia consistently exhibited high mean arterial pressure levels from the first trimester that remained unchanged during pregnancy, high uterine artery pulsatility index levels and low placental growth factor levels starting from the second trimester, and high soluble fms-like tyrosine kinase-1 levels in the third trimester compared with those who did not develop preeclampsia despite the administration of low-dose aspirin. These findings underscore the role of these biomarkers in further risk stratification for the development of preeclampsia among high-risk women following aspirin administration.

Synopsis of the 2023 U.S. Department of VA and U.S. DoD Clinical Practice Guideline for the Management of Pregnancy

INTRODUCTION

This Clinical Practical Guideline provides recommendations based on a systematic review of the evidence to address critical decision points in the management of pregnancy. The guideline is intended to improve patient outcomes and local management of patients who are pregnant. This CPG is based on a systematic review of both clinical and epidemiological evidence and was developed by a panel of multidisciplinary experts. The Work Group provides clear and comprehensive evidence-based recommendations incorporating current information and practices targeting practitioners throughout the DoD and VA Health Care systems. The guideline is intended to improve patient outcomes and local management of patients who are pregnant. This CPG does not address every aspect of routine pregnancy care and is not intended to be a comprehensive guide to all care needed in pregnancy. It also addresses some clinically important and generally accepted standards of pregnancy care interventions that do not have sufficient high-quality evidence to support standalone recommendations. Additionally, it highlights emerging topics that have the potential to impact pregnancy care in the future and identifies gaps in the literature that warrant further research.

MATERIALS AND METHODS

The development of all VA/DoD guidelines is directed by the Evidence-Based Practice Guideline Work Group and adheres to the standards for trustworthy guidelines that were set by the National Academy of Medicine. A patient focus group was convened to assess important aspects of treatment for patients and to gain information about patient values and preferences. The Lewin Group, a contracted third party with expertise in CPG development, facilitated meetings and the development of key questions using the population, intervention, comparison, outcome, timing, and setting format. Consensus was achieved among the Work Group through an iterative process involving discussions on conference calls and in person during the recommendation development meeting. An independent third party, ECRI, conducted the systematic evidence review, which the guideline Work Group then used to develop recommendations using the Grading of Recommendations Assessment, Development and Evaluation system (7-9). The search methods and results are detailed in the full guideline.

RESULTS

This CPG provides 28 clinical practice recommendations that cover selected topics that the Work Group deemed had high priority need for evidence-based standards. The recommendations are divided into 3 main categories: routine care, complicated obstetrics, and mental health. An algorithm delineating recommended interventions and appropriate timing of these interventions over the course of the pregnancy and postpartum period was also created.

CONCLUSION

The CPG is not intended to define standards of care nor address all care needed in pregnancy; it does provide comprehensive guidance for routine pregnancy care. It aligns with the VA and DOD's goal of providing care that is consistent in quality and utilization of resources in efforts to reduce errors and inappropriate variations in practices. In total, the Work Group identified 71 items needing further study, including areas requiring stronger evidence to support current recommendations and newer topics that will guide future guideline development.

Obstetric care provider's knowledge about the use of low dose aspirin for preeclampsia prevention in low and middle income countries: a systematic review and meta-analysis

INTRODUCTION

Preeclampsia can elevate the likelihood of unfavorable consequences for a mother, such as severe morbidity and mortality. World Health Organization recommends low dose acetylsalicylic acid (aspirin, 75 mg per day) for the prevention of preeclampsia in women at moderate or high risk of developing the condition. The use of low dose aspirin is dependent on the knowledge of health care providers working in the antenatal care units. We found inconsistent figures regarding the knowledge level of health care providers on low dose aspirin for preeclampsia prevention around different low and middle income countries in the world. Thus, determining the pooled knowledge level of health care providers is very important.

METHODS

This systematic review and meta-analysis (SRMA) was conducted on the knowledge level of among obstetric care providers towards preeclampsia prevention in low and middle income countries. We identified relevant literature in the English language only. A comprehensive search was conducted on databases such as PubMed, Google Scholar, HINARI, and Scopus. Subsequently, all datasets were exported to Mendeley reference manager and transferred to a Microsoft Excel spreadsheet to eliminate duplicate data during the review process. The extracted Microsoft Excel spreadsheet format data was imported to STATA software version 17 (STATA corporation, Texas, USA) for analysis. Then random effect model was used to estimate the pooled level of knowledge of health care providers on low dose aspirin for preeclampsia prevention in low income countries. Cochrane Q-test and I2 statistics were computed to assess heterogeneity among all the studies included in this SRMA.

RESULT

A total of 1231 articles were identified through our search strategies, including Google Scholar, PubMed, Hinari and Scopus. Ultimately, six articles met the eligibility criteria for inclusion in the final SRMA. The pooled knowledge level of healthcare providers regarding the use of low-dose aspirin for preeclampsia prevention in low-income countries was found to be 16.38% (95% CI: 4.36-28.40). The Cochrane heterogeneity index, with a substantial I2 value of 98.89% and a significant P-value of 0.01, indicated significant heterogeneity among the primary studies included.

CONCLUSION

the knowledge level of obstetric care providers in low and middle income countries is found very low and all the governmental and non-governmental organizations should strive to enhance the knowledge of obstetric care providers on the use of low dose aspirin for preeclampsia prevention in low and middle income countries.

Reducing the Risk of Pre-Eclampsia in Women with Polycystic Ovary Syndrome Using a Combination of Pregnancy Screening, Lifestyle, and Medical Management Strategies

Polycystic ovary syndrome (PCOS) is a multisystem disorder that presents with a variety of phenotypes involving metabolic, endocrine, reproductive, and psychological symptoms and signs. Women with PCOS are at increased risk of pregnancy complications including implantation failure, miscarriage, gestational diabetes, fetal growth restriction, preterm labor, and pre-eclampsia (PE). This may be attributed to the presence of specific susceptibility features associated with PCOS before and during pregnancy, such as chronic systemic inflammation, insulin resistance (IR), and hyperandrogenism, all of which have been associated with an increased risk of pregnancy complications. Many of the features of PCOS are reversible following lifestyle interventions such as diet and exercise, and pregnant women following a healthy lifestyle have been found to have a lower risk of complications, including PE. This narrative synthesis summarizes the evidence investigating the risk of PE and the role of nutritional factors in women with PCOS. The findings suggest that the beneficial aspects of lifestyle management of PCOS, as recommended in the evidence-based international guidelines, extend to improved pregnancy outcomes. Identifying high-risk women with PCOS will allow targeted interventions, early-pregnancy screening, and increased surveillance for PE. Women with PCOS should be included in risk assessment algorithms for PE.

Molecular epidemiology of pregnancy using omics data: advances, success stories, and challenges

Multi-omics approaches have been successfully applied to investigate pregnancy and health outcomes at a molecular and genetic level in several studies. As omics technologies advance, research areas are open to study further. Here we discuss overall trends and examples of successfully using omics technologies and techniques (e.g., genomics, proteomics, metabolomics, and metagenomics) to investigate the molecular epidemiology of pregnancy. In addition, we outline omics applications and study characteristics of pregnancy for understanding fundamental biology, causal health, and physiological relationships, risk and prediction modeling, diagnostics, and correlations.

An Examination of the Effect of Aspirin and Salicylic Acid on Soluble Fms-like Tyrosine Kinase-1 Release from Human Placental Trophoblasts

Low-dose aspirin (LDA) is efficacious in preventing preeclampsia, but its mechanism of action is unclear. Conflicting evidence suggests that it may inhibit placental trophoblast release of soluble fms-like tyrosine kinase-1 (sFlt1), a key mediator of preeclampsia. We examined whether, and at what concentrations, aspirin and its principal metabolite, salicylic acid, modulate sFlt1 release and/or expression in trophoblasts. Human trophoblast lines BeWo and HTR-8/SVneo were cultured; BeWo cells were also treated with 1% oxygen vs. normoxia to mimic hypoxia in preeclamptic placentas. Cells were treated with aspirin or salicylic acid vs. vehicle for 24 h at concentrations relevant to LDA and at higher concentrations. Protein concentrations (ELISA) and mRNA expression (RT-PCR) of sFlt1 were determined. Under normoxia, LDA-relevant concentrations of aspirin (10-50 µmol/L) or salicylic acid (20-100 µmol/L) had no significant effect on sFlt1 protein release or mRNA expression in BeWo cells. However, inhibition was observed at higher concentrations (1 mmol/L for aspirin and ≥200 μmol/L for salicylic acid). Hypoxia enhanced sFlt1 protein release and mRNA expression in BeWo cells, but these responses were not significantly affected by either aspirin or salicylic acid at LDA concentrations. Similarly, neither drug altered sFlt1 protein secretion or mRNA expression in normoxic HTR-8/SVneo cells at LDA concentrations. We suggest that direct modulation of trophoblast release or expression of sFlt1 is unlikely to be a mechanism underlying the clinical efficacy of LDA in preeclampsia.

