Excess placental soluble fms-like tyrosine kinase 1 (sFlt1) may contribute to endothelial dysfunction, hypertension, and proteinuria in preeclampsia

Single-cell RNA sequencing reveals heterogeneity and differential expression of the maternal-fetal interface during ICP and normal pregnancy

OBJECTIVE

Intrahepatic cholestasis of pregnancy (ICP) can cause adverse perinatal outcomes. Previous studies have demonstrated that the placenta of an ICP pregnancy differs in morphology and gene expression from the placenta of a normal pregnancy. To date, however, the genetic mechanism by which ICP affects the placenta is poorly understood. Therefore, the aim of this study was to investigate the differences in main cell types, gene signatures, cell ratio, and functional changes in the placenta between ICP and normal pregnancy.

METHODS

Single-cell RNA sequencing (scRNA-seq) technology was used to detect the gene expression of all cells at the placental maternal-fetal interface. Two individuals were analyzed - one with ICP and one without ICP. The classification of cell types was determined by a graph-based clustering algorithm. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed using the R software phyper () function and DAVID website. The differentially expressed genes (DEGs) encoding transcription factors (TFs) were identified using getorf and DIAMOND software.

RESULTS

We identified 14 cell types and 22 distinct cell subtypes that showed unique functional properties. Additionally, we found differences in the proportions of fibroblasts 1, helper T (Th) cells, extravillous trophoblasts, and villous cytotrophoblasts, and we observed heterogeneity of gene expression between ICP and control placentas. Furthermore, we identified 263 DEGs that belonged to TF families, including zf-C2H2, HMGI/HMGY, and Homeobox. In addition, 28 imprinted genes were preferentially expressed in specific cell types, such as PEG3 and PEG10 in trophoblasts as well as DLK1 and DIO3 in fibroblasts.

CONCLUSIONS

Our results revealed the differences in cell-type ratios, gene expression, and functional changes between ICP and normal placentas, and heterogeneity was found among cell subgroups. Hence, the imbalance of various cell types affects placental activity to varying degrees, indicating the complexity of the cell networks that form the placental tissue system, and this alteration of placental function is associated with adverse events in the perinatal period.

A mitochondrial regulator protein, MNRR1, is elevated in the maternal blood of women with preeclampsia

OBJECTIVE

Preeclampsia, one of the most serious obstetric complications, is a heterogenous disorder resulting from different pathologic processes. However, placental oxidative stress and an anti-angiogenic state play a crucial role. Mitochondria are a major source of cellular reactive oxygen species. Abnormalities in mitochondrial structures, proteins, and functions have been observed in the placentae of patients with preeclampsia, thus mitochondrial dysfunction has been implicated in the mechanism of the disease. Mitochondrial nuclear retrograde regulator 1 (MNRR1) is a newly characterized bi-organellar protein with pleiotropic functions. In the mitochondria, this protein regulates cytochrome c oxidase activity and reactive oxygen species production, whereas in the nucleus, it regulates the transcription of a number of genes including response to tissue hypoxia and inflammatory signals. Since MNRR1 expression changes in response to hypoxia and to an inflammatory signal, MNRR1 could be a part of mitochondrial dysfunction and involved in the pathologic process of preeclampsia. This study aimed to determine whether the plasma MNRR1 concentration of women with preeclampsia differed from that of normal pregnant women.

METHODS

This retrospective case-control study included 97 women with preeclampsia, stratified by gestational age at delivery into early (<34 weeks, n = 40) and late (≥34 weeks, n = 57) preeclampsia and by the presence or absence of placental lesions consistent with maternal vascular malperfusion (MVM), the histologic counterpart of an anti-angiogenic state. Women with an uncomplicated pregnancy at various gestational ages who delivered at term served as controls (n = 80) and were further stratified into early (n = 25) and late (n = 55) controls according to gestational age at venipuncture. Maternal plasma MNRR1 concentrations were determined by an enzyme-linked immunosorbent assay.

RESULTS

1) Women with preeclampsia at the time of diagnosis (either early or late disease) had a significantly higher median (interquartile range, IQR) plasma MNRR1 concentration than the controls [early preeclampsia: 1632 (924-2926) pg/mL vs. 630 (448-4002) pg/mL, p = .026, and late preeclampsia: 1833 (1441-5534) pg/mL vs. 910 (526-6178) pg/mL, p = .021]. Among women with early preeclampsia, those with MVM lesions in the placenta had the highest median (IQR) plasma MNRR1 concentration among the three groups [with MVM: 2066 (1070-3188) pg/mL vs. without MVM: 888 (812-1781) pg/mL, p = .03; and with MVM vs. control: 630 (448-4002) pg/mL, p = .04]. There was no significant difference in the median plasma MNRR1 concentration between women with early preeclampsia without MVM lesions and those with an uncomplicated pregnancy (p = .3). By contrast, women with late preeclampsia, regardless of MVM lesions, had a significantly higher median (IQR) plasma MNRR1 concentration than women in the control group [with MVM: 1609 (1392-3135) pg/mL vs. control: 910 (526-6178), p = .045; and without MVM: 2023 (1578-8936) pg/mL vs. control, p = .01].

CONCLUSIONS

MNRR1, a mitochondrial regulator protein, is elevated in the maternal plasma of women with preeclampsia (both early and late) at the time of diagnosis. These findings may reflect some degree of mitochondrial dysfunction, intravascular inflammation, or other unknown pathologic processes that characterize this obstetrical syndrome.

Metformin inhibits activation of NLRP3 inflammasome and inflammatory response in preeclamptic rats

BACKGROUD

It is widely acknowledged that Metformin (MET), an established medication for managing type 2 diabetes, possesses diverse pharmacological effects. This study aims to investigate the protective effects of MET against Nω-Nitro-L-arginine methyl ester (L-NAME)-induced preeclampsia (PE).

METHODS

Sprague Dawley (SD) rats were exposed to 200 mg/kg L-NAME with or without prior MET treatment. Histopathological analysis was performed using Hematoxylin and Eosin staining. Serum levels of inflammatory, antiangiogenic, and angiogenic factors were quantified using ELISA kits. Immunohistochemistry (IHC) staining was employed to observe NLRP3 and IL-1β expressions in placental tissues. Western blot and Quantitative Real-Time PCR (q-PCR) analyses were conducted to assess protein and mRNA expressions of NLRP3, caspase-1, ASC, and IL-1β.

RESULTS

We found that MET could mitigate placental histopathological deterioration and improve pregnancy outcomes in L-NAME-induced PE rat models. MET not only suppressed L-NAME-induced elevation of antiangiogenic factors but also stimulated the production of pro-angiogenic factors. Additionally, MET treatment reversed the excessive inflammatory response induced by L-NAME. Furthermore, MET inhibited the activation of the NLRP3 inflammasome triggered by L-NAME, evidenced by the downregulation of NLRP3 expression, caspase-1, and IL-1β.

CONCLUSIONS

MET demonstrates a protective effect against L-NAME-induced PE rats, potentially mediated through inhibition of the inflammatory response, downregulation of NLRP3 inflammasome expression in the placenta, and regulation of the balance between anti-angiogenic and pro-angiogenic factors.

Characterization of Mild Delayed Gestational Hypertension in Rats Following Ozone Exposure

The contribution of air pollution-induced cardiopulmonary damage on the development of hypertensive disorders of pregnancy and other adverse outcomes of pregnancy has gained increased attention as epidemiological data continue to highlight spatiotemporal pregnancy trends related to air pollution exposure. However clinical mechanistic data surrounding gestational complications remain sparse, necessitating the need for the use of animal models to study these types of complications of pregnancy. The current study seeks to examine the real-time effects of mid-gestational ozone exposure on maternal blood pressure and body temperature through the use of radiotelemetry in a rat model. The exposure resulted in acute depression of heart rate and core body temperature as compared to control animals. Ozone-exposed animals also presented with a slight but significant increase in arterial blood pressure which was perpetuated until term. The data presented here illustrates the feasibility of murine models to assess cardiovascular complications caused by inhaled toxicants during the window of pregnancy.

Maternal angiogenic factor disruptions prior to clinical diagnosis of preeclampsia: insights from the REVAMP study

Preeclampsia is characterized by impaired angiogenesis and assessment of angiogenic factors can play a crucial role in the early diagnosis of preeclampsia. The current study reports the levels of angiogenic factors longitudinally from early pregnancy in women with preeclampsia and in the subtypes of preeclampsia, to identify their role in early prediction of preeclampsia. A total of 1154 women with singleton pregnancies were recruited in early pregnancy from 2 hospitals. Blood samples were collected, plasma samples were separated and stored at four time points across gestation: V1 = 11-14 weeks, V2 = 18-22 weeks, V3 = 26-28 weeks, and V4 = at delivery. The current study includes a total of 108 women developed preeclampsia (PE), and 216 matched controls. Angiogenic factors were estimated using commercially available ELISA kits. Receiver operating characteristic (ROC) curves were used to evaluate the potential diagnostic value in the prediction of PE. Lower levels of VEGF, PlGF, and higher levels of sEng and sEng/PlGF ratio (p < 0.05 for all) predate clinical diagnosis in women with preeclampsia. sEng levels and sEng/PlGF ratio showed significant correlation with odds of preeclampsia at all the timepoints. This study identifies a cut off of 33.5 for sFlt-1/PlGF and 25.9 for sEng/PlGF for prediction of early onset preeclampsia. This study reports various angiogenic factors serially across gestation in a general population to identify women at risk of developing preeclampsia and its subtypes. The study also reports a potential biomarker and a pragmatic window for estimation of angiogenic markers to identify women at risk.

Association of elevated tricuspid regurgitation velocity with cerebrovascular and kidney disease in children with sickle cell disease

BACKGROUND

Tricuspid regurgitation velocity (TRV), measured by echocardiography, is a surrogate marker for pulmonary hypertension. Limited pediatric studies have considered the association between TRV and surrogate markers of end-organ disease.

