Is Maternal Cardiovascular Performance Impaired in Altitude-Associated Fetal Growth Restriction?

Mundo, William, Lilian Toledo-Jaldin, Alexandrea Heath-Freudenthal, Jaime Huayacho, Litzi Lazo-Vega, Alison Larrea-Alvarado, Valquiria Miranda-Garrido, Rodrigo Mizutani, Lorna G. Moore, Any Moreno-Aramayo, Richard Gomez, Patricio Gutierrez, and Colleen G. Julian. Is maternal cardiovascular performance impaired in altitude-associated fetal growth restriction? High Alt Med Biol. 23:352-360, 2022. Introduction: The incidence of fetal growth restriction (FGR) is elevated in high-altitude resident populations. This study aims to determine whether maternal central hemodynamics during the last trimester of pregnancy are altered in high-altitude FGR. Methods: In this cross-sectional study of maternal-infant pairs (FGR, n = 27; controls, n = 26) residing in La Paz, Bolivia, maternal heart rate, cardiac output (CO), stroke volume, and systemic vascular resistance (SVR) were assessed using continuous-wave Doppler ultrasound. Transabdominal Doppler ultrasound was used for uterine artery (UtA) resistance indices and fetal measures. Maternal venous soluble fms-like tyrosine kinase-1 (sFlt1) levels were measured. Results: FGR pregnancies had reduced CO, elevated SVR and UtA resistance, fetal brain sparing, and increased maternal sFlt1 versus controls. Maternal SVR was positively associated with UtA resistance and inversely associated with middle cerebral artery resistance and birth weight. Maternal sFlt1 was greater in FGR than controls and positively associated with UtA pulsatility index. Women with elevated sFlt1 levels also tended to have lower CO and higher SVR. Conclusion: Noninvasive assessment of maternal cardiovascular function may be an additional method for detecting high-risk pregnancies at high altitudes, thereby informing the need for increased surveillance and appropriate allocation of resources to minimize adverse outcomes.

Oxidative and Inflammatory Imbalance in Placenta and Kidney of sFlt1-Induced Early-Onset Preeclampsia Rat Model

Preeclampsia (PE) is a pregnancy-specific disorder characterized by the new onset of hypertension plus proteinuria and/or end-organ dysfunction. Here, we investigate the role of the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase system as a major component of reactive oxygen species generation, in a rodent model of early-onset preeclampsia induced by excess sFlt1 (soluble fms-like tyrosine kinase 1). Placenta and kidney samples were obtained from normal pregnant and PE rats to measure the sFlt1/PlGF (placental growth factor) ratio in addition to oxidative stress-related parameters, including the activities and expressions of NADPH oxidase isoforms (NOX1, NOX2, and NOX4), components of nitric oxide (NO) metabolism, and antioxidant enzymes. Peroxisome proliferator-activated receptors (PPARα, PPARγ) and cytokines IL1β, IL3, IL6, IL10, and IL18 were also measured to evaluate the inflammation status in our experimental setting. Excessive O₂^●− production was found in rats that were treated with sFlt1; interestingly, this alteration appears to be mediated mainly by NOX2 in the placenta and by NOX4 in the kidney. Altered NO metabolism and antioxidant defense systems, together with mitochondrial dysfunction, were observed in this model of PE. Preeclamptic animals also exhibited overexpression of proinflammatory biomarkers as well as increased collagen deposition. Our results highlight the role of NADPH oxidase in mediating oxidative stress and possibly inflammatory processes in the placenta and kidney of an sFlt1-based model of early-onset preeclampsia.

Interdependence of Angiogenesis and Arteriogenesis in Development and Disease

The structure of arterial networks is optimized to allow efficient flow delivery to metabolically active tissues. Optimization of flow delivery is a continuous process involving synchronization of the structure and function of the microcirculation with the upstream arterial network. Risk factors for ischemic cardiovascular diseases, such as diabetes mellitus and hyperlipidemia, adversely affect endothelial function, induce capillary regression, and disrupt the micro- to macrocirculation cross-talk. We provide evidence showing that this loss of synchronization reduces arterial collateral network recruitment upon arterial stenosis, and the long-term clinical outcome of current revascularization strategies in these patient cohorts. We describe mechanisms and signals contributing to synchronized growth of micro- and macrocirculation in development and upon ischemic challenges in the adult organism and identify potential therapeutic targets. We conclude that a long-term successful revascularization strategy should aim at both removing obstructions in the proximal part of the arterial tree and restoring “bottom-up” vascular communication.

VEGF Maintains Maternal Vascular Space Homeostasis in the Mouse Placenta through Modulation of Trophoblast Giant Cell Functions

Vascular endothelial growth factor (VEGF) is an angiogenic growth factor that acts primarily on endothelial cells, but numerous studies suggest that VEGF also acts on non-endothelial cells, including trophoblast cells. Inhibition of VEGF signaling by excess production of the endogenous soluble VEGF receptor sFlt1 in trophoblast cells has been implicated in several pregnancy complications. Our previous studies and other reports have shown that VEGF directly regulates placental vascular development and functions and that excess VEGF production adversely affects placental vascular development. Trophoblast giant cells (TGCs) line the maternal side of the placental vasculature in mice and function like endothelial cells. In this study, we specifically examined the effect of excess VEGF signaling on TGC development associated with defective placental vascular development using two mouse models an endometrial VEGF overexpression model and a placenta-specific sFlt1 knockdown model. Placentas of endometrial VEGF-overexpressing dams at embryonic days (E) 11.5 and 14.5 showed dramatic enlargement of the venous maternal spaces in junctional zones. The size and number of the parietal TGCs that line these venous spaces in the placenta were also significantly increased. Although junctional zone venous blood spaces from control and VEGF-overexpressing dams were not markedly different in size at E17.5, the number and size of P-TGCs were both significantly increased in the placentas from VEGF-overexpressing dams. In sFlt1 knockdown placentas, however, there was a significant increase in the size of the sinusoidal TGC-lined, alkaline phosphatase-positive maternal blood spaces in the labyrinth. These results suggest that VEGF signaling plays an important role in maintaining the homeostasis of the maternal vascular space in the mouse placenta through modulation of TGC development and differentiation, similar to the effect of VEGF on endothelial cells in other vascular beds.