Advances in preeclampsia testing

Preeclampsia is a multisystem hypertensive disorder and one of the leading causes of maternal and fetal morbidity and mortality. The clinical hallmarks such as hypertension and proteinuria, and additional laboratory tests currently available including liver enzyme testing, are neither specific nor sufficiently sensitive. Therefore, biomarkers for timely and accurate identification of patients at risk of developing preeclampsia are extremely valuable to improve patient outcomes and safety. In this chapter, we will first discuss the clinical characteristics of preeclampsia and current evidence of the role of angiogenic factors, such as placental growth factor (PlGF) and soluble FMS like tyrosine kinase 1 (sFlt-1) in the pathogenesis of preeclampsia. Second, we will review the clinical practice guidelines for preeclampsia diagnostic criteria and their recommendations on laboratory testing. Third, we will review the currently available PlGF and sFlt-1 assays in terms of their methodologies, analytical performance, and clinical diagnostic values. Finally, we will discuss the future research needs from both an analytical and clinical perspective.

The Role of Acetylsalicylic Acid in the Prevention of Pre-Eclampsia, Fetal Growth Restriction, and Preterm Birth

BACKGROUND

Recent studies suggest that low-dose acetylsalicylic acid (ASA) can lower pregnancy-associated morbidity.

METHODS

This review is based on pertinent publications that were retrieved by a selective search in PubMed, with special attention to systematic reviews, metaanalyses, and randomized controlled trials.

RESULTS

Current meta-analyses document a reduction of the risk of the occurrence of pre-eclampsia (RR 0.85, NNT 50), as well as beneficial effects on the rates of preterm birth (RR 0.80, NNT 37), fetal growth restriction (RR 0.82, NNT 77), and perinatal death (RR 0.79, NNT 167). Moreover, there is evidence that ASA raises the rate of live births after a prior spontaneous abortion, while also lowering the rate of spontaneous preterm births (RR 0.89, NNT 67). The prerequisites for therapeutic success are an adequate ASA dose, early initiation of ASA, and the identification of women at risk of pregnancy-associated morbidity. Side effects of treatment with ASA in this patient group are rare and mainly involve bleeding in connection with the pregnancy (RR 0.87, NNH 200).

CONCLUSION

ASA use during pregnancy has benefits beyond reducing the risk of pre-eclampsia. The indications for taking ASA during pregnancy may be extended at some point in the future; at present, in view of the available evidence, it is still restricted to high-risk pregnancies.

Low-Dose Aspirin after ASPRE-More Questions Than Answers? Current International Approach after PE Screening in the First Trimester

Preeclampsia (PE) is a multi-factorial disorder of pregnancy, and it continues to be one of the leading causes of fetal and maternal morbidity and mortality worldwide. Aspirin is universally recommended for high-risk women to reduce preeclampsia risk. The purpose of this review is to summarize the recommendations of various scientific societies on predicting preeclampsia and their indications for the inclusion of acetylsalicylic acid (ASA) prophylaxis. Fourteen guidelines were compared. The recommended dose, screening method, and gestational age at the start of the test vary depending on the recommendation. The societies are inclined to recommend using increasingly higher doses (>75 mg) of ASA, with many encouraging doses from 100 mg upward. Most societies indicate that the optimal time for implementing aspirin is prior to 16 weeks' gestation. Following the publication of the Aspirin for Evidence-Based Preeclampsia Prevention (ASPRE) trial results and other papers evaluating the Fetal Medicine Foundation (FMF) screening model, a large number of societies have changed their recommendations from those based on risk factors alone to the ones based on the risk assessment proposed by the FMF. This allows for the detection of a high-risk pregnancy population in whom aspirin will be remarkably effective in preventing preterm PE, thereby decreasing maternal and fetal morbidity.

Aspirin and Pravastatin for Preeclampsia Prevention in High-Risk Pregnancy

Preeclampsia is a hypertensive disorder of pregnancy affecting up to 8% of pregnancies. It is associated with significant neonatal and maternal morbidities and mortality. Although its pathogenesis is not completely understood, abnormal placentation resulting in imbalance in angiogenic factors, increased inflammation, and endothelial dysfunction are thought to be key pathways in the development of the disease. Administration of low-dose aspirin is recommended by professional societies for the prevention of preeclampsia in high-risk individuals. In this review, we summarize the evidence behind the use of low-dose aspirin and pravastatin in pregnant individuals at high risk of preeclampsia.

Prenatal Low-Dose Aspirin Use Associated with Reduced Incidence of Postpartum Hypertension among Women with Preeclampsia

OBJECTIVE

Postpartum hypertension (PP-HTN), defined as systolic/diastolic blood pressure (SBP/DBP) ≥140/90, on two occasions at least 4 hours apart after delivery occurs in up to 50% of preeclamptic pregnancies, and is associated with adverse maternal outcomes. Excessive production of antiangiogenic factors (i.e., soluble fms-like tyrosine kinase 1 [sFLT1]) and reduced levels of proangiogenic factors (i.e., placental growth factor [PlGF]) are associated with preeclamptic pregnancies. The aim of this study was to identify clinical risk factors and/or serum biomarkers associated with PP-HTN in preeclampsia.

STUDY DESIGN

Preeclamptic women (n = 82, aged ≥18 years) were prospectively enrolled in an observational study. Serial blood pressures were obtained through the labor course and until 48 hours postpartum, and serum was obtained within 24 hours postpartum. Statistical analysis was performed by using Student's two-tailed t-test and Fisher's exact test.

RESULTS

Baseline comorbidities and antihypertensive use were similar among those who developed PP-HTN and those who did not. Among preeclamptic patients, 33% developed PP-HTN; these had significantly more severe preeclampsia features versus no PP-HTN (96 vs. 78%, p = 0.05). PP-HTN was associated with higher re-hospitalization rates (26 vs. 6%, p = 0.01). Among those taking low-dose aspirin (ASA) for preeclampsia prophylaxis (n = 12), PP-HTN was significantly less frequent versus those not taking low-dose ASA (0 vs. 22%, p = 0.007). Low-dose ASA use was associated with significantly lower peripartum sFLT1 levels (4,650 ± 2,335 vs. 7,870 ± 6,282 pg/mL, p = 0.03) and sFLT1/PlGF ratio (397 ± 196 vs. 1,527 ± 2,668, p = 0.03).

CONCLUSION

One-third of women with preeclampsia develop PP-HTN; these patients have more severe preeclampsia and have higher re-hospitalization rates. Prenatal low-dose ASA use was associated with significantly lower incidence of PP-HTN, reduced levels of antiangiogenic factors, and lower 6-week re-hospitalization rates. These findings, if replicated, may have clinical implications on the use of low-dose ASA during pregnancy to reduce incidence of postpartum HTN.

KEY POINTS

· Postpartum hypertension is common in preeclampsia.. · Prenatal aspirin may reduce postpartum hypertension.. · Prenatal aspirin may reduce sFLT1 levels..

Application of low dose aspirin in pre-eclampsia

Aspirin is widely used in the primary and secondary prevention of cardiovascular and cerebrovascular diseases. Low-dose aspirin is also widely used to prevent pre-eclampsia and fetal growth retardation in utero. However, the use of aspirin during pregnancy is controversial. Since 1985, when aspirin was reported to be effective in obstetrics, numerous studies have attempted to determine the effect of low-dose aspirin on the morbidity of pre-eclampsia but have remained inconclusive. Guidelines for aspirin in preventing pre-eclampsia are different in different countries and regions. This article summarizes the research progress, mechanism, and application prospect of aspirin in preventing pre-eclampsia, providing a theoretical basis for the rational use of aspirin in pregnancy.

