Preeclampsia, a disease of the maternal endothelium: the role of antiangiogenic factors and implications for later cardiovascular disease

Preeclampsia and maternal cardiovascular disease: consequence or predisposition?

Formerly preeclamptic women stand a higher chance of developing cardiovascular disease (CVD) later in life and may experience a shortened life span. This review updates the pathophysiology and definition of this complex disease and highlights the protective role of pregnancy by considering the relationship between pregnancy interval and likelihood of disease recurrence. The evidence for persistent maternal cardiovascular impairment following preeclampsia (PE) is considered, e.g. postpartum changes in CVD occurrence, blood pressure elevation and changes in the renin-angiotensin-aldosterone system). Since maternal endothelial dysfunction is a hallmark of PE, we summarize the evidence for reduced flow-mediated dilation in women with previous PE, and consider the utility and shortcomings of this clinical measure. In addition to viewing postpartum changes as a consequence of this disease, we consider the alternative view that PE might be the manifestation of a maternal phenotype that already has some predisposition to or is in the earlier stages of CVD; in this case, some of the postpartum residual deficits (or their antecedents) may have already been present prior to pregnancy. Finally, we consider the use of novel biomarkers for predicting or detecting PE prior to the appearance of clinical symptoms.

Hypertension in pregnancy

Hypertensive disorders of pregnancy represent the second commonest cause of direct maternal death and complicate an estimated 5-10 % of pregnancies. Classification systems aim to separate hypertension similar to that seen outside pregnancy (chronic and gestational hypertension) from the potentially fatal pregnancy-specific conditions. Preeclampsia, HELLP syndrome, and eclampsia represent increasing severities of this disease spectrum. The American College of Obstetricians and Gynecologists' 2013 guidelines no longer require proteinuria as a diagnostic criterion, because of its variable appearance in the disease spectrum. The cause involves inadequate cytotrophoblastic invasion of the myometrium, resulting in placental hypoperfusion and diffuse maternal endothelial dysfunction. Changes in angiogenic and antiangiogentic peptide profiles precede the onset of clinical preeclampsia. Women with preeclampsia should be closely monitored and receive magnesium sulfate intravenously if severe features, HELLP syndrome, or eclampsia occur. Definitive therapy is delivery of the fetus. Hypertension in pregnancy increases future maternal risk of hypertension and cardiovascular disorders.

Placental disease and the maternal syndrome of preeclampsia: missing links?

Preeclampsia remains a significant obstetric risk worldwide. The pathophysiology of preeclampsia is complex, with multiple stages involving maladaptations in both placental and maternal physiology. The placenta links the pre-clinical stage of impaired remodeling of the uterine vasculature, occurring in early pregnancy, to the later clinical stages characterised by the maternal syndrome of hypertension and proteinuria. This review focuses on some of the recent candidates for the missing links in this process.

Proteinuria in preeclampsia from a podocyte injury perspective

Preeclampsia is a frequent cause of maternal and fetal morbidity and mortality worldwide. The underlying causes of this hypertensive complication have remained elusive. The placenta seems to be at the origin of the disease, as its removal appears to be the only effective treatment available. Many organs can potentially be affected. Nonetheless, kidney alterations are always present: proteinuria is one of the hallmarks for a preeclampsia diagnosis. VEGF is pivotal for maintaining glomerular filtration barrier function; hence, the elevated concentrations of placental-derived VEGF inhibitors, such as sFlt-1, may largely explain the renal alterations observed. Classically, glomerular endothelial injury was considered responsible for the renal impairment present in preeclampsia. Recent findings, however, have shown that podocytes are crucial in explaining the loss of filtration capacity of the preeclamptic kidney. The aims of this manuscript are to detail the main findings that associate podocyte injury with proteinuria in preeclampsia, and discuss the eventual applications of podocyte damage biomarkers in clinical practice.

Evaluation of glycosaminoglycans and heparanase in placentas of women with preeclampsia

BACKGROUND

Preeclampsia is a multisystem disorder whose etiology remains unclear. It is already known that circulation of soluble fms-like tyrosine kinase-1 (sFlt-1) is directly involved in pre-eclampsia development. However, the molecular mechanisms involved with sFlt-1 shedding are still unidentified. We identified, quantified glycosaminoglycans and determined the enzymatic activity of heparanase in placentas of women with preeclampsia, in order to possibly explain if these compounds could be related to cellular processes involved with preeclampsia.

METHODS

A total of 45 samples collected from placentas, 15 samples from placentas of preeclampsia women and 30 samples from non-affected women. Heparan sulfate and dermatan sulfate were identified and quantified by agarose gel electrophoresis, whilst hyaluronic acid was quantified by an ELISA like assay. Heparanase activity was determined using biotynilated heparan sulfate as substrate.

RESULTS

The results showed that dermatan sulfate (P=0.019), heparan sulfate levels (P=0.015) and heparanase activity (P=0.006) in preeclampsia were significantly higher than in the control group. There was no significant difference between the groups for hyaluronic acid expression in placentas (P=0.110). The present study is the first to demonstrate directly the increase of heparan sulfate in human placentas from patients with preeclampsia, suggesting that endogenous heparan sulfate could be involved in the release of sFlt-1 from placenta, increasing the level of circulating sFlt-1.

CONCLUSION

Alterations of extracellular matrix components in placentas with preeclampsia raise the possibility that heparan sulfate released by heparanase is involved in mechanisms of preeclampsia development.

Measurement of aortic augmentation index in pregnant women with raised blood pressure and subsequent outcomes: a preliminary prospective cohort study

OBJECTIVE

Preeclampsia is associated with arterial dysfunction and augmentation index (AIX%) is an established indicator of arterial dysfunction. Our aim was to investigate the relationship of AIX% with time-to-delivery and other outcomes in women admitted to an antenatal triage unit.