Mechanisms driving the initiation and direction of endothelial sprouting in organotypic co-culture of aorta and spinal cord tissues

The resumption of blood supply in spinal cord (SC) after injury is a prerequisite of its recovery. To expose the mechanisms of damaged SC revascularization we have used an organotypic SC/aortic fragments (AF) co-culture where, as we showed previously, damaged SC tissue induces AF cell sprouting but repels them away. Supplementation of culture medium with exogenous VEGF-A₁₆₅ redirects the migrating aortic endothelial cells towards SC tissue. This effect and the pattern of sFlt1 expression (a soluble form of VEGFR1) suggest that the low level of SC-secreted VEGF and the presence of sFlt1 in SC slices together prevent the migration of aortic CD31⁺ cells to the SC in the absence of exogenous VEGF. VEGF-A₁₆₅ supplementation sequesters this inhibitory activity of sFlt1 by direct binding thus allowing CD31⁺ cell migration in to SC tissue. Proteome analysis has shown that migration/proliferation of CD31⁺ and αSMA⁺ aortic cells in neuronal culture medium used in our SC/AF model (which obstruct sprouting by itself) was resumed by combined action of several pro- (aFGF, bFGF, Osteopontin, TF, IGFBP2, SDF1) and anti-angiogenic (Endostatin/Collagen18) factors. The mutual influence of AF and SC tissues is a key factor balancing these factors and thus driving endothelial sprouting in SC injury zone.

SARS-CoV-2 colonization of maternal and fetal cells of the human placenta promotes alteration of local renin-angiotensin system

Background

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection appears to increase the risk of adverse pregnancy outcomes, such as pre-eclampsia in pregnant women. The mechanism(s) by which this occurs remains unclear.

Methods

We investigated the pathophysiology of SARS-CoV-2 at maternal-fetal interface in pregnant women who tested positive for the virus using RNA in situ hybridization (viral RNA), immunohistochemistry, and hematoxylin and eosin staining. To investigate whether viral infection alters the renin angiotensin system (RAS) in placenta, which controls blood pressure, we treated human trophoblasts with recombinant spike protein or a live modified virus with a vesicular stomatitis viral backbone expressing spike protein (VSV-S).

Findings

Viral colonization was highest in maternal decidua, fetal trophoblasts, Hofbauer cells, and in placentas delivered prematurely. We localized SARS-CoV-2 to cells expressing angiotensin-converting enzyme 2 (ACE2) and demonstrate that infected placentas had significantly reduced ACE2. In response to both spike protein and VSV-S, cellular ACE2 decreased although angiotensin II receptor type 1 (AT₁R) increased with concomitant increase in soluble fms-like tyrosine kinase-1 (sFlt1). Viral infection decreased pro-angiogenic factors, AT₂R, and placental growth factor, which competitively binds to sFlt1. Sera from infected pregnant women had elevated levels of sFlt1 and angiotensin II type 1-receptor autoantibodies prior to delivery, both signatory markers of pre-eclampsia.

Conclusions

SARS-CoV-2 colonizes ACE2-expressing maternal and fetal cells in the placenta. Infection in pregnant women correlates with alteration of placental RAS. As RAS regulates blood pressure, SARS-CoV-2 infection may thus increase adverse hemodynamic outcomes, such as pre-eclampsia in pregnant women.

Funding

NIH/NICHD grants R01 HD091218 and 3R01HD091218-04S1 (RADx-UP Supplement).

Histone chaperone APLF level dictates the implantation of mouse embryos

Our recent findings demonstrated that the histone chaperone and DNA repair factor aprataxin and PNK-like factor (APLF) could regulate epithelial to mesenchymal transition (EMT) during the reprogramming of murine fibroblasts and in breast cancer metastasis. Therefore, we investigated the function of APLF in EMT associated with mouse development. Here, we show that APLF is predominantly enhanced in trophectoderm (TE) and lineages derived from TE in pre- and post-implantation embryos. Downregulation of APLF induced the hatching of embryos in vitro, with a significant increase in Cdh1 and Cdx2 expression. Aplf short hairpin RNA-microinjected embryos failed to implant in vivo Rescue experiments neutralized the knockdown effects of APLF both in vitro and in vivo Reduced expression of Snai2 and Tead4, and the gain in Cdh1 and sFlt1 (also known as Flt1) level, marked the differentiation of APLF-knocked down trophoblast stem cells that might contribute towards the impaired implantation of embryos. Hence, our findings suggest a novel role for APLF during implantation and post-implantation development of mouse embryos. We anticipate that APLF might contribute to the establishment of maternal-fetal connection, as its fine balance is required to achieve implantation and thereby attain proper pregnancy.

Preserved efficiency of sickle cell disease placentas despite altered morphology and function

INTRODUCTION

Pregnant women with sickle cell disease (SCD) are at high risk for sickle cell-related complications, obstetrical complications, and perinatal morbidity. Chronic inflammation and the proangiogenic environment associated with SCD have been associated with endothelial damage. It is unknown whether SCD complications could be associated with placental dysfunction or abnormal placental morphology. Moreover, circulating angiogenic factors in pregnant women with SCD are unexplored.

METHODS

Clinical records, placental and blood samples were collected at term delivery for 21 pregnant patients with SCD and 19 HbAA pregnant controls with adapted to gestational age birth weight newborns. Histological and stereological analyses and scanning electron microscopy (SEM) of the placenta, and PlGF and sFlt1 measurements in blood were performed.