The Role of Different Lymphoid Cell Populations in Preeclampsia Pathophysiology

Preeclampsia (PE), new-onset hypertension during pregnancy, affects up to 10% of pregnancies worldwide. Despite being the leading cause of maternal and fetal morbidity and mortality, PE has no cure beyond the delivery of the fetal-placental unit. Although the exact pathogenesis of PE is unclear, there is a strong correlation between chronic immune activation; intrauterine growth restriction; uterine artery resistance; dysregulation of the renin-angiotensin system. Which contributes to renal dysfunction; and the resulting hypertension during pregnancy. The genesis of PE is thought to begin with insufficient trophoblast invasion leading to reduced spiral artery remodeling, resulting in decreased placental perfusion and thereby causing placental ischemia. The ischemic placenta releases factors that shower the endothelium and contribute to peripheral vasoconstriction and chronic immune activation and oxidative stress. Studies have shown imbalances in proinflammatory and anti-inflammatory cell types in women with PE and in animal models used to examine mediators of a PE phenotype during pregnancy. T cells, B cells, and natural killer cells have all emerged as potential mediators contributing to the production of vasoactive factors, renal and endothelial dysfunction, mitochondrial dysfunction, and hypertension during pregnancy. The chronic immune activation seen in PE leads to a higher risk for other diseases, such as cardiovascular disease, CKD, dementia during the postpartum period, and PE during a subsequent pregnancy. The purpose of this review is to highlight studies demonstrating the role that different lymphoid cell populations play in the pathophysiology of PE. Moreover, we will discuss treatments focused on restoring immune balance or targeting specific immune mediators that may be potential strategies to improve maternal and fetal outcomes associated with PE.

Emerging pharmacologic interventions for pre-eclampsia treatment

INTRODUCTION

Pre-eclampsia is a serious pregnancy complication and a major global concern for the mortality of both mother and fetus. Existing symptomatic treatments do not delay disease progression; thus, timely delivery of the baby is the most effective measure. However, the risk of various maternal and fetal injuries remains.

AREAS COVERED

In this review, we summarize the potential strategies for pharmacologic interventions in pre-eclamptic therapy. Specifically, we discuss the pathophysiological process of various effective candidate therapeutics that act on potential pathways and molecular targets to inhibit key stages of the disease. We refer to this pathogenesis-focused drug discovery model as a pathogenesis-target-drug (P-T-D) strategy. Finally, we discuss the introduction of nanotechnologies to improve the safety and efficacy of therapeutics via their specific placental targeting ability and placental retention effects.

EXPERT OPINION

Despite the active development of novel pharmacological treatments based on our current knowledge of pre-eclamptic pathogenesis, investigations are still in the early phase. Thus, further exploration of the pathological mechanisms, integrated with the P-T-D strategy and novel nanosystems, could encourage the development of more effective and safer strategies. Such advances could lead to a shift from expectant management to mechanistic-based therapy for pre-eclampsia.

An Overview of Obesity, Cholesterol, and Systemic Inflammation in Preeclampsia

Preeclampsia (PE), an inflammatory state during pregnancy, is a significant cause of maternal and fetal morbidity and mortality. Adverse outcomes associated with PE include hypertension, proteinuria, uterine/placental abnormalities, fetal growth restriction, and pre-term birth. Women with obesity have an increased risk of developing PE likely due to impaired placental development from altered metabolic homeostasis. Inflammatory cytokines from maternal adipose tissue and circulating cholesterol have been linked to systemic inflammation, hypertension, and other adverse outcomes associated with PE. This review will summarize the current knowledge on the role of nutrients, obesity, and cholesterol signaling in PE with an emphasis on findings from preclinical models.

[Use of aspirin 100 mg / day to prevent Preeclampsia, in high risk pregnancies, in a cohort from Argentina]

Objectives

The objective of the present study was to analyse the use of 100 g aspirin dose as prevention method for preeclampsia in high risk pregnant patients.

Methods

A retrospective cohort study was performed in high risk pregnant patients with a blood pressure protocol, and the use of 100 mg of aspirin vs. its non-use was evaluated in the incidence of PREEC. Estimations between the two groups were performed with and without variable adjustment by means of binary logistic regression models.

Results

633 high risk pregnant patients were evaluated. The average age was 30±7 years old, and 25±8 weeks of pregnancy. 281 women (44.3 %) within this group received aspirin. The total prevalence of PREEC in our sample was 151 pregnant women (23.8 %). Pregnant patients under the aspirin treatment developed less PREEC events (19.2% vs 27.5%, p=0.019); with OR not adjusted 0.62 (IC95% 0.43-0.91 p= 0.017). The risk was similar when it was adjusted by age, preeclampsia history, diabetes mellitus and chronic high blood pressure. (OR adjusted 0.63 IC95% 0.43-0.92 p= 0.017).

Conclusions

The use of 100 mg of aspirin a day before the 20th week of pregnancy in high risk pregnant patients decreased the risk of developing PREEC, regardless the age and risk factors.

Imbalances in circulating angiogenic factors in the pathophysiology of preeclampsia and related disorders

Preeclampsia is a devastating medical complication of pregnancy that can lead to significant maternal and fetal morbidity and mortality. It is currently believed that there is abnormal placentation in as early as the first trimester in women destined to develop preeclampsia. Although the etiology of the abnormal placentation is being debated, numerous epidemiologic and experimental studies suggest that imbalances in circulating angiogenic factors released from the placenta are responsible for the maternal signs and symptoms of preeclampsia. In particular, circulating levels of soluble fms-like tyrosine kinase 1, an antiangiogenic factor, are markedly increased in women with preeclampsia, whereas free levels of its ligand, placental, growth factor are markedly diminished. Alterations in these angiogenic factors precede the onset of clinical signs of preeclampsia and correlate with disease severity. Recently, the availability of automated assays for the measurement of angiogenic biomarkers in the plasma, serum, and urine has helped investigators worldwide to demonstrate a key role for these factors in the clinical diagnosis and prediction of preeclampsia. Numerous studies have reported that circulating angiogenic biomarkers have a very high negative predictive value to rule out clinical disease among women with suspected preeclampsia. These blood-based biomarkers have provided a valuable tool to clinicians to accelerate the time to clinical diagnosis and minimize maternal adverse outcomes in women with preeclampsia. Angiogenic biomarkers have also been useful to elucidate the pathogenesis of related disorders of abnormal placentation such as intrauterine growth restriction, intrauterine fetal death, twin-to-twin transfusion syndrome, and fetal hydrops. In summary, the discovery and characterization of angiogenic proteins of placental origin have provided clinicians a noninvasive blood-based tool to monitor placental function and health and for early detection of disorders of placentation. Uncovering the mechanisms of altered angiogenic factors in preeclampsia and related disorders of placentation may provide insights into novel preventive and therapeutic options.

Prevention of preeclampsia with aspirin

Preeclampsia is defined as hypertension arising after 20 weeks of gestational age with proteinuria or other signs of end-organ damage and is an important cause of maternal and perinatal morbidity and mortality, particularly when of early onset. Although a significant amount of research has been dedicated in identifying preventive measures for preeclampsia, the incidence of the condition has been relatively unchanged in the last decades. This could be attributed to the fact that the underlying pathophysiology of preeclampsia is not entirely understood. There is increasing evidence suggesting that suboptimal trophoblastic invasion leads to an imbalance of angiogenic and antiangiogenic proteins, ultimately causing widespread inflammation and endothelial damage, increased platelet aggregation, and thrombotic events with placental infarcts. Aspirin at doses below 300 mg selectively and irreversibly inactivates the cyclooxygenase-1 enzyme, suppressing the production of prostaglandins and thromboxane and inhibiting inflammation and platelet aggregation. Such an effect has led to the hypothesis that aspirin could be useful for preventing preeclampsia. The first possible link between the use of aspirin and the prevention of preeclampsia was suggested by a case report published in 1978, followed by the first randomized controlled trial published in 1985. Since then, numerous randomized trials have been published, reporting the safety of the use of aspirin in pregnancy and the inconsistent effects of aspirin on the rates of preeclampsia. These inconsistencies, however, can be largely explained by a high degree of heterogeneity regarding the selection of trial participants, baseline risk of the included women, dosage of aspirin, gestational age of prophylaxis initiation, and preeclampsia definition. An individual patient data meta-analysis has indicated a modest 10% reduction in preeclampsia rates with the use of aspirin, but later meta-analyses of aggregate data have revealed a dose-response effect of aspirin on preeclampsia rates, which is maximized when the medication is initiated before 16 weeks of gestational age. Recently, the Aspirin for Evidence-Based Preeclampsia Prevention trial has revealed that aspirin at a daily dosage of 150 mg, initiated before 16 weeks of gestational age, and given at night to a high-risk population, identified by a combined first trimester screening test, reduces the incidence of preterm preeclampsia by 62%. A secondary analysis of the Aspirin for Evidence-Based Preeclampsia Prevention trial data also indicated a reduction in the length of stay in the neonatal intensive care unit by 68% compared with placebo, mainly because of a reduction in births before 32 weeks of gestational age with preeclampsia. The beneficial effect of aspirin has been found to be similar in subgroups according to different maternal characteristics, except for the presence of chronic hypertension, where no beneficial effect is evident. In addition, the effect size of aspirin has been found to be more pronounced in women with good compliance to treatment. In general, randomized trials are underpowered to investigate the treatment effect of aspirin on the rates of other placental-associated adverse outcomes such as fetal growth restriction and stillbirth. This article summarizes the evidence around aspirin for the prevention of preeclampsia and its complications.