METHODS

We recruited 28 women with singleton pregnancies attending antenatal triage ward for assessment of hypertension. After 10 min rest, seated brachial blood pressure (Omron HEM-757) and AIX% (SphygmoCor applanation tonometry pulse wave analysis, PWA) were measured by a single investigator; other clinicians remained blinded to PWA results. Routine assessment included cardiotocography, urine analysis and blood tests. Subsequent outcomes were extracted from the obstetric records.

RESULTS

Mean AIX% was 19.7% (SD 11.5; range -4% to +36%), maternal age 31 years, gestation 37 weeks, brachial BP 145/95, proteinuria 39%. Nine women had preeclampsia at assessment and six subsequently developed preeclampsia. Median time-to-delivery was 10 d (IQR 1.6-25 d) and was shorter for AIX% ≥ 20% (median 8.9 versus 19.8 d). AIX% was higher with preeclampsia (24.0%; SD 9.5) versus gestational hypertension (15.2%; SD 12.4); absolute difference 8.8% (95%CI 0.1-17.5; p = 0.05). A one-point higher AIX% (adjusted for age, urate and gestation) was associated with 0.3 d (95%CI -0.5 to 0.0; p = 0.06) reduced time-to-delivery. A higher AIX% was also associated with induction for preeclampsia, severe preeclampsia, peripartum-anti-hypertensives and discharge-on-anti-hypertensives. Area under the curve (AUC) for AIX% predicting preeclampsia was 0.80 (95%CI 0.59-1.00; p = 0.04).

CONCLUSION

AIX% is associated with time-to-delivery and other outcomes in pregnancy.

Important aspects of placental-specific gene transfer

The placenta is a unique and highly complex organ that develops only during pregnancy and is essential for growth and survival of the developing fetus. The placenta provides the vital exchange of gases and wastes, the necessary nutrients for fetal development, acts as immune barrier that protects against maternal rejection, and produces numerous hormones and growth factors that promote fetal maturity to regulate pregnancy until parturition. Abnormal placental development is a major underlying cause of pregnancy-associated disorders that often result in preterm birth. Defects in placental stem cell propagation, growth, and differentiation are the major factors that affect embryonic and fetal well-being and dramatically increase the risk of pregnancy complications. Understanding the processes that regulate placentation is important in determining the underlying factors behind abnormal placental development. The ability to manipulate genes in a placenta-specific manner provides a unique tool to analyze development and eliminates potentially confounding results that can occur with traditional gene knockouts. Trophoblast stem cells and mouse embryos are not overly amenable to traditional gene transfer techniques. Most viral vectors, however, have a low infection rate and often lead to mosaic transgenesis. Although the traditional method of embryo transfer is intrauterine surgical implantation, the methodology reported here, combining lentiviral blastocyst infection and nonsurgical embryo transfer, leads to highly efficient and placental-specific gene transfer. Numerous advantages of our optimized procedures include increased investigator safety, a reduction in animal stress, rapid and noninvasive embryo transfer, and higher a rate of pregnancy and live birth.

Ouabain inhibits placental sFlt1 production by repressing HSP27-dependent HIF-1α pathway

Up-regulation of placental soluble fms-like tyrosine kinase 1 (sFlt1) contributes to the pathogenesis of preeclampsia. To evaluate novel upstream pathways that regulate placental sFlt1 production, we screened a library of natural compounds (n=502) in human placental cell lines. Here, we report 3 compounds in the cardiac glycoside family, ouabain, gitoxigenin, and digitoxin, that inhibit placental sFlt1 production at nanomolar concentrations in vitro. We further characterized ouabain and demonstrated that it inhibits sFlt1 mRNA and protein expression in human placental cytotrophoblasts and explant cultures in a dose- and time-dependent manner. Ouabain down-regulated sFlt1 production by inhibiting hypoxia-inducible factor 1 (HIF-1α) protein expression in the placenta. Furthermore, we found that phosphorylation of heat-shock protein 27 (HSP27) was necessary for ouabain to inhibit HIF-1α translation. In a rat model of pregnancy-induced hypertension, ouabain reduced mean arterial pressure and enhanced placental HSP27 phosphorylation without any adverse effects on pups. Further studies are needed to explore the usefulness of targeting HIF-1α/HSP27 pathway in preeclampsia.

Angiogenic factors in preeclampsia: potential for diagnosis and treatment

PURPOSE OF REVIEW

The review summarizes new observations of key roles for circulating angiogenic factors in diagnosing, managing, and treating preeclampsia.

RECENT FINDINGS

Alterations in circulating angiogenic factors (soluble fms-like tyrosine kinase-1 and placental growth factor) in preeclampsia correlate with the diagnosis and adverse outcomes, particularly when the disease presents prematurely (<34 weeks). Measurement of these angiogenic biomarkers further helps differentiate preeclampsia and its complications from other disorders that present with similar clinical profiles. A ratio of soluble fms-like tyrosine kinase-1/placental growth factor greater than 85 appears ideal as the cut-off for both diagnosis and prognosis. There is also evidence that modulating these factors has therapeutic effects, suggesting a future role for angiogenic factors in treatment and prevention of preeclampsia.

SUMMARY

Circulating angiogenic biomarkers help in diagnostic and prognostic profiling of preeclampsia and may facilitate better management of these patients.

MiR-101 regulates apoptosis of trophoblast HTR-8/SVneo cells by targeting endoplasmic reticulum (ER) protein 44 during preeclampsia

To investigate a possible association between miR-101 and apoptosis of human trophoblast cells mediated by endoplasmic reticulum protein 44 (ERp44) in preeclampsia (PE), we explored the expression of miR-101 in PE placentas (n=30) compared with normotensive pregnant placentas (n=30) and the correlation between miR-101 and ERp44 was also analyzed. Furthermore, both the apoptotic rate of trophoblast cells and the ER stress-induced apoptotic proteins were assayed when the HTR-8/SVneo cells were treated with miR-101 mimics or inhibitors in vitro. We found a lower expression of miR-101 and an inverse correlation between miR-101 and ERp44 protein in PE placentas. Upregulation of miR-101 expression could inhibit trophoblast HTR-8/SVneo cell apoptosis and repress ER stress-induced apoptotic proteins by targeting ERp44 in vitro, whereas inhibition of miR-101 could induce HTR-8/SVneo cell apoptosis. Our findings indicated that overexpression of miR-101 could downregulate ERp44 and suppress apoptosis in trophoblast cells during PE. Therefore, loss of miR-101 expression could contribute to ER stress-induced trophoblast cell apoptosis by targeting ERp44.