RESULTS

In the SCD group, the parenchyma-forming villi of placentas were thinner than in controls, and increased fibrinoid necrosis and an overabundance of syncytial knots were seen. SEM revealed elongated intermediate villous endings with a reduction in the number of terminal villi compared to controls, indicating a significant branching defect in SCD placentas. Finally, SCD patients had an imbalance in the angiogenic ratio of sFlt1/PlGF (p = 0.008) with a drop of PlGF concentrations.

DISCUSSION

We evidence for the first time both abnormal placenta morphology and altered sFlt1/PlGF ratio in SCD patients, uncorrelated with maintained placental efficiency and fetal growth.

sFlt-1/PlGF ratio for the prediction of delivery within 48 hours and adverse outcomes in expectantly managed early-onset preeclampsia

OBJECTIVE

To analyze if sFlt-1/PlGF ratio is more useful than other parameters at diagnosis of early-onset (<34 weeks) preeclampsia (PE) in the prediction of delivery within 48 h and adverse maternal and perinatal outcomes.

METHOD

Observational retrospective study of a cohort of 76 singleton pregnancies with early-onset PE and expectant management. The predictive value of sFlt-1/PlGF ratio, blood pressure, proteinuria, creatinine, liver enzymes and platelets at diagnosis for delivery < 48 h and adverse outcomes was determined.

RESULTS

Maternal and perinatal adverse outcomes occurred in 25/76 (32.9%) cases and 13/69 (18.8%) livebirths, respectively. Areas under the curve (AUC) for sFlt-1/PlGF ratio were 0.59 (95%CI 0.42-0.75) and 0.75 (95%CI 0.62-0.88) for maternal and perinatal complications, respectively. Mean (standard deviation) time to delivery for a sFlt-1/PlGF ratio > 655 vs. ≤ 655 was of 4.4 (7.5) vs. 12.1 (9.3) days, p < 0.01. Relative risk for delivery within 48 h for a sFlt-1/PlGF ratio > 655 was 5.3 (95% confidence interval 2.7-10.6), p < 0.01.

CONCLUSIONS

sFlt-1/PlGF ratio > 655 at diagnosis was associated with a 5-fold increased risk of delivery in ≤ 48 h. None of the parameters were good predictors of adverse maternal or perinatal outcomes.

Inhibition of the Notch1 pathway induces peripartum cardiomyopathy

Increased expression and activity of cardiac and circulating cathepsin D and soluble fms‐like tyrosine kinase‐1 (sFlt‐1) have been demonstrated to induce and promote peripartum cardiomyopathy (PPCM) via promoting cleavage of 23‐kD prolactin (PRL) to 16‐kD PRL and neutralizing vascular endothelial growth factor (VEGF), respectively. We hypothesized that activation of Hes1 is proposed to suppress cathepsin D via activating Stat3, leading to alleviated development of PPCM. In the present study, we aimed to investigate the role of Notch1/Hes1 pathway in PPCM. Pregnant mice between prenatal 3 days and postpartum 3 weeks were fed with LY‐411575 (a notch inhibitor, 10 mg/kg/d). Ventricular function and pathology were evaluated by echocardiography and histological analysis. Western blotting analysis was used to examine the expression at the protein level. The results found that inhibition of Notch1 significantly promoted postpartum ventricular dilatation, myocardial hypertrophy and myocardial interstitial fibrosis and suppressed myocardial angiogenesis. Western blotting analysis showed that inhibition of Notch1 markedly increased cathepsin D and sFlt‐1, reduced Hes1, phosphorylated Stat3 (p‐Stat3), VEGFA and PDGFB, and promoted cleavage of 23k‐D PRL to 16‐kD PRL. Collectively, inhibition of Notch1/Hes1 pathway induced and promoted PPCM via increasing the expressions of cathepsin D and sFlt‐1. Notch1/Hes1 was a promising target for prevention and therapeutic regimen of PPCM.

Enhanced Serum Levels of sFlt1: Impact on Materno-Fetal CMV Transmission

Background: Antenatal Cytomegalovirus infection (CMV) can be associated with severe fetal symptoms and newborn outcome. The current prenatal diagnosis is based on amniocentesis (AC). No reliable biomarker for fetal infection is available. Methods: We measured Placenta-derived growth factor (PlGF), and soluble fms-like tyrosine kinase 1 (sFlt1), concentrations in maternal serum and amniotic fluid (AF) in context of maternal CMV primary infection. Blood sampling was carried out at the time of AC for detection of fetal CMV infection. The study cohort was divided into four subcohorts according to the presence or absence of fetal infection and preemptive hyperimmunoglobulin (HIG) treatment during the time interval between diagnosis of the CMV primary infection and AC. Results: The study cohort involved 114 pregnancies. In the non-transmitting subcohorts (NT) with and without prior HIG treatment, the median sFlt1 concentrations were 1.5 ng/mL (NT, HIG+) and 1.4 ng/mL (NT, HIG−), respectively. In the two transmitting groups (T) the concentrations were 1.3 ng/mL (T, HIG+) and 2.3 ng/mL (T, HIG−), respectively (NT, HIG− vs. T, HIG−, p < 0.001). The corresponding PlGF levels and the sFlt1/PlGF ratios showed no significant differences between the cohorts. The empirical cut-off values <1504 pg/mL sFlt1 and <307 pg/mL PlGF, were associated with the exclusion of CMV transmission (p < 0.001). Conclusion: sFlt1 concentration in the maternal blood could be a predictive biomarker for maternofetal CMV transmission.

