Low placental growth factor across pregnancy identifies a subset of women with preterm preeclampsia: type 1 versus type 2 preeclampsia?

Metabolic abnormalities and obesity's impact on the risk for developing preeclampsia

Preeclampsia (PE), a hypertensive disorder of pregnancy, is increasing as a major contributor to perinatal and long-term morbidity of mother and offspring. PE is thought to originate from ischemic insults in the placenta driving the release of prohypertensive anti-angiogenic [soluble fms-like tyrosine kinase-1 (sFlt-1)] and proinflammatory [tumor necrosis factor-α (TNF-α)] factors into the maternal circulation. Whereas the increased incidence of PE is hypothesized to be largely due to the obesity pandemic, the mechanisms whereby obesity increases this risk are unknown. The maternal endothelium is targeted by placental and adipose tissue-derived factors like sFlt-1 and TNF-α that promote hypertension during pregnancy, resulting in vascular dysfunction and hypertension. Interestingly, not all obese pregnant women develop PE. Data suggest that obese pregnant women with the greatest metabolic abnormalities have the highest incidence of PE. Identifying obesity-related mechanisms driving hypertension in some obese pregnant women and pathways that protect normotensive obese pregnant women, may uncover novel protocols to treat PE. Metabolic abnormalities, such as increased circulating leptin, glucose, insulin, and lipids, are likely to increase the risk for PE in obese women. It is not only important to understand whether each of these metabolic factors contribute to the increased risk for PE in obesity, but also their cumulative effects. This is particularly relevant to obese pregnant women with gestational diabetes mellitus (GDM) where all of these factors are increased and the risk for PE is highest. It is speculated that these factors potentiate the anti-angiogenic and proinflammatory mechanisms of placental ischemia-induced vascular dysfunction thereby contributing to the increasing incidence of PE.

Preconception Cardiovascular Risk Factor Differences Between Gestational Hypertension and Preeclampsia: Cohort Norway Study

Supplemental Digital Content is available in the text.

Preconception predictors of gestational hypertension and preeclampsia may identify opportunities for early detection and improve our understanding of the pathogenesis and life course epidemiology of these conditions. Female participants in community-based Cohort Norway health surveys, 1994 to 2003, were prospectively followed through 2012 via record linkages to Medical Birth Registry of Norway. Analyses included 13 217 singleton pregnancies (average of 1.59 births to 8321 women) without preexisting hypertension. Outcomes were gestational hypertension without proteinuria (n=237) and preeclampsia (n=429). Mean age (SD) at baseline was 27.9 years (4.5), and median follow-up was 4.8 years (interquartile range 2.6–7.8). Gestational hypertension and preeclampsia shared several baseline risk factors: family history of diabetes mellitus, pregravid diabetes mellitus, a high total cholesterol/high-density lipoprotein cholesterol ratio (>5), overweight and obesity, and elevated blood pressure status. For preeclampsia, a family history of myocardial infarction before 60 years of age and elevated triglyceride levels (≥1.7 mmol/L) also predicted risk while physical activity was protective. Preterm preeclampsia was predicted by past-year binge drinking (≥5 drinks on one occasion) with an adjusted odds ratio of 3.7 (95% confidence interval 1.3–10.8) and by past-year physical activity of ≥3 hours per week with an adjusted odds ratio of 0.5 (95% confidence interval 0.3–0.8). The results suggest similarities and important differences between gestational hypertension, preeclampsia, and preterm preeclampsia. Modifiable risk factors could be targeted for improving pregnancy outcomes and the short- and long-term sequelae for mothers and offspring.

Urinary tract infection during pregnancy, angiogenic factor profiles, and risk of preeclampsia

BACKGROUND

Despite decades of research, and much progress in discernment of biomarkers in the maternal circulation, the pathogenesis of preeclampsia (PE) remains elusive. The pathophysiology of PE is believed to involve aberrant placentation and an associated increase in systemic inflammation. In this conceptualization, PE becomes more likely when the level of systemic inflammatory burden inherent in pregnancy itself exceeds the maternal capacity to compensate for this additional stress. If this is the case, then it is possible to hypothesize that conditions, such as infectious disease, that increase systemic inflammatory burden should also increase the risk of PE. As urinary tract infection (UTI) represents a common source of inflammation during pregnancy, we tested whether presence of UTI during pregnancy increased the odds of developing PE. Prior work has documented this association. However many of these studies were limited by small cohort sizes and insufficient control for covariates.