SFlt-1 elevates blood pressure by augmenting endothelin-1-mediated vasoconstriction in mice

Objective

Scavenging of vascular endothelial growth factor (VEGF) elevates blood pressure (BP) in patients receiving anti-angiogenic therapy. Similarly, inhibition of circulation VEGF by its soluble receptor fms-like tyrosine kinase-1 (sFlt-1) underlies BP elevation in pre-eclampsia. Both phenotypes are characterized by augmented production of endothelin-1 (ET-1), suggesting a role for ET-1 in anti-angiogenic hypertension. We aimed to assess the effect of VEGF inhibition on ET-1-induced contractility and downstream ET-1 signaling.

Approach and Results

Male C57BL/6N mice were treated with either sFlt-1 or vehicle and BP was assessed via tail-cuff. Mean arterial pressure of sFlt-1-treated mice markedly increased compared to vehicle-treated controls (N = 11–12, p<0.05). After sacrifice, carotid and mesenteric arteries were isolated for isometric tension measurements. ET-1-induced contractions were similar in mesenteric arteries of vehicle and sFlt-1-treated mice, but augmented in carotid segments of sFlt-1-treated mice compared to controls (N = 9–10, p<0.05). The increased contraction in carotid segments could be completely abrogated by the cyclooxygenase (COX) inhibitor indomethacin (N = 9–10, p<0.05), indicating heightened prostaglandin-mediated vasoconstriction. This was associated with a shift towards procontractile ET_B signaling in sFlt-1-treated mice, possibly explaining the increased ET-1-induced prostaglandin-mediated vasoconstriction. In line with the ex vivo findings, sFlt-1-induced BP elevation could be prevented in vivo by oral treatment with either a high-dose of the COX inhibitor aspirin (N = 7) or with picotamide (N = 9), a dual thromboxane A₂ synthase inhibitor and receptor antagonist.

Conclusions

VEGF inhibition augments the pressor response to ET-1. The cyclooxygenase-thromboxane signaling route downstream of ET-1 might be a possible target to prevent BP elevation during VEGF inhibition.

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.

End-stage renal disease after hypertensive disorders in pregnancy

OBJECTIVE

The purpose of this study was to determine the long-term postpartum risk of end-stage renal disease in women with hypertensive disorders in pregnancy. Although most women with hypertensive disorders in pregnancy recover after delivery, some may experience acute renal failure.

STUDY DESIGN

We searched Taiwan's National Health Insurance Research Database to identify women with hypertensive disorders in pregnancies and deliveries between 1998 and 2002. All cases were followed for a maximum of 11 years (median, 9 years; interquartile range, 7.79-10.02 years) to estimate the incidence of end-stage renal disease; Cox regression analysis that was adjusted for potential confounding was used to determine the relative risk.

RESULTS

Of the 13,633 women with hypertensive disorders in pregnancy, 46 experienced end-stage renal disease. Women with hypertensive disorders in pregnancy had a risk of end-stage renal disease that was 10.64 times greater than did women without them (95% confidence interval [CI], 7.53-15.05). The risk was highest in women with a history of preeclampsia superimposed on chronic hypertension (hazard ratio, 44.72; 95% CI, 22.59-88.51). Women with gestational hypertension had a higher risk of end-stage renal disease than did women without hypertensive disorders in pregnancy (hazard ratio, 5.82; 95% CI, 2.15-15.77).

CONCLUSION

Women with hypertensive disorders in pregnancy have a higher risk of postpartum end-stage renal disease, regardless of which type of hypertensive disorder they have. Women with a history of hypertensive disorders in pregnancy are encouraged to have regular postpartum checkups, especially of renal function.

Maternal cardiac metabolism in pregnancy

Pregnancy causes dramatic physiological changes in the expectant mother. The placenta, mostly foetal in origin, invades maternal uterine tissue early in pregnancy and unleashes a barrage of hormones and other factors. This foetal 'invasion' profoundly reprogrammes maternal physiology, affecting nearly every organ, including the heart and its metabolism. We briefly review here maternal systemic metabolic changes during pregnancy and cardiac metabolism in general. We then discuss changes in cardiac haemodynamic during pregnancy and review what is known about maternal cardiac metabolism during pregnancy. Lastly, we discuss cardiac diseases during pregnancy, including peripartum cardiomyopathy, and the potential contribution of aberrant cardiac metabolism to disease aetiology.

Gestational diabetes and hypertensive disorders of pregnancy as vascular risk signals: an overview and grading of the evidence

The occurrence of common pregnancy-related medical disorders identifies women at high risk of developing future vascular disease. Systematic reviews of cohort studies demonstrate that gestational diabetes confers a 7-fold risk increase for type 2 diabetes, and preeclampsia confers a 1.8-fold risk increase for type 2 diabetes and 3.4-fold risk increase for hypertension. Gestational diabetes and hypertensive disorders of pregnancy (HDP) increase the risk of premature vascular disease, but the 2-fold risk increase associated with preeclampsia is only partially explained by the development of traditional vascular risk factors. Despite the compelling evidence for gestational diabetes and HDP as vascular risk indicators, there are no published Canadian vascular prevention guidelines that recognize these postpartum women. In contrast, the 2011 American Heart Association guidelines on cardiovascular disease in women include gestational diabetes and HDP in their vascular risk assessment. Studies indicate that the importance surveillance of vascular risk factors in these women after pregnancy is underappreciated by the women themselves and their physicians. Although a prudent diet and physically active lifestyle were demonstrated to reduce diabetes risk in women with a gestational diabetes history in the American Diabetes Prevention Program trial, adoption of these health behaviours is low; qualitative studies confirm a need for tailored strategies that address barriers and provide social support. Further research is also needed on approaches to reduce vascular risk in women with a history of gestational diabetes and HDP. Otherwise, an early window of opportunity for chronic disease prevention in young, high-risk women will be missed.

