Spiral artery remodeling and maternal cardiovascular risk: the spiral artery remodeling (SPAR) study

Prevalence of placental bed spiral artery pathology in preeclampsia and fetal growth restriction: A prospective cohort study

BACKGROUND

Preeclampsia and fetal growth restriction (PE/FGR) are pregnancy complications known to be associated with poor utero-placental function due to abnormal "physiological" remodeling of spiral arteries and unfavorable maternal cardiovascular health. However, the prevalence and degree of impaired spiral artery remodeling has not been clearly established.

METHOD

Prospective, multi-center observational cohort study to assess the prevalence of lesions associated with abnormal development of spiral arteries in placental bed biopsies systematically obtained from 121 women undergoing Caesarian section for PE/FGR compared with a reference group of 149 healthy controls.

RESULTS

PE/FGR was associated with a high prevalence of impaired spiral artery remodeling compared with controls (63.6 vs 10.1 %, p < 0.001), and a higher prevalence of non-remodeled spiral arteries without the presence of intramural trophoblast (45.5 vs 6.7 %, p < 0.001), despite abundant interstitial trophoblast invasion in surrounding decidua and myometrium. Normal remodeling was associated with circumferential presence of intramural trophoblast and hardly any trophoblast in surrounding tissue. Acute atherosis (28.9 vs 3.4 %, p < 0.001) and thrombosis (16.5 vs 5.4 %, p = 0.003) lesions were significantly more prevalent in PE/FGR. Impaired remodeling, acute atherosis and thrombosis lesions were equally present in both decidual and myometrial segments of the spiral arteries in both groups. Impaired remodeling was most prominent in the groups with FGR (with or without PE) and thrombosis was most often seen in the group with PE and FGR.

CONCLUSION

PE/FGR is associated with a high prevalence of impaired physiological remodeling and vascular lesions of the uterine spiral arteries in the placental bed.

Overexpressed Trophoblast Glycoprotein Contributes to Preeclampsia Development by Inducing Abnormal Trophoblast Migration and Invasion Toward the Uterine Spiral Artery

BACKGROUND

Preeclampsia is a significant pregnancy disorder with an unknown cause, mainly attributed to impaired spiral arterial remodeling.

METHODS

Using RNA sequencing, we identified key genes in placental tissues from healthy individuals and preeclampsia patients. Placenta and plasma samples from pregnant women were collected to detect the expression of TPBG (trophoblast glycoprotein). Pregnant rats were injected with TPBG-carrying adenovirus to detect preeclamptic features. HTR-8/SVneo cells transfected with a TPBG overexpression lentiviral vector were used in cell function experiments. The downstream molecular mechanisms of TPBG were explored using RNA sequencing and single-cell RNA sequencing data. TPBG expression was knocked down in the lipopolysaccharide-induced preeclampsia-like rat model to rescue the preeclampsia features. We also assessed TPBG's potential as an early preeclampsia predictor using clinical plasma samples.

RESULTS

TPBG emerged as a crucial differentially expressed gene, expressed specifically in syncytiotrophoblasts and extravillous trophoblasts. Subsequently, we established a rat model with preeclampsia-like phenotypes by intravenously injecting TPBG-expressing adenoviruses, observing impaired spiral arterial remodeling, thus indicating a causal correlation between TPBG overexpression and preeclampsia. Studies with HTR-8/SVneo cells, chorionic villous explants, and transwell assays showed TPBG overexpression disrupts trophoblast/extravillous trophoblast migration/invasion and chemotaxis. Notably, TPBG knockdown alleviated the lipopolysaccharide-induced preeclampsia-like rat model. We enhanced preeclampsia risk prediction in early gestation by combining TPBG expression with established clinical predictors.

CONCLUSIONS

These findings are the first to show that TPBG overexpression contributes to preeclampsia development by affecting uterine spiral artery remodeling. We propose TPBG levels in maternal blood as a predictor of preeclampsia risk. The proposed mechanism by which TPBG overexpression contributes to the occurrence of preeclampsia via its disruptive effect on trophoblast and extravillous trophoblast migration/invasion on uterine spiral artery remodeling, thereby increasing the risk of preeclampsia.

Impact of ferroptosis on preeclampsia: A review

Preeclampsia (PE) is usually associated with the accumulation of reactive oxygen species (ROS) resulting from heightened oxidative stress (OS). Ferroptosis is a unique type of lipid peroxidation-induced iron-dependent cell death distinct from traditional apoptosis, necroptosis, and pyroptosis and most likely contributes considerable to PE pathogenesis. At approximately 10-12 weeks of gestation, trophoblasts create an environment rich in oxygen and iron. In patients with PE, ferroptosis-related genes such as HIF1 and MAPK8 are downregulated, whereas PLIN2 is upregulated. Furthermore, miR-30b-5p overexpression inhibits solute carrier family 11 member 2, resulting in a decrease in glutathione levels and an increase in the labile iron pool. At the maternal-fetal interface, physiological hypoxia/reperfusion and excessive iron result in lipid peroxidation and ROS production. Owing to the high expression of Fpn and polyunsaturated fatty acid-containing phospholipid-related enzymes, including acyl-CoA synthetase long-chain family member 4, lysophosphatidylcholine acyl-transferase 3, and spermidine/spermine N1-acetyltransferase 1, trophoblasts become more susceptible to OS and ROS damage. In stage 1, the injured trophoblasts exhibit poor invasion and incomplete uterine spiral artery remodeling caused by ferroptosis, leading to placental ischemia and hypoxia. Subsequently, ferroptosis marked by OS occurs in stage 2, eventually causing PE. We aimed to explore the new therapeutic target of PE through OS in ferroptosis.

Hypertensive disorders of pregnancy in moyamoya disease: A single institution experience

OBJECTIVE

The characteristics of pregnancy and delivery in patients with moyamoya disease (MMD) remain unclear. We retrospectively investigated perinatal outcomes in patients with MMD to evaluate the risks associated to this condition.

MATERIALS AND METHODS

Clinical data of women with MMD who delivered at the University of Tokyo Hospital between 2000 and 2021 were collected. Maternal characteristics including genetic data, obstetric complications, method of delivery and anesthesia, neonatal outcomes, neurological events during pregnancy, delivery, and postpartum course, were reviewed.

RESULTS

Thirteen pregnancies with MMD were identified. The median maternal age was 30 years. The initial clinical symptoms were identified as transient ischemic attack, infarction, and headache. Eight patients had a history of bypass surgery. The median gestational age at delivery was 37 weeks. DNA samples were collected from five patients, responsible for six pregnancies. Of these six cases, five had the RNF213 c.14429G > A (p.Arg4810Lys) heterozygous variant. Of the 13 pregnancies, seven had hypertensive disorder of pregnancy (HDP). Additionally, three of five pregnancy cases with RNF213 p.Arg4810Lys heterozygous variant presented with HDP. Nine patients underwent cesarean section, and four delivered vaginally with epidural anesthesia. One case of ischemic stroke was confirmed during the postpartum period. Regarding newborns, neither Apgar scores lower than 7 nor neonatal intensive care unit admissions were reported.