METHODS

We conducted a cross-sectional study that evaluated the prevalence of elevated TRV ≥2.5 m/s and its associations with renal and cerebrovascular outcomes in children with sickle cell disease (SCD) 1-21 years of age in two large sickle cell cohorts, the University of Alabama at Birmingham (UAB) sickle cell cohort, and the Sickle Cell Clinical Research and Intervention Program (SCCRIP) cohort at St. Jude Children's Research Hospital. We hypothesized that patients with SCD and elevated TRV would have higher odds of having either persistent albuminuria or cerebrovascular disease.

RESULTS

We identified 166 children from the UAB cohort (mean age: 13.49 ± 4.47 years) and 325 children from the SCCRIP cohort (mean age: 13.41 ± 3.99 years) with echocardiograms. The prevalence of an elevated TRV was 21% in both UAB and SCCRIP cohorts. Elevated TRV was significantly associated with cerebrovascular disease (odds ratio [OR] 1.88, 95% confidence interval [CI]: 1.12-3.15; p = .017) and persistent albuminuria (OR 1.81, 95% CI: 1.07-3.06; p = .028) after adjusting for age, sex, treatment, and site.

CONCLUSION

This cross-sectional, multicenter study identifies associations between surrogate markers of pulmonary hypertension with kidney disease and cerebrovascular disease. A prospective study should be performed to evaluate the longitudinal outcomes for patients with multiple surrogate markers of end-organ disease.

Both endothelial mineralocorticoid receptor expression and hyperleptinemia are required for clinical characteristics of placental ischemia in mice

One of the initiating events in preeclampsia (PE) is placental ischemia. Rodent models of placental ischemia do not present with vascular endothelial dysfunction, a hallmark of PE. We previously demonstrated a role for leptin in endothelial dysfunction in pregnancy in the absence of placental ischemia. We hypothesized that placental ischemia requires hyperleptinemia and endothelial mineralocorticoid receptor (ECMR) expression to induce PE-associated endothelial dysfunction in pregnant mice. We induced placental ischemia via the reduced uterine perfusion pressure (RUPP) procedure in pregnant ECMR-intact (ECMR+/+) and ECMR deletion (ECMR-/-) mice at gestational day (GD) 13. ECMR+/+ RUPP pregnant mice also received concurrent leptin infusion via miniosmotic pump (0.9 mg/kg/day). RUPP increased blood pressure via radiotelemetry and decreased fetal growth in ECMR+/+ pregnant mice. Both increases in blood pressure and reduced fetal growth were abolished in RUPP ECMR-/- mice. Placental ischemia did not decrease endothelial-dependent relaxation to acetylcholine (ACh) but increased phenylephrine (Phe) contraction in mesenteric arteries of pregnant mice, which was ablated by ECMR deletion. Addition of leptin to RUPP mice significantly reduced ACh relaxation in ECMR+/+ pregnant mice, accompanied by an increase in soluble FMS-like tyrosine kinase-1 (sFlt-1)/placental growth factor (PLGF) ratio. In conclusion, our data indicate that high leptin levels drive endothelial dysfunction in PE and that ECMR is required for clinical characteristics of hypertension and fetal growth restriction in placental ischemia PE. Collectively, we show that both ECMR and leptin play a role to mediate PE.NEW & NOTEWORTHY Leptin is a key feature of preeclampsia that initiates vascular endothelial dysfunction in preeclampsia characterized by placental ischemia. Endothelial mineralocorticoid receptor (ECMR) deletion in placental ischemia protects pregnant mice from elevations in blood pressure and fetal growth restriction in pregnancy. Increases in leptin production mediate the key pathological feature of endothelial dysfunction in preeclampsia in rodents. ECMR activation contributes to the increase in blood pressure and fetal growth restriction in preeclampsia.

Maternal Blood Angiogenic Factors and the Prediction of Critical Adverse Perinatal Outcomes Among Small-for-Gestational-Age Pregnancies

OBJECTIVE

 Our objective was to determine whether maternal blood angiogenic factors in suspected-small-for-gestational-age (sSGA) fetuses can predict critical adverse perinatal outcomes (CAPO) and improve risk assessment.

METHODS

 Women with singleton pregnancies diagnosed with sSGA, between 24 and 356/7 weeks' gestation, were included. Clinical and sonographic comprehensive evaluations were performed at enrolment. Plasma angiogenic factors, soluble fms-like tyrosine kinase-1 (sFlt-1) and placental growth factor (PlGF), were obtained at diagnosis. In parallel, three attending maternal-fetal-medicine specialists predicted the risk (1-5 scale) of these pregnancies to develop CAPO, based on the clinical presentation. CAPOs were defined as prolonged neonatal intensive care unit hospitalization, fetal or neonatal death, and major neonatal morbidity. Statistical analysis included sensitivity, specificity, positive and negative predictive values, and receiver-operating characteristic (ROC) curve analyses.

RESULTS

 Of the 79 cases included, 32 were complicated by CAPO (40.5%). In SGA fetuses with CAPO, the sFlt-1/PlGF ratio was higher (p < 0.001) and PlGF was lower (p < 0.001) as compared with uncomplicated pregnancies. The areas under the ROC curves for specialists were 0.913, 0.824, and 0.811 and for PlGF and sFlt-1/PlGF ratio 0.926 and 0.900, respectively. CAPO was more common in pregnancies with absent end-diastolic flow or reversed end-diastolic flow (AEDF or REDF) in the umbilical artery upon enrolment (91.6%). Yet, 65.6% of cases involving CAPO occurred in patients without AEDF or REDF, and 66.6% of these cases were not identified by one or more of the experts. The sFlt-1/PlGF ratio identified 92.9% of the experts' errors in this group and 100% of the errors in cases with AEDF or REDF.

CONCLUSION

 Among sSGA pregnancies prior to 36 weeks' gestation, angiogenic factors testing can identify most cases later complicated with CAPO. Our data demonstrate for the first time that these markers can reduce clinician judgment errors. Incorporation of these measures into decision-making algorithms could potentially improve management, outcomes, and even health care costs.

KEY POINTS

· Angiogenic factors at diagnosis of sSGA can be used to predict CAPO.. · The sFlt-1/PlGF ratio can flag sSGA pregnancies at increased risk.. · The sFlt-1/PlGF ratio at admission of sSGA adds to clinical assessment..

Urinary sFlt-1 and PlGF as preeclampsia predictors: sFlt-1/creatinine ratio improves the prediction value

OBJECTIVES

To evaluate the correlation between maternal serum and urinary soluble Fms-like tyrosine kinase-1 (sFlt-1) and placental growth factor (PlGF) levels and to assess their potential value in preeclampsia and fetal growth restriction.

STUDY DESIGN

This case-control longitudinal prospective study was performed in 49 singleton pregnant women, divided into two clinical groups, low risk pregnancy (n = 23) and pregnancy complicated by preeclampsia (n = 26). Maternal serum and urinary sFlt-1 and PlGF levels were quantified by electrochemiluminescence. Every patient underwent an ultrasound for fetal biometry. Doppler assessment was done when estimated fetal weight was under the 10th centile. ROC curves were used to evaluate the predictive capability of serum and urinary angiogenic biomarkers and their ratios on preeclampsia. Linear regression was used to compare the values of serum and urinary sFlt-1 and PlGF and their ratios.

RESULTS

Urine biomarkers were positively associated with their serum values, being the best associated urinary PlGF (R2 = 0.73), which also showed the highest predictive capability of preeclampsia of urine biomarkers (AUC 0.866). The predictive capability of urinary sFlt-1 was much lower (AUC 0.640), but increased when adjusting by serum creatinine, a more precise parameter (AUC 0.863).

CONCLUSIONS

Urinary PlGF could be a lesser invasive alternative to circulating biomarkers to monitor pregnancies complicated with preeclampsia that need repeated controls of their pregnancy complication. Urinary sFlt-1 values need adjustment by serum creatinine to be reliable.

Connecting the Dots: Exploring the Interplay Between Preeclampsia and Peripartum Cardiomyopathy

Preeclampsia and peripartum cardiomyopathy (PPCM) are significant obstetric problems that can arise during or after pregnancy. Both are known to be causes of maternal mortality and morbidity. Several recent studies have suggested a link between preeclampsia and the pathophysiology of PPCM. However, the common thread that connects the two has yet to be thoroughly and fully articulated. Here, we investigate the complex dynamics of preeclampsia and PPCM in this review. Our analysis focuses mainly on inflammatory and immunological responses, endothelial dysfunction as a shared pathway, and potential genetic predisposition to both diseases. To begin, we will look at how excessive inflammatory and immunological responses can lead to clinical symptoms of both illnesses, emphasizing the role of proinflammatory cytokines and immune cells in modifying vascular and tissue responses. Second, we consider endothelial dysfunction to be a crucial point at which endothelial damage and activation contribute to pathogenesis through increased vascular permeability, vascular dysfunction, and thrombus formation. Finally, we examine recent information suggesting genetic predispositions to preeclampsia and PPCM, such as genetic variants in genes involved in the management of blood pressure, the inflammatory response, and heart structural integrity. With this synergistic study, we seek to encourage more research and creative therapy solutions by emphasizing the need for an interdisciplinary approach to understanding and managing the connection between preeclampsia and PPCM.

Association of angiogenic factors (placental growth factor and soluble FMS-like tyrosine kinase-1) in preeclamptic women of African ancestry comorbid with HIV infection

BACKGROUND

Preeclampsia is a significant cause of maternal and fetal morbidity and mortality, particularly in low- and middle-income countries like South Africa.