Low-dose aspirin for primary prevention of adverse pregnancy outcomes in twin pregnancies: an observational cohort study based on propensity score matching

Background

Since the effectiveness of low-dose aspirin (LDA) in twin pregnancies is uncertain, we aimed to preliminarily assess whether LDA is beneficial in preventing preeclampsia in twin pregnancies.

Methods

This study is an observational study in two hospitals in China. Among 932 women, 277 in the First Affiliated Hospital of Chongqing Medical University were routinely treated with aspirin (100 mg daily) from 12 to 16 weeks to 35 weeks of gestational age, while 655 in Chongqing Health Center for Women and Children were not taking aspirin during pregnancy. We followed each subject and the individual details were recorded.

Results

LDA significantly reduced the risk of preeclampsia (RR 0.48; 95% CI 0.24–0.95) and preterm birth 34 weeks (RR 0.50; 95% CI 0.29–0.86) and showed possible benefits to lower the rate of SGA babies (RR 0.74; 95% CI 0.55–1.00). Moreover, the risk of postpartum hemorrhage was not increased by LDA (RR 0.89; 95% CI 0.35–2.26).

Conclusions

Treatment with low-dose aspirin in twin pregnancies could offer some protection against adverse pregnancy outcomes in the absence of significantly increased risk of postpartum hemorrhage.

Trial registration

Chinese Clinical Trial Registry (ChiCTR); ChiCTR-OOC-16008203, Retrospectively registered date: April 1st, 2016;

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-021-04217-2.

Efficacy of Low Doses of Acetylsalicylic Acid in the Prevention of Preeclampsia in Women with Type 1 and 2 Diabetes Mellitus

Background: The effective approach to preventing preeclampsia (PE) is administering acetylsalicylic acid (ASA) to high-risk patients. However, there are not enough data analyzing the effectiveness of ASA intake by pregnant women with diabetes mellitus (DM). This study aims to evaluate the effect of ASA on perinatal outcomes in pregnant women with different types of pregestational DM. Methods: This retrospective study included 735 pregnant women with DM (types 1 and 2). At 12–14 weeks of gestation, some patients were prescribed daily ASA at a 100–150 mg dose continuously for up to 36 weeks. The effect of ASA on the development of PE and other outcomes of pregnancy was assessed. The times of delivery and the onset of PE were evaluated as well. Results: When taking ASA, PE developed significantly less frequently in pregnant women with DM. This was significantly more evident in patients with type 2 DM (OR 0.65; 95% CI: 0.52–0.79). In patients with type 1 DM, the mean period of development of PE was 1.5 weeks later relative to those pregnant women who did not take the drug and was 35.5 weeks of gestation. The OR for the development of preterm birth was reduced by 3 times (OR 0.33; 95% CI: 0.15–0.62). In women with DM who took ASA during pregnancy, babies were born with greater body weight, and the frequency of small for gestational age births decreased. Conclusions: ASA administration is associated with a reduction of the incidence of PE, a delay in its manifestations, and a mitigating the risk of other adverse perinatal outcomes typical for pregnant women with DM.

Syncytiotrophoblast stress in early onset preeclampsia: The issues perpetuating the syndrome

Preeclampsia is a pregnancy-specific syndrome characterized by a sudden increase in blood pressure accompanied by proteinuria and/or maternal multi-system damage associated to poor fetal outcome. In early-onset preeclampsia, utero-placental perfusion is altered, causing constant and progressive damage to the syncytiotrophoblast, generating syncytiotrophoblast stress. The latter leads to the detachment and release of syncytiotrophoblast fragments, anti-angiogenic factors and pro-inflammatory molecules into maternal circulation, resulting in the emergence and persistence of the characteristic symptoms of this syndrome during pregnancy. Therefore, understanding the origin and consequences of syncytiotrophoblast stress in preeclampsia is vital to develop new therapeutic alternatives, focused on reducing the burden of this syndrome. In this review, we describe five central characteristics of syncytial stress that should be targeted or prevented in order to reduce preeclampsia symptoms: histological alterations, syncytiotrophoblast damage, antiangiogenic protein export, placental deportation, and altered syncytiotrophoblast turnover. Therapeutic management of these characteristics may improve maternal and fetal outcomes.

Adaptations of the human placenta to hypoxia: opportunities for interventions in fetal growth restriction

BACKGROUND

The placenta is the functional interface between the mother and the fetus during pregnancy, and a critical determinant of fetal growth and life-long health. In the first trimester, it develops under a low-oxygen environment, which is essential for the conceptus who has little defense against reactive oxygen species produced during oxidative metabolism. However, failure of invasive trophoblasts to sufficiently remodel uterine arteries toward dilated vessels by the end of the first trimester can lead to reduced/intermittent blood flow, persistent hypoxia and oxidative stress in the placenta with consequences for fetal growth. Fetal growth restriction (FGR) is observed in ∼10% of pregnancies and is frequently seen in association with other pregnancy complications, such as preeclampsia (PE). FGR is one of the main challenges for obstetricians and pediatricians, as smaller fetuses have greater perinatal risks of morbidity and mortality and postnatal risks of neurodevelopmental and cardio-metabolic disorders.

OBJECTIVE AND RATIONALE

The aim of this review was to examine the importance of placental responses to changing oxygen environments during abnormal pregnancy in terms of cellular, molecular and functional changes in order to highlight new therapeutic pathways, and to pinpoint approaches aimed at enhancing oxygen supply and/or mitigating oxidative stress in the placenta as a mean of optimizing fetal growth.

SEARCH METHODS

An extensive online search of peer-reviewed articles using PubMed was performed with combinations of search terms including pregnancy, placenta, trophoblast, oxygen, hypoxia, high altitude, FGR and PE (last updated in May 2020).

OUTCOMES

Trophoblast differentiation and placental establishment are governed by oxygen availability/hypoxia in early pregnancy. The placental response to late gestational hypoxia includes changes in syncytialization, mitochondrial functions, endoplasmic reticulum stress, hormone production, nutrient handling and angiogenic factor secretion. The nature of these changes depends on the extent of hypoxia, with some responses appearing adaptive and others appearing detrimental to the placental support of fetal growth. Emerging approaches that aim to increase placental oxygen supply and/or reduce the impacts of excessive oxidative stress are promising for their potential to prevent/treat FGR.

WIDER IMPLICATIONS

There are many risks and challenges of intervening during pregnancy that must be considered. The establishment of human trophoblast stem cell lines and organoids will allow further mechanistic studies of the effects of hypoxia and may lead to advanced screening of drugs for use in pregnancies complicated by placental insufficiency/hypoxia. Since no treatments are currently available, a better understanding of placental adaptations to hypoxia would help to develop therapies or repurpose drugs to optimize placental function and fetal growth, with life-long benefits to human health.

Prevention of preeclampsia

Preeclampsia is an obstetric disorder that affects 3-8% of pregnant women and remains a leading cause of short- and long-term neonatal and maternal morbidity and mortality. Professional societies recommend the use of low dose aspirin to prevent preeclampsia in high-risk women. However, interest in prevention of this disease and better understanding of its pathophysiology have led to growing research on other agents. This review focuses on the main therapeutic agents evaluated or in use for preeclampsia prevention.