CONCLUSIONS

This study suggests that the frequency of HDP is higher in patients with MMD compared to those with normal pregnancies. Strict blood pressure control should be performed in patients with MMD during pregnancy and postpartum period.

Ferritin light chain deficiency-induced ferroptosis is involved in preeclampsia pathophysiology by disturbing uterine spiral artery remodelling

The proteomic analysis from samples of patients with preeclampsia (PE) displayed a low level of ferritin light chains (FTL), but we do not know what the significance of reduced FTL in PE pathophysiology is. To address this question, we first demonstrated that FTL was expressed in first- and third-trimester cytotrophoblasts, including extravillous trophoblasts (EVTs), of the human placenta. Furthermore, a pregnant rat model of FTL knockdown was successfully established by intravenously injecting adenoviruses expressing shRNA targeting FTL. In pregnant rats with downregulated FTL, we observed PE-like phenotypes and impaired spiral arterial remodelling, implying a causal relationship between FTL downregulation and PE. Blocking ferroptosis with ferrostatin-1 (Fer-1) significantly rescued the above PE-like phenotypes in pregnant rats with FTL knockdown. Furthermore, using trophoblast cell line and chorionic villous explant culture assays, we showed that FTL downregulation induced cell death, especially ferroptosis, resulting in defective uterine spiral artery remodelling. Eventually, this conclusion from the animal model was verified in PE patients' placental tissues. Taken together, this study revealed for the first time that FTL reduction during pregnancy triggered ferroptosis and then caused defective uterine spiral artery remodelling, thereby leading to PE.

Differential affinity chromatography reveals a link between Porphyromonas gingivalis-induced changes in vascular smooth muscle cell differentiation and the type 9 secretion system

Porphyromonas gingivalis is implicated in adverse pregnancy outcome. We previously demonstrated that intrauterine infection with various strains of P. gingivalis impairs the physiologic remodeling of the uterine spiral arteries (IRSA) during pregnancy, which underlies the major obstetrical syndromes. Women diagnosed with IRSA also have a greater risk for premature cardiovascular disease in later life. The dysregulated plasticity of vascular smooth muscle cells (VSMCs) is present in both IRSA and premature cardiovascular events. We hypothesized that VSMCs could serve as a bait to identify P. gingivalis proteins associated with dysregulated VSMC plasticity as seen in IRSA. We first confirmed that dams with P. gingivalis A7UF-induced IRSA also show perturbed aortic smooth muscle cell (AoSMC) plasticity along with the P. gingivalis colonization of the tissue. The in vitro infection of AoSMCs with IRSA-inducing strain A7UF also perturbed AoSMC plasticity that did not occur with infection by non-IRSA-inducing strain W83. Far-Western blotting with strain W83 and strain A7UF showed a differential binding pattern to the rat aorta and primary rat AoSMCs. The affinity chromatography/pull-down assay combined with mass spectrometry was used to identify P. gingivalis/AoSMC protein interactions specific to IRSA. Membrane proteins with a high binding affinity to AoSMCs were identified in the A7UF pull-down but not in the W83 pull-down, most of which were the outer membrane components of the Type 9 secretion system (T9SS) and T9SS cargo proteins. Additional T9SS cargo proteins were detected in greater abundance in the A7UF pull-down eluate compared to W83. None of the proteins enriched in the W83 eluate were T9SS components nor T9SS cargo proteins despite their presence in the prey preparations used in the pull-down assay. In summary, differential affinity chromatography established that the components of IRSA-inducing P. gingivalis T9SS as well as its cargo directly interact with AoSMCs, which may play a role in the infection-induced dysregulation of VSMC plasticity. The possibility that the T9SS is involved in the microbial manipulation of host cell events important for cell differentiation and tissue remodeling would constitute a new virulence function for this system.

Porphyromonas gingivalis-mediated disruption in spiral artery remodeling is associated with altered uterine NK cell populations and dysregulated IL-18 and Htra1

Impaired spiral artery remodeling (IRSA) underpins the great obstetrical syndromes. We previously demonstrated that intrauterine infection with the periodontal pathogen, Porphyromonas gingivalis, induces IRSA in rats. Since our previous studies only examined the end stage of arterial remodeling, the aim of this study was to identify the impact of P. gingivalis infection on the earlier stages of remodeling. Gestation day (GD) 11 specimens, a transition point between trophoblast-independent remodeling and the start of extravillous trophoblast invasion, were compared to late stage GD18 tissues. P. gingivalis was found in decidual stroma of GD11 specimens that already had reduced spiral artery remodeling defined as smaller arterial lumen size, increased retention of vascular smooth muscle, and decreased invasion by extravillous trophoblasts. At GD11, P. gingivalis-induced IRSA coincided with altered uterine natural killer (uNK) cell populations, decreased placental bed expression of interleukin-18 (IL-18) with increased production of temperature requirement A1 (Htra1), a marker of oxidative stress. By GD18, placental bed IL-18 and Htra1 levels, and uNK cell numbers were equivalent in control and infected groups. However, infected GD18 placental bed specimens had decreased TNF + T cells. These results suggest disturbances in placental bed decidual stroma and uNK cells are involved in P. gingivalis-mediated IRSA.

Failure of physiological transformation and spiral artery atherosis: their roles in preeclampsia

Physiological transformation with remodeling of the uteroplacental spiral arteries is key to a successful placentation and normal placental function. It is an intricate process that involves, but is not restricted to, complex interactions between maternal decidual immune cells and invasive trophoblasts in the uterine wall. In normal pregnancy, the smooth muscle cells of the arterial tunica media of uteroplacental spiral arteries are replaced by invading trophoblasts and fibrinoid, and the arterial diameter increases 5- to 10-fold. Poor remodeling of the uteroplacental spiral arteries is linked to early-onset preeclampsia and several other major obstetrical syndromes, including fetal growth restriction, placental abruption, and spontaneous preterm premature rupture of membranes. Extravillous endoglandular and endovenous trophoblast invasions have recently been put forth as potential contributors to these syndromes as well. The well-acknowledged disturbed extravillous invasion of maternal spiral arteries in preeclampsia is summarized, as are briefly novel concepts of disturbed extravillous endoglandular and endovenous trophoblast invasions. Acute atherosis is a foam cell lesion of the uteroplacental spiral arteries associated with poor remodeling. It shares some morphologic features with early stages of atherosclerosis, but several molecular differences between these lesions have also recently been revealed. Acute atherosis is most prevalent at the maternal-fetal interface, at the tip of the spiral arteries. The localization of acute atherosis downstream of poorly remodeled arteries suggests that alterations in blood flow may trigger inflammation and foam cell development. Acute atherosis within the decidua basalis is not, however, confined to unremodeled areas of spiral arteries or to hypertensive disorders of pregnancy and may even be present in some clinically uneventful pregnancies. Given that foam cells of atherosclerotic lesions are known to arise from smooth muscle cells or macrophages activated by multiple types of inflammatory stimulation, we have proposed that multiple forms of decidual vascular inflammation may cause acute atherosis, with or without poor remodeling and/or preeclampsia. Furthermore, we propose that acute atherosis may develop at different gestational ages, depending on the type and degree of the inflammatory insult. This review summarizes the current knowledge of spiral artery remodeling defects and acute atherosis in preeclampsia. Some controversies will be presented, including endovascular and interstitial trophoblast invasion depths, the concept of 2-stage trophoblast invasion, and whether the replacement of maternal spiral artery endothelium by fetal endovascular trophoblasts is permanent. We will discuss the role of acute atherosis in the pathophysiology of preeclampsia and short- and long-term health correlates. Finally, we suggest future opportunities for research on this intriguing uteroplacental interface between the mother and fetus.