Maternal and Perinatal Outcomes Associated With Extremely High Values for the sFlt-1 (Soluble fms-Like Tyrosine Kinase 1)/PlGF (Placental Growth Factor) Ratio

Background There is little knowledge about the significance of extremely high values (>655) for the ratio of sFlt-1 (soluble fms-like tyrosine kinase 1) to PlGF (placental growth factor). We aim to describe the time-to-delivery interval and maternal and perinatal outcomes when such values are demonstrated while assessing suspected or confirmed placental dysfunction based on clinical or sonographic criteria. Methods and Results A multicenter retrospective cohort study was performed on 237 singleton gestations between 20+0 and 37+0 weeks included at the time of first demonstrating a sFlt-1/PlGF ratio >655. Clinicians were aware of this result, but standard protocols were followed for delivery indication. Main outcomes were compared for women with and without preeclampsia at inclusion. In those with preeclampsia (n=185, of whom 77.3% had fetal growth restriction), severe preeclampsia features and fetal growth restriction in stages III or IV were present in 49.2% and 13.5% cases, respectively, at inclusion and in 77.3% and 28.6% cases, respectively, at delivery. In the group without preeclampsia (n=52, 82.7% had fetal growth restriction), these figures were 0% and 30.8%, respectively, at inclusion and 21.2% and 50%, respectively, at delivery. Interestingly, 28% of women without initial preeclampsia developed it later. The median time to delivery was 4 days (interquartile range: 1-6 days) and 7 days (interquartile range: 3-12 days), respectively (P<0.01). Overall, perinatal mortality was 62.1% before 24 weeks; severe morbidity surpassed 50% before 29 weeks but became absent from 34 weeks. Maternal serious morbidity was high at any gestational age. Conclusions An sFlt-1/PlGF ratio >655 is almost invariably associated with preeclampsia or fetal growth restriction that progresses rapidly. In our tertiary care settings, we observed that maternal adverse outcomes were high throughout gestation, whereas perinatal adverse outcomes diminished as pregnancy advanced.

Ozone Exposure During Implantation Increases Serum Bioactivity in HTR-8/SVneo Trophoblasts

Implantation is a sensitive window in reproductive development during which disruptions may increase the risk of adverse pregnancy outcomes including intrauterine growth restriction. Ozone exposure during implantation in rats reduces fetal weight near the end of gestation, potentially though impaired trophoblast migration and invasion and altered implantation. The current study characterized changes in ventilation, pulmonary injury, and circulating factors including hormonal, inflammatory, and metabolic markers related to exposure to ozone (0.4-1.2 ppm) for 4-h on gestation days 5 and 6 (window of implantation) in Long-Evans dams. To determine the effects of this exposure on trophoblast function, placental-derived, first trimester, HTR-8/SVneo cells were exposed to serum from air- or ozone (0.8 ppm×4 h)-exposed dams and examined for impacts on metabolic capacity, wound-closure, and invasion. Peri-implantation exposure to ozone induced ventilatory dysfunction and lung vascular leakage in pregnant rats, with little effect on most of the circulating markers measured. However, ozone inhalation induced a significant reduction in several serum cytokines (interferon-γ, interleukin-6, and interleukin-13). Treatment of HTR-8/SVneo trophoblasts with serum from ozone-exposed dams for 16-h downregulated metabolic capacity, wound-closure, and invasion through a Matrigel membrane compared with both air-serum and fetal bovine serum-treated cells. Ozone-serum treated cells increased the release of a critical inhibitor of invasion and angiogenesis (soluble fms-like receptor 1; sFlt1) compared with air-serum treatment. Together, our data suggest that circulating factors in the serum of pregnant rats exposed to ozone during implantation receptivity can hinder critical processes of implantation (eg, invasion and migration) and impair trophoblast metabolic capacity.

Correlation of Kryptor and Elecsys® immunoassay sFlt-1/PlGF ratio on early diagnosis of preeclampsia and fetal growth restriction: A case-control study

OBJECTIVES

The measurement of the soluble fms-like tyrosine kinase-1 to placental growth factor (sFlt-1/PlGF) ratio on automated platforms has improved the detection of preeclampsia and fetal growth restriction (PE/FGR). The cut-off points of >38 and ≥85 has been defined for "rule in" and "aid in diagnosis", respectively, using the Elecsys® platform. We aimed to compare the performance of these cut-offs between the Elecsys® and Kryptor platforms at 24-28 weeks.

STUDY DESIGN

Observational case-control study of singleton pregnancies at high risk for PE/FGR and sFlt-1/PlGF measurement at 24-28 weeks' gestation: 21 cases (9 early PE/FGR with delivery <32 weeks) were 1:1 matched for body mass index and parity with 21 controls. Correlations of the sFlt-1, PlGF and sFlt-1/PlGF values and diagnostic accuracy of the >38 and ≥85 cutoffs for early and late PE/FGR using Elecsys® and Kryptor assays were evaluated.

MAIN OUTCOME MEASURES

PE/FGR cases showed significantly higher median (IQR) sFlt-1/PlGF values at 24-28 weeks vs. controls, using both Elecsys® and Kryptor platforms: 55 (13-254) and 97 (13-530) vs. 4.1 (2.0-6.5) and 3.9 (1.8-7.7), respectively. The sFlt-1/PlGF correlation between both methods was excellent (r² = 0.95) although lower PlGF and higher sFlt-1/PlGF values were observed with Kryptor. The higher diagnostic accuracy was obtained for early PE/FGR with the ≥85 cutoff (95.2%; 95%CI: 83.8-99.4%) in both platforms.

CONCLUSION

sFlt-1/PlGF measurements correlates well between Elecsys® and Kryptor platforms, and the cutoffs of >38 and ≥85 exhibit high diagnostic accuracy for assessing early PE/FGR at 24-28 weeks with both methods.

Therapeutic potential of combination therapy of soluble VEGF receptor 1 and conventional chemotherapy for ovarian cancer growth

AIM

This study aimed at evaluating the additional anti-tumor effects of exogenous rVEGFR1 (sFlt1) on conventional chemotherapy in ovarian cancer cell lines.

METHODS

We utilized cells from two ovarian cancer cell lines, SKOV3 and HeyA8, and treated them with a combination of rVEGFR1 (sFlt1) and carboplatin as well as rVEGFR1 (sFlt1) alone. First, we evaluated cell survival after treatment by using cell counting and MTS assays. Next, we performed Ki67 staining for evaluating the inhibitory effects of the treatment on cell proliferation, and a lactate dehydrogenase (LDH) assay for evaluating cytotoxicity. Finally, to determine whether MAP kinase signaling is involved in this process, we performed western blot analysis of extracellular signal-regulated kinase (ERK), phospho-ERK, c-jun n-terminal kinase (JNK) and phospho-JNK.