Hemodynamic Complications in Pregnancy: Preeclampsia and Beyond

Normal pregnancy is a complex and dynamic process that requires significant adaptation from the maternal system. Failure of this adaptive process in pregnancy contributes to many pregnancy related disorders, including the hypertensive disorders of pregnancy. This article discusses placental development and how abnormalities in the process of vascular remodeling contribute to the multisystem maternal and fetal disease that is preeclampsia and fetal growth restriction. We review some of the consequences of this condition on the mother and fetus, aspects of the clinical management of preeclampsia and how it can influence both mother and infant in the postnatal period and beyond.

Hydroxychloroquine as a Preventive and Therapeutic Option in Preeclampsia - a Literature Review

Preeclampsia is one of the most feared complications of pregnancy and puerperium and represents a serious threat to mother and child. In addition, a history of preeclampsia increases the risk of future cardiovascular events. New diagnostic and therapeutic approaches are needed. New therapeutic options are currently being discussed, one of which is the administration of hydroxychloroquine. It is an antimalarial drug which is also used to treat rheumatological disease and its use in pregnancy is considered safe. A reduced incidence of preeclampsia in patients with selected rheumatological disorders after administration of hydroxychloroquine has already been shown; however, the case numbers are very low. Neither the full pathogenesis of preeclampsia nor the exact modes of action of hydroxychloroquine have been completely elucidated, but there are several common features which make hydroxychloroquine a promising option for the prevention and treatment of preeclampsia. Further research, especially prospective, randomized controlled trials, is needed to prove its efficacy. This review discusses the pathogenesis of preeclampsia and gives an overview of new options for its prevention and treatment, including the administration of hydroxychloroquine in pregnancy.

Aspirin enhances trophoblast invasion and represses soluble fms-like tyrosine kinase 1 production: a putative mechanism for preventing preeclampsia

OBJECTIVE

Recent studies suggested that prophylactic aspirin prior to 16 weeks of gestation in high-risk patients may reduce the risk of developing preeclampsia; however, the exact mechanism of aspirin's effect on the pathophysiology of preeclampsia is not clear. This study was designed to investigate the effect of aspirin on trophoblast cell function and its effect on soluble fms-like tyrosine kinase 1 (sFlt-1) production to elucidate the preventive mechanisms for preeclampsia.

METHODS AND RESULTS

We used two human trophoblastic cell lines (HTR-8/SVneo and JAR) and freshly isolated cytotrophoblasts from normal and preeclamptic placenta at term to determine the effect of aspirin on trophoblast cell function. Trophoblasts were pretreated with aspirin, and then cell functions and sFlt-1 expression were assessed. Our results showed that aspirin promoted trophoblast invasion not only in HTR-8/SVneo and JAR cells, but also in isolated cytotrophoblasts. sFlt-1 production was repressed by aspirin in a dose-dependent manner. By adding Flt-1 recombinant protein, the trophoblast invasion ability was inhibited in HTR-8/SVneo cells, which was reversed by Flt-1 small interfering ribonucleic acid knockdown. In addition, metalloproteinase 2/9 expression and activity were activated by aspirin but inhibited by sFlt-1. Aspirin also downregulated Akt phosphorylation, and trophoblast invasiveness was facilitated under Akt inhibitor treatment.

CONCLUSION

Aspirin enhances cell invasiveness and inhibits sFlt-1 production in trophoblasts. Moreover, sFlt-1 itself also inhibits trophoblast invasion. Our novel findings suggest that the preeclampsia prevention effect of aspirin may be exerted through these two mechanisms.

Pre-eclampsia screening in the first trimester - preemptive action to prevent the peril

Pre-eclampsia complicating 2-5% of pregnancies is an obstetrical syndrome associated with deleterious short-and long-term consequences to the gravid women, the fetus and the neonate. Majority of the obstetrical complications occur in early pre-eclampsia (requiring delivery <34 weeks). The risk factor based approach recommended by the professional organizations for pre-eclampsia screening has shown suboptimal clinical performance. The combined multimarker screening for pre-eclampsia encompassing documentation of maternal medical history, measurement of mean arterial pressure, estimation of the maternal serum levels of placental growth factor, pregnancy associated plasma protein-A, and recording the Uterine artery mean pulsatility index, performed in the first trimester between 11 and 13 + 6 weeks has proven to be an effective screening strategy. The a-priori risk is determined by multivariate analysis of the factors from history, while the other parameters are converted to log 10 transformed multiple of median values. Bayes' theorem is used to calculate the final risk. The above model has shown to detect 77% of preterm pre-eclampsia (<37 weeks), 96% of early preterm pre-eclampsia (<34 weeks), 38% of term pre-eclampsia and 54% of all pre-eclampsia, at a false positive rate of 10%. Uterine artery Doppler is key to pre-eclampsia screening. Currently a risk of >1:100 for pre-eclampsia developing before 37 weeks (preterm pre-eclampsia) is regarded as screen positive. Aspirin at a dose of 150 mg at bedtime given to screen positive subjects is associated with a significant reduction of preterm pre-eclampsia and early pre-eclampsia. The intervention is now supported by a well conducted randomized trial and metanalysis data. Aspirin acts by diminishing stores of constitutive cyclooxygenase enzyme in the non-nucleated platelets without disturbing systemic prostaglandin production. Selective use of aspirin in screen positive women is associated with a very low incidence of adverse maternal, fetal and neonatal side effects. The screening protocol can be applied to twin pregnancies albeit minor differences. Hence, screening for pre-eclampsia in first trimester, which is now endorsed by the federation of international obstetrical and gynecological societies, should be offered universally to all women at 11 to 13 + 6 weeks of gestation, followed by the administration of aspirin and serial maternal-fetal surveillance in the screen positive woman.

The effect of antithrombotic therapy on the recurrence of placenta-mediated diseases in pregnancy

Objectives: To analyze the recurrence rate of placenta-mediated diseases (PMDs) such as preeclampsia (PE) and/or intrauterine growth restriction (IUGR), intrauterine fetal death (IUFD), and placental abruption (PA) in high-risk patients on antithrombotic therapy (AT) because of a previous obstetrical history for such complications.Methods: The study group (SG) included 150 patients to whom either 100 mg of aspirin or low-molecular weight heparin (LMWH) was administered due to a previous history of PMDs. The AT in the SG was started before 16 gestational weeks (g.w.). The patients in the first control group (CG-1) were 150 who also had a previous obstetrical history of PMDs, but did not receive antithrombotic therapy (AT) throughout their ongoing pregnancies. The second CG (CG-2) comprised 320 patients with a previous history of normally developing pregnancies and without AT throughout their ongoing pregnancies.Results: The total percentage of PE in pregnant patients from the SG was 25.3% (38/150 patients), with 22.2% (10/45) in the SG on AT only with LDA (SG-LDA group), 25% (17/68) in the SG on AT only with LMWHs (SG-LMWH group) and 29.7% (11/37) in the SG on combined AT with LDA and LMWHs (SG-LDA + LMWH group), as opposed to 18.67% (28/150) in CG-1 and 0.62% (2/320) in CG-2. The recurrent severe PE/total PE ratio in the SG was 44.7% (17/38), with 30% (3/10) in the SG-LDA group, 47% (8/17) in the SG-LMWH group and 54% (6/11) in the SG-LDA + LMWH group, against 75% (21/28) in CG-1. There were no cases with severe PE in CG-2. All cases with recurrent IUGR from the SG were equal to 13.3% (20/150), with 13.3% (6/45) in the SG-LDA group, 11.76% (8/68) in the SG-LMWH group and 16.2% (6/37) in the SG-LDA + LMWH group, as compared to 30% (45/150) in CG-1 and 5% (16/320) in CG-2. As a whole, the overall recurrence rate of PMDs in the SG was 38.67% (58/150), with 35.56% (16/45) in the SG-LDA group, 36.76% (25/68) in the SG-LMWH group and 45.9% (17/37) in the SG-LDA + LMWH group, as compared to 50.67% (76/150) in CG-1 and 5.94% (19/320) in CG-2.Conclusion: AT had a partial beneficial effect on the prophylaxis of recurrent PMDs. On the one hand, AT led to a significant reduction in the recurrent severe PE/total PE ratio, as well as in the total PMDs' recurrence rate in the SG as compared to the one in CG-1. On the other hand, the percentage of recurrent PMDs still remained significantly higher in the SG as compared to CG-2. Pregnant patients with previous PMDs still need close surveillance in subsequent pregnancies as they remain at a high risk for complications.