Maternal Vascular Lesions in the Placenta Predict Vascular Impairments a Decade After Delivery

Women with adverse pregnancy outcomes later experience excess hypertension and cardiovascular disease, but how the events are linked is unknown. Examination of the placenta may provide clues to vascular impairments after delivery. Maternal vascular malperfusion lesions (MVMs) were abstracted from clinical reports, validated and characterized using clinical guidelines and severity score. A total of 492 women (170 with MVMs and 322 without MVMs) participated in a study visit 8 to 10 years after delivery to assess blood pressure, cardiometabolic factors, and sublingual microvascular features using sidestream dark field imaging. Covariates included age, race, adverse pregnancy outcomes (preeclampsia, small for gestational age, and preterm birth), and health behaviors. Women with versus without MVM had a distinct sublingual microvascular profile comprised of (1) lower microvascular density (-410 μm/mm², P=0.015), (2) higher red blood cell filling as a marker of perfusion (2%, P=0.004), and (3) smaller perfused boundary region (-0.07 µm, P=0.025) as a measure of glycocalyx integrity, adjusted for covariates including adverse pregnancy outcomes. Women with MVM also had higher adjusted diastolic blood pressure (+2.6 mm Hg, P=0.021), total and LDL (low-density lipoprotein)-cholesterol (+11.2 mg/dL, P=0.016; +8.7 mg/dL, P=0.031). MVM associations with subsequent cardiovascular measures did not vary by type of adverse pregnancy outcome, except among women with preterm births where blood pressure was higher only among those with MVM. Results were similar when evaluated as MVM severity. A decade after delivery, women with placental vascular lesions had an adverse cardiovascular profile comprised of microvascular rarefaction, higher blood pressure and more atherogenic lipids. Placental histopathology may reveal a woman's early trajectory toward subsequent vascular disease.

miR‑129‑5p inhibits oxidized low‑density lipoprotein‑induced A7r5 cell viability and migration by targeting HMGB1 and the PI3k/Akt signaling pathway

The mechanisms underlying gene therapy for the treatment of cardiovascular diseases remain to be elucidated. microRNAs (miRs) have been recognized as key regulators in vascular smooth muscle cells, which are involved in the formation of atherosclerosis. The present study aimed to explore the role of miR-129-5p in the regulation of high-mobility group box 1 protein (HMGB1) and the PI3k/Akt signaling pathway, and further explore the role of miR-129-5p in the viability and migration of A7r5 cells induced by oxidized low-density lipoprotein (ox-LDL). Cell viability, viability and migration were determined using Cell Counting Kit-8, colony formation, wound healing and Transwell assays. The expression levels of miR-129-5p and HMGB1 were detected using reverse transcription-quantitative PCR and western blotting. A dual-luciferase assay was used to confirm the association between miR-129-5p and HMGB1. RT-qPCR results in the present study demonstrated that the expression levels of miR-129-5p in A7r5 cells induced by ox-LDL were significantly decreased, compared with the control cells. Moreover, the viability and migration of A7r5 cells induced by ox-LDL were increased compared with control group. Western blot and RT-qPCR results showed that miR-129-5p decreased the expression of HMGB1 in A7r5 cells compared with control group. The present results demonstrated that miR-129-5p inhibited the viability, viability and migration of A7r5 cells induced by ox-LDL, and directly targeted HMGB1 to regulate the PI3k/Akt signaling pathway. In conclusion, miR-129-5p inhibited the PI3k/Akt signaling pathway by directly targeting HMGB1, and reduced the viability, viability and migration of A7r5 cells induced by ox-LDL.

Acute Atherosis Lesions at the Fetal-Maternal Border: Current Knowledge and Implications for Maternal Cardiovascular Health

Decidua basalis, the endometrium of pregnancy, is an important interface between maternal and fetal tissues, made up of both maternal and fetal cells. Acute atherosis is a uteroplacental spiral artery lesion. These patchy arterial wall lesions containing foam cells are predominantly found in the decidua basalis, at the tips of the maternal arteries, where they feed into the placental intervillous space. Acute atherosis is prevalent in preeclampsia and other obstetric syndromes such as fetal growth restriction. Causal factors and effects of acute atherosis remain uncertain. This is in part because decidua basalis is challenging to sample systematically and in large amounts following delivery. We summarize our decidua basalis vacuum suction method, which facilitates tissue-based studies of acute atherosis. We also describe our evidence-based research definition of acute atherosis. Here, we comprehensively review the existing literature on acute atherosis, its underlying mechanisms and possible short- and long-term effects. We propose that multiple pathways leading to decidual vascular inflammation may promote acute atherosis formation, with or without poor spiral artery remodeling and/or preeclampsia. These include maternal alloreactivity, ischemia-reperfusion injury, preexisting systemic inflammation, and microbial infection. The concept of acute atherosis as an inflammatory lesion is not novel. The lesions themselves have an inflammatory phenotype and resemble other arterial lesions of more extensively studied etiology. We discuss findings of concurrently dysregulated proteins involved in immune regulation and cardiovascular function in women with acute atherosis. We also propose a novel hypothesis linking cellular fetal microchimerism, which is prevalent in women with preeclampsia, with acute atherosis in pregnancy and future cardiovascular and neurovascular disease. Finally, women with a history of preeclampsia have an increased risk of premature cardiovascular disease. We review whether presence of acute atherosis may identify women at especially high risk for premature cardiovascular disease.

lncRNA DANCR promotes the migration an invasion and of trophoblast cells through microRNA-214-5p in preeclampsia

Studies have shown that lncRNA DANCR is down-regulated in placental tissues of patients with preeclampsia (PE). The aim of this study was to explore the effect of lncRNA DANCR on trophoblast cells as well as its acting mechanism. We disrupted or overexpressed lncRNA DANCR in trophoblast cells HTR-8/SVneo and JEG-3 and detected the associated cellular functional changes by MTT, flow cytometry, Transwell experiment, and scratch experiment. The results showed that overexpression of lncRNA DANCR significantly increased the proliferation, invasion, migration, and EMT process of trophoblast cells. Interfering with lncRNA DANCR showed the opposite result. Further, the targeted interaction between lncRNA DANCR and miR-214-5p was confirmed by the dual-luciferase reporter gene assay. In addition, the expression of PI3K/AKT signaling pathway-related proteins was analyzed by Western blot. Overexpression of lncRNA DANCR can increase the phosphorylation of PI3K/AKT protein and activate this signaling pathway. In conclusion, the enforcing of lncRNA DANCR activates the activation of the PI3K/AKT pathway by down-regulating miR-214-5p, and promotes the migration and invasion of chorionic trophoblast cells. This provides a potential new target for PE therapy.