AIM

The aim of our study was to investigate the association between placental growth factor (PlGF) and soluble FMS-like tyrosine kinase-1 (sFlt-1) in South African preeclamptic women of African ancestry, comorbid with HIV infection.

METHODS

The study population consisted of women attending a regional hospital in Durban, South Africa, stratified by pregnancy type (normotensive pregnant and preeclampsia) and HIV status. Preeclampsia was defined as new-onset hypertension and proteinuria. DNA was obtained from whole blood. The SNPs of interest were rs722503 in sFlt-1 and rs4903273 in PlGF.

RESULTS

Our findings suggest that single nucleotide polymorphisms of rs722503 analysis show no significant associations between the genotypic frequencies of rs722503 variants and preeclampsia risk in either HIV-negative or HIV-positive groups of women of African ancestry. Similarly, the rs493273 polymorphism showed no significant association with preeclampsia risk in either HIV-negative or HIV-positive pregnant women. Additionally, comparisons of dominant, recessive, and over-dominant allele models did not reveal significant associations. These findings suggest that these genetic variants may not significantly contribute to preeclampsia development in this African ancestry population. However, significant differences were observed in the rs4903273 genotype frequencies between normotensive and preeclamptic women, regardless of HIV status, over dominant alleles AA + GG vs AG showed a significant difference [OR = 2.706; 95% Cl (1.199-5.979); adjusted p = 0.0234*], also in normotensive compared to EOPE (OR = 2.804; 95% Cl (1.151-6.89) p = 0.0326* and LOPE (OR = 2.601; 95% Cl (1.0310-6.539) p = 0.0492*), suggesting that they may be the potential role of this variant in preeclampsia susceptibility.

CONCLUSION

The findings suggest that the rs722503 and rs493273 polymorphisms do not significantly contribute to preeclampsia susceptibility in HIV-negative or HIV-positive pregnant women. However, the rs4903273 genotype frequencies showed notable differences between normotensive and preeclamptic women, indicating a potential association with preeclampsia development in the African ancestry population irrespective of HIV status.

Immunological mechanisms in preeclampsia: A narrative review

Maternal immunologic mechanisms for tolerance are essential for a successful pregnancy because they prevent maladaptive immune responses to the placenta and semi-allogeneic fetus and promote fetal growth. Preeclampsia is a major global cause of fetal mortality and morbidity. It is characterized by new-onset hypertension and proteinuria that occurs at twenty weeks of pregnancy or later. Preeclampsia is defined by a rise in cytokines that are pro-inflammatory and antiangiogenic components in the fetoplacental unit and the vascular endothelium of pregnant women, as well as an excessive and increasing stimulation of the immune system. Crucially, inflammation can result in low birth weight and inadequate placental perfusion in neonates. Preeclampsia, which is ultimately connected to inflammatory responses, can be impacted by several immunological mechanisms. Our goal in this work was to compile the most recent research on the pathoimmunology of preeclampsia, including studies on angiogenic variables and, in particular, immunological components.

IL-6 Polymorphism as a Predisposing Genetic Factor for Gestational Diabetes or Preeclampsia Development in Pregnancy with Obesity in Relation to VEGF and VEGFF Receptor Gene Expression Modalities

The increased prevalence of obesity worldwide has been implicated in the alarming rise of the incidence of gestational diabetes and preeclampsia, which are both considered threatening conditions for both mother and fetus. We studied gene polymorphisms of the proinflammatory cytokine Interleukin 6 (IL-6) and the gene expression levels of VEGF (vascular endothelial growth factor) and VEGF-R (endothelial growth factor receptor), all known to be involved in pregnancy complications, aiming to identify possible predisposing risk factors in pregnancies with obesity. The G allele of IL-6 was found to correspond with an increased risk for gestational diabetes and preeclampsia occurrence. Furthermore, in obese pregnant mothers with either gestational diabetes or pre-existing type 2 diabetes and those who developed preeclampsia, it was confirmed that gene expression levels of VEGF were reduced while they were increased for VEGF receptors. We conclude that the genetic profile of an obese pregnant woman shares a common background with that of a patient with pre-existing type 2 diabetes mellitus, and therefore predisposes them to complications in pregnancy.

The Effects of Low Concentrations of Pravastatin on Placental Cells

Pravastatin is a promising medication to treat preeclampsia. However, the appropriate dose of pravastatin for managing preeclampsia has not been established. In this in vitro study, we examined the effects of low concentrations of pravastatin (0.01 to 10 µM) under hypoxic conditions on two types of placental cells and found that pravastatin decreased sFlt-1 levels up to 34% in cytotrophoblast cells isolated from human term placentas. Furthermore, we showed that sFlt-1 levels in HTR-8/SVneo cells, a cell line derived from first trimester trophoblast cells, decreased after exposure to very low concentrations of pravastatin (0.01, 0.1 µM). We also examined the effects of pravastatin on uterine spiral artery remodeling-related events and showed in wound healing and tube formation assays that low concentrations of pravastatin upregulated cell migration and invasion in HTR-8/SVneo cells. These results demonstrated that a low dose of pravastatin has in vitro effects that suggest a potential for anti-preeclamptic effects in vivo.

Differential proteomics of circulating extracellular vesicles of placental origin isolated from women with early-onset preeclampsia reveal aberrant innate immune and hemostasis processes

PROBLEM

Early-onset preeclampsia (EOPE) is a severe gestational hypertensive disorder with significant feto-maternal morbidity and mortality due to uteroplacental insufficiency. Circulating extracellular vesicles of placental origin (EV-P) are known to be involved in the pathophysiology of EOPE and might serve as an ideal reservoir for its specific biomarkers. Therefore, we aimed to characterize and perform comparative proteomics of circulating EV-P from healthy pregnant and EOPE women before delivery.

METHOD OF STUDY

The EV-P from both groups were isolated using immunoaffinity and were characterized using transmission electron microscopy, dynamic light scattering, nanoparticle tracking analysis, and immunoblotting. Following IgG albumin depletion, the pooled proteins that were isolated from EV-P of both groups were subjected to quantitative TMT proteomics.

RESULTS

Circulating term EV-P isolated from both groups revealed ∼150 nm spherical vesicles containing CD9 and CD63 along with placental PLAP and HLA-G proteins. Additionally, the concentration of EOPE-derived EV-P was significantly increased. A total of 208 proteins were identified, with 26 among them being differentially abundant in EV-P of EOPE women. This study linked the pathophysiology of EOPE to 19 known and seven novel proteins associated with innate immune responses such as complement and TLR signaling along with hemostasis and oxygen homeostasis.

CONCLUSION

The theory suggesting circulating EVs of placental origin could mimic molecular information from the parent organ-"the placenta"-is strengthened by this study. The findings pave the way for possible discovery of novel prognostic and predictive biomarkers as well as provide insight into the mechanisms driving the pathogenesis of EOPE.

Placental and serum levels of human α-Klotho in preeclampsia & intra-uterine growth retardation: A potential sensitive biomarker?

INTRODUCTION

α-Klotho protein has three isoforms: a transmembrane (mKL), a shed- soluble isoform, and a circulating soluble isoform (sKL). mKL is expressed in the kidney and placenta, while sKL is detectable in blood and urine. It is known that α-Klotho levels fluctuate during pregnancy mainly in women with complications such as preeclampsia (PE) and intra-uterine growth restriction (IUGR).

METHODS

Forty-nine participants were divided into two groups: healthy and complicated pregnancy (PE, IUGR or both). Tissue samples (2 cm3) from the maternal side, Blood and urine samples were collected during pregnancy and postpartum. Samples were subjected to biochemical (WB), histological (H&E and IHC) staining as well as genetic analysis (qPCR).

RESULTS

Blood αKL levels were preserved in both healthy and complicated pregnancies. Significantly lower blood αKL concentrations were found in PE postpartum (PP) compared to levels during pregnancy, and were significantly lower compared with postpartum of a healthy pregnancy. αKL activity was reduced in complicated pregnancies vs. healthy pregnancies. Placen tal mKL levels (ELISA) and expression (WB) were lowered in complicated pregnancies compared with the healthy pregnancies group. Additionally, we found a significant decline in the expression of mKL mRNA in PE/IUGR placentas compared with the healthy group.

DISCUSSION

Several studies have focused on the involvement of αKL in normal placentation during pregnancy. Our results suggest lower function of sKL in complicated pregnancy compared with a control, and present differences in placental mKL levels as well as tissue and gene expression between healthy and complicated pregnancy. In light of our results, we conclude that complicated pregnancy is associated with in decline in mKL.

Angiogenic factors and the lectin pathway of complement in women with secondary recurrent pregnancy loss

The poor remodeling of placental spiral arteries seen in preeclampsia is also discussed to contribute to recurrent pregnancy loss (RPL) preceded by abnormal angiogenesis and excessive complement activation. Low levels of Mannose-binding-lectin (MBL), a pattern recognition molecule (PRM) of the lectin pathway, have been found in women with RPL. We propose that pregnancy loss is connected to defective angiogenesis with reperfusion damage in the placenta and decreased levels of PRM in the lectin pathway in women with RPL. In this cohort study, we investigate the angiogenic factors and the lectin complement pathway in early pregnancy and their time-dependent relationship with pregnancy outcomes in 76 women with secondary RPL (sRPL) who have at least four prior pregnancy losses and a live birth. We evaluated levels of Angiopoietin-1 (Ang-1), Angiopoietin-2 (Ang-2), Vascular Endothelial Growth Factor (VEGF), soluble fms-like tyrosine kinase-1 (sFlt-1), and the PRMs, MBL, ficolin-1, -2, -3 and an additional soluble PRM, Pentraxin-3, during the 5th, 6th, and 7th gestational weeks. Our results showed that, compared to live births, pregnancies that ended in loss were associated with elevated VEGF levels and decreased levels of the Ang-2/Ang-1 ratio. Also, increasing levels of ficolin-2 were significantly associated with pregnancy loss, with MBL showing no association. Our research suggests that women with sRPL may have inadequate placentation with impaired angiogenesis in pregnancies ending in a loss.