OBJECTIVE

The present study is a secondary analysis of a robust contemporary obstetrical cohort recruited to examine the ability of longitudinally sampled maternal angiogenic concentrations to predict PE. We hypothesize that the occurrence of UTI during a pregnancy is associated with the later occurrence of PE in that pregnancy. As PE is believed to be associated with aberrations in systemic angiogenic levels (placental growth factor and soluble isoform of VEGF receptor), we further hypothesize that there will be significant interactions between maternal angiogenic protein levels and the occurrence of UTI.

STUDY DESIGN

Women aged ≥18 years (n = 2607) were recruited and followed up prospectively from the initiation of prenatal care through delivery at 3 regional academic centers. PE was defined by American Congress of Obstetricians and Gynecologists criteria and was independently validated by a panel of physicians. UTI was defined by the presence of clinical symptoms necessitating treatment in addition to supportive laboratory evidence. Multivariate logistic regression models were used and controlled for maternal age, race, parity, body mass index, hypertension, diabetes, in vitro fertilization, and smoking status.

RESULTS

There were 129 women with diagnosed UTIs and 235 with PE. Patients with UTI in pregnancy had higher rates of PE (31.1% vs 7.8%, P < .001) compared to those without reported UTI. The mean gestational age (SD) for UTI diagnosis in PE cases and controls was 25.6 (10.4) and 21.9 (10.9) weeks, respectively (P = .08). The unadjusted odds ratio for PE in the setting of UTI was 5.29 (95% confidence interval, 3.54-7.89). After controlling for confounders, UTI was associated with an odds ratio for PE of 3.2 (95% confidence interval, 2.0-5.1).

CONCLUSION

Presence of UTI in pregnancy, particularly in the third trimester, is strongly associated with PE. This association supports the hypothesis that the risk of PE is enhanced by an increased maternal inflammatory burden. Prophylaxis against UTI represents a potentially low-cost global intervention to slow or halt the development of PE.

Preeclampsia: Syndrome or Disease?

The focus on disease mechanisms underlying the hypertension and proteinuria defining preeclampsia has increased knowledge of the pathophysiology yet we lack both therapy and predictors. We propose this is in part due to the fact that diagnostic findings identify a "preeclampsia syndrome" but do not necessarily indicate the most important pathophysiology nor if organs are involved as cause or consequence. The increased risk for later life cardiovascular disease in women who develop preeclampsia suggests the stress test of pregnancy exposes pre-existing subclinical vascular disease. The dogma that inadequate trophoblast invasion and ischemia/reperfusion injury to the placenta is "the" cause of preeclampsia is more relevant to early onset preeclampsia (<34 weeks). There is much less evidence for defective placentation in late onset preeclampsia where maternal constitutive factors or susceptibility to vascular damage is more relevant. The contribution of differing disease phenotypes to the syndrome may explain the inability of biomarker studies to identify all preeclampsia. Identification of phenotypes will require large amounts of prospective clinical data and biospecimens, collected in a harmonized manner with analysis in an unbiased discovery approach.

Placental growth factor deficiency is associated with impaired cerebral vascular development in mice

STUDY HYPOTHESIS

Placental growth factor (PGF) is expressed in the developing mouse brain and contributes to vascularization and vessel patterning.

STUDY FINDING

PGF is dynamically expressed in fetal mouse brain, particularly forebrain, and is essential for normal cerebrovascular development.

WHAT IS KNOWN ALREADY

PGF rises in maternal plasma over normal human and mouse pregnancy but is low in many women with the acute onset hypertensive syndrome, pre-eclampsia (PE). Little is known about the expression of PGF in the fetus during PE. Pgf  (-/-) mice appear normal but recently cerebral vascular defects were documented in adult Pgf  (-/-) mice.