Does soluble fms-like tyrosine kinase-1 regulate placental invasion? Insight from the invasive placenta

OBJECTIVE

Soluble fms-like tyrosine kinase (sFLT-1) is a potent antiangiogenic growth factor that has been found to be markedly elevated in preeclampsia. In healthy pregnancy, serum sFLT-1 concentrations are 50-fold higher than in the nonpregnant state. The functional significance of this physiologic elevation in serum sFLT-1 in normal pregnancy is unknown. We hypothesized that sFLT-1 regulates placental cytotrophoblast invasion and that lower levels of sFLT-1 would be observed locally in invasive placentas (accreta/increta/percreta).

STUDY DESIGN

We performed a retrospective case-control study comparing placental sFLT-1 expression in hysterectomy specimens from 3 groups: group 1, focally invasive placenta; group 2, normal invasion from the same specimen; and group 3, normal invasion associated with placenta previa. Immunohistochemistry for sFLT-1 was performed, and staining intensity was graded on a scale from 1+ (weak) to 5+ (strong).

RESULTS

We identified 10 hysterectomy specimens from women with invasive placentation and 3 with placenta previa. The median sFLT-1 staining score for group 1 was 1.75 compared to 4.0 for group 2 (P = .01). A significant difference was also found between group 1 and group 3 (P = .01). When comparing depth of invasion, there was a trend toward lower staining score as depth of invasion increased (P = .11). Interobserver agreement for immunohistochemistry scoring was 87%.

CONCLUSION

Lower levels of sFLT-1 protein expression were associated with invasive placentation suggesting a critical functional role for sFLT-1 in regulation of placental invasion.

PAPPA2 is increased in severe early onset pre-eclampsia and upregulated with hypoxia

Severe early onset pre-eclampsia is a serious pregnancy complication, believed to arise as a result of persistent placental hypoxia due to impaired placentation. Pregnancy-associated plasma protein A2 (PAPPA2) is very highly expressed in the placenta relative to all other tissues. There is some evidence that PAPPA2 mRNA and protein are increased in association with pre-eclampsia. The aim of the present study was to characterise the mRNA and protein expression, as well as localisation, of PAPPA2 in an independent cohort of severe early onset pre-eclamptic placentas. We also examined whether exposing placental explants to hypoxia (1% oxygen) changed the expression of PAPPA2. Expression of PAPPA2 mRNA and protein was upregulated in severe early onset pre-eclamptic placentas compared with preterm controls and localised to the syncytiotrophoblast. Interestingly, protein localisation was markedly reduced in term placenta. Syncytialisation of BeWo cells did not change PAPPA2 expression. However, hypoxia upregulated PAPPA2 mRNA and protein expression in primary placental explants. Together, our data suggest that PAPPA2 may be upregulated in severe pre-eclampsia and, functionally, this may be mediated via increased placental hypoxia known to occur with this pregnancy disorder.

Neurology of pregnancy

Pregnancy creates alterations in maternal physiology which predispose to unique neurologic disorders. Pre-eclampsia, eclampsia, certain types of ischemic and hemorrhagic stroke, reversible cerebral vasoconstriction syndrome, posterior reversible encephalopathy syndrome, and thunderclap headache all appear to share a common origin from vascular endothelial dysfunction, with overlapping clinical presentations. Multiple sclerosis often improves during pregnancy. Compression mononeuropathies may occur in the extremities. Myasthenia gravis may affect second stage labor. Various inflammatory peripheral neuropathies, dystrophies, myopathies may occur during pregnancy. The safety of specific immune suppressants is reviewed. Epilepsy does not have a significant effect upon the course of pregnancy, albeit there is a modest increase in the need for cesarean section. Certain antiepileptic drugs may produce fetal malformations, most notably valproic acid. Brain tumors are rare during pregnancy, but may increase in size due to activation of hormonal receptors on tumor cells surfaces, water retention, and engorged blood vessels.

Development and Testing of the Preeclampsia Prenatal Symptom-Monitoring Checklist (PPSMC)

Background and Purpose: Preeclampsia, a common disorder of unknown origin, presents with signs and symptoms that can be subtle, making assessment and intervention challenging. The purpose of this study was to refine the psychometric properties of an instrument designed to assess a comprehensive range of preeclampsia symptoms. Methods: Testing of the Preeclampsia Prenatal Symptom-Monitoring Scale (PPSMC) was accomplished through a retrospective, correlational, and comparative study of 100 postpartum women with preeclampsia and gestational hypertension. Results: The initial 17-item Cronbach’s alpha was .73; reliability of the current 11-item PPSMC increased to .77. Content validity index for the PPSMC (17 items) was .88; for the PPSMC (11 items), .93. Exploratory factor analysis, known group comparisons, and predictive validity lend beginning support of the instrument’s construct validity. Conclusion: This instrument may be useful in examining in greater detail the symptomatology of women with preeclampsia in practice and research settings.

The association of circulating angiogenic factors and HbA1c with the risk of preeclampsia in women with preexisting diabetes

Objective:

To assess whether glycemic control, soluble fms-like tyrosine kinase 1 (sFlt1) and placental growth factor (PlGF) were associated with the development of preeclampsia (PE) or gestational hypertension (GHTN) in women with preexisting diabetes.