Does low-dose aspirin initiated before 11 weeks' gestation reduce the rate of preeclampsia?

OBJECTIVE DATA

Preconception or early administration of low-dose aspirin might improve endometrial growth, placental vascularization, and organogenesis. Most studies have evaluated the potential benefit of preconception or early administration of low-dose aspirin in women with a history of recurrent pregnancy loss, women who have undergone in vitro fertilization, or women with thrombophilia or antiphospholipid syndrome. These women are at an increased risk of placenta-associated complications of pregnancy, including preeclampsia, preterm delivery, and fetal growth restriction.

STUDY OUTCOMES

We performed a systematic review and meta-analysis to evaluate the effect of low-dose aspirin initiated at <11 weeks' gestation on the risk of preeclampsia, gestational hypertension, or any hypertensive disorder of pregnancy. Secondary outcomes included preterm delivery at <37 weeks' gestation and fetal growth restriction.

STUDY APPRAISAL AND SYNTHESIS METHODS

We searched in MEDLINE via PubMed, EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL), ClinicalTrials.gov, and the World Health Organization International Clinical Trials Registry Platform from 1985 to November 2018. Entry criteria were randomized controlled trials evaluating the effect of aspirin administered at <11 weeks' gestation in preventing preeclampsia and/or hypertensive disorders in pregnancy or improving pregnancy outcomes in women with recurrent miscarriage as compared with placebo or no treatment and outcome data available or provided by authors for >85% of the study population. Relative risks with 95% confidence intervals were calculated for each study and pooled for global analysis as the effect measure. We assessed statistical heterogeneity in each meta-analysis using the χ² statistics, I², and Tau². Heterogeneity was considered substantial if an I² was greater than 50% and either the Tau² was greater than zero or there was a low P value (<0.10) in the χ² test for heterogeneity. Random-effects meta-analysis, weighted by the size of the studies, was performed to produce an overall summary on aspirin effect for each outcome. Sensitivity analysis by sequential omission of each individual study and by fixed-effects model was performed. Publication bias was not assessed because of the small number of included studies. Statistical analysis was performed using Stata release 14.0 (StataCorp).

RESULTS

The entry criteria were fulfilled by 8 randomized controlled trials on a combined total of 1426 participants. Low-dose aspirin initiated at <11 weeks' gestation was associated with a nonsignificant reduction in the risk of preeclampsia (relative risk, 0.52; 95% confidence interval, 0.23-1.17, P = .115), gestational hypertension (relative risk, 0.49; 95% confidence interval, 0.20-1.21; P = .121), and any hypertensive disorder of pregnancy (relative risk, 0.59; 95% confidence interval, 0.33-1.04, P = .067). Early administration of low-dose aspirin reduced the risk of preterm delivery (relative risk, 0.52; 95% confidence interval, 0.27-0.97, P = .040) but had no impact on the risk of fetal growth restriction (relative risk, 1.10; 95% confidence interval, 0.58-2.07, P = .775). Except for preterm delivery and any hypertensive disorder of pregnancy, sensitivity analysis demonstrated similar observations, therefore confirming the robustness of the analysis.

CONCLUSION

The administration of low-dose aspirin at <11 weeks' gestation in women at high risk does not decrease the risk of preeclampsia, gestational hypertension, any hypertensive disorder of pregnancy, and fetal growth restriction. However, it might reduce the risk of preterm delivery. Larger randomized controlled trials will be required to substantiate the findings.

Novel Interventions for the Prevention of Preeclampsia

PURPOSE OF REVIEW

To review the rationale and biological plausibility and discuss the current research on novel interventions for the prevention of preeclampsia.

RECENT FINDINGS

Preeclampsia affects up to 8% of pregnancies worldwide and remains a major cause of maternal and neonatal morbidity and mortality. Multiple medications have been investigated or repurposed as potential effective interventions for preeclampsia prevention. Aspirin is currently the only drug for which there is some evidence of benefit for preeclampsia prevention, and its use is recommended by professional societies for pregnancies at risk. Statins have shown promise for prevention of preeclampsia in animal models and human pilot studies, without any trend or concerns for safety signals or teratogenicity. The use of metformin has also gained popularity in experimental studies, but observations from randomized clinical trials were not consistent on its utility as a possible intervention for preeclampsia prevention. While initial studies evaluating esomeprazole were promising, randomized trials failed to show benefit. Contemporary research shows exciting new opportunities for prophylactic treatment for preeclampsia, to prevent this debilitating and life-threatening disease.

Aspirin for prevention of preeclampsia and fetal growth restriction

For the past decades, growing attention has been given to aspirin use during pregnancy. It favors placentation by its proangiogenic, antithrombotic, and anti-inflammatory effects. Therefore, low doses of aspirin are prescribed in the prevention of placenta-mediated complications, mainly preeclampsia and fetal growth restriction. However, questions regarding its clinical application are still debated. Aspirin is effective in preventing preeclampsia in a high-risk population. Most guidelines recommend that risk stratification should rely on medical history. Nevertheless, screening performances dramatically improve if biochemical and biophysical markers are included. Concerning the appropriate timing and dose, latest studies suggest aspirin should be started before 16 weeks of pregnancy and at a daily dose of 100 mg or more. Further studies are needed to improve the identification of patients likely to benefit from prophylactic aspirin. Besides, the role of aspirin in the prevention of fetal growth restriction is still questioned.

The intervention effect of aspirin on a lipopolysaccharide-induced preeclampsia-like mouse model by inhibiting the nuclear factor-κB pathway

Preeclampsia is a severe pregnancy-related disorder, and patients usually present with high circulating inflammatory factor levels and excessive activation of the nuclear factor-κB (NF-κB) pathway. Administration of aspirin (ASP) is effective for preventing preeclampsia, and thus, we propose that ASP might affect placental function by regulating the NF-κB pathway. Systemic lipopolysaccharide (LPS) (20 μg/kg) was used to induce preeclampsia-like pregnant mouse model, and low-dose ASP (15.2 mg/kg) was administrated. Here, we report significantly increased circulatory expression levels of the proinflammatory cytokines tumor necrosis factor-alpha, interleukin-6, and soluble Fms-related tyrosine kinase-1 in LPS-treated pregnant mice, accompanied by kidney and placental dysfunction. Low-dose ASP treatment significantly reversed the preeclampsia-like phenotype, lowering hypertension, decreasing proteinuria, and ameliorating fetal growth retardation. Moreover, the excessive activation of NF-κB signaling in mice placentae induced by LPS was significantly reduced by ASP. In JEG-3 cells, LPS activated the NF-κB signaling pathway by upregulating the expression of cyclooxygenase-2 (COX-2) and related inflammatory factors, whereas the invasion ability of JEG-3 cells was weakened. However, ASP administration impeded NF-κB signaling activation, downregulated COX-2 and inflammatory factor expression, and rescued trophoblast invasion. This study provides new evidence that low-dose ASP is beneficial for preeclampsia prevention by inhibiting NF-κB and its downstream signaling pathways in trophoblast cells.

Aspirin for the prevention and treatment of pre-eclampsia: A matter of COX-1 and/or COX-2 inhibition?

Since the 1970s, we have known that aspirin can reduce the risk of pre‐eclampsia. However, the underlying mechanisms explaining this risk reduction are poorly understood. Both cyclooxygenase (COX)‐1‐ and COX‐2‐dependent effects might be involved. As a consequence of this knowledge hiatus, the optimal dose and timing of initiation of aspirin therapy are not clear. Here, we review how (COX‐1 versus COX‐2 inhibition) and when (prevention versus treatment) aspirin therapy may interfere with the mechanisms implicated in the pathogenesis of pre‐eclampsia. The available evidence suggests that both COX‐1‐ and COX‐2‐dependent effects play important roles in the early stage of aberrant placental development and in the next phase leading to the clinical syndrome of pre‐eclampsia. Collectively, these data suggest that high‐dose (dual COX inhibition) aspirin may be superior to standard low‐dose (selective COX‐1 inhibition) aspirin for the prevention and also treatment of pre‐eclampsia. Therefore, we conclude that more functional and biochemical tests are needed to unravel the contribution of prostanoids in the mechanisms implicated in the pathogenesis of pre‐eclampsia and the potential of dual COX and/or selective COX‐2 inhibition for the prevention and treatment of pre‐eclampsia. This information is vital if we are to deduce the suitability, optimal timing and dose of aspirin and/or a specific COX‐2 inhibitor (most likely using modified forms that do not cross the placenta) that can then be tested in a randomized, controlled trial instead of the current practice of empirical dosing regimens.