STUDY DESIGN, SAMPLES/MATERIALS, METHODS

Here, temporal-spatial expression of PGF is mapped in normal fetal mouse brains and cerebral vasculature development is compared between normal and congenic Pgf  (-/-) fetuses to assess the actions of PGF during cerebrovascular development. Pgf/PGF, Vegfa/VEGF, Vegf receptor (Vegfr)1 and Vegfr2 expression were examined in the brains of embryonic day (E)12.5, 14.5, 16.5 and 18.5 C57BL/6 (B6) mice using quantitative PCR and immunohistochemistry. The cerebral vasculature was compared between Pgf  (-/-) and B6 embryonic and adult brains using whole mount techniques. Vulnerability to cerebral ischemia was investigated using a left common carotid ligation assay.

MAIN RESULTS AND THE ROLE OF CHANCE

Pgf/PGF and Vegfr1 are highly expressed in E12.5-14.5 forebrain relative to VEGF and Vegfr2. Vegfa/VEGF is relatively more abundant in hindbrain (HB). PGF and VEGF expression were similar in midbrain. Delayed HB vascularization was seen at E10.5 and 11.5 in Pgf  (-/-) brains. At E14.5, Pgf  (-/-) circle of Willis showed unilateral hypoplasia and fewer collateral vessels, defects that persisted post-natally. Functionally, adult Pgf  (-/-) mice experienced cerebral ischemia after left common carotid arterial occlusion while B6 mice did not.

LIMITATIONS, REASONS FOR CAUTION

Since Pgf  (-/-) mice were used, consequences of complete absence of maternal and fetal PGF were defined. Therefore, the effects of maternal versus fetal PGF deficiency on cerebrovascular development cannot be separated. However, as PGF was strongly expressed in the developing brain at all timepoints, we suggest that local PGF has a more important role than distant maternal or placental sources. Full PGF loss is not expected in PE pregnancies, predicting that the effects of PGF deficiency identified in this model will be more severe than any effects in PE-offspring.

WIDER IMPLICATIONS OF THE FINDINGS

These studies provoke the question of whether PGF expression is decreased and cerebral vascular maldevelopment occurs in fetuses who experience a preeclamptic gestation. These individuals have already been reported to have elevated risk for stroke and cognitive impairments.

LARGE SCALE DATA

N/A.

STUDY FUNDING AND COMPETING INTERESTS

This work was supported by awards from the Natural Sciences and Engineering Research Council, the Canada Research Chairs Program and the Canadian Foundation for Innovation to B.A.C. and by training awards from the Universidade Federal de Pernambuco and Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq), Brazil to R.L.L.; Queen's University to V.R.K. and the Canadian Institutes of Health Research to M.T.R. The work of P.C. is supported by the Belgian Science Policy BELSPO-IUAP7/03, Structural funding by the Flemish Government-Methusalem funding, and the Flemish Science Fund-FWO grants. There were no competing interests.

Brain Structural and Vascular Anatomy Is Altered in Offspring of Pre-Eclamptic Pregnancies: A Pilot Study

BACKGROUND AND PURPOSE

Pre-eclampsia is a serious clinical gestational disorder occurring in 3%-5% of all human pregnancies and characterized by endothelial dysfunction and vascular complications. Offspring born of pre-eclamptic pregnancies are reported to exhibit deficits in cognitive function, higher incidence of depression, and increased susceptibility to stroke. However, no brain imaging reports exist on these offspring. We aimed to assess brain structural and vascular anatomy in 7- to 10-year-old offspring of pre-eclamptic pregnancies compared with matched controls.

MATERIALS AND METHODS

Offspring of pre-eclamptic pregnancies and matched controls (n = 10 per group) were recruited from an established longitudinal cohort examining the effects of pre-eclampsia. Children underwent MR imaging to identify brain structural and vascular anatomic differences. Maternal plasma samples collected at birth were assayed for angiogenic factors by enzyme-linked immunosorbent assay.

RESULTS

Offspring of pre-eclamptic pregnancies exhibited enlarged brain regional volumes of the cerebellum, temporal lobe, brain stem, and right and left amygdalae. These offspring displayed reduced cerebral vessel radii in the occipital and parietal lobes. Enzyme-linked immunosorbent assay analysis revealed underexpression of the placental growth factor among the maternal plasma samples from women who experienced pre-eclampsia.