Methods:

Maternal circulating angiogenic factors (sFlt1 and PlGF) measured on automated platform were studied at four time points during pregnancy in women with diabetes (N = 159) and reported as multiples of the median (MOM) of sFlt1/PlGF ratio (median, 25th–75th percentile) noted in non-diabetic non-hypertensive control pregnant population (N = 139). Diagnosis of PE or GHTN was determined by review of de-identified clinical data.

Results:

PE developed in 12% (N = 19) and GHTN developed in 23% (N = 37) of the women with diabetes. Among diabetic women without PE or GHTN, median sFlt1/PlGF levels at 35–40 weeks was threefold higher than in non-diabetic controls [MOM 3.21(1.19–7.24), p = 0.0001]. Diabetic women who subsequently developed PE had even greater alterations in sFlt1/PlGF ratio during the third trimester [MOM for PE at 27–34 weeks 15.18 (2.37–26.86), at 35–40 weeks 8.61(1.20–18.27), p ≤ 0.01 for both windows compared to non-diabetic controls]. Women with diabetes who subsequently developed GHTN also had significant alterations in angiogenic factors during third trimester; however, these findings were less striking. Among women with diabetes, glycosylated hemoglobin (HbA1c) during the first trimester was higher in subjects who subsequently developed PE (7.7 vs 6.7%, p = 0.0001 for diabetic PE vs diabetic non-PE).

Conclusions:

Women with diabetes had a markedly altered anti-angiogenic state late in pregnancy that was further exacerbated in subjects who developed PE. Altered angiogenic factors may be one mechanism for the increased risk of PE in this population. Increased HbA1c in the first trimester of pregnancies in women with diabetes was strongly associated with subsequent PE.

Expression levels of seven candidate genes in human peripheral blood mononuclear cells and their association with preeclampsia

Objective

To evaluate the peripheral blood mononuclear cell (PBMC) expression levels of hemeoxygenase 1 (HMOX-1), superoxide dismutase 1 (SOD-1), vascular endothelial growth factor A (VEGF-A), transforming growth factor beta 1 (TGF-β1), interleukin (IL)-6, IL-15 and AdipoQ genes to study their association with preeclampsia (PE).

Methods

A total of 177 pregnant women were recruited: 108 cases and 69 controls. Quantification of gene expression was measured by quantitative real-time polymerase chain reaction (PCR) using TaqMan probes.

Results

Underexpression of VEGF-A and TGF-β1 was a constant in most of the cases (80.91% and 76.36%, respectively) and their expression was associated with onset and/or severity of disease (p values < 0.05). IL-6, IL-15 and AdipoQ, showed low or no expression in PBMC samples evaluated.

Conclusion

PBMC underexpression of VEGF-A and TGF-β1 is a hallmark of PE in the study population.

Co-expression network analysis and genetic algorithms for gene prioritization in preeclampsia

BACKGROUND

In this study, we explored the gene prioritization in preeclampsia, combining co-expression network analysis and genetic algorithms optimization approaches. We analysed five public projects obtaining 1,146 significant genes after cross-platform and processing of 81 and 149 microarrays in preeclamptic and normal conditions, respectively.

METHODS

After co-expression network construction, modular and node analysis were performed using several approaches. Moreover, genetic algorithms were also applied in combination with the nearest neighbour and discriminant analysis classification methods.

RESULTS

Significant differences were found in the genes connectivity distribution, both in normal and preeclampsia conditions pointing to the need and importance of examining connectivity alongside expression for prioritization. We discuss the global as well as intra-modular connectivity for hubs detection and also the utility of genetic algorithms in combination with the network information. FLT1, LEP, INHA and ENG genes were identified according to the literature, however, we also found other genes as FLNB, INHBA, NDRG1 and LYN highly significant but underexplored during normal pregnancy or preeclampsia.

CONCLUSIONS

Weighted genes co-expression network analysis reveals a similar distribution along the modules detected both in normal and preeclampsia conditions. However, major differences were obtained by analysing the nodes connectivity. All models obtained by genetic algorithm procedures were consistent with a correct classification, higher than 90%, restricting to 30 variables in both classification methods applied.Combining the two methods we identified well known genes related to preeclampsia, but also lead us to propose new candidates poorly explored or completely unknown in the pathogenesis of preeclampsia, which may have to be validated experimentally.

Upregulation of long noncoding RNA SPRY4-IT1 modulates proliferation, migration, apoptosis, and network formation in trophoblast cells HTR-8SV/neo

SPRY4-IT1 has been reported to have extremely high expression in normal placenta tissues. It is a Long noncoding RNA (lncRNA), which is associated with cell growth, migration, invasion, and apoptosis in melanoma. A 2.8-fold increase of SPRY4-IT1 expression was validated by Real-time reverse transcription-polymerase chain reaction (qRT-PCR) in severe preeclamptic placenta as compared with that of the normal ones (n=25) in this study. Furthermore, the role of SPRY4-IT1 in proliferation, migration, apoptosis, and network formation ability of trophoblast cells HTR-8/SVneo was assessed. Suppression of SPRY4-IT1 using siRNA treatment and its overexpression using plasmid targeting SPRY4-IT1 were performed in order to explore the biological function of SPRY4-IT1 in the development and progression of trophoblast cells HTR-8/SVneo, in vitro. The results showed that SPRY4-IT1 knockdown enhanced the cell migration and proliferation, and reduced the response of cells to apoptosis. However, exogenous SPRY4-IT1 overexpression significantly decreased the cell migration and proliferation, while increased cell apoptosis. Our study showed for the first time that aberrant expression of lncRNA SPRY4-IT1 might contribute to the abnormal condition of trophoblast cells HTR-8/SVneo. Therefore, we proposed SPRY4-IT1 as a novel lncRNA molecule, which might be associated with the pathogenesis of preeclampsia and might provide a new target for its early diagnosis and treatment.