Effect of Low-Dose Aspirin on Soluble FMS-Like Tyrosine Kinase 1/Placental Growth Factor (sFlt-1/PlGF Ratio) in Pregnancies at High Risk for the Development of Preeclampsia

BACKGROUND

Soluble FMS-like Tyrosine Kinase 1 (sFlt-1) and placental growth factor (PlGF) have been reported to be highly predictive several weeks before the onset of preeclampsia.

OBJECTIVE

To investigate longitudinal changes of serum levels sFlt-1 and PlGF in pregnant women at high risk for the development of preeclampsia and to reveal an impact of aspirin on maternal serum concentrations of sFlt-1 and PlGF.

METHODS

This was a prospective longitudinal study in 394 women with various risk factors for the development of preeclampsia (chronic hypertension, antiphospholipid syndrome/APS or systemic lupus erythematosus/SLE, thrombophilia, women with a history of preeclampsia, pathologic first trimester screening for preeclampsia) and 68 healthy women. Serum levels of sFlt-1 and PlGF were measured prospectively at 4-week intervals (from gestational weeks 12 until postpartum).

RESULTS

The sFlt-1/PlGF ratio was significantly higher in women with an adverse obstetric outcome compared to women with a normal pregnancy, starting between 20 and 24 weeks of gestation. There was no effect of aspirin on sFlt-1/PlGF ratio in women with chronic hypertension, APS/SLE, thrombophilia and controls. The use of aspirin showed a trend towards an improvement of the sFlt-1/PlGF ratio in women with preeclampsia in a previous pregnancy and a significant effect on the sFlt-1/PlGF ratio in women with a pathologic first trimester screening for preeclampsia.

CONCLUSIONS

Our findings reveal an impact of aspirin on sFlt-1/PlGF ratio in women with a pathologic first trimester screening for preeclampsia, strongly supporting its prophylactic use.

Molecular Targets of Aspirin and Prevention of Preeclampsia and Their Potential Association with Circulating Extracellular Vesicles during Pregnancy

Uncomplicated healthy pregnancy is the outcome of successful fertilization, implantation of embryos, trophoblast development and adequate placentation. Any deviation in these cascades of events may lead to complicated pregnancies such as preeclampsia (PE). The current incidence of PE is 2–8% in all pregnancies worldwide, leading to high maternal as well as perinatal mortality and morbidity rates. A number of randomized controlled clinical trials observed the association between low dose aspirin (LDA) treatment in early gestational age and significant reduction of early onset of PE in high-risk pregnant women. However, a substantial knowledge gap exists in identifying the particular mechanism of action of aspirin on placental function. It is already established that the placental-derived exosomes (PdE) are present in the maternal circulation from 6 weeks of gestation, and exosomes contain bioactive molecules such as proteins, lipids and RNA that are a “fingerprint” of their originating cells. Interestingly, levels of exosomes are higher in PE compared to normal pregnancies, and changes in the level of PdE during the first trimester may be used to classify women at risk for developing PE. The aim of this review is to discuss the mechanisms of action of LDA on placental and maternal physiological systems including the role of PdE in these phenomena. This review article will contribute to the in-depth understanding of LDA-induced PE prevention.

Preeclampsia: Maternal Systemic Vascular Disorder Caused by Generalized Endothelial Dysfunction Due to Placental Antiangiogenic Factors

Preeclampsia, a systemic vascular disorder characterized by new-onset hypertension and proteinuria after 20 weeks of gestation, is the leading cause of maternal and perinatal morbidity and mortality. Maternal endothelial dysfunction caused by placental factors has long been accepted with respect to the pathophysiology of preeclampsia. Over the past decade, increased production of placental antiangiogenic factors has been identified as a placental factor leading to maternal endothelial dysfunction and systemic vascular dysfunction. This review summarizes the recent advances in understanding the molecular mechanisms of endothelial dysfunction caused by placental antiangiogenic factors, and the novel clinical strategies based on these discoveries.

Low-dose aspirin reduces hypoxia-induced sFlt1 release via the JNK/AP-1 pathway in human trophoblast and endothelial cells

Pre-eclampsia (PE) is a serious hypertensive disorder of pregnancy that remains a leading cause of perinatal and maternal morbidity and mortality worldwide. Placental ischemia/hypoxia and the secretion of soluble fms-like tyrosine kinase 1 (sFlt1) into maternal circulation are involved in the pathogenesis of PE. Although low-dose aspirin (LDA) has beneficial effects on the prevention of PE, the exact mechanisms of action of LDA, particularly on placental dysfunction, and sFlt1 release, have not been well investigated. This study aimed to determine whether LDA exists the protective effects on placental trophoblast and endothelial functions and prevents PE-associated sFlt1 release. First, we observed that LDA mitigated hypoxia-induced trophoblast apoptosis, showed positive effects on trophoblast cells migration and invasion activity, and increased the tube-forming activity of human umbilical vein endothelial cells (HUVECs). In addition, LDA decreased hypoxia-induced sFlt1 production, and the c-Jun NH₂ -terminal kinase/activator protein-1 (JNK/AP-1) pathway was shown to mediate the induction of sFlt1. Moreover, the transcription factor AP-1 was confirmed to regulate the Flt1 gene expression by directly binding to the Flt1 promoter in luciferase assays. The result of chromatin immunoprecipitation assays further demonstrated that LDA could directly decrease the expression of the transcription factor AP-1, and thus decrease sFlt1 production. Finally, the effects of LDA on sFlt1 production were proved in human placental explants. Taken together, our data show the protective effects of LDA against trophoblast and endothelial cell dysfunction and reveal that the LDA-mediated inhibition of sFlt1 via the JNK/AP-1 pathway may be a potential cellular/molecular mechanism for the prevention of PE.

[Aspirin and preeclampsia]

Indications for aspirin during pregnancy are a matter of debate and there is a recent trend to an extended prescription and an overuse of aspirin in pregnancy. Aspirin is efficient in secondary prevention of preeclampsia essentially in patients with a personal history of preeclampsia. The effect of aspirin on platelet aggregation and on the TXA2/PGI2 balance is dose-dependent. The optimum dosage, from 75mg/day to 150mg/day, needs to be determined. Fetal safety data at 150mg/day are still limited. The efficacy of aspirin seems to be subject to a chronobiological effect. It is recommended to prescribe an evening or bedtime intake. Aspirin, in primary prevention of preeclampsia, given to high-risk patients identified in the first trimester by screening tests, seems to reduce the occurrence of early-onset preeclampsia. Nevertheless, there are insufficient data for the implementation of such screening procedures in practice.

Low-dose aspirin in the prevention of pre-eclampsia in China (APPEC study): protocol for a multicentre randomized controlled trial

BACKGROUND

Low-dose aspirin (LDA) has been proposed as a safe and inexpensive prophylactic agent. Studies in European/Western populations have shown promising results indicating that LDA can reduce the occurrence of pre-eclampsia (PE) in women with identifiable risk factors. However, few controlled trials, particularly large randomized controlled trials, have been performed in Asian populations. The aim of this project is to evaluate the effect of LDA for PE prevention on high-risk pregnant women in China, where PE is highly prevalent and the LDA supply status is commonly suboptimal.

METHODS/DESIGN

An open-label, multicentre randomized controlled trial is being conducted at 13 tertiary hospitals in 11 provinces in China. A total of 1000 eligible women with high-risk factors for developing PE according to their medical histories are being randomized into two groups: a control group (n = 500) and an intervention group (n = 500). Women with high-risk factors, such as a history of PE, chronic hypertension, type 1 or 2 diabetes, advanced maternal age, obesity, family history of PE or nulliparity are eligible. The control group is advised to undergo routine examinations, whereas the intervention group undergoes the routine examinations and receives LDA. LDA (100 mg/d) should be prescribed at night, initiating from early pregnancy (12-20 weeks of gestation) and lasting until 34 weeks of gestation. Demographic data and clinical endpoint outcomes, as well as biological samples (e.g., maternal blood, cord blood, amniotic fluid and placental samples), will be collected. The primary outcome is the occurrence of PE, and the secondary outcomes include maternal and neonatal outcomes and maternal biomarker levels.