CONCLUSIONS

This study is the first to report brain structural and vascular anatomic alterations in the population of offspring of pre-eclamptic pregnancies. Brain structural alterations shared similarities with those seen in autism. Vascular alterations may have preceded these structural alterations. This pilot study requires further validation with a larger population to provide stronger estimates of brain structural and vascular outcomes among the offspring of pre-eclamptic pregnancies.

Relationship between insulin resistance and circulating endothelial cells in pre-eclampsia

Endothelial dysfunction and insulin resistance (IR) are established features of pre-eclampsia, however the cause and effect relationship between them remain unexplained. Circulating endothelial cells (CEC) are increased in pre-eclampsia and appear to correlate with the degree of endothelial dysfunction. We hypothesised that CEC count in pre-eclampsia would correlate with IR and might provide a simple measure of IR in pregnancies complicated by the disease. CEC count and IR were measured in 10 women with pre-eclampsia and 10 normal pregnant controls matched for maternal age, body mass index and gestational age during the third trimester. CEC count was determined using an established immunomagnetic bead separation method and IR was measured by the homeostasis model test. CEC count and IR were significantly increased in pre-eclampsia compared to normal pregnancy. However, there was no correlation between the CEC count and IR in pre-eclampsia. The data suggest that CEC count in pre-eclampsia is not a useful measure on its own of IR in pregnancies complicated by the disease.

Uterine natural killer cells: supervisors of vasculature construction in early decidua basalis

Mammalian pregnancy involves tremendousde novomaternal vascular construction to adequately support conceptus development. In early mouse decidua basalis (DB), maternal uterine natural killer (uNK) cells oversee this process directing various aspects during the formation of supportive vascular networks. The uNK cells recruited to early implantation site DB secrete numerous factors that act in the construction of early decidual vessels (neoangiogenesis) as well as in the alteration of the structural components of newly developing and existing vessels (pruning and remodeling). Although decidual and placental development sufficient to support live births occur in the absence of normally functioning uNK cells, development and structure of implantation site are optimized through the presence of normally activated uNK cells. Human NK cells are also recruited to early decidua. Gestational complications including recurrent spontaneous abortion, fetal growth restriction, preeclampsia, and preterm labor are linked with the absence of human NK cell activation via paternally inherited conceptus transplantation antigens. This review summarizes the roles that mouse uNK cells normally play in decidual neoangiogenesis and spiral artery remodeling in mouse pregnancy and briefly discusses changes in early developmental angiogenesis due to placental growth factor deficiency.

Placental growth factor influences maternal cardiovascular adaptation to pregnancy in mice

In healthy human pregnancies, placental growth factor (PGF) concentrations rise in maternal plasma during early gestation, peak over Weeks 26-30, then decline. Because PGF in nongravid subjects participates in protection against and recovery from cardiac pathologies, we asked if PGF contributes to pregnancy-induced maternal cardiovascular adaptations. Cardiovascular function and structure were evaluated in virgin, pregnant, and postpartum C56BL/6-Pgf(-) (/) (-) (Pgf(-) (/) (-)) and C57BL/6-Pgf(+/+) (B6) mice using plethysmography, ultrasound, quantitative PCR, and cardiac and renal histology. Pgf(-/-) females had higher systolic blood pressure in early and late pregnancy but an extended, abnormal midpregnancy interval of depressed systolic pressure. Pgf(-/-) cardiac output was lower than gestation day (gd)-matched B6 after midpregnancy. While Pgf(-) (/) (-) left ventricular mass was greater than B6, only B6 showed the expected gestational gain in left ventricular mass. Expression of vasoactive genes in the left ventricle differed at gd8 with elevated Nos expression in Pgf(-) (/) (-) but not at gd14. By gd16, Pgf(-) (/) (-) kidneys were hypertrophic and had glomerular pathology. This study documents for the first time that PGF is associated with the systemic maternal cardiovascular adaptations to pregnancy.