RESULTS

The cytotoxic and growth-restriction effects were more pronounced in the group co-administered with rVEGFR1 (sFlt1) and carboplatin than in cells treated with either rVEGFR1 (sFlt1) or carboplatin alone. Quantitative analysis of Ki67-positive cells also showed a decreased proportion of Ki67-positive cells in SKOV3 cells treated with a combination of exogeneous rVEGFR1 (sFlt1) and carboplatin compared to that in cells treated with either rVEGFR1 (sFlt1) or carboplatin alone. In the LDH assay, we also found significantly enhanced cell toxicity from the combination therapy. Finally, western blotting analysis showed that the MAPK signaling pathway was not affected by sFlt1 treatment.

CONCLUSION

This study confirmed the additive effects of rVEGFR1 (sFlt1) combined with conventional chemotherapy for ovarian cancer growth in in vitro assays, thus suggesting the combination of rVEGFR1 (sFlt1) and carboplatin as a potential novel therapeutic option for ovarian cancer.

Angiogenesis biomarkers for the prediction of severe adverse outcomes in late-preterm preeclampsia

OBJECTIVES

The optimal timing for delivery in non-severe late-preterm (34 + 0-36 + 6 weeks) preeclampsia (PE) is uncertain. It is attempted to reach term pregnancy safely but current clinical and analytical parameters fail to determine which cases will develop severe features that require preterm delivery. We aim to establish if angiogenic biomarkers may identify cases that would benefit from earlier delivery.

STUDY DESIGN

Prospective case-control study of 96 women (n = 48 controls and n = 48 cases with PE) with maternal determinations of the sFlt-1/PlGF ratio between 34 + 0 and 36 + 6 weeks. The PE group was classified in two groups based on the need (n = 26) or not (n = 22) for preterm delivery due to criteria of severity. Diagnostic accuracy of these biomarkers for predicting preterm delivery for severe PE was evaluated.

MAIN OUTCOME MEASURES

Women with PE showed higher median sFlt-1/PlGF ratio than controls (122 vs 5, p < 0.01) and lower PlGF MoM (0.7 vs 1.0, p < 0.01). However, these differences did not remain when both PE subgroups were compared. Diagnostic performance of the sFlt-1/PlGF ratio and PlGF at different cut-offs was poor for detecting PE requiring delivery before term.

CONCLUSIONS

Angiogenic biomarkers are not useful to predict which late-preterm PE cases will develop severe features that require preterm delivery.

Effects of Supraphysiologic Levels of Estradiol on Endometrial Decidualization, sFlt1, and HOXA10 Expression

OBJECTIVE

Supraphysiologic estradiol (E₂) levels associated with controlled ovarian hyperstimulation in high in vitro fertilization (IVF) responders may alter implantation and placentation and increase the risk of preeclampsia. Our hypothesis is that elevated E₂ levels in vitro significantly alter endometrial decidualization, sFlt1, and HOXA10 expression.

METHODS

Human endometrial stromal cells were treated with a decidualization cocktail of medroxyprogesterone, cyclic adenosine monophosphate, and 3 concentrations of E₂ 10 nM (standard), 100 nM (intermediate), or 1000 nM E₂ (high). Effects on sFlt1, prolactin (PRL), insulin-like growth factor binding protein 1 (IGFBP-1), vascular endothelial growth factor (VEGF), and HOXA10 were studied.

RESULTS

Prolactin, IGFBP-1, and VEGF significantly increased at all 3 E₂ concentrations. While IGFBP-1 and VEGF did not change with increasing E₂, PRL was less with high E₂ (6.0 ng/mL ± 1.4 standard error of the mean) compared to standard (21.4 ± 3.2) and intermediate (19.8 ± 3.8). sFlt1 decrease was similar at all E₂ concentrations. HOXA10 was lower at standard (10%) and intermediate (30%) as expected, but did not change with high E₂.

CONCLUSIONS

Supraphysiologic E₂ levels associated with high IVF responders that exceed in vivo levels may impair in vitro endometrial decidualization. Although PRL did increase with high E₂, the levels were, however, attenuated and 3.4-fold lower than standard and intermediate E₂. sFlt1 was decreased under all 3 conditions with no differences between concentrations. Reduced HOXA10 was not observed with high E₂. These findings suggest that elevated E₂ levels in vitro may alter endometrial decidualization and subsequently affect implantation and placentation.

Decidual cells from women with preeclampsia exhibit inadequate decidualization and reduced sFlt1 suppression

Uterine stromal cell decidualization of maternal tissue is essential for implantation of and local adaptation to the fetal allograft, as well as growth and maintenance of the placenta in healthy pregnancies. Maternal defects in decidualization have been suggested as a possible driver of preeclampsia. Preeclampsia (PE) pregnancies demonstrate shallow implantation, inadequate spiral artery remodeling, and elevated levels of the anti-angiogenic protein, sFlt1. To test whether stromal cells (DSCs) isolated from PE placentas exhibit inadequate re-decidualization and increased expression of sFlt1, DSCs from normotensive (NT-DSCs) and PE (PE-DSCs) placentas were treated for 8 days (D8) with cAMP to induce decidualization and levels of decidualization markers (PRL, IGFBP1, VEGF) and sFlt1 were measured at day 0 (D0), D8, and after reversal of treatment. NT-DSCs achieved statistically significant elevations in PRL and IFGBP1 expression (25.72 [5.78-50.04], p = 0.0008 and 92.09 [1.79-543.10], p = 0.005). PE-DSCs increased PRL and IFGBP1 expression to 6.15 [2.30-10.73] (p = 0.18) and 8.67 [1.64-376.10] (p = 0.04). NT-DSCs reduced sFlt1 expression at D8 to 0.25 [0.17-0.49] (p = 0.0021) compared to 0.31 [0.25-0.82] (p = 0.087) in PE-DSCs. These results show that, when induced to decidualize, PE-DSCs fail to increase expression of decidualization markers to levels achieved by NT-DSCs. sFlt1 expression is higher in PE-DSCs during decidualization, suggesting inadequate suppression during the crucial implantation period. These defects at the maternal fetal interface may lead to the failed spiral artery modification, decreased placental invasion of the uterus, and elevated circulating sFlt1 levels seen in PE pathology.