DISCUSSION

This is the first and largest multicentre randomized controlled trial to assess the effect of LDA in preventing PE in a Chinese population. The results will potentially influence the prenatal care recommendations in China regarding intervention with LDA for PE.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02797249 . Registered on 7 June 2016.

A prophylactic low-dose aspirin earlier than 12 weeks until delivery should be considered to prevent preeclampsia

Clinical trials and meta-analyses have demonstrated that low-dose aspirin can reduce the risk of preeclampsia and fetal growth restriction in high-risk pregnant women. Current obstetric guidelines recommend that the administration of low-dose aspirin to prevent preeclampsia be initiated after 12 weeks' gestation. This starting time was chosen to minimize possible risks of maternal bleeding and fetal anomalies. However, evidence from reproductive medicine, where low-dose aspirin is commonly recommended to use before and in early pregnancy, as well as existing literature, does not support these concerns. On the other hand, defective placentation resulting in a subsequent ischemic placenta is considered as the starting point of preeclampsia. Low-dose aspirin initiated in early pregnancy can balance the levels of thromboxane A₂ and prostacyclin and maintain adequate uteroplacental blood flow and, therefore, improve placentation. Thus, an initiation of low-dose aspirin earlier than 12 weeks can be considered. Meanwhile, evidence shows that low-dose aspirin can improve maternal vascular endothelial function without increasing the risks of adverse maternal and perinatal outcomes. Therefore, it appears safe to use low-dose aspirin as a prophylactic until delivery.

Positive and Negative Regulation of Angiogenesis by Soluble Vascular Endothelial Growth Factor Receptor-1

Vascular endothelial growth factor receptor (VEGFR)-1 exists in different forms, derived from alternative splicing of the same gene. In addition to the transmembrane form, endothelial cells produce a soluble VEGFR-1 (sVEGFR-1) isoform, whereas non-endothelial cells produce both sVEGFR-1 and a different soluble molecule, known as soluble fms-like tyrosine kinase (sFlt)1-14. By binding members of the vascular endothelial growth factor (VEGF) family, the soluble forms reduce the amounts of VEGFs available for the interaction with their transmembrane receptors, thereby negatively regulating VEGFR-mediated signaling. In agreement with this activity, high levels of circulating sVEGFR-1 or sFlt1-14 are associated with different pathological conditions involving vascular dysfunction. Moreover, sVEGFR-1 and sFlt1-14 have an additional role in angiogenesis: they are deposited in the endothelial cell and pericyte extracellular matrix, and interact with cell membrane components. Interaction of sVEGFR-1 with &alpha;5&beta;1 integrin on endothelial cell membranes regulates vessel growth, triggering a dynamic, pro-angiogenic phenotype. Interaction of sVEGFR-1/sFlt1-14 with cell membrane glycosphingolipids in lipid rafts controls kidney cell morphology and glomerular barrier functions. These cell⁻matrix contacts represent attractive novel targets for pharmacological intervention in addition to those addressing interactions between VEGFs and their receptors.

The effect of low-dose aspirin on serum placental growth factor levels in a high-risk PREDO cohort

OBJECTIVES

Our first aim was to study the longitudinal changes of serum placental growth factor (PlGF) concentration between 12⁺⁰ and 28⁺⁰ weeks of gestation in the prospective PREDO cohort. Our second aim was to study the effect of low-dose acetylsalicylic acid (LDA; 100 mg/day), started before the 14th week of gestation, on PlGF concentration.

STUDY DESIGN

Blood samples were collected at 12⁺⁰-14⁺⁰, 18⁺⁰-20⁺⁰ and 26⁺⁰-28⁺⁰ weeks of gestation in 101 women without and 309 with clinical risk factors for pre-eclampsia. Risk-women were divided into two groups: to those who had medium risk for pre-eclampsia and to those who had high risk for pre-eclampsia. Finally there were seven groups according to risk, treatment (no prevention/placebo/LDA) and outcome measure pre-eclampsia. Longitudinal changes in the PlGF concentration between groups were compared. To investigate the effect of LDA on serum PlGF concentration, placebo (N = 62) and LDA (N = 61) groups were compared. A repeated measures ANOVA was used to analyze differences in PlGF levels between the groups.

RESULTS

The increase in serum PlGF concentration was higher in LDA than in placebo group (time × group effect, p = 0.046). The increase in serum PlGF concentration during pregnancy was lower in high-risk women who had placebo and developed pre-eclampsia and in medium-risk women who developed pre-eclampsia compared to the other women (time × group effect, p < 0.001). There were no differences in PlGF change between low-risk women, medium-risk women who did not develop pre-eclampsia, high-risk women in the placebo group without pre-eclampsia and high-risk women in the LDA group with and without pre-eclampsia (p = 0.15).

CONCLUSIONS

Our finding suggests an association between LDA started before 14 weeks of gestation and higher increase in serum PlGF concentration.

Impact of particulate matter on mothers and babies in Antwerp (IPANEMA): a prospective cohort study on the impact of pollutants and particulate matter in pregnancy

INTRODUCTION

Air pollution is a hot topic and is known to cause multiple health issues. Especially pregnant women seem to be vulnerable to environmental issues. There are data suggesting that exposure contributes to hypertensive disorders.This study aims to evaluate the effects of exposure to particulate matter (PM) and outdoor air pollutants on the clinical pregnancy outcome for mother and child and to determine which biochemical changes in maternal, placental and cord blood best explain this effect.

METHODS AND ANALYSIS

This study is a prospective cohort study. We aim to recruit 200 pregnant women. The outcome measurements will include maternal parameters, labour parameters and neonatal parameters.Multiple samples will be analysed such as maternal urine samples (8-oxo-deoxyguanosine), maternal blood samples (routine blood sampling, biomarkers of pre-eclampsia and transcript markers), maternal hair samples, neonatal blood samples (transcript markers) combined with extensive questionnaires.

ETHICS AND DISSEMINATION

We obtain informed consent from each participant prior to enrolment in the study.The study has received approval by the Ethical Committee of the Antwerp University Hospital (14/40/411).IPANEMA is the first prospective study to assess the impact of PM on mothers and babies in Antwerp, Belgium.Findings from this study will contribute to improve knowledge on the impact of exposure to air pollution on mothers and babies and will also define biomarkers as predictors for pregnant women at risk.

TRIAL REGISTRATION

ClinicalTrials.gov: 14/40/411. Registered 22-10-2015.

Placental-specific sFLT-1: role in pre-eclamptic pathophysiology and its translational possibilities for clinical prediction and diagnosis

Pre-eclampsia is a common obstetric complication globally responsible for a significant burden of maternal and perinatal morbidity and mortality. Central to its pathophysiology is the anti-angiogenic protein, soluble fms-like tyrosine kinase-1 (sFLT-1). sFLT-1 is released from a range of tissues into the circulation, where it antagonizes the activity of vascular endothelial growth factor and placental growth factor leading to endothelial dysfunction. It is this widespread endothelial dysfunction that produces the clinical features of pre-eclampsia including hypertension and proteinuria. There are multiple splice variants of sFLT-1. One, known as sFLT-1 e15a, evolved quite recently and is only present in humans and higher order primates. This sFLT-1 variant is also the main sFLT-1 secreted from the placenta. Recent work has shown that sFLT-1 e15a is significantly elevated in the placenta and circulation of women with pre-eclampsia. It is also biologically active, capable of causing endothelial dysfunction and the end-organ dysfunction seen in pre-eclampsia. Indeed, the over-expression of sFLT-1 e15a in mice recapitulates the pre-eclamptic phenotype in pregnancy. Therefore, here we propose that sFLT-1 e15a may be the sFLT-1 variant primarily responsible for pre-eclampsia, a uniquely human disease. Furthermore, this placental-specific sFLT-1 variant provides promise for use as an accurate biomarker in the prediction or diagnosis of pre-eclampsia.