Early pregnancy prediction of preeclampsia in nulliparous women, combining clinical risk and biomarkers: the Screening for Pregnancy Endpoints (SCOPE) international cohort study

More than half of all cases of preeclampsia occur in healthy first-time pregnant women. Our aim was to develop a method to predict those at risk by combining clinical factors and measurements of biomarkers in women recruited to the Screening for Pregnancy Endpoints (SCOPE) study of low-risk nulliparous women. Forty-seven biomarkers identified on the basis of (1) association with preeclampsia, (2) a biological role in placentation, or (3) a role in cellular mechanisms involved in the pathogenesis of preeclampsia were measured in plasma sampled at 14 to 16 weeks' gestation from 5623 women. The cohort was randomly divided into training (n=3747) and validation (n=1876) cohorts. Preeclampsia developed in 278 (4.9%) women, of whom 28 (0.5%) developed early-onset preeclampsia. The final model for the prediction of preeclampsia included placental growth factor, mean arterial pressure, and body mass index at 14 to 16 weeks' gestation, the consumption of ≥3 pieces of fruit per day, and mean uterine artery resistance index. The area under the receiver operator curve (95% confidence interval) for this model in training and validation cohorts was 0.73 (0.70-0.77) and 0.68 (0.63-0.74), respectively. A predictive model of early-onset preeclampsia included angiogenin/placental growth factor as a ratio, mean arterial pressure, any pregnancy loss <10 weeks, and mean uterine artery resistance index (area under the receiver operator curve [95% confidence interval] in training and validation cohorts, 0.89 [0.78-1.0] and 0.78 [0.58-0.99], respectively). Neither model included pregnancy-associated plasma protein A, previously reported to predict preeclampsia in populations of mixed parity and risk. In nulliparous women, combining multiple biomarkers and clinical data provided modest prediction of preeclampsia.

Pre-eclampsia part 2: prediction, prevention and management

An antiangiogenic state might constitute a terminal pathway for the multiple aetiologies of pre-eclampsia, especially those resulting from placental abnormalities. The levels of angiogenic and antiangiogenic proteins in maternal blood change prior to a diagnosis of pre-eclampsia, correlate with disease severity and have prognostic value in identifying women who will develop maternal and/or perinatal complications. Potential interventions exist to ameliorate the imbalance of angiogenesis and, hence, might provide opportunities to improve maternal and/or perinatal outcomes in pre-eclampsia. Current strategies for managing pre-eclampsia consist of controlling hypertension, preventing seizures and timely delivery of the fetus. Prediction of pre-eclampsia in the first trimester is of great interest, as early administration of aspirin might reduce the risk of pre-eclampsia, albeit modestly. Combinations of biomarkers typically predict pre-eclampsia better than single biomarkers; however, the encouraging initial results of biomarker studies require external validation in other populations before they can be used to facilitate intervention in patients identified as at increased risk. Angiogenic and antiangiogenic factors might also be useful in triage of symptomatic patients with suspected pre-eclampsia, differentiating pre-eclampsia from exacerbations of pre-existing medical conditions and performing risk assessment in asymptomatic women. This Review article discusses the performance of predictive and prognostic biomarkers for pre-eclampsia, current strategies for preventing and managing the condition and its long-term consequences.

Impact of placental growth factor deficiency on early mouse implant site angiogenesis

Effects of placental growth factor (PGF), an angiokine product of fetal trophoblasts and maternal decidual cells, on early decidual angiogenesis are undefined. We used whole-mount immunofluorescence analyses to compare uterus and gestation day 4.5-9.5 mouse implantation sites that differed genetically in fetal or maternal PGF deficiency. Implant site number and embryonic development were similar in Pgf(-/-) and Pgf(+/+) females although Pgf(-/-) lymphatic vessels were anomalous. Correct, fine branching angiogenesis of anti-mesometrial vessels required both conceptus and maternal PGF; correct mesometrial branching angiogenesis depended solely upon conceptus PGF. Thus, PGF is non-redundant for optimizing branching angiogenesis in early decidua.