Integrating multiple 'omics' analyses identifies serological protein biomarkers for preeclampsia

BACKGROUND

Preeclampsia (PE) is a pregnancy-related vascular disorder which is the leading cause of maternal morbidity and mortality. We sought to identify novel serological protein markers to diagnose PE with a multi-'omics' based discovery approach.

METHODS

Seven previous placental expression studies were combined for a multiplex analysis, and in parallel, two-dimensional gel electrophoresis was performed to compare serum proteomes in PE and control subjects. The combined biomarker candidates were validated with available ELISA assays using gestational age-matched PE (n=32) and control (n=32) samples. With the validated biomarkers, a genetic algorithm was then used to construct and optimize biomarker panels in PE assessment.

RESULTS

In addition to the previously identified biomarkers, the angiogenic and antiangiogenic factors (soluble fms-like tyrosine kinase (sFlt-1) and placental growth factor (PIGF)), we found 3 up-regulated and 6 down-regulated biomakers in PE sera. Two optimal biomarker panels were developed for early and late onset PE assessment, respectively.

CONCLUSIONS

Both early and late onset PE diagnostic panels, constructed with our PE biomarkers, were superior over sFlt-1/PIGF ratio in PE discrimination. The functional significance of these PE biomarkers and their associated pathways were analyzed which may provide new insights into the pathogenesis of PE.

The relationship between preeclampsia, pregnancy-induced hypertension and maternal risk of breast cancer: a meta-analysis

BACKGROUND

It has long been recognized that some human breast cancers are hormone dependent. Preeclampsia is a syndrome of pregnancy defined by the onset of hypertension and proteinuria and characterized by dysfunction of the maternal endothelium. Many hormonal changes occur with preeclampsia, and we hypothesize that these changes may influence the risk of maternal breast cancer. We also analyzed the relation between pregnancy-induced hypertension (PIH) and maternal risk of breast cancer.

METHODS

Among 13 relevant publications about preeclampsia and six relevant publications about PIH, some studies find preeclampsia associated with a lower risk of breast cancer, but others did not. Therefore, these results are inconclusive. We conducted meta-analysis to evaluate more precisely the relationship between preeclampsia, PIH and maternal risk of breast cancer.

RESULTS

The pooled estimate of the hazard ratio (HR) associated with preeclampsia was 0.86 (95% CI 0.73-1.01), and that associated with PIH was 0.83 (0.66-1.06), both based on the random effects model.

CONCLUSION

Some suggestive but not entirely consistent nor conclusive evidence was found on the association between the history of preeclampsia or PIH with the subsequent risk of breast cancer.

The relationship between pre-eclampsia and peripartum cardiomyopathy: a systematic review and meta-analysis

OBJECTIVES

The goal of this study was to systematically review the peripartum cardiomyopathy (PPCM) literature and determine the prevalence of pre-eclampsia (PE) in women with PPCM. Secondary analyses included evaluation of the prevalence of hypertensive disorders, multiple gestations, and multiparity.

BACKGROUND

PPCM is a significant cause of maternal and infant morbidity and mortality worldwide, yet its etiology remains unknown. PE is often cited as a risk factor for the development of PPCM and recent research suggests that PE and PPCM share mechanisms that contribute to their pathobiology. No comprehensive evaluation of the relationship between PE and PPCM exists.

METHODS

A systematic predetermined search strategy was performed in multiple databases to identify studies describing ≥3 women with PPCM. Prevalence rates of PE, hypertension, multiple gestations, and multiparity were pooled.

RESULTS

Data from 22 studies (n = 979) were included in this analysis. The pooled prevalence of 22% (95% confidence interval [CI]: 16% to 28%) was more than quadruple the 5% average worldwide background rate of PE in pregnancy (p < 0.001). There were no geographic or racial differences detected in the prevalence of PE in women with PPCM. The rates of hypertension during pregnancy (37% [95% CI: 29% to 45%]) and multiple gestations (9% [95% CI: 7% to 11%]) were also elevated.

CONCLUSIONS

The prevalence of PE, hypertensive disorders, and multiple gestations in women with PPCM is markedly higher than that in the general population. These findings support the concept of a shared pathogenesis between PE and PPCM and highlight the need for awareness of the overlap between these 2 diseases.

Ambient air pollution and hypertensive disorder of pregnancy

BACKGROUND

Ambient air pollution has been implicated in the development of hypertensive disorders of pregnancy (HDP). However, evidence of the association between air pollution and HDP is still limited, and the effects of gaseous air pollutants on HDP and their time windows of exposure have not been well studied.

METHODS

We used the Florida birth registry data to investigate the associations between air pollutants (NO2, SO2, PM(2.5), O3 and CO) and the risks of HDP in 22,041 pregnant women in Jacksonville, Florida, USA from 2004 to 2005. Further, we examined whether air pollution exposure during different time windows defined by trimesters and the entire pregnancy had different effects on HDP.

RESULTS

The single-pollutant logistic regression model showed that exposure to four pollutants during the full pregnancy period was significantly associated with prevalence of HDP after adjusting for covariates: NO2 (OR=1.21, 95% CI 1.09 to 1.35), PM2.5 (OR=1.24, 95% CI 1.08 to 1.43), SO2 (OR=1.13, 95% CI 1.01 to 1.25) and CO (OR=1.12, 95% CI 1.03 to 1.22) per IQR increase. Similar effects were observed when first trimester exposure to NO2, SO2 and CO, and second trimester exposures to PM2.5 were examined. Consistent results were confirmed in multiple-pollutant models.

CONCLUSIONS

This study suggests that exposure to high levels of air pollution during early pregnancy and the full gestational period was associated with increased prevalence of HDP in Florida, USA.