Coronary Microvascular Function Following Severe Preeclampsia

BACKGROUND

Preeclampsia is a pregnancy-specific hypertensive disorder associated with an imbalance in circulating proangiogenic and antiangiogenic proteins. Preclinical evidence implicates microvascular dysfunction as a potential mediator of preeclampsia-associated cardiovascular risk.

METHODS

Women with singleton pregnancies complicated by severe antepartum-onset preeclampsia and a comparator group with normotensive deliveries underwent cardiac positron emission tomography within 4 weeks of delivery. A control group of premenopausal, nonpostpartum women was also included. Myocardial flow reserve, myocardial blood flow, and coronary vascular resistance were compared across groups. sFlt-1 (soluble fms-like tyrosine kinase receptor-1) and PlGF (placental growth factor) were measured at imaging.

RESULTS

The primary cohort included 19 women with severe preeclampsia (imaged at a mean of 15.3 days postpartum), 5 with normotensive pregnancy (mean, 14.4 days postpartum), and 13 nonpostpartum female controls. Preeclampsia was associated with lower myocardial flow reserve (β, -0.67 [95% CI, -1.21 to -0.13]; P=0.016), lower stress myocardial blood flow (β, -0.68 [95% CI, -1.07 to -0.29] mL/min per g; P=0.001), and higher stress coronary vascular resistance (β, +12.4 [95% CI, 6.0 to 18.7] mm Hg/mL per min/g; P=0.001) versus nonpostpartum controls. Myocardial flow reserve and coronary vascular resistance after normotensive pregnancy were intermediate between preeclamptic and nonpostpartum groups. Following preeclampsia, myocardial flow reserve was positively associated with time following delivery (P=0.008). The sFlt-1/PlGF ratio strongly correlated with rest myocardial blood flow (r=0.71; P<0.001), independent of hemodynamics.

CONCLUSIONS

In this exploratory cross-sectional study, we observed reduced coronary microvascular function in the early postpartum period following preeclampsia, suggesting that systemic microvascular dysfunction in preeclampsia involves coronary microcirculation. Further research is needed to establish interventions to mitigate the risk of preeclampsia-associated cardiovascular disease.

Impact of Survivin rs9904341 and rs17878467 Polymorphisms On Risk of Preeclampsia in Iran

Preeclampsia (PE) is a hypertensive disorder that affects pregnancy, mother, and fetus. Early diagnosis of PE remains a challenge. This study aimed to investigate the association between survivin two (rs9904341 and rs17878467) SNPs and PE risk in healthy pregnant women compared to women with preeclampsia. A sample of 166 healthy pregnant women and 160 cases with preeclampsia was included and genotyped for rs9904341 with polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and rs17878467 with amplification-refractory mutation system (ARMS) PCR. The genotypic and allelic assessments were performed using various statistical approaches. The frequency of rs9904341 and rs17878467 polymorphisms was not significantly different between PE and healthy pregnant women. rs9904341: codominant (p = 0.5), dominant (p = 0.24), recessive (p = 0.61), over-dominant model (p = 0.38), and log additive (p = 0.25). rs17878467: codominant (p = 0.41), dominant (p = 0.23), recessive (p = 0.4), over-dominant model (p = 0.42), and log additive (p = 0.24). The frequency of survivin rs9904341 CG and CC genotypes was higher in severe PE women compared to controls and this polymorphism was associated with PE severity only in the dominant model (OR = 1.84, CI 1.04-3.26, P = 0.034). There was a significant association between survivin rs9904341 polymorphism and PE severity. No relationship was found between survivin rs9904341 and rs17878467 polymorphisms and PE onset. The allelic and genotypic frequencies of survivin rs9904341 and rs17878467 polymorphisms are not significantly different between the preeclampsia and control groups in all genetic models. Haplotype analysis showed lower frequency G rs9904341 T rs17878467 haplotype in PE woman and this haplotype was associated with lower risk of PE (OR = 0.54, CI 0.33-0.91, P = 0.02).

Pre-eclampsia: Re-visiting pathophysiology, role of immune cells, biomarker identification and recent advances in its management

Pre-eclampsia (PE) is a hypertension condition that occurs exclusively during pregnancy and has the potential to impact nearly all organ systems. It is estimated to complicate approximately 2-8% of pregnancies worldwide. PE is a prominent medical disorder that poses a significant risk to pregnant mothers and their infants. This review commences by giving the most up-to- date concepts about the pathophysiology of PE. The condition involves atypical infiltration of trophoblast cells into the spiral arteries of the decidua and myometrium, resulting in an insufficient establishment of proper blood flow between the uterus and placenta. The aberrant activation of natural killer (NK) cells in both the peripheral blood and the decidua has been identified as one of the contributing factors to the development of PE. The strong evidence for the genetic etiology of PE is provided by the association between maternal killer cell immunoglobulin-like receptor (KIR) and Human Leukocyte Antigen (HLA-C) in trophoblast cells. Recent observations provide evidence that changes in the expression of anti-angiogenic factors in the placenta are the underlying cause of the clinical symptoms associated with the condition. This review also provides a comprehensive overview of the latest advancements in understanding the underlying causes of PE. It specifically highlights the emergence of new diagnostic biomarkers and their potential implications for therapeutic interventions in managing this medical condition.

Pathophysiology of Preeclampsia-Induced Vascular Dysfunction and Implications for Subclinical Myocardial Damage and Heart Failure

Tragically, preeclampsia is a leading cause of pregnancy-related complications and is linked to a heightened risk for morbid and fatal cardiovascular disease (CVD) outcomes. Although the mechanism connecting preeclampsia to CVD risk has yet to be fully elucidated, evidence suggests distinct pathways of early and late preeclampsia with shared CV risk factors but with profound differences in perinatal and postpartum risk to the mother and infant. In early preeclampsia, <34 weeks of gestation, systemic vascular dysfunction contributes to near-term subclinical myocardial damage. Hypertrophy and diastolic abnormalities persist postpartum and contribute to early onset heart failure (HF). This HF risk remains elevated decades later and contributes to premature death. Black women are at the highest risk of preeclampsia and HF. These findings support closer monitoring of women postpartum, especially for those with early and severe preeclampsia to control chronic hypertension and reduce the potentially preventable sequelae of heightened CVD and HF risk.

Plasma soluble fms-like tyrosine kinase 1 to placental growth factor ratio of 11.5 multiples of median predicts preeclampsia with severe features within 2 weeks of testing

BACKGROUND

Angiogenic imbalances, characterized by an excess of antiangiogenic factors (soluble fms-like tyrosine kinase 1) and reduced angiogenic factors (vascular endothelial growth factor and placental growth factor), contribute to the mechanisms of disease in preeclampsia. The ratio of soluble fms-like tyrosine kinase 1 to placental growth factor has been used as a biomarker for preeclampsia, but the cutoff values may vary with gestational age and assay platform.

OBJECTIVE

This study aimed to compare multiples of the median of the maternal plasma soluble fms-like tyrosine kinase 1 to placental growth factor ratio, soluble fms-like tyrosine kinase 1, placental growth factor, and conventional clinical and laboratory values in their ability to predict preeclampsia with severe features.

STUDY DESIGN

We conducted a cohort study across 18 United States centers involving hospitalized individuals with hypertension between 23 and 35 weeks' gestation. Receiver operating characteristic curve analyses of maternal plasma biomarkers, highest systolic or diastolic blood pressures, and laboratory values at enrollment were performed for the prediction of preeclampsia with severe features. The areas under the curve were compared, and quasi-Poisson regression models were fitted to estimate relative risks. The primary outcome was preeclampsia with severe features within 2 weeks of enrollment. Secondary outcomes were a composite of severe adverse maternal outcomes (elevated liver enzymes, low platelets count, placental abruption, eclampsia, disseminated intravascular coagulation, and pulmonary edema) and a composite of severe adverse perinatal outcomes (birth weight below the third percentile, very preterm birth [<32 weeks' gestation], and fetal or neonatal death).

RESULTS

Of the 543 individuals included in the study, preeclampsia with severe features within 2 weeks was observed in 33.1% (n=180) of them. A receiver operating characteristic curve-derived cutoff of 11.5 multiples of the median for the soluble fms-like tyrosine kinase 1 to placental growth factor plasma ratio provided good sensitivity (90.6%), specificity (76.9%), positive predictive value (66.0%), negative predictive value (94.3%), positive likelihood ratio (3.91), negative likelihood ratio (0.12), and accuracy (81.4%) for preeclampsia with severe features within 2 weeks. This cutoff was used to compare test positive cases (≥ cutoff) and test negative cases (< cutoff). Preeclampsia with severe features (66.0% vs 5.7%; P<.001) and composites of severe adverse maternal (8.11% vs 2.7%; P=.006) or perinatal (41.3% vs 10.14%; P=.001) outcomes within 2 weeks were more frequent in test positive cases than in test negative cases. A soluble fms-like tyrosine kinase 1 to placental growth factor plasma ratio ≥11.5 multiples of the median was independently associated with preeclampsia with severe features (adjusted incidence rate ratio, 9.08; 95% confidence interval, 6.11-14.06; P<.001) and a composite of severe adverse perinatal outcomes (adjusted incidence rate ratio, 9.42; 95% confidence interval, 6.36-14.53; P<.001) but not with a composite of severe adverse maternal outcomes (adjusted incidence rate ratio, 2.20; 95% confidence interval, 0.95-5.54; P=.08). The area under the curve for the soluble fms-like tyrosine kinase 1 to placental growth factor plasma ratio in multiples of the median (0.91; 95% confidence interval, 0.89-0.94) for preeclampsia with severe features within 2 weeks was significantly higher (P<.001 for all comparisons) than either plasma biomarker alone or any other parameter with the exception of absolute soluble fms-like tyrosine kinase 1 to placental growth factor plasma ratio values.