Clinical characterization and outcomes of preeclampsia with normal angiogenic profile

OBJECTIVE

To compare the clinical characteristics and outcomes of preeclamptic women presenting with a normal plasma angiogenic profile with those subjects who are characterized by an abnormal angiogenic profile.

METHODS

This was a secondary analysis of a prospective cohort study in women presenting to obstetrical triage at <37 weeks of gestation and diagnosed with preeclampsia within 2 weeks of enrollment and in whom angiogenic factors (sFlt1 and PlGF) measurements were available. Patients were divided into two groups based on their circulating levels of these factors described as a ratio; the sFlt1/PlGF ratio, non-angiogenic preeclampsia (sFlt1/PlGF ratio <85) and angiogenic preeclampsia (sFlt1/PlGF ratio ≥85). The data are presented by sFlt1/PlGF category using median and quartile 1-quartile 3 for continuous variables and by frequency and sample sizes for categorical variables.

RESULTS

In our cohort, the patients with non-angiogenic preeclampsia (N = 46) were more obese [BMI: 35.2 (31.6, 38.7) versus 31.1 (28.0, 39.0), p = 0.04], more likely to have preexisting diabetes (21.7% versus 2.0%, p = 0.002) and presented at a later gestational age [35 (32, 37) versus 32 (29, 34) weeks, p < 0.0001] as compared with women with angiogenic preeclampsia (N = 51). Women with non-angiogenic preeclampsia had no serious adverse outcomes (elevated liver function tests/low platelets: 0% versus 23.5%, abruption: 0% versus 9.8%, pulmonary edema: 0% versus 3.9%, eclampsia: 0% versus 2.0 %, small for gestational age: 0% versus 17.7% and fetal/neonatal death: 0% versus 5.9%) as compared with women with angiogenic preeclampsia. The rate of preterm delivery <34 weeks was 8.7% in non-angiogenic preeclampsia compared with 64.7% in angiogenic preeclampsia (p < 0.0001). Interestingly, delivery between 34 and 37 weeks and resource utilization (hospital admission days) were similar in the two groups.

CONCLUSION

In contrast to the angiogenic form, the non-angiogenic form of preeclampsia is characterized by little to no risk of preeclampsia-related adverse outcomes, other than iatrogenic prematurity. Incorporation of angiogenic biomarkers in the evaluation of preeclampsia may allow accurate and early identification of severe disease.

Pathophysiology of ischemic placental disease

The pregnancy disorders associated with placental ischemia share many similar pathological and pathophysiological features and are associated with the failure to deliver adequate nutrients and oxygen to the placenta. The origins of this deficiency are a subject of intense study. In this article, I review the genesis and consequences of this pathology addressing the similarities and the differences with the different disorders and addressing current gaps in our knowledge.

Advances in the pathophysiology of pre-eclampsia and related podocyte injury

Pre-eclampsia is a pregnancy-specific hypertensive disorder that may lead to serious maternal and fetal complications. It is a multisystem disease that is commonly, but not always, accompanied by proteinuria. Its cause(s) remain unknown, and delivery remains the only definitive treatment. It is increasingly recognized that many pathophysiological processes contribute to this syndrome, with different signaling pathways converging at the point of systemic endothelial dysfunction, hypertension, and proteinuria. Different animal models of pre-eclampsia have proven utility for specific aspects of pre-eclampsia research, and offer insights into pathophysiology and treatment possibilities. Therapeutic interventions that specifically target these pathways may optimize pre-eclampsia management and may improve fetal and maternal outcomes. In addition, recent findings regarding placental, endothelial, and podocyte pathophysiology in pre-eclampsia provide unique and exciting possibilities for improved diagnostic accuracy. Emerging evidence suggests that testing for urinary podocytes or their markers may facilitate the prediction and diagnosis of pre-eclampsia. In this review, we explore recent research regarding placental, endothelial, and podocyte pathophysiology. We further discuss new signaling and genetic pathways that may contribute to pre-eclampsia pathophysiology, emerging screening and diagnostic strategies, and potential targeted interventions.

If we know so much about preeclampsia, why haven't we cured the disease?