Changes in retinal microvascular caliber precede the clinical onset of preeclampsia

Preeclampsia is a leading cause of maternal morbidity and mortality. The degree of maternal cardiovascular dysfunction that precedes the onset of preeclampsia is largely unknown. This prospective cohort study aimed to characterize differences in vivo in retinal microvascular caliber and blood pressure throughout pregnancy in relation to preeclampsia development. Women were recruited from Royal Prince Alfred Hospital, Sydney, Australia, of which 92 women were included in the study. Retinal images and blood pressures were collected at 13, 19, 29, and 38 weeks of gestation. Retinal vessels were analyzed as the central retinal arteriolar equivalent corrected for mean arterial blood pressure and the central retinal venular equivalent corrected for mean arterial blood pressure, using generalized linear models adjusted for age and body mass index. The preeclampsia group were significantly older (P=0.002) and had a significantly higher mean body mass index (P=0.005). The central retinal arteriolar equivalent corrected for mean arterial blood pressure was significantly reduced at 13 (P=0.03), 19 (P=0.007), and 38 (P=0.03) weeks of gestation in the preeclampsia group. The central retinal venular equivalent corrected for mean arterial blood pressure was also significantly lower at 13 (P=0.04) and 19 (P=0.001) weeks of gestation in the women who progressed to preeclampsia. This study directly documents increased peripheral resistance in vivo, observed as the combination of constricted retinal arterioles or venules and elevated blood pressure, in women who later developed preeclampsia. This difference preceded the clinical signs of preeclampsia.

Galectin signature in normal pregnancy and preeclampsia

Members of the galectin family are expressed within the female reproductive tract and have been shown to be involved in multiple biological functions that support the progression of pregnancy. Specific expression patterns of different members of this family have been identified at the maternal decidua and on the placental side. In some cases, mechanisms by which galectins exert their functions have been delineated in adverse pregnancy outcomes. This review summarizes studies on galectins that have been documented to be important for pregnancy maintenance, either supporting the maternal adaptation to pregnancy or the placentation process. In addition, we focus our discussion on the role of galectins in preeclampsia, a specific life-threatening pregnancy disorder.

Reversal of gene dysregulation in cultured cytotrophoblasts reveals possible causes of preeclampsia

During human pregnancy, a subset of placental cytotrophoblasts (CTBs) differentiates into cells that aggressively invade the uterus and its vasculature, anchoring the progeny and rerouting maternal blood to the placenta. In preeclampsia (PE), CTB invasion is limited, reducing placental perfusion and/or creating intermittent flow. This syndrome, affecting 4%-8% of pregnancies, entails maternal vascular alterations (e.g., high blood pressure, proteinuria, and edema) and, in some patients, fetal growth restriction. The only cure is removal of the faulty placenta, i.e., delivery. Previously, we showed that defective CTB differentiation contributes to the placental component of PE, but the causes were unknown. Here, we cultured CTBs isolated from PE and control placentas for 48 hours, enabling differentiation and invasion. In various severe forms of PE, transcriptomics revealed common aberrations in CTB gene expression immediately after isolation, including upregulation of SEMA3B, which resolved in culture. The addition of SEMA3B to normal CTBs inhibited invasion and recreated aspects of the PE phenotype. Additionally, SEMA3B downregulated VEGF signaling through the PI3K/AKT and GSK3 pathways, effects that were observed in PE CTBs. We propose that, in severe PE, the in vivo environment dysregulates CTB gene expression; the autocrine actions of the upregulated molecules (including SEMA3B) impair CTB differentiation, invasion and signaling; and patient-specific factors determine the signs.

Elucidating immune mechanisms causing hypertension during pregnancy

Preeclampsia is associated with hypertension and increased infant and maternal morbidity and mortality. The underlying cause of preeclampsia is largely unknown, but it is clear that an immunological component plays a key pathophysiological role. This review will highlight immunological key players in the pathology of preeclampsia and discuss their role in the pathophysiology observed in the reduced placental perfusion (RUPP) rat model of preeclampsia.

Individual common carotid artery wall layer dimensions, but not carotid intima-media thickness, indicate increased cardiovascular risk in women with preeclampsia: an investigation using noninvasive high-frequency ultrasound

BACKGROUND

Preeclampsia (PE) is associated with increased risk of cardiovascular disease later in life. Ultrasound assessment of the common carotid artery intima-media thickness (IMT) during or after PE has not indicated any increased cardiovascular risk.

METHODS AND RESULTS

We used high-frequency ultrasound (22 MHz) to estimate the individual common carotid artery IMTs in 55 women at PE diagnosis and in 64 women with normal pregnancies at a similar stage. All were re-examined about 1 year postpartum. A thick intima, thin media, and high intima/media (I/M) ratio are signs of a less healthy artery wall. PE was associated with a significantly thicker mean common carotid artery intima, thinner media, and higher I/M ratio than in normal pregnancy (mean I/M difference, 0.21; 95% confidence interval, 0.17-0.25; P<0.0001). After adjustment for first trimester body mass index and mean arterial pressure, differences in intima thickness and I/M remained significant. About 1 year postpartum, these values had improved in both groups, but group differences remained significant (all adjusted P<0.0001). There were no significant differences in IMT between groups. In receiver-operating characteristic curve analysis, intima thickness and I/M were strongly predictive of prevalent PE (area under the curve, ≈0.95), whereas IMT was not (area under the curve, 0.49).

CONCLUSIONS

The arteries of women with PE were negatively affected during pregnancy and 1 year postpartum compared with women with normal pregnancies, indicating increased cardiovascular risk. Estimation of intima thickness and I/M ratio seem preferable to estimation of common carotid artery IMT in imaging cardiovascular risk in PE. Results from this pilot study warrant further confirmation.