CONCLUSION

A soluble fms-like tyrosine kinase 1 to placental growth factor plasma ratio ≥11.5 multiples of the mean among hospitalized patients with hypertension between 23 and 35 week's gestation predicts progression to preeclampsia with severe features and severe adverse perinatal outcomes within 2 weeks.

Hypertensive disorders of pregnancy & vascular dysfunction

Hypertensive disorders of pregnancy (HDP) are a leading cause of maternal and fetal morbidity and mortality. One of the more severe HDP diagnoses is preeclampsia, which is recognized as a sex-specific cardiovascular risk enhancer with long-term implications for women's health, increasing lifetime risk of ischemic heart disease, stroke, and heart failure. Though the mechanisms accounting for the increased risk of cardiovascular disease following HDP are not yet well understood, vascular dysfunction has been implicated. In this perspective piece, we summarize the existing evidence for vascular dysfunction in HDP with a focus on non-invasive assessments, highlight advances in the field, and suggest future directions for improving risk stratification of women with HDP.

Placenta-targeted Treatment Strategies for Preeclampsia and Fetal Growth Restriction: An Opportunity and Major Challenge

The placenta plays a crucial role in maintaining normal pregnancy. The failure of spiral artery remodeling (SAR) is a key factor leading to placental ischemia and poor perfusion which is strongly associated with obstetric diseases, including preeclampsia (PE) and fetal growth restriction (FGR). Existing interventions for PE and FGR are limited and termination of pregnancy is inevitable when the maternal or fetus condition deteriorates. Considering the safety of the mother and fetus, treatments that may penetrate the placental barrier and harm the fetus are not accepted. Developing targeted treatment strategies for these conditions is urgent and necessary. With the proven efficacy of targeted therapy in treating conditions such as endometrial cancer and trophoblastic tumors, research on placental dysfunction continues to deepen. This article reviews the studies on placenta-targeted treatment and drug delivery strategies, summarizes the characteristics proposes corresponding improvement measures in targeted treatment, provides solutions for existing problems, and makes suggestions for future studies.

sFlt-1 impairs neurite growth and neuronal differentiation in SH-SY5Y cells and human neurons

Pre-eclampsia (PE) is a hypertensive disorder of pregnancy which is associated with increased risk of neurodevelopmental disorders in exposed offspring. The pathophysiological mechanisms mediating this relationship are currently unknown, and one potential candidate is the anti-angiogenic factor soluble Fms-like tyrosine kinase 1 (sFlt-1), which is highly elevated in PE. While sFlt-1 can impair angiogenesis via inhibition of VEGFA signalling, it is unclear whether it can directly affect neuronal development independently of its effects on the vasculature. To test this hypothesis, the current study differentiated the human neural progenitor cell (NPC) line ReNcell® VM into a mixed culture of mature neurons and glia, and exposed them to sFlt-1 during development. Outcomes measured were neurite growth, cytotoxicity, mRNA expression of nestin, MBP, GFAP, and βIII-tubulin, and neurosphere differentiation. sFlt-1 induced a significant reduction in neurite growth and this effect was timing- and dose-dependent up to 100 ng/ml, with no effect on cytotoxicity. sFlt-1 (100 ng/ml) also reduced βIII-tubulin mRNA and neuronal differentiation of neurospheres. Undifferentiated NPCs and mature neurons/glia expressed VEGFA and VEGFR-2, required for endogenous autocrine and paracrine VEGFA signalling, while sFlt-1 treatment prevented the neurogenic effects of exogenous VEGFA. Overall, these data provide the first experimental evidence for a direct effect of sFlt-1 on neurite growth and neuronal differentiation in human neurons through inhibition of VEGFA signalling, clarifying our understanding of the potential role of sFlt-1 as a mechanism by which PE can affect neuronal development.

Biomarkers for Early Prediction and Management of Preeclampsia: A Comprehensive Review

Preeclampsia is a common complication of pregnancy. It is a multi-organ disorder that remains one of the main causes of maternal morbidity and mortality. Additionally, preeclampsia leads to many complications that can occur in the fetus or newborn. Preeclampsia occurs in about 1 in 20 pregnant women. This review focuses on the prediction of preeclampsia in women, using various biomarkers, in particular, a factor combining the use of soluble FMS-like tyrosinokinase-1 (sFlt-1) and placental growth factor (PlGF). A low value of the sFlt-1/PlGF ratio rules out the occurrence of preeclampsia within 4 weeks of the test result, and its high value predicts the occurrence of preeclampsia within even 1 week. The review also highlights other factors, such as pregnancy-associated plasma protein A, placental protein 13, disintegrin and metalloprotease 12, ß-human chorionic gonadotropin, inhibin-A, soluble endoglin, nitric oxide, and growth differentiation factor 15. Biomarker testing offers reliable and cost-effective screening methods for early detection, prognosis, and monitoring of preeclampsia. Early diagnosis in groups of women at high risk for preeclampsia allows for quick intervention, preventing the undesirable effects of preeclampsia. However, further research is needed to validate and optimize the use of biomarkers for more accurate prediction and diagnosis. This article aims to review the role of biomarkers, including the sFlt1/PlGF ratio, in the prognosis and management of preeclampsia.

Epigallocatechin gallate (EGCG) alleviates inflammation and endothelial dysfunction and improves pregnancy outcomes in preeclampsia (PE)-like rats via eNOS/Nrf2/HO-1 pathway

BACKGROUND AND PURPOSE

Epigallocatechin gallate (EGCG), a natural antioxidant, has shown protective effect in many diseases. We explore the effect and potential regulatory mechanisms of EGCG in preeclampsia (PE)-like rats.

METHODS AND MATERIALS

PE was mimicked in pregnant rats. EGCG was orally administered at a dosage of 25(Low, L) or 50 mg/kg (High, H) from gestational day (GD) 6-17. The blood pressure signatures, heart rates were monitored. The 24-h proteinuria and serum were analyzed. On GD 18, rats were sacrificed, and pups and placentas were weighed. Kidneys and placentas were analyzed using immunohistochemistry (IHC) and hematoxylin-eosin staining (H&E). Placentas were examined using western blot for sFlt1, eNOS, Nrf2, HO-1, SLC7A11. MDA, GSH, GPx and Fe2+ were measured.

RESULTS

EGCG inhibits systolic blood pressure, BUN, CREA, ALT, AST, UA and proteinuria levels in PE-like rats. EGCG enhances the pup weight and crown-rump length and reduces the rate of fetus growth restriction in PE group. Endothelial dysfunction and infiltration of inflammatory cells were found in kidney cortex and placenta tissues in PE group and were inhibited by EGCG treatment. sFlt1 was activated in placentas in PE group and inhibited by EGCG while eNOS/Nrf2/HO-1 were inhibited in PE group and restored by EGCG. MDA and Fe concentrations were elevated in PE group and reduced by EGCG while the GSH level, SLC7A11 and the GPx activity were inhibited in PE group and restored by EGCG.

CONCLUSION

EGCG alleviates inflammation, endothelial dysfunction and placental ferroptosis, improves pregnancy outcomes in PE-like rats via eNOS/Nrf2/HO-1.

Acute response to pathogens in the early human placenta at single-cell resolution

The placenta is a selective maternal-fetal barrier that provides nourishment and protection from infections. However, certain pathogens can attach to and even cross the placenta, causing pregnancy complications with potential lifelong impacts on the child's health. Here, we profiled at the single-cell level the placental responses to three pathogens associated with intrauterine complications-Plasmodium falciparum, Listeria monocytogenes, and Toxoplasma gondii. We found that upon exposure to the pathogens, all placental lineages trigger inflammatory responses that may compromise placental function. Additionally, we characterized the responses of fetal macrophages known as Hofbauer cells (HBCs) to each pathogen and propose that they are the probable niche for T. gondii. Finally, we revealed how P. falciparum adapts to the placental microenvironment by modulating protein export into the host erythrocyte and nutrient uptake pathways. Altogether, we have defined the cellular networks and signaling pathways mediating acute placental inflammatory responses that could contribute to pregnancy complications.

Adipokines in pregnancy

Reproductive success consists of a sequential events chronology, starting with the ovum fertilization, implantation of the embryo, placentation, and cellular processes like proliferation, apoptosis, angiogenesis, endocrinology, or metabolic changes, which taken together finally conduct the birth of healthy offspring. Currently, many factors are known that affect the regulation and proper maintenance of pregnancy in humans, domestic animals, or rodents. Among the determinants of reproductive success should be distinguished: the maternal microenvironment, genes, and proteins as well as numerous pregnancy hormones that regulate the most important processes and ensure organism homeostasis. It is well known that white adipose tissue, as the largest endocrine gland in our body, participates in the synthesis and secretion of numerous hormones belonging to the adipokine family, which also may regulate the course of pregnancy. Unfortunately, overweight and obesity lead to the expansion of adipose tissue in the body, and its excess in both women and animals contributes to changes in the synthesis and release of adipokines, which in turn translates into dramatic changes during pregnancy, including those taking place in the organ that is crucial for the proper progress of pregnancy, i.e. the placenta. In this chapter, we are summarizing the current knowledge about levels of adipokines and their role in the placenta, taking into account the physiological and pathological conditions of pregnancy, e.g. gestational diabetes mellitus, preeclampsia, or intrauterine growth restriction in humans, domestic animals, and rodents.