Association between proteinuria and placental pathology in preeclampsia: A retrospective study

Introduction:

Preeclampsia develops due to placental insufficiency and systemic proinflammatory and antiangiogenic mediator release, with ensuing systemic endothelial dysfunction. Nephrotic-range proteinuria appears to be associated with worse pregnancy outcomes. The relationship between differing degrees of proteinuria and the severity of placental alterations has not been studied.

Methods:

This is a single-centre retrospective comparison of 150 singleton pregnancies complicated by preeclampsia and varying degrees of proteinuria. Maternal demographic, obstetrical and fetal outcome data were obtained from chart review. The placental histologic evaluations were performed by a placental pathologist blinded to all other clinical information.

Results:

Preeclamptic women with massive proteinuria had evidence of more severe maternal vascular malperfusion lesions. The severity of the lesions was progressive through mild, moderate and massive proteinuria. Women with massive proteinuria had a higher incidence of renal dysfunction and severe hypertension, and had earlier preterm deliveries compared to preeclamptic women with mild and moderate proteinuria (p < 0.05).

Conclusion:

Preeclampsia with more severe proteinuria is associated with a higher prevalence of placental maternal vascular malperfusion.

Placenta morphology and biomarkers in pregnancies with congenital heart disease - A systematic review

Impaired placentation is an important contributing factor to intra-uterine growth restriction and pre-eclampsia in fetuses with congenital heart defects (CHD). These pregnancy complications occur more frequently in pregnancies with fetal CHD. One of the most important factors influencing the life of children with CHD is neurodevelopmental delay, which seems to start already in utero. Delayed neurodevelopment in utero may be correlated or even (partly) explained by impaired placentation in CHD cases. This systematic review provides an overview of published literature on placental development in pregnancies with fetal CHD. A systematic search was performed and the Newcastle-Ottawa scale was used to access data quality. Primary outcomes were placenta size and weight, vascular and villous architecture, immunohistochemistry, angiogenic biomarkers and/or placental gene expression. A total of 1161 articles were reviewed and 21 studies were included. Studies including CHD with a genetic disorder or syndrome and/or multiple pregnancies were excluded. Lower placental weight and elevated rates of abnormal umbilical cord insertions were found in CHD. Cases with CHD more frequently showed microscopic placental abnormalities (i.e. abnormal villous maturation and increased maternal vascular malperfusion lesions), reduced levels of angiogenic biomarkers and increased levels of anti-angiogenic biomarkers in maternal serum and umbilical cord blood. Altered gene expression involved in placental development and fetal growth were found in maternal serum and CHD placentas. In conclusion, abnormal placentation is found in CHD. More extensive studies are needed to elucidate the contribution of impaired placentation to delayed neurodevelopment in CHD cases.

MicroRNA‑524‑5p regulates the proliferation and invasion of HTR‑8/SVneo trophoblasts by targeting NUMB in the Notch signaling pathway

Preeclampsia is a pregnancy disorder that is primarily associated with maternal and neonatal or fetal morbidity and mortality. The discovery of dysregulated microRNAs (miRs) and their roles in preeclampsia has provided new insight into the mechanisms involved in pregnancy‑related disorders. In the present study, quantitative PCR demonstrated that the expression levels of miR‑524‑5p were lower in patients with preeclampsia than those in normal pregnant women. Cell Counting Kit‑8 and Transwell assays indicated that overexpression of miR‑524‑5p promoted the proliferation and invasion of HTR‑8/SVneo cells, whereas inhibition of miR‑524‑5p suppressed HTR‑8/SVneo cell proliferation and invasion. Furthermore, NUMB endocytic adaptor protein (NUMB), a negative regulator of the Notch signaling pathway and a target gene of miR‑524‑5p, limited the effects of miR‑524‑5p on HTR‑8/SVneo cell invasion and migration. The present study demonstrated that miR‑524‑5p regulated the proliferation and invasion of HTR‑8/SVneo cells at least partly by targeting NUMB to regulate the Notch signaling pathway.

Human Tregs at the materno-fetal interface show site-specific adaptation reminiscent of tumor Tregs

Tregs are crucial for maintaining maternal immunotolerance against the semiallogeneic fetus. We investigated the elusive transcriptional profile and functional adaptation of human uterine Tregs (uTregs) during pregnancy. Uterine biopsies, from placental bed (materno-fetal interface) and incision site (control) and blood were obtained from women with uncomplicated pregnancies undergoing cesarean section. Tregs and CD4⁺ non-Tregs were isolated for transcriptomic profiling by Cel-Seq2. Results were validated on protein and single cell levels by flow cytometry. Placental bed uTregs showed elevated expression of Treg signature markers, including FOXP3, CTLA-4, and TIGIT. Their transcriptional profile was indicative of late-stage effector Treg differentiation and chronic activation, with increased expression of immune checkpoints GITR, TNFR2, OX-40, and 4-1BB; genes associated with suppressive capacity (HAVCR2, IL10, LAYN, and PDCD1); and transcription factors MAF, PRDM1, BATF, and VDR. uTregs mirrored non-Treg Th1 polarization and tissue residency. The particular transcriptional signature of placental bed uTregs overlapped strongly with that of tumor-infiltrating Tregs and was remarkably pronounced at the placental bed compared with uterine control site. In conclusion, human uTregs acquire a differentiated effector Treg profile similar to tumor-infiltrating Tregs, specifically at the materno-fetal interface. This introduces the concept of site-specific transcriptional adaptation of Tregs within 1 organ.

Human regulatory T cells at the maternal-fetal interface show uterine site-specific functional adaptation with late-stage effector differentiation, chronic activation, Th1 polarization, and tumor-infiltrating, Treg-like features.

Hypertension During Pregnancy

PURPOSE OF REVIEW

Hypertensive disorders of pregnancy affect about 5-10% of pregnancies impacting maternal, fetal, and neonatal outcomes. We review the recent studies in this field and discuss the pathophysiology, diagnosis, and management of hypertension during pregnancy, as well as the short- and long-term consequences on the cardiovascular health of women.

RECENT FINDINGS

Although the American College of Cardiology/American Heart Association revised their guidelines for hypertension in the general population in 2017, hypertension during pregnancy continues to be defined as a systolic blood pressure (SBP) ≥ 140 mmHg and/or a diastolic blood pressure (DBP) ≥ 90 mmHg, measured on two separate occasions. The addition of stage 1 hypertension will increase the prevalence of hypertension during pregnancy, identifying more women at risk of preeclampsia; however, more research is needed before changing the BP goal because a lower target BP has a risk of poor placental perfusion. Women with chronic hypertension have a higher incidence of superimposed preeclampsia, cesarean section, preterm delivery before 37 weeks' gestation, birth weight less than 2500 g, neonatal unit admission, and perinatal death. They also have a higher risk of developing cardiovascular disease later in life. The guidelines recommend low-dose aspirin for women with moderate and high risk of preeclampsia. While treating pregnant women with hypertension, the effectiveness of the antihypertensive agent must be balanced with risks to the fetus. Hypertensive disorders of pregnancy should be appropriately and promptly recognized and treated during pregnancy. They should further be co-managed by the obstetrician and cardiologist to decrease the long-term negative impact on the cardiovascular health of women.