Esomeprazole to treat women with preterm preeclampsia: a randomized placebo controlled trial

BACKGROUND

Preterm preeclampsia has a high rate of fetal death or disability. There is no treatment to slow the disease, except delivery. Preclinical studies have identified proton pump inhibitors as a possible treatment.

OBJECTIVE

The purpose of this study was to examine whether esomeprazole could prolong pregnancy in women who have received a diagnosis of preterm preeclampsia.

STUDY DESIGN

We performed a double-blind, randomized controlled trial at Tygerberg Hospital in South Africa. Women with preterm preeclampsia (gestational age 26 weeks+0 days to 31 weeks+6 days) were assigned randomly to 40-mg daily esomeprazole or placebo. The primary outcome was a prolongation of gestation of 5 days. Secondary outcomes were maternal and neonatal outcomes. We compared circulating markers of endothelial dysfunction that was associated with preeclampsia and performed pharmacokinetic studies.

RESULTS

Between January 2016 and April 2017, we recruited 120 participants. One participant was excluded because of incorrect randomization, which left 59 participants in the esomeprazole and 60 participants in the placebo group. Median gestational age at enrolment was 29+4 weeks gestation. There were no between-group differences in median time from randomization to delivery: 11.4 days (interquartile range, 3.6-19.7 days) in the esomeprazole group and 8.3 days (interquartile range, 3.8-19.6 days) in the placebo group (3 days longer in the esomeprazole arm; 95% confidence interval, -2.9-8.8; P=.31). There were no placental abruptions in the esomeprazole group and 6 (10%) in the placebo group (P=.01, P=.14 adjusted). There were no differences in other maternal or neonatal outcomes or markers of endothelial dysfunction. Esomeprazole and its metabolites were detected in maternal blood among those treated with esomeprazole, but only trace amounts in the umbilical cord blood.

CONCLUSION

Daily esomeprazole (40 mg) did not prolong gestation in pregnancies with preterm preeclampsia or decrease circulating soluble fms-like tyrosine kinase 1 concentrations. Higher levels in the maternal circulation may be needed for clinical effect.

Villous explants from preeclamptic placentas induce sFlt1 in PBMCs: An ex vivo co-culture study

OBJECTIVES

Soluble Flt1 (sFlt1) is an anti-angiogenic protein linked to the pathology of preeclampsia (PE). While the placenta serves as the major organ producing sFlt1 during normal pregnancy, peripheral blood mononuclear cells (PBMCs), endothelial cells, and stromal cells also produce sFlt1. The key question is 'what drives the overexpression of sFlt1 observed during PE?' In the present work we show evidence for sFlt1 over-expression in PBMCs due to interaction with placental villi from PE patients.

STUDY DESIGN

sFlt1 production by PBMCs is estimated by using two blood collection methods with different coagulation chemistry. PBMCs were then cultured with homologous villous explants and heterologous villous explants to determine the effects of the interaction between the two tissues.

MAIN OUTCOME MEASURES

sFlt1 levels were estimated using real time PCR, ELISA, and gel electrophoresis.

RESULTS

Plasma samples obtained using CTAD as anti-coagulant showed 16-23% less sFlt1 compared to plasma collected in EDTA. Preeclamptic PBMCs showed higher basal level of sFlt1 mRNA. In addition, we show evidence of placental interaction as a cause of sFlt1 overexpression in PBMCs using homologous and heterologous co-culture system. However, during co-culture, we observed that while the sFlt1 expression in PE PBMCs is increased, PE villous explants show reduced sFlt1 RNA expression.

CONCLUSION

sFlt1 was produced in significant amounts by preeclamptic PBMCs, and ex vivo studies show that the placenta induces this over-expression. In contrast, exposure to PBMCs appears to decrease sFlt1 production by preeclamptic placenta.

Increased placental sFlt-1 but unchanged PlGF expression in late-onset preeclampsia

OBJECTIVE

To investigate whether differences between late-onset preeclampsia (PE) and intrauterine growth restriction (IUGR) can be explained by differential placental expression patters of sFlt-1, Flt-1, and placental growth factor (PlGF).

METHODS

Placental tissues and maternal blood samples from seven patients with PE, five IUGR, and seven age-matched controls were studied for mRNA and protein levels as well as protein localization and expression intensity.

RESULTS

Placental PlGF mRNA and protein expression were not altered by placental dysfunction while placental villous trophoblast expression intensity of PlGF was increased.

CONCLUSION

High sFlt-1 concentrations may account for diminished maternal serum PlGF levels.

Relationship between hypoxia and downstream pathogenic pathways in preeclampsia

Defects in angiogenesis and mitochondrial function in the placenta contribute to the pathogenesis of preeclampsia; however upstream regulators of these pathways are not known. It has been argued that placental hypoxia secondary to abnormal spiral artery remodeling may play a causal role in the angiogenic and mitochondrial abnormalities noted in preeclampsia. The aim of this study was to evaluate the relationship between hypoxia-inducible factor-1α (HIF-1α) ¸ a surrogate of hypoxia, and soluble fms-tyrosine kinase 1 (sFlt1), a circulating anti-angiogenic factor, and microRNA 210 (miR-210), a microRNA that regulates mitochondrial function, in human placentas from preeclamptic and non-hypertensive pregnancies. We first confirmed a 2.5-fold upregulation of HIF-1α protein in placentas from preeclampsia when compared to non-hypertensive controls. Consistent with prior studies, we also observed a 10-fold upregulated sFlt1 mRNA and 2-fold upregulated miR-210 in preeclamptic tissue. Interestingly, while sFlt1 mRNA correlated with miR-210 in preeclampsia (R² = 0.77, p = 0.0004), there were no significant correlations between these molecules and HIF1α expression. We conclude that non-hypoxia pathways may be involved in the abnormal angiogenic and metabolic alterations noted in preeclampsia.