Alleviation of preeclampsia-like symptoms through PlGF and eNOS regulation by hypoxia- and NF-κB-responsive miR-214-3p deletion

Preeclampsia is caused by placental hypoxia and systemic inflammation and is associated with reduced placental growth factor (PlGF) and endothelial nitric oxide synthase (eNOS) levels. The molecular signaling axes involved in this process may play a role in the pathogenesis of preeclampsia. Here, we found that hypoxic exposure increased hypoxia-inducible factor-1α (HIF-1α)/Twist1-mediated miR-214-3p biogenesis in trophoblasts, suppressing PlGF production and trophoblast invasion. TNF-α stimulation increased NF-κB-dependent miR-214-3p expression in endothelial cells, impairing eNOS expression and causing endothelial dysfunction. Synthetic miR-214-3p administration to pregnant mice decreased PlGF and eNOS expression, resulting in preeclampsia-like symptoms, including hypertension, proteinuria, and fetal growth restriction. Conversely, miR-214-3p deletion maintained the PlGF and eNOS levels in hypoxic pregnant mice, alleviating preeclampsia-like symptoms and signs. These findings provide new insights into the role of HIF-1/Twist1- and NF-κB-responsive miR-214-3p-dependent PlGF and eNOS downregulation in the pathogenesis of preeclampsia and establish miR-214-3p as a therapeutic or preventive target for preeclampsia and its complications.

Disruption of maternal vascular remodeling by a fetal endoretrovirus-derived gene in preeclampsia

BACKGROUND

Preeclampsia, one of the most lethal pregnancy-related diseases, is associated with the disruption of uterine spiral artery remodeling during placentation. However, the early molecular events leading to preeclampsia remain unknown.

RESULTS

By analyzing placentas from preeclampsia, non-preeclampsia, and twin pregnancies with selective intrauterine growth restriction, we show that the pathogenesis of preeclampsia is attributed to immature trophoblast and maldeveloped endothelial cells. Delayed epigenetic reprogramming during early extraembryonic tissue development leads to generation of excessive immature trophoblast cells. We find reduction of de novo DNA methylation in these trophoblast cells results in selective overexpression of maternally imprinted genes, including the endoretrovirus-derived gene PEG10 (paternally expressed gene 10). PEG10 forms virus-like particles, which are transferred from the trophoblast to the closely proximate endothelial cells. In normal pregnancy, only a low amount of PEG10 is transferred to maternal cells; however, in preeclampsia, excessive PEG10 disrupts maternal vascular development by inhibiting TGF-beta signaling.

CONCLUSIONS

Our study reveals the intricate epigenetic mechanisms that regulate trans-generational genetic conflict and ultimately ensure proper maternal-fetal interface formation.

A case-based narrative review of pregnancy-associated atypical hemolytic uremic syndrome/complement-mediated thrombotic microangiopathy

Atypical hemolytic uremic syndrome is a complement-mediated thrombotic microangiopathy caused by uncontrolled activation of the alternative complement pathway in the setting of autoantibodies to or rare pathogenic genetic variants in complement proteins. Pregnancy may serve as a trigger and unmask atypical hemolytic uremic syndrome/complement-mediated thrombotic microangiopathy (aHUS/CM-TMA), which has severe, life-threatening consequences. It can be difficult to diagnose aHUS/CM-TMA in pregnancy due to overlapping clinical features with other thrombotic microangiopathy syndromes including hypertensive disorders of pregnancy. However, the distinction among thrombotic microangiopathy etiologies in pregnancy is important because each syndrome has specific disease management and treatment. In this narrative review, we discuss 2 cases to illustrate the diagnostic challenges and evolving approach in the management of pregnancy-associated aHUS/CM-TMA. The first case involves a 30-year-old woman presenting in the first trimester who was diagnosed with aHUS/CM-TMA and treated with eculizumab from 19 weeks' gestation. Genetic testing revealed a likely pathogenic variant in CFI. She successfully delivered a healthy infant at 30 weeks' gestation. In the second case, a 22-year-old woman developed severe postpartum HELLP syndrome, requiring hemodialysis. Her condition improved with supportive management, yet investigations assessing for aHUS/CM-TMA remained abnormal 6 months postpartum consistent with persistent complement activation but negative genetic testing. Through detailed case discussion describing tests assessing for placental health, fetal anatomy, complement activation, autoantibodies to complement regulatory proteins, and genetic testing for aHUS/CM-TMA, we describe how these results aided in the clinical diagnosis of pregnancy-associated aHUS/CM-TMA and assisted in guiding patient management, including the use of anticomplement therapy.

Cadmium exposure activates mitophagy through downregulating thyroid hormone receptor/PGC1α signal in preeclampsia

Gestational cadmium exposure increases the risk of preeclampsia. Placenta mitophagy was activated in preeclampsia. The aim of present study was to explore the mechanism of cadmium-induced mitophagy activation and its association with preeclampsia. Mitophagy markers expression levels were detected by quantitative real-time PCR, Western blot, immunofluorescence and immunochemistry in preeclampsia placenta. JEG3 cells were treated with CdCl2, iopanoic acid (IOP), 3-methyladenine and PGC1α SiRNA to verify mechanism of cadmium-induced mitophagy. Mitophagy marker LC3BII/I and P62 expression were increased and mitochondrial membrane receptor protein TOM20 and FUNDC1 expression were decreased in preeclampsia placenta as compared with that in normotension control. Mitophagy marker LC3BII/I and P62 expression were increased and TOM20 and FUNDC1 expression was decreased in CdCl2-treated JEG3 cells. Meanwhile, mitochondrial biogenesis regulator, PGC1α expression was decreased in preeclampsia and CdCl2-treated JEG3 cells. The expressions of LC3B and P62 were increased and the expressions of TOM20, FUNDC1 and PGC1α were decreased in IOP-treated cell. PGC1α SiRNA transfection led to increased expression of LC3BII/I and P62 and decreased expression of TOM20 and FUNDC1. The expression of sFlt1 was increased in preeclampsia placenta, CdCl2-treated cells, in IOP-treated cells and in PGC1α SiRNA transfected cells. 3-methyladenine treatment protected the increased expression of sFlt1 in CdCl2-treated cells, in IOP-treated cells and in PGC1α SiRNA transfected cells. Meanwhile, co-treatment of cadmium and IOP or PGC1αSiRNA led to a reduce expressions of OPA1, MFN1, MFN2 and FUNDC1 as compared to cadmium-treated, IOP-treated and PGC1α SiRNA-treated cells. These results elucidated that maternal cadmium exposure activated placenta mitophagy through downregulation of thyroid hormone receptor signal mediated decreased expression of PGC1α and was associated with the occurrence of preeclampsia.

Exploiting sweet relief for preeclampsia by targeting autophagy-lysosomal machinery and proteinopathy

The etiology of preeclampsia (PE), a severe complication of pregnancy with several clinical manifestations and a high incidence of maternal and fetal morbidity and mortality, remains unclear. This issue is a major hurdle for effective treatment strategies. We recently demonstrated that PE exhibits an Alzheimer-like etiology of impaired autophagy and proteinopathy in the placenta. Targeting of these pathological pathways may be a novel therapeutic strategy for PE. Stimulation of autophagy with the natural disaccharide trehalose and its lacto analog lactotrehalose in hypoxia-exposed primary human trophoblasts restored autophagy, inhibited the accumulation of toxic protein aggregates, and restored the ultrastructural features of autophagosomes and autolysosomes. Importantly, trehalose and lactotrehalose inhibited the onset of PE-like features in a humanized mouse model by normalizing autophagy and inhibiting protein aggregation in the placenta. These disaccharides restored the autophagy-lysosomal biogenesis machinery by increasing nuclear translocation of the master transcriptional regulator TFEB. RNA-seq analysis of the placentas of mice with PE indicated the normalization of the PE-associated transcriptome profile in response to trehalose and lactotrehalose. In summary, our results provide a novel molecular rationale for impaired autophagy and proteinopathy in patients with PE and identify treatment with trehalose and its lacto analog as promising therapeutic options for this severe pregnancy complication.

Advances in pathogenesis of preeclampsia

PURPOSE

Preeclampsia is a major cause of health problems for both pregnant women and unborn babies worldwide. However, the underlying causes of preeclampsia are not fully understood, leading to limited effective treatments. The goal of this study is to enhance our knowledge of its causes, devise prevention strategies, and develop treatments.

METHODS

We performed a systematic literature search. Six models regarding the pathogenesis of preeclampsia are discussed in this review.

RESULTS

This review focuses on the latest advancements in understanding preeclampsia's origins. Preeclampsia is a complex condition caused by various factors, processes, and pathways. Reduced blood flow and oxygen to the uterus and placenta, heightened inflammatory reactions, immune imbalances, altered genetic changes, imbalanced blood vessel growth factors, and disrupted gut bacteria may contribute to its development.

CONCLUSION

Preeclampsia is thought to result from the interplay of these factors.

Exploring melatonin's multifaceted role in female reproductive health: From follicular development to lactation and its therapeutic potential in obstetric syndromes

BACKGROUND

Melatonin is mainly secreted by the pineal gland during darkness and regulates biological rhythms through its receptors in the suprachiasmatic nucleus of the hypothalamus. In addition, it also plays a role in the reproductive system by affecting the function of the hypothalamic-pituitary-gonadal axis, and by acting as a free radical scavenger thus contributing to the maintenance of the optimal physiological state of the gonads. Besides, melatonin can freely cross the placenta to influence fetal development. However, there is still a lack of overall understanding of the role of melatonin in the reproductive cycle of female mammals.

AIM OF REVIEW

Here we focus the role of melatonin in female reproduction from follicular development to delivery as well as the relationship between melatonin and lactation. We further summarize the potential role of melatonin in the treatment of preeclampsia, polycystic ovary syndrome, endometriosis, and ovarian aging.

KEY SCIENTIFIC CONCEPTS OF REVIEW

Understanding the physiological role of melatonin in female reproductive processes will contribute to the advancement of human fertility and reproductive medicine research.