Understanding decidual vasculopathy and the link to preeclampsia: A review

Preeclampsia is the archetype of a spectrum of clinical disorders related to abnormal placental development or function, characterized by placental histological lesions. Among those lesions, decidual vasculopathy is a term used to describe lesions of maternal spiral arteries, which are encountered on placental examination in about half of the women with preeclampsia. The morphological features of the lesions include perivascular lymphocytic infiltration, fibrinoid necrosis and foam cell incorporation within the vessel wall. Due to the resemblance of the latter characteristic to atherosclerosis, they are alternatively termed acute atherosis. Decidual vasculopathy correlates with worse maternal and neonatal outcomes, as well as placental pathology. In this article, we review the available literature on decidual vasculopathy and address the pitfalls in histological analysis of the lesions, including the varying definitions of the lesions and sample collection methods. We also discuss the current evidence on the etiology of the lesions and propose a novel hypothesis linking the three etiological pathways to the formation of decidual vasculopathy and, ultimately, the emergence of the heterogeneous group of placental dysfunction disorders, known as the great obstetric syndromes.

Inflammasomes-A Molecular Link for Altered Immunoregulation and Inflammation Mediated Vascular Dysfunction in Preeclampsia

Preeclampsia (PE) is a pregnancy-specific multisystem disorder and is associated with maladaptation of the maternal cardiovascular system and abnormal placentation. One of the important characteristics in the pathophysiology of PE is a dysfunction of the placenta. Placental insufficiency is associated with poor trophoblast uterine invasion and impaired transformation of the uterine spiral arterioles to high capacity and low impedance vessels and/or abnormalities in the development of chorionic villi. Significant progress in identifying potential molecular targets in the pathophysiology of PE is underway. The human placenta is immunologically functional with the trophoblast able to generate specific and diverse innate immune-like responses through their expression of multimeric self-assembling protein complexes, termed inflammasomes. However, the type of response is highly dependent upon the stimuli, the receptor(s) expressed and activated, the downstream signaling pathways involved, and the timing of gestation. Recent findings highlight that inflammasomes can act as a molecular link for several components at the syncytiotrophoblast surface and also in maternal blood thereby directly influencing each other. Thus, the inflammasome molecular platform can promote adverse inflammatory effects when chronically activated. This review highlights current knowledge in placental inflammasome expression and activity in PE-affected pregnancies, and consequently, vascular dysfunction in PE that must be addressed as an interdependent interactive process.

The Placenta as a Window to Maternal Vascular Health

Cardiovascular disease remains the leading killer of women, with sex-specific manifestation, mechanisms, and morbidity. Preeclampsia, fetal growth restriction, and a subset of preterm births demonstrate aberrancies in the maternal vessels supplying the placenta and damage to the placental parenchyma consistent with hypoxic/ischemic or oxidative injury. This constellation of findings, maternal vascular malperfusion (MVM) lesions, may hold the key to understanding and identifying the elevated risk for early cardiovascular disease in women who experience adverse pregnancy outcomes. This intriguing possibility has only begun to be examined, but accumulating evidence is compelling and is reviewed here.

Study protocol for a prospective cohort study to investigate Hemodynamic Adaptation to Pregnancy and Placenta-related Outcome: the HAPPO study

INTRODUCTION

The importance of cardiovascular health in relation to pregnancy outcome is increasingly acknowledged. Women who develop certain pregnancy complications, in particular preeclampsia, are at higher risk for future cardiovascular disease. Independent of its outcome, pregnancy requires a substantial adaptive response of the maternal cardiovascular system. In the Hemodynamic Adaptation to Pregnancy and Placenta-related Outcome (HAPPO) study, we aim to examine longitudinal maternal haemodynamic adaptation to pregnancy from the preconception period onwards. We hypothesise that women who will develop adverse pregnancy outcomes have impaired cardiovascular health before conception, leading to haemodynamic maladaptation to pregnancy and diminished uteroplacental vascular development.

METHODS AND ANALYSIS

In this prospective cohort study embedded in the Rotterdam periconception cohort, 200 women with a history of placenta-related pregnancy complications (high-risk group) and 100 women with an uncomplicated obstetric history (low-risk group) will be included. At five moments (preconception, first, second and third trimester and postdelivery), women will undergo an extensive examination of the macrocirculatory and microcirculatory system and uteroplacental vascular development. The main outcome measures are differences in maternal haemodynamic adaptation to pregnancy between women with and without placenta-related pregnancy complications. In a multivariate linear mixed model, the relationship between maternal haemodynamic adaptive parameters, (utero)placental vascularisation indices and clinical outcomes (occurrence of pregnancy complications, embryonic and fetal growth trajectories, miscarriage rate, gestational age at delivery, birth weight) will be studied. Subgroup analysis will be performed to study baseline and trajectory differences between high-risk and low-risk women, independent of subsequent pregnancy outcome.

ETHICS AND DISSEMINATION

This study protocol was approved by the Medical Ethics Committee of the Erasmus MC, Rotterdam, the Netherlands (MEC 2018-150). Results will be disseminated to the medical community by publications in peer-reviewed journals and presentations at scientific congresses. Also, patient associations will be informed and the public will be informed by dissemination through (social) media.

TRIAL REGISTRATION NUMBER

NL7394 (www.trialregister.nl).

Placental bed research: II. Functional and immunological investigations of the placental bed