Steroid sulfatase is increased in the placentas and whole blood of women with early-onset preeclampsia

INTRODUCTION

Preeclampsia is a serious complication of pregnancy affecting 5% of pregnancies. Our team identified 137 genes highly expressed in placenta relative to other human tissues. Here, we have explored a role for steroid sulfatase (STS) in preeclampsia by characterising STS expression and the functional effects of STS on primary placental trophoblasts.

METHODS

Characterisation of STS was performed on preterm preeclamptic and gestation-matched normotensive preterm controls who delivered at <34 weeks gestation. We characterised placental and maternal whole blood STS mRNA and placental protein expression via qRT-PCR, immunohistochemistry and Western Blot. To assess whether STS is involved in sFlt1 secretion and syncytialisation, we administered siRNA to silence STS in primary trophoblasts before measuring sFlt1 and hCG secretion and E-Cadherin expression.

RESULTS

A custom array containing 45 placental specific genes identified 10 genes significantly altered in the placentas of preeclamptic patients relative to normotensive gestation-matched controls. Of these genes, qRT-PCR and western blot on a larger cohort confirmed that the expression of STS was significantly elevated in preeclamptic placentas (n = 44) relative to gestation matched controls (n = 26). Given placental RNA leaks in to the maternal circulation, we also assessed STS mRNA expression in the whole blood of patients with preeclampsia and found it was significantly increased relative to normotensive controls. siRNA knockdown of STS in primary trophoblast resulted in a modest but significant reduction in sFlt1 secretion, but had no affect on hCG secretion or E-Cadherin protein expression.

DISCUSSION

STS is increased in preeclamptic placentas and maternal whole blood. Our data suggests that STS may affect sFlt1 secretion by regulating sFlt1-i13 transcription, and not via alterations in syncytialisation.

Gelsolin is an endogenous inhibitor of syncytiotrophoblast extracellular vesicle shedding in pregnancy

BACKGROUND

Preeclampsia, a pregnancy-specific inflammatory disorder, is characterized by high levels of anti-angiogenic protein, soluble fms-like tyrosine kinase 1 (sFlt1), in the maternal circulation. sFlt1 producing molecular machinery is present in syncytiotrophoblast extracellular vesicles that are released by the placenta into maternal plasma during normal pregnancy, a process greatly accelerated in preeclampsia. We hypothesized that syncytiotrophoblast extracellular vesicles exposes cytoplasmic actin to plasma resulting in depletion of plasma gelsolin (pGSN), an abundant plasma protein that scavenges circulating actin and other pro-inflammatory mediators.

OBJECTIVE

To test whether pGSN levels would be lower in preeclampsia and to assess whether recombinant human plasma gelsolin (rhpGSN) may promote placental health by decreasing shedding of syncytiotrophoblast extracellular vesicles.

METHODS

We tested pGSN levels in third trimester plasma samples from women with preeclampsia and non-hypertensive pregnancies. We then assessed whether rhpGSN may act as a negative regulator of syncytial shedding in placental explant culture and dynamic mechanical stretch studies.

RESULTS

pGSN levels fall in late pregnancy and decline further in preeclampsia patients. Recombinant human pGSN (rhpGSN) at 100μg/ml limits spontaneous syncytiotrophoblast vesicle release and sFlt1 protein dissemination by normal placental explants. Higher rhpGSN doses (500μg/ml) also limit syncytiotrophoblast vesicle and sFlt1 dissemination from preeclamptic placental explants. rhpGSN also mitigates syncytiotrophoblast vesicle during dynamic mechanical stretch.

CONCLUSIONS

1) pGSN, an anti-inflammatory factor of maternal origin is reduced in preeclampsia and may contribute to disease progression and 2) exogenous rhpGSN supplementation can limit the dissemination of toxic syncytiotrophoblast vesicle that characterizes the disease state.

A wash step at collection of placental biopsies from preeclamptic pregnancies does not adversely affect levels of sFlt-1 or endoglin

There is recent interest for uniform placental collection protocols so laboratories can share samples. However, concerns have been raised a wash step at collection causes significant loss of sFlt-1 and soluble endoglin, among the most studied proteins in placentology. We measured Flt-1 and endoglin mRNA and protein in 10 preeclamptic placentas that were washed, or left unwashed. Reassuringly, there was no significant change in the Flt-1, sFlt-1-e15a or sFlt-1-i13 mRNA or Flt-1 or sFlt-1 protein expression or localization. There was also no change in endoglin mRNA expression or protein localization. Washing preeclamptic placental samples does not alter anti-angiogenic factor expression.

Pre-eclampsia and cardiovascular disease

Heart disease is the leading cause of death in women in all countries. A history of pre-eclampsia, one of the most deadly hypertensive complications of pregnancy, increases cardiovascular risk by two to four times, which is comparable with the risk induced by smoking. Substantial epidemiological data reveal that pregnancy-related hypertensive complications are associated with a predisposition to chronic hypertension, premature heart attacks, strokes, and renal complications. In this review, we summarize clinical studies that demonstrate this relationship and also discuss the pathogenesis of these long-term complications of pre-eclampsia. Future studies should focus on strategies to prevent the progression of cardiovascular disease in women exposed to pre-eclampsia, thereby improving long-term cardiovascular health in women.

Gestational angiogenic biomarker patterns in high risk preeclampsia groups

OBJECTIVE

Several conditions are associated with increased preeclampsia (PE) risk. Whether altered maternal angiogenic factor levels contribute to risk in these conditions is unknown. Our objective was to compare angiogenic biomarker patterns in high-risk pregnancies and low-risk controls.