Preeclampsia has been recognized for at least 100 years. In the last 20 years, the consideration of the disorder as more than simply hypertension in pregnancy has led to an explosion in knowledge about preeclampsia pathophysiology. It is now evident that for most cases of preeclampsia, the root cause is the placenta. Relatively reduced placental perfusion leads to inflammation, oxidative stress, and endoplasmic reticulum stress, which converge to modify maternal physiology, with endothelium an important target. Although preeclampsia is characteristically diagnosed in the last third of pregnancy, it is evident that many of these pathophysiological changes can be detected long before clinically evident disease. Furthermore, it is evident that the "maternal constitution," including genetic, behavioral, and metabolic factors, influences the maternal response to the abnormal placentation of preeclampsia. These insights would seem to provide a guide for the prediction of the disorder in early pregnancy, along with targets for intervention. However, this has not been the case. Predictive tests guided by this knowledge do not predict well and several interventions guided by the expanded understanding of pathophysiology do not prevent the disease. We propose that these failures are secondary to the fact that preeclampsia is more than one disorder. Further, we suggest that future progress toward prediction and prevention will require research guided by this concept.

New developments in the pathogenesis of preeclampsia

Preeclampsia affects 3% to 5% of all pregnancies and is a major cause of maternal and perinatal morbidity and mortality worldwide. This disorder is characterized by a constellation of signs and symptoms, most notably new-onset hypertension and proteinuria during the last trimester of pregnancy. In this review, the molecular mechanisms of preeclampsia with an emphasis on the role of circulating antiangiogenic proteins in the pathogenesis of preeclampsia and its complications will be discussed.

Serum placental growth factor as a predictor of early onset preeclampsia in overweight/obese pregnant women

The purpose of this study was to analyze whether maternal serum placental growth factor (PlGF) could predict early onset preeclampsia (<32 weeks of gestation) in overweight/obese pregnant women, and whether it could do it more effectively than in normal/underweight pregnant women. A prospective cohort study was conducted on 1678 pregnant women with singleton pregnancies, who were grouped as underweight, normal, overweight, and obese on the basis of body mass index, followed by serum PlGF estimation at 20 to 22 weeks of gestation. A cut-off value of <144 pg/mL for PlGF was determined by Receiver Operating Characteristic curve analysis to identify risk of early onset preeclampsia. Univariate logistic regression analysis revealed significantly stronger association between PlGF <144 pg/mL and early onset preeclampsia in overweight/obese pregnant women (odds ratio 7.64; 95% confidence interval 5.34-10.12; P = .000) than in normal/underweight pregnant women (odds ratio 2.95; 95% confidence interval 1.74-4.26; P = .007). Weight and PlGF levels in study women had a significant negative correlation (r = 0.663; P = .002). Serum PlGF in early second trimester could be an effective predictor of early onset preeclampsia in overweight/obese pregnant women and may be more effective than in normal/underweight pregnant women.

Haptoglobin phenotype, angiogenic factors, and preeclampsia risk

OBJECTIVE

We sought to determine whether haptoglobin (Hp) phenotype is related to preeclampsia risk, or to plasma concentrations of soluble endoglin (sEng), soluble fms-like tyrosine kinase 1 (sFlt-1), and placental growth factor (PlGF).

STUDY DESIGN

Hp phenotype was retrospectively determined in primiparous women with uncomplicated pregnancies (n = 309), gestational hypertension (n = 215), and preeclampsia (n = 249). Phenotype was assessed by peroxidase staining following native polyacrylamide gel electrophoresis of hemoglobin-supplemented serum.

RESULTS

Compared with Hp 1-1, Hp 2-1 was associated with a significantly increased risk of preeclampsia (odds ratio, 2.11; 95% confidence interval, 1.07-4.18) and term preeclampsia (odds ratio, 2.45; 95% confidence interval, 1.07-5.83) in Caucasian women. Hp phenotype was not associated with preeclampsia risk in African Americans. Preeclamptic women had higher plasma sEng and sFlt-1, and lower PlGF, than control subjects. sEng, sFlt-1, and PlGF did not differ among women of different Hp phenotypes.

CONCLUSION

Hp 2-1 is associated with higher preeclampsia risk in primiparous Caucasian women.