Research on the placenta as the interface between the mother and the fetus has been undertaken for some 150 years, and in 2 subsequent reviews, we attempted to summarize the situation. In the first part, we described the discovery of unique physiological modifications of the uteroplacental spiral arteries, enabling them to cope with a major increase in blood flow necessary to ensure proper growth of the fetus. These consist of an invasion of the arterial walls by trophoblast and a progressive disappearance of its normal structure. Researchers then turned to the pathophysiology of the placental bed and in particular to its maternal vascular tree. This yielded vital information for a better understanding of the so-called great obstetrical syndromes (preeclampsia, fetal growth restriction, premature labor and delivery, placenta accreta). Systematic morphological investigations of the uteroplacental vasculature showed that preeclampsia is associated with decreased or failed transformation of spiral arteries and the persistence of endothelial and smooth muscle cells in segments of their myometrial portion. Here we report on recent functional investigations of the placental bed, including in situ biophysical studies of uteroplacental blood flow and vascular resistance, and manipulation of uteroplacental perfusion. These new methodologies have provided a novel way of identifying pregnancies in which remodeling is impaired. In animals it is now possible to manipulate uteroplacental blood flow, leading to an enhancement of fetal growth; this opens the way to trials in abnormal human pregnancies. In this second part, we explored a new, extremely important area of research that deals with the role of specific subsets of leukocytes and macrophages in the placental bed. The human first-trimester decidua is rich in leukocytes called uterine natural killer cells. Both macrophages and uterine natural killer cells increase in number from the secretory endometrium to early pregnancy and play a critical role in mediating the process of spiral artery transformation by inducing initial structural changes. It seems therefore that vascular remodeling of spiral arteries is initiated independently of trophoblast invasion. Dysregulation of the immune system may lead to reproductive failure or pregnancy complications, and in this respect, recent studies have advanced our understanding of the mechanisms regulating immunological tolerance during pregnancy, with several mechanisms being proposed for the development of tolerance to the semiallogeneic fetus. In particular, these include several strategies by which the trophoblast avoids maternal recognition. Finally, an important new dimension is being explored: the likelihood that pregnancy syndromes and impaired uteroplacental vascular remodeling may be linked to future maternal and even the child's cardiovascular disease risk. The functional evidence underlying these observations will be discussed.

Autonomic Dysfunction in Preeclampsia: A Systematic Review

Background: Preeclampsia (PE) is a major obstetric complication that leads to severe maternal and fetal morbidity. Early detection of preeclampsia can reduce the severity of complications and improve clinical outcomes. It is believed that the autonomic nervous system (ANS) is involved in the pathogenesis of PE. We aimed to review the current literature on the prevalence and nature of ANS dysfunction in women with PE and the possible prognostic value of ANS testing in the early detection of PE.

Methods: Literature search was performed using Medline (1966–2018), EMBase (1947–2018), Google Scholar (1970–2018), BIOSIS (1926–2018), Web of science (1900–2018); CINAHL (1937–2018); Cochrane Library, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials (CENTRAL) and Cochrane Methodology Register (1999–2018). Additionally, the reference lists of articles included were screened.

Results: A total of 26 studies were included in the present review presenting data of 1,854 pregnant women. Among these women, 453 were diagnosed with PE, 93.6% (424/453) of which displayed autonomic dysfunction. ANS function was assessed by cardiovascular reflex tests (n = 9), heart rate variability (n = 11), cardiac baroreflex gain (n = 5), muscle sympathetic nerve activity (MSNA) (n = 3), and biomarkers of sympathetic activity (n = 4). Overall, 21 studies (80.8%) reported at least one of the following abnormalities in ANS function in women diagnosed with PE compared to healthy pregnant control women: reduced parasympathetic activity (n = 16/21, 76%), increased sympathetic activity (n = 12/20, 60%), or reduced baroreflex gain (n = 4/5, 80%). Some of these studies indicated that pressor and orthostatic stress test may be useful in early pregnancy to help estimate the risk of developing PE. However, autonomic function tests seem not to be able to differentiate between mild and severe PE.

Conclusions: Current evidence suggests that autonomic dysfunction is highly prevalent in pre-eclamptic women. Among autonomic functions, cardiovascular reflexes appear to be predominantly affected, seen as reduced cardiac parasympathetic activity and elevated cardiac sympathetic activity. The diagnostic value of autonomic testing in the prediction and monitoring of autonomic failure in pre-eclamptic women remains to be determined.

Vascular Endothelial Growth Factor Delivery to Placental Basal Plate Promotes Uterine Artery Remodeling in the Primate

Extravillous trophoblast (EVT) uterine artery remodeling (UAR) promotes placental blood flow, but UAR regulation is unproven. Elevating estradiol (E2) in early baboon pregnancy suppressed UAR and EVT vascular endothelial growth factor (VEGF) expression, but this did not prove that VEGF mediated this process. Therefore, our primate model of prematurely elevating E2 and contrast-enhanced ultrasound cavitation of microbubble (MB) carriers was used to deliver VEGF DNA to the placental basal plate (PBP) to establish the role of VEGF in UAR. Baboons were treated on days 25 to 59 of gestation (term, 184 days) with E2 alone or with E2 plus VEGF DNA-conjugated MBs briefly infused via a maternal peripheral vein on days 25, 35, 45, and 55. At each of these times an ultrasound beam was directed to the PBP to collapse the MBs and release VEGF DNA. VEGF DNA-labeled MBs per contrast agent was localized in the PBP but not the fetus. Remodeling of uterine arteries >25 µm in diameter on day 60 was 75% lower (P < 0.001) in E2-treated (7% ± 2%) than in untreated baboons (30% ± 4%) and was restored to normal by E2/VEGF. VEGF protein levels (signals/nuclear area) within the PBP were twofold lower (P < 0.01) in E2-treated (4.2 ± 0.9) than in untreated (9.8 ± 2.8) baboons and restored to normal by E2/VEGF (11.9 ± 1.6), substantiating VEGF transfection. Thus, VEGF gene delivery selectively to the PBP prevented the decrease in UAR elicited by prematurely elevating E2 levels, establishing the role of VEGF in regulating UAR in vivo during primate pregnancy.

Sympathetic nervous system control of vascular function and blood pressure during pregnancy and preeclampsia

: Proper vascular tone and blood pressure regulation during pregnancy are important for immediate and long-term cardiovascular health of the mother and her offspring. Preeclampsia is clinically defined as new-onset maternal hypertension accompanied by cardiovascular, renal, and/or neural abnormalities presenting in the second half of pregnancy. There is strong evidence to support that preeclampsia is mediated by attenuations in uteroplacental vascular remodeling and increases in vasoconstriction with subsequent placental ischemia/reperfusion-induced release of hypertensive substances into the maternal circulation. These include antiangiogenic and pro-inflammatory factors. There is also evidence implicating increased sympathetic nervous system activity (SNA) in this maternal disorder, but this mostly includes data correlating severity of disease with catecholamine levels and elevated muscle SNA. These measurements have not confirmed a causative role for SNA in the pathogenesis of preeclampsia. Therefore, studies are needed to provide a comprehensive understanding of SNA and its control of vascular function and blood pressure regulation during normal pregnancy in order to set the stage for exploring the mechanisms mediating the exaggerated SNA and signaling during preeclampsia. This review examines the role of SNA in control of uteroplacental vascular tone and blood pressure regulation during normal pregnancy. Furthermore, it is proposed that over-activation of the SNA contributes to altered uteroplacental vascular tone and perfusion leading to placental ischemic events and modulates the systemic vasoconstriction and hypertensive responses to soluble placenta ischemic factors. Recognizing the integrative role and importance of SNA in the pathophysiology of preeclampsia will advance our understanding of this maternal disorder.