STUDY DESIGN

We conducted a planned secondary analysis of a 2-center observational study of angiogenic biomarkers in high-risk women. A total of 156 pregnant women with a PE risk factor and 59 low-risk controls were studied. Serial maternal serum samples were collected during 3 gestational windows: 23-27 weeks, 28-31 weeks, and 32-35 weeks. Soluble fms-like tyrosine kinase 1 (sFlt1), soluble endoglin (sEng), and placental growth factor (PlGF) were measured by enzyme-linked immunosorbent assay. Geometric mean angiogenic biomarker levels and angiogenic ratio (sFlt1 + sEng):PlGF were compared with low-risk controls for each risk group, at each gestational window.

RESULTS

Gestational biomarker patterns differed in PE risk groups as compared with low-risk controls. Women with multiple gestations had markedly higher sFlt1 and sEng at all gestational windows. Women with prior PE had higher sFlt1 and angiogenic ratio, and lower PlGF, from 28 weeks onward. Women with chronic hypertension had significantly higher angiogenic ratio for all 3 gestational windows, but differences disappeared when women with PE were excluded. Obese and nulliparous women had significantly lower PlGF, but no differences in the angiogenic ratio.

CONCLUSION

High-risk groups have altered angiogenic biomarker patterns compared with controls, suggesting that altered production or metabolism of these factors may contribute to PE risk, particularly in women with multiple gestations and prior PE.

Soluble fms-like tyrosine kinase-1 and soluble endoglin in HIV-associated preeclampsia

OBJECTIVE

Preeclampsia is characterized by endothelial dysfunction combined with increased concentrations of sFlt1, which antagonizes the biological effects of VEGF and PlGF, and of sEng, which antagonizes TGFβ1. This angiogenic imbalance may have a role in its etiology. This study evaluated the expression of VEGF, PlGF, sFlt1 and sEng amongst third trimester pregnancies in women with HIV-associated pre-eclampsia.

METHOD

Serum and placental tissue were obtained from 76 pregnancies in women who were normotensive and HIV negative (N-) or positive (N+), and in women who were pre-eclamptic and HIV negative (P-) or positive (P+). The serum and placental samples were quantitatively evaluated using ELISAs and RT-PCR respectively.

RESULTS

Placental sFlt1 expression differed significantly between the N- and P- groups (p=0.001). Similarly, sEng expression differed between the N- and P- groups (p=0.001). No significant effect was shown between HIV status and pregnancy. Serum sFlt1 (p=0.02) and sEng (p=0.001) were up-regulated in the P- compared to the N- groups. Similarly, no significant effect was shown between HIV status and pregnancy. Both VEGF and PlGF did not differ significantly between groups. Notably, sEng expression was elevated in both placenta and serum, whilst placental sFlt1 differed from serum. A weak but significant correlation between serum and placental concentration for sFlt1, sEng and PlGF (r=0.26, p=0.031; r=0.42, p<0.001 and r=-0.3, p=0.014) was observed.

CONCLUSIONS

This novel study demonstrates an up-regulation of serum sFlt1 and sEng in preeclamptic compared to normotensive groups irrespective of the HIV status of the pregnancy. This implicates a contributory role of sFlt1 and sEng in preeclampsia development. The serum reduction of sFlt1 and sEng within the HIV positive compared to HIV negative cohorts may imply a neutralization of the immune hyperreactivity of preeclampsia.

Vascular endothelial growth factor is important for brown adipose tissue development and maintenance

Vascular endothelial growth factor (VEGF) is critical for angiogenesis, but also has pleiotropic effects on several nonvascular cells. Our aim was to investigate the role of VEGF in brown adipose tissue (BAT). We show that VEGF expression increases 2.5-fold during differentiation of cultured murine brown adipocytes and that VEGF receptor-2 is phosphorylated, indicating VEGF signaling. VEGF increased proliferation in brown preadipocytes in vitro by 70%, and blockade of VEGF signaling using anti-VEGFR2 antibody DC101 increased brown adipocyte apoptosis, as determined by cell number and activation of caspase 3. Systemic VEGF neutralization in mice, accomplished by adenoviral expression of soluble Flt1, resulted in 7-fold increase in brown adipocyte apoptosis, mitochondrial degeneration, and increased mitophagy compared to control mice expressing a null adenovirus. Absence of the heparan sulfate-binding VEGF isoforms, VEGF164 and VEGF188, resulted in abnormal BAT development in mice at E15.5, with fewer brown adipocytes and lower mitochondrial protein compared to wild-type littermates. These results suggest a role for VEGF in brown adipocytes and preadipocytes to promote survival, proliferation, and normal mitochondria and development.

Soluble fms-like tyrosine kinase 1 and soluble endoglin are elevated circulating anti-angiogenic factors in pre-eclampsia

Pre-eclampsia, characterized by hypertension and proteinuria, affects approximately 3-5% of all pregnancies worldwide and is a major cause of maternal and fetal morbidity and mortality. Maternal endothelial dysfunction is associated with disease pathogenesis. Recently, reports have shown that elevated levels of circulating soluble fms-like tyrosine kinase 1 [sFlt1] and soluble endoglin [sEng] are associated with pre-eclampsia. Flt1 is a receptor for vascular endothelial growth factor receptor [VEGF], whereas endoglin [Eng] is an auxiliary receptor for transforming growth factor-β [TGF-β] super-family members. Both signaling pathways modulate angiogenesis and are involved in vascular homeostasis. Increased levels of sFlt1 and sEng dysregulate VEGF and TGF-β signaling respectively, resulting in endothelial dysfunction of maternal blood vessels. This review summarizes our current knowledge of Flt1 and endoglin and soluble forms in pre-eclampsia. Furthermore, it highlights the predictive and early-screening value of circulating levels of sFlt1 and sEng for the risk of developing pre-eclampsia.