Immunometric and functional measurement of endogenous vasoinhibin in human sera

Introduction

Circulating levels of the antiangiogenic protein vasoinhibin, a fragment of prolactin, are of interest in vasoproliferative retinopathies, preeclampsia, and peripartum cardiomyopathy; however, it is difficult to determine the circulating levels of vasoinhibin due to the lack of quantitative assays.

Methods

This study used human serum samples to assess the concentration and bioactivity of vasoinhibin using a novel enzyme-linked immunosorbent assay (ELISA) for human vasoinhibin, which employs an anti-vasoinhibin monoclonal antibody, a human umbilical vein endothelial cell (HUVEC) proliferation assay, and a chick chorioallantoic membrane (CAM) angiogenesis assay.

Results

Serum samples from 17 pregnant women without (one group) and with preeclampsia and pregnancy induced hypertension (another group) demonstrated endogenous vasoinhibin concentrations in the range of 5-340 ng/ml. Immunoactive vasoinhibin levels were significantly higher in preeclampsia serum compared to healthy pregnancy serum (mean 63.09 ± 22.15 SD vs. 19.67 ± 13.34 ng/ml, p = 0.0003), as was the bioactive vasoinhibin level as determined by the HUVEC proliferation assay (56.12 ± 19.83 vs. 13.38 ± 4.88 ng/ml, p < 0.0001). There was a correlation between the concentration of vasoinhibin measured by ELISA and the HUVEC proliferation assay (Pearson r = 0.95, p < 0.0001). Healthy serum demonstrated a proangiogenic effect in the CAM assay (p < 0.05, compared to control), while serum from preeclamptic patients demonstrated an antiangiogenic effect (p < 0.05 vs. control), as did recombinant human vasoinhibin and a synthetic circular retro-inverse vasoinhibin analogue (CRIVi45-51). The antiangiogenic effects in the CAM assay and the inhibition of HUVEC proliferation were abolished by addition of the ELISA anti-vasoinhibin monoclonal antibody, but not by mouse IgG.

Discussion

These results demonstrate the first quantitation of endogenous vasoinhibin in human sera and the elevation of it levels and antiangiogenic activity in sera from women with preeclampsia. The development and implementation of a quantitative assay for vasoinhibin overcomes a long-standing barrier and suggests the thorough clinical verification of vasoinhibin as a relevant biomarker.

Oxidative stress contributes to hypermethylation of Histone H3 lysine 9 in placental trophoblasts from preeclamptic pregnancies

Background and objective

Aberrant epigenetic regulation and increased oxidative stress in the placenta play a significant role in placental pathophysiology and fetal programming in preeclampsia, a hypertensive disorder in human pregnancy. The purpose of the study is to investigate if hypermethylation of histone H3K9 occurs in placental trophoblasts from preeclampsia.

Methods

Trophoblasts were isolated and cultured from 14 placentas, 7 from normotensive pregnant women and 7 from preeclamptic pregnancies. Methylated H3K9 expression and antioxidant superoxide dismutase expression were determined by Western blot. We also examined consequences of oxidative stress and the downstream effects of histone methyltransferase inhibition on H3K9 expression associated with antioxidant CuZn-SOD and Mn-SOD expression in placental trophoblasts.

Results

We found that expression of mono-, di-, and tri-methylation of histone H3 lysine 9 (H3K9me1, H3K9me2 and H3K9me3) was significantly increased, p<0.01, which correlated with downregulation of antioxidant superoxide dismutase CuZn-SOD and Mn-SOD expression, in trophoblasts from preeclamptic placentas compared to those from uncomplicated control placentas. We further demonstrated hypoxia could promote histone H3K9 methylation in placental trophoblasts, and hypoxia-induced upregulation of H3K9me1, H3K9me2 and H3K9me3 expression was reversible when hypoxic condition was removed. In addition, we also uncovered that inhibition of methyltransferase not only prevented hypoxia-induced upregulation of H3K9me1, H3K9me2 and H3K9me3 expression, but also abolished hypoxia-induced downregulation of CuZn-SOD and Mn-SOD expression in placental trophoblasts.

Conclusions

These findings are noteworthy and provide further evidence that increased oxidative stress in the intrauterine environment is likely a mechanism to induce aberrant histone modification in placental trophoblasts in preeclampsia. Moreover, CuZn-SOD and Mn-SOD expression/activity are possibly H3K9 methylation-dependent in placental trophoblasts, which further suggest that oxidative stress and aberrant histone modification have significant impact on placental trophoblasts/fetal programming in preeclampsia.

CCN1-Mediated Signaling in Placental Villous Tissues after SARS-CoV-2 Infection in Term Pregnant Women: Implications for Dysregulated Angiogenesis

The global spread of SARS-CoV-2 has increased infections among pregnant women. This study aimed to explore placental pathology alterations and angiogenic factor levels in term pregnant women after SARS-CoV-2 infection in a retrospective single-center study. Additionally, we investigated the role and underlying mechanism of the vascular inflammation-promoting, cysteine-rich protein 61 (CYR61/CCN1) in this context. All analyses were performed in term pregnant women infected with or without SARS-CoV-2. The sFlt-1, PlGF, and sEng serum levels were quantified using ELISA. Placental protein expressions were examined by immunoblot and immunostaining. Additionally, the effect of CCN1 protein on SGHPL-5 trophoblast cells was examined. We found that SARS-CoV-2 activated the inflammatory response in pregnant women, leading to pronounced vascular alterations in placental villous tissues. Elevated serum anti-angiogenic factors (sFlt-1, sEng) upon SARS-CoV-2 infection may directly contribute to these pathological changes. Upregulated CCN1 and pNF-κB in placental villous tissues of infected patients are identified as crucial factors in placental alterations. As a conclusion, CCN1 was significantly elevated in the placentas of term pregnant women infected with SARS-CoV-2. By activating a cascade of inflammatory responses, CCN1 induced the production of the anti-angiogenic factors sFlt-1 and sEng, which may lead to abnormal placental vascular architecture.

Placental senescence pathophysiology is shared between peripartum cardiomyopathy and preeclampsia in mouse and human

Peripartum cardiomyopathy (PPCM) is an idiopathic form of pregnancy-induced heart failure associated with preeclampsia. Circulating factors in late pregnancy are thought to contribute to both diseases, suggesting a common underlying pathophysiological process. However, what drives this process remains unclear. Using serum proteomics, we identified the senescence-associated secretory phenotype (SASP), a marker of cellular senescence associated with biological aging, as the most highly up-regulated pathway in young women with PPCM or preeclampsia. Placentas from women with preeclampsia displayed multiple markers of amplified senescence and tissue aging, as well as overall increased gene expression of 28 circulating proteins that contributed to SASP pathway enrichment in serum samples from patients with preeclampsia or PPCM. The most highly expressed placental SASP factor, activin A, was associated with cardiac dysfunction or heart failure severity in women with preeclampsia or PPCM. In a murine model of PPCM induced by cardiomyocyte-specific deletion of the gene encoding peroxisome proliferator-activated receptor γ coactivator-1α, inhibiting activin A signaling in the early postpartum period with a monoclonal antibody to the activin type II receptor improved heart function. In addition, attenuating placental senescence with the senolytic compound fisetin in late pregnancy improved cardiac function in these animals. These findings link senescence biology to cardiac dysfunction in pregnancy and help to elucidate the pathogenesis underlying cardiovascular diseases of pregnancy.

The sFLT-1/PlGF Ratio for the Prediction of Preeclampsia-Related Adverse Fetal and Maternal Outcomes in Women with Preexisting Diabetes

To evaluate the predictive value of the sFlt-1/PlGF ratio for the prediction of preeclampsia in women with preexisting diabetes mellitus. This is a monocentric retrospective observational study conducted between January 2018 and December 2020. All singleton pregnancies with preexisting diabetes mellitus, who had a dosage of the sFlt-1/PlGF ratio between 30 and 34 + 6 weeks of gestation were included. The principal outcome was preeclampsia. The secondary outcomes were preterm preeclampsia, gestational hypertension, placental abruption, intrauterine fetal death, IUGR, small for gestational age and a composite outcome named "hypertensive disorder of pregnancy" including gestational hypertension, preeclampsia and HELLP syndrome (hemolysis, elevated liver enzymes and low platelet count). Of 63 patients, 22% presented preeclampsia. The area under the curve of sFlt-1/PlGF ratio was 0.90 (95% CI: 0.79-0.96) for the prediction of preeclampsia. The receiver operator characteristic analysis suggested that the optimal sFlt-1/PlGF cutoff to predict preeclampsia was 29, with a sensitivity of 86% (95% CI: 60.1-96.0) and a specificity of 92% (95% CI: 80.8-96.8). A cut-off of 38 provided a sensitivity of 71% (95% CI: 45.4-88.3), a specificity of 92% (95% CI: 80.8-96.8). Further analysis using multivariable methods revealed nephropathy was significantly associated with PE (p = 0.014). The use of the sFlt-1/PlGF ratio during the third trimester of pregnancy seems to be of interest as a prognostic tool to improve multidisciplinary management of patients with preexisting diabetes mellitus.

Comparison of Placental Location on Ultrasound in Preeclampsia and Normotensive Pregnancy in Third Trimester

Background

Hypertensive disorders in pregnancy account for 15%-20% maternal and 20%-25% perinatal mortality. There is interest in predicting preeclampsia (PE) early in pregnancy to reduce PE and its subsequent complications. There is no cheap and easily available, reliable predictor for PE. Some studies have shown that the lateral location of placenta is associated with adverse pregnancy outcomes due to PE. The lateral placenta is yet to be proven as a strong predictor of PE to initiate preventive measures. Placental localization can be easily done on routine ultrasonography during pregnancy. In the light of these observations, a prospective study was done to study any association between PE and placental location by ultrasound in third trimester. Research Question: Is there any association between placental location on ultrasound and preeclampsia in third trimester? The objective is to study association between location of placenta and preeclampsia and compare placental location in normotensive pregnancies with that in PE in third trimester.