Role of Endoplasmic Reticulum Stress in Proinflammatory Cytokine-Mediated Inhibition of Trophoblast Invasion in Placenta-Related Complications of Pregnancy

Shallow extravillous trophoblast (EVT) invasion is central to the pathophysiology of many pregnancy complications. Invasion is mediated partially by matrix metalloproteinases (MMPs). MMP-2 is highly expressed in early pregnancy. MMP activity can be regulated by proinflammatory cytokines, which also induce endoplasmic reticulum (ER) stress in other cells. We investigated whether proinflammatory cytokines regulate MMP-2 activity through ER stress response pathways in trophoblast before exploring potential regulatory mechanisms. There was increased immunoreactivity of heat shock 70-kDa protein 5, also known as 78-kDa glucose regulated protein, in cells of the placental bed, including EVTs, in cases of early-onset preeclampsia compared with normotensive controls. Treating EVT-like JEG-3 and HTR8/SVneo cells with ER stress inducers (tunicamycin and thapsigargin) suppressed MMP2 mRNA and protein expression, secretion, and activity and reduced their invasiveness. A cocktail of proinflammatory cytokines (IL-1β, tumor necrosis factor-α, and interferon-γ) suppressed MMP-2 activity in JEG-3 cells and was accompanied by activation of the PKR-like ER kinase (PERK)-eukaryotic translation initiation factor 2A (EIF2A) arm of the ER stress pathway. Knockdown of ATF4, a downstream transcriptional factor of the PERK-EIF2A pathway, by small interference RNA, restored MMP2 expression but not cellular proteins. However, suppression of EIF2A phosphorylation with a PERK inhibitor, GSK2606414, under ER stress, restored MMP-2 protein. ER stress regulates MMP-2 expression at both the transcriptional and translational levels. This study provides the first mechanistic linkage by which proinflammatory cytokines may modulate trophoblast invasion through ER stress pathways.

Recurrence of pre-eclampsia and the risk of future hypertension and cardiovascular disease: a systematic review and meta-analysis

Background

Women with a history of hypertensive disorders, including pre‐eclampsia, during pregnancy have a two‐ to‐five‐fold increased risk of cardiovascular disease (CVD). In 15% of women, pre‐eclampsia recurs in the following pregnancy.

Objectives

To evaluate all evidence on the future risk of developing hypertension and CVD after multiple pregnancies complicated by pre‐eclampsia compared with pre‐eclampsia in a single pregnancy followed by normal subsequent pregnancy.

Search strategy

Embase and Medline were searched until June 2017.

Selection criteria

All relevant studies on the risk of developing hypertension, atherosclerosis, ischaemic heart disease, cerebrovascular accident (CVA), thromboembolism, heart failure or overall hospitalisation and mortality due to CVD after having had recurrent pre‐eclampsia.

Data collection and analysis

Twenty‐two studies were included in the review. When possible, we calculated pooled risk ratios (RR) with 95% CI through random‐effect analysis.

Main results

Recurrent pre‐eclampsia was consistently associated with an increased pooled risk ratio of hypertension (RR 2.3; 95% CI 1.9–2.9), ischaemic heart disease (RR 2.4; 95% CI 2.2–2.7), heart failure (RR 2.9; 95% CI 2.3–3.7), CVA (RR 1.7; 95% CI 1.2–2.6) and hospitalisation due to CVD (RR 1.6; 95% CI 1.3–1.9) when compared with women with subsequent uncomplicated pregnancies. Other studies on thromboembolism, atherosclerosis and cardiovascular mortality found a positive effect, but data could not be pooled.

Conclusions

This systematic review and meta‐analysis support consistent higher risk for future development of hypertension and CVD in women with recurring pre‐eclampsia as opposed to women with a single episode of pre‐eclampsia.

Tweetable abstract

The risk of future cardiovascular disease increases when women have recurrence of pre‐eclampsia compared with a single episode.

The risk of future cardiovascular disease increases when women have recurrence of pre‐eclampsia compared to a single episode.

This paper includes Author Insights, a video abstract available at https://vimeo.com/rcog/authorinsights15394

H3K27 acetylation and gene expression analysis reveals differences in placental chromatin activity in fetal growth restriction

Background

Posttranslational modification of histone tails such as histone 3 lysine 27 acetylation (H3K27ac) is tightly coupled to epigenetic regulation of gene expression. To explore whether this is involved in placenta pathology, we probed genome-wide H3K27ac occupancy by chromatin immunoprecipitation sequencing (ChIP-seq) in healthy placentas and placentas from pathological pregnancies with fetal growth restriction (FGR). Furthermore, we related specific acetylation profiles of FGR placentas to gene expression changes.

Results

Analysis of H3K27ac occupancy in FGR compared to healthy placentas showed 970 differentially acetylated regions distributed throughout the genome. Principal component analysis and hierarchical clustering revealed complete segregation of the FGR and control group. Next, we identified 569 upregulated genes and 521 downregulated genes in FGR placentas by RNA sequencing. Differential gene transcription largely corresponded to expected direction based on H3K27ac status. Pathway analysis on upregulated transcripts originating from hyperacetylated sites revealed genes related to the HIF-1-alpha transcription factor network and several other genes with known involvement in placental pathology (LEP, FLT1, HK2, ENG, FOS). Downregulated transcripts in the vicinity of hypoacetylated sites were related to the immune system and growth hormone receptor signaling. Additionally, we found enrichment of 141 transcription factor binding motifs within differentially acetylated regions. Of the corresponding transcription factors, four were upregulated, SP1, ARNT2, HEY2, and VDR, and two downregulated, FOSL and NR4A1.

Conclusion

We demonstrate a key role for genome-wide alterations in H3K27ac in FGR placentas corresponding with changes in transcription profiles of regions relevant to placental function. Future studies on the role of H3K27ac in FGR and placental-fetal development may help to identify novel targets for therapy of this currently incurable disease.

Electronic supplementary material

The online version of this article (10.1186/s13148-018-0508-x) contains supplementary material, which is available to authorized users.

miR-362-3p regulates cell proliferation, migration and invasion of trophoblastic cells under hypoxia through targeting Pax3

Preeclampsia (PE), a common obstetrical disorder, is one of the leading causes of pregnancy associated death. PE is closely linked with impaired migration and invasion ability of trophoblastic cells. miR-362-3p recently received our particular attention due not only to its aberrant expression in the placentas of patients with PE, but also to its important roles in regulating migration and invasion of various cells. This study was thus conducted to investigate the roles of miR-362-3p in PE and the related mechanism. The expression of miR-362-3p and Pax3 was examined in placentas of patients with PE and in normal placentas. HTR8/SVneo cells were cultured under hypoxia and transfected with miR-362-3p mimics, miR-362-3p inhibitors or Pax3 over-expression vectors. Results showed up-regulation of miR-362-3p but down-regulation of Pax3 in placentas of preeclamptic pregnancies. Luciferase report assay confirmed that Pax3 is a direct target of miR-362-3p. Although Pax3 was predicted to be targeted by miR-30a-3p and miR-181a-5p as well, their expression either had no difference between placentas of PE patients and normal placentas or showed less increment in placentas of PE patients than miR-362-3p. Exposure to hypoxia inhibited cell viability, migration and invasion of HTR8/SVneo cells. Increasing miR-362-3p by the mimics conferred improved effects on the inhibition. However, deletion of miR-362-3p or overexpression of Pax3 abolished the inhibiton. These results suggest that miR-362-3p/Pax3 axis regulates cell viability, migration and invasion of HTR8/SVneo cells under hypoxia. The present study adds to the further understanding of the pathogenesis of PE.