Peptidomic Identification of Serum Peptides Diagnosing Preeclampsia

We sought to identify serological markers capable of diagnosing preeclampsia (PE). We performed serum peptide analysis (liquid chromatography mass spectrometry) of 62 unique samples from 31 PE patients and 31 healthy pregnant controls, with two-thirds used as a training set and the other third as a testing set. Differential serum peptide profiling identified 52 significant serum peptides, and a 19-peptide panel collectively discriminating PE in training sets (n = 21 PE, n = 21 control; specificity = 85.7% and sensitivity = 100%) and testing sets (n = 10 PE, n = 10 control; specificity = 80% and sensitivity = 100%). The panel peptides were derived from 6 different protein precursors: 13 from fibrinogen alpha (FGA), 1 from alpha-1-antitrypsin (A1AT), 1 from apolipoprotein L1 (APO-L1), 1 from inter-alpha-trypsin inhibitor heavy chain H4 (ITIH4), 2 from kininogen-1 (KNG1), and 1 from thymosin beta-4 (TMSB4). We concluded that serum peptides can accurately discriminate active PE. Measurement of a 19-peptide panel could be performed quickly and in a quantitative mass spectrometric platform available in clinical laboratories. This serum peptide panel quantification could provide clinical utility in predicting PE or differential diagnosis of PE from confounding chronic hypertension.

[Endothelial dysfunction: role in the maternal syndrome of preeclampsia and long-term consequences for the cardiovascular system]

Preeclampsia is a pregnancy disorder being a leading cause of maternal and fetal mortality and morbidity. It is a complex multisystem disease characterized by hypertension and proteinuria. In preeclampsia the placenta releases factors into the maternal circulation which cause a systemic endothelial dysfunction. Here, we review data demonstrating the central role played by the endothelium in the development of the maternal syndrome of preeclampsia. We present also original data showing how circulating factors present in the plasma of preeclamptic women can alter the transcriptome of endothelial cells. The expression of genes involved in essential functions such as vasoregulation, oxidative stress, apoptosis and cell proliferation show differential expression when endothelial cells are exposed to preeclamptic or normal pregnancy plasma. We conclude by discussing the growing evidences that the alterations of the endothelium during preeclampsia are linked to an increased risk of cardiovascular diseases latter on life. Therefore, a better understanding of the modifications undergone by the endothelial cells during preeclampsia is essential to develop new therapeutic approaches to both, manage preeclampsia and to prevent the long-term sequelae of the disease on women cardiovascular system.

Maternal adiposity as an independent risk factor for pre-eclampsia: a meta-analysis of prospective cohort studies

Studies investigating the association between maternal adiposity and risk of pre-eclampsia showed contradictory results. Therefore, we performed a meta-analysis of prospective cohort studies to estimate the effect of maternal adiposity on pre-eclampsia. We reviewed 1,286 abstracts and finally included 29 prospective cohort studies with 1,980,761 participants and 67,075 pre-eclampsia events. We pooled data with a random-effects model, and obtained risk estimates for five predetermined bodyweight groups: low, normal-weight (reference), overweight, obese and severely obese. In the cohort studies that unadjusted for pre-eclampsia risk factors, the pooled unadjusted relative risks (RR) with 95% confidence intervals (95%CI) for pre-eclampsia of overweight, obese and severely obese women were 1.58 (95% CI 1.44-1.72, P < 0.001), 2.68 (95% CI 2.39-3.01, P < 0.001) and 3.12 (95% CI 2.24-4.36, P < 0.001), respectively. In those cohorts that adjusted for pre-eclampsia risk factors, the pooled unadjusted RRs for pre-eclampsia of overweight, obese and severely obese women were 1.70 (95% CI 1.60-1.81, P < 0.001), 2.93 (95% CI 2.58-3.33, P < 0.001) and 4.14 (95% CI 3.61-4.75, P < 0.001), respectively. Sensitivity analysis showed maternal adiposity was associated with increased risk of pre-eclampsia in both nulliparous and multiparas women. In conclusion, overweight or obese pregnant women have a substantially increased risk of pre-eclampsia, and maternal adiposity is an independent risk factor of pre-eclampsia.

Vasoactive agents for the prediction of early- and late-onset preeclampsia in a high-risk cohort

Background

To evaluate the soluble fms-like tyrosine kinase-1 (sFlt-1), placental growth factor (PlGF), and sFlt-1/PlGF ratio for the prediction of early- and late-onset preeclampsia in a high-risk cohort.

Methods

We studied serial serum samples collected prospectively at 12 + 0 - 14 + 0, 18 + 0 - 20 + 0, and 26 + 0 - 28 + 0 weeks + days of gestation in 6 women who developed early-onset preeclampsia (before 34 weeks of gestation) and in 21 women who developed late-onset preeclampsia (after 34 weeks of gestation) with automated ElecSys 2010 immunoanalyzer (Roche Diagnostics, Germany). Twenty-six high-risk women and 53 women without risk factors with normal pregnancies served as controls.

Results

Serum PlGF concentrations were lower at 18 + 0 to 20 + 0, and 26 + 0 to 28 + 0 weeks of gestation in women who developed early-onset preeclampsia compared to women who developed late-onset preeclampsia and to controls (p < 0.05 for all comparisons). At 18 + 0 to 20 + 0 weeks of gestation area under the receiver-operating characteristic curve (AUC) for serum PlGF was 99.8% (p = 0.0007, 95% CI 99.0-100.0). At 26 + 0 to 28 + 0 weeks of gestation serum sFlt-1/PlGF ratio explicitly detects those women who developed early-onset preeclampsia (AUC 100.0%, p = 0.0007, 95% CI 100–100). Amongst women with late-onset preeclampsia, those who developed severe form of the disease (N = 8) had significantly higher serum sFlt-1 concentrations at all three timepoints (p = 0.004, p = 0.006, and p = 0.003, respectively) compared to women with non-severe form (N = 13).

Conclusions

Low serum PlGF concentration predicts early-onset preeclampsia from the second trimester and elevated serum sFlt-1/PlGF ratio from 26 to 28 weeks of gestation. Elevated serum sFlt-1 concentration in the first trimester in women who later develop late-onset, severe preeclampsia may suggest different etiology compared to the late-onset non-severe form of the disease.