Methods

A prospective comparative, case-control, observational study was conducted in the Department of Obstetrics and Gynecology at North DMC Medical College and Hindu Rao Hospital, Delhi, India, from August 2019 to April 2020. The study population included 200 pregnant women with singleton pregnancy in third trimester, without any medical disorders such as diabetes mellitus, hypertension, renal disease, cardiac disease, and coagulation disorder or smoking. One hundred women had preeclampsia and 100 were normotensive controls. Ultrasound was done after filling F form as per the Government of India guidelines to rule out sex determination, and placenta was localized by ultrasound. Placenta was classified as central when it was equally distributed between the right and left sides of the uterus irrespective of anterior, posterior, or fundal position and lateral when 75% or more of the placental mass was on one side of the midline. Placental location was compared in hypertensive and normotensive pregnancies.

Results

Out of the total 200 women, 152 (76%) had central and 48 (24%) had lateral placenta. Ninety-two percent of controls and 60% of cases had central placenta. Forty percent of cases and only 8% normotensive women had lateral placenta. Lateral placenta was five times more frequent in presence of PE as compared to normotensive controls. Out of 152 women with central placenta, 92 (60.5%) women were normotensive but with lateral placenta, only 8 (16.7%) had normal blood pressure. PE was present in 83% of women with lateral placenta and in only 39.47% with central placenta. This difference was statistically significant as P < 0.0001 as per Chi-square test. This reflects a significant association between lateral position of placenta and occurrence of PE. As per odds ratio (0.1304) patients without lateral placenta had 90% protection against preeclampsia.

Conclusion

Central placenta is more common than lateral placenta. Lateral placenta is seen five times more frequently among hypertensive women and this difference is statistically significant. The absence of lateral placenta provides 90% protection against PE but the severity of PE was not affected by placental location..

Preeclampsia at term: evidence of disease heterogeneity based on the profile of circulating cytokines and angiogenic factors

BACKGROUND

Intravascular inflammation and an antiangiogenic state have been implicated in the pathophysiology of preeclampsia. On the basis of the profiles of their angiogenic/antiangiogenic factors, women with preeclampsia at term may be classified into 2 subgroups with different characteristics and prevalence of adverse outcomes. This study was undertaken to examine whether these 2 subgroups of preeclampsia at term also show differences in their profiles of intravascular inflammation.

OBJECTIVE

This study aimed to determine the plasma profiles of cytokines and chemokines in women with preeclampsia at term who had a normal or an abnormal angiogenic profile.

STUDY DESIGN

A nested case-control study was conducted to include women classified into 3 groups: women with an uncomplicated pregnancy (n=213) and women with preeclampsia at term with a normal (n=55) or an abnormal (n=41) angiogenic profile. An abnormal angiogenic profile was defined as a plasma ratio of placental growth factor and soluble fms-like tyrosine kinase-1 multiple of the median <10th percentile for gestational age. Concentrations of cytokines were measured by multiplex immunoassays.

RESULTS

Women with preeclampsia at term and an abnormal angiogenic profile showed evidence of the greatest intravascular inflammation among the study groups. These women had higher plasma concentrations of 5 cytokines (interleukin-6, interleukin-8, interleukin-12/interleukin-23p40, interleukin-15, and interleukin-16) and 7 chemokines (eotaxin, eotaxin-3, interferon-γ inducible protein-10, monocyte chemotactic protein-4, macrophage inflammatory protein-1β, macrophage-derived chemokine, and thymus and activation-regulated chemokine compared to women with an uncomplicated pregnancy. By contrast, women with preeclampsia at term and a normal angiogenic profile, compared to women with an uncomplicated pregnancy, had only a higher plasma concentration of monocyte chemotactic protein-4. A correlation between severity of the antiangiogenic state, blood pressure, and plasma concentrations of a subset of cytokines was observed.

CONCLUSION

Term preeclampsia can be classified into 2 clusters. One is characterized by an antiangiogenic state coupled with an excessive inflammatory process, whereas the other has neither of these features. These findings further support the heterogeneity of preeclampsia at term and may explain the distinct clinical outcomes.

Angiogenic Biomarkers in Preeclampsia

Preeclampsia contributes disproportionately to maternal and neonatal morbidity and mortality throughout the world. A critical driver of preeclampsia is angiogenic imbalance, which is often present weeks to months before overt disease. Two placenta-derived angiogenic biomarkers, soluble fms-like tyrosine kinase 1 (sFlt-1) and placental growth factor (PlGF), have proved useful as diagnostic and prognostic tests for preeclampsia. Recently, the U.S. Food and Drug Administration approved the sFlt-1/PlGF assay to aid in the prediction of preeclampsia with severe features among women with hypertensive disorders of pregnancy at 24-34 weeks of gestation. In this narrative review, we summarize the body of work leading to this approval and describe how the sFlt-1/PlGF ratio may be implemented in clinical practice as an adjunctive measure to help optimize care and to reduce adverse outcomes in preeclampsia.

Prior Exposure to Experimental Preeclampsia Increases Atherosclerotic Plaque Inflammation in Atherogenic Mice-Brief Report

BACKGROUND

Women with a history of preeclampsia have evidence of premature atherosclerosis and increased risk of myocardial infarction and stroke compared with women who had a normotensive pregnancy. Whether this is due to common risk factors or a direct impact of prior preeclampsia exposure has never been tested in a mouse atherosclerosis model.

METHODS

Pregnant LDLR-KO (low-density lipoprotein receptor knockout; n=35) female mice were randomized in midgestation to sFlt1 (soluble fms-like tyrosine kinase 1)-expressing adenovirus or identical control adenovirus. Postpartum, mice were fed high-fat diet for 8 weeks to induce atherogenesis. Comparison between the control and preeclampsia models was made for metabolic parameters, atherosclerosis burden and composition by histology, plaque inflammation by flow cytometry, and aortic cytokines and inflammatory markers using a cytokine array.

RESULTS

In pregnant LDLR-KO mice, sFlt1 adenovirus significantly induced serum sFlt1, blood pressure, renal endotheliosis, and decreased pup viability. After 8 weeks of postpartum high fat feeding, body weight, fasting glucose, plasma cholesterol, HDL (high-density lipoprotein), and LDL (low-density lipoprotein) were not significantly different between groups with no change in aortic root plaque size, lipid content, or necrotic core area. Flow cytometry demonstrated significantly increased CD45+ aortic arch leukocytes and CD3+T cells and aortic lysate contained more CCL (CC motif chemokine ligand) 22 and fetuin A and decreased expression of IGFBP6 (insulin-like growth factor-binding protein 6) and CCL21 in preeclampsia-exposed mice compared with controls.

CONCLUSIONS

In atherogenic LDLR-KO mice, exposure to sFlt1-induced preeclampsia during pregnancy increases future atherosclerotic plaque inflammation, supporting the concept that preeclampsia directly exacerbates atherosclerotic inflammation independent of preexisting risk factors. This mechanism may contribute to ischemic vascular disease in women after preeclampsia pregnancy.

Pathologic maternal and neonatal outcomes associated with programmed embryo transfer: potential etiologies and strategies for prevention

PURPOSE

In the first of two companion papers, we comprehensively reviewed the recent evidence in the primary literature, which addressed the increased prevalence of hypertensive disorders of pregnancy, late-onset or term preeclampsia, fetal overgrowth, postterm birth, and placenta accreta in women conceiving by in vitro fertilization. The preponderance of evidence implicated frozen embryo transfer cycles and, specifically, those employing programmed endometrial preparations, in the higher risk for these adverse maternal and neonatal pregnancy outcomes. Based upon this critical appraisal of the primary literature, we formulate potential etiologies and suggest strategies for prevention in the second article.

METHODS

Comprehensive review of primary literature.

RESULTS

Presupposing significant overlap of these apparently diverse pathological pregnancy outcomes within subjects who conceive by programmed autologous FET cycles, shared etiologies may be at play. One plausible but clearly provocative explanation is that aberrant decidualization arising from suboptimal endometrial preparation causes greater than normal trophoblast invasion and myometrial spiral artery remodeling. Thus, overly robust placentation produces larger placentas and fetuses that, in turn, lead to overcrowding of villi within the confines of the uterine cavity which encroach upon intervillous spaces precipitating placental ischemia, oxidative and syncytiotrophoblast stress, and, ultimately, late-onset or term preeclampsia. The absence of circulating corpus luteal factors like relaxin in most programmed cycles might further compromise decidualization and exacerbate the maternal endothelial response to deleterious circulating placental products like soluble fms-like tyrosine kinase-1 that mediate disease manifestations. An alternative, but not mutually exclusive, determinant might be a thinner endometrium frequently associated with programmed endometrial preparations, which could conspire with dysregulated decidualization to elicit greater than normal trophoblast invasion and myometrial spiral artery remodeling. In extreme cases, placenta accreta could conceivably arise. Though lower uterine artery resistance and pulsatility indices observed during early pregnancy in programmed embryo transfer cycles are consistent with this initiating event, quantitative analyses of trophoblast invasion and myometrial spiral artery remodeling required to validate the hypothesis have not yet been conducted.

CONCLUSIONS

Endometrial preparation that is not optimal, absent circulating corpus luteal factors, or a combination thereof are attractive etiologies; however, the requisite investigations to prove them have yet to be undertaken. Presuming that in ongoing RCTs, some or all adverse pregnancy outcomes associated with programmed autologous FET are circumvented or mitigated by employing natural or stimulated cycles instead, then for women who can conceive using these regimens, they would be preferable. For the 15% or so of women who require programmed FET, additional research as suggested in this review is needed to elucidate the responsible mechanisms and develop preventative strategies.