The placental bed vascular pathology revisited: a risk indicator for cardiovascular disease

AIM

The present paper intends in the first place to clarify the confusing terminology for describing the vascular pathology of the placental bed in relation to long-term risk of cardiovascular disease.

METHODS

Systematic review of relevant topics.

RESULTS

The maternal blood supply to the placenta is achieved by some 100 utero-placental spiral arteries with an outside diameter varying between 200 and 600 microns. Defective physiological changes of the myometrial segment of utero-placental spiral arteries and, particularly in preeclampsia associated to hypertensive disease, the presence of atherosclerosis in their proximal segment are a cause of obstructive vascular pathology. On the other hand, basal arteries which supply the inner myometrium and basal decidua are not affected by physiological change and maintain their musculoelastic structure. They can be identified by their external diameter of less than 120 microns. Acute atherosis is an aspecific vascular lesion that occurs in basal as well as spiral arteries inside, as well as outside, the placental bed in association with a variety of obstetrical conditions.

CONCLUSIONS

An increased risk of future cardiovascular disease, should be linked to atherosis or, at a later stage, atherosclerosis of utero-placental spiral arteries, rather than to that of decidual basal arteries.

Maternal Vascular Malperfusion and Adverse Perinatal Outcomes in Low-Risk Nulliparous Women

OBJECTIVE

To evaluate the disease burden of placental maternal vascular malperfusion pathology in a low-risk nulliparous population and test the hypothesis that a multiparameter model in the second trimester can predict maternal vascular malperfusion with high precision.

METHODS

A single-center, prospective cohort study was conducted in healthy nulliparous women. Maternal vascular malperfusion disease burden was estimated by incidence, relative risk (RR), and population-attributable risk percent. Maternal risk factors, serum biomarkers, Doppler, and placental morphologic ultrasonography were examined in isolation and in combination for prediction of this placental pathology.

RESULTS

The incidence of maternal vascular malperfusion pathology was 8.4% (72/856). Women with pathology had higher risk of preeclampsia (8.33% compared with 1.79%; RR 4.67, 95% CI 1.85-11.77%; population-attributable risk 23.6%, 95% CI 16.9-31.6%), small for gestational age (SGA) (47.22% compared with 9.45%; RR 5.00, 95% CI 3.6-6.93%; population-attributable risk 25.2%, 95% CI 22.1-28.5%), and the composite of adverse outcomes (defined as SGA or preeclampsia) (47.22% compared with 10.59%; RR 4.46, 95% CI 3.25-6.13; population-attributable risk 22.5%, 95% CI 19.8-25.5%). The combination of parameters was superior to individual modalities alone in predicting maternal vascular malperfusion, but achieved only moderate precision (area under the curve 0.77, 95% CI 0.71-0.84).

CONCLUSION

One in 12 healthy nulliparous women develop maternal vascular malperfusion placental pathology, and these pregnancies had a 4.5 times higher risk of developing preeclampsia or delivering a SGA neonate compared with those without this pathology. A multiparameter model achieved modest precision to predict placental maternal vascular malperfusion. Importantly, in low-risk pregnancies, maternal vascular malperfusion accounts for one fourth of pregnancy outcomes with SGA or preeclampsia. The low population-attributable risk of this placental pathology for SGA and preeclampsia illustrates the importance of discovering novel associations to reduce the disease burden of these pregnancy complications.

Preeclampsia and coronary plaque erosion: Manifestations of endothelial dysfunction resulting in cardiovascular events in women

Atherosclerosis is the major underlying pathology of cardiovascular disease (CVD). The risk for CVD is increased in women with a history of preeclampsia. Multiple studies have indicated that accelerated atherosclerosis underlies this increased CVD risk. Furthermore, it has been suggested that endothelial dysfunction and inflammation play an important role in the increased CVD risk of women with preeclampsia. Rupture or erosion of atherosclerotic plaques can induce the formation of thrombi that underlie the onset of acute clinical CVD such as myocardial infarction and stroke. In relatively young women, cardiovascular events are mainly due to plaque erosions. Eroded plaques have a distinct morphology compared to ruptured plaques, but have been understudied as a substrate for CVD. The currently available evidence points towards lesions with features of stability such as high collagen content and smooth muscle cells and with distinct mechanisms that further promote the pro-thrombotic environment such as Toll Like Receptor (TLR) signaling and endothelial apoptosis. These suggested mechanisms, that point to endothelial dysfunction and intimal thickening, may also play a role in preeclampsia. Pregnancy is considered a stress test for the cardiovascular system with preeclampsia as an additional pathological substrate for earlier manifestation of vascular disease. This review provides a summary of the possible common mechanisms involved in preeclampsia and accelerated atherosclerosis in young females and highlights plaque erosion as a likely substrate for CVD events in women with a history of preeclampsia.

Evidence-Based Revised View of the Pathophysiology of Preeclampsia

Preeclampsia is a life-threatening vascular disorder of pregnancy due to a failing stressed placenta. Millions of women risk death to give birth each year and globally each year, almost 300,000 lose their life in this process and over 500,000 babies die as a consequence of preeclampsia. Despite decades of research, we lack pharmacological agents to treat it. Maternal endothelial oxidative stress is a central phenomenon responsible for the preeclampsia phenotype of high maternal blood pressure and proteinuria. In 1997, it was proposed that preeclampsia arises due to the loss of VEGF activity, possibly due to elevation in anti-angiogenic factor, soluble Flt-1 (sFlt-1). Researchers showed that high sFlt-1 and soluble endoglin (sEng) elicit the severe preeclampsia phenotype in pregnant rodents. We demonstrated that heme oxygenase-1 (HO-1)/carbon monoxide (CO) pathway prevents placental stress and suppresses sFlt-1 and sEng release. Likewise, hydrogen sulphide (H₂S)/cystathionine-γ-lyase (Cth) systems limit sFlt-1 and sEng and protect against the preeclampsia phenotype in mice. Importantly, H₂S restores placental vasculature, and in doing so improves lagging fetal growth. These molecules act as the inhibitor systems in pregnancy and when they fail, preeclampsia is triggered. In this review, we discuss what are the hypotheses and models for the pathophysiology of preeclampsia on the basis of Bradford Hill causation criteria for disease causation and how further in vivo experimentation is needed to establish 'proof of principle'. Hypotheses that fail to meet the Bradford Hill causation criteria include abnormal spiral artery remodelling and inflammation and should be considered associated or consequential to the disorder. In contrast, the protection against cellular stress hypothesis that states that the protective pathways mitigate cellular stress by limiting elevation of anti-angiogenic factors or oxidative stress and the subsequent clinical signs of preeclampsia appear to fulfil most of Bradford Hill causation criteria. Identifying the candidates on the roadmap to this pathway is essential in developing diagnostics and therapeutics to target the pathogenesis of preeclampsia.