Platelets and the beginnings of preeclampsia

The Relationship between the Level of Coagulative Function Hypertensive Disorder Complicating Pregnancy

BACKGROUND AND AIM

Preeclampsia, a pregnancy complication associated with significant maternal and perinatal mortality and morbidity, has been found to be closely linked to dysfunction in the blood coagulation-fibrinolysis system. However, the relationship between hematologic data and severity and onset time of preeclampsia remains unclear. This study aimed to identify specific hematologic parameters in both preeclamptic and normotensive pregnant women and determine their potential significance in the pathogenesis of preeclampsia.

MATERIALS AND METHODS

A total of 112 patients with gestational hypertension disease were divided into two groups: early-onset preeclampsia (32 cases) and late-onset preeclampsia (80 cases). A control group of 82 normotensive pregnant women matched for age and parity was also selected. Blood samples were collected from all participants to test for specific hematologic parameters.

RESULTS

Mild and severe preeclampsia were associated with lower hemoglobin level (P = 0.01 and P = 0.03, respectively), higher mean platelet volume (P = 0.01 and P = 0.01, respectively) and fibrinogen (P = 0.01 and P = 0.01, respectively), and shorter prothrombin time (P = 0.02 and P = 0.01, respectively) and activated partial thromboplastin time (P = 0.01 and P = 0.02, respectively).

CONCLUSION

These findings have provided evidence on the hematologic coagulative actors in the pathogenesis and severity of preeclampsia.

Evaluating mean platelet volume and platelet distribution width as predictors of early-onset pre-eclampsia: a prospective cohort study

BACKGROUND

Platelets are pivotal players in the pathophysiology of pre-eclampsia, with observed lower counts in affected individuals compared to normotensive counterparts. Despite advancements, the elusive cause of pre-eclampsia persists, motivating intense global efforts to identify reliable predictors. The currently recommended predictors of pre-eclampsia are not readily available in many resource-limited regions like Nigeria. This cohort study explores the potential of mean platelet volume (MPV) and platelet distribution width (PDW) as predictive markers of early-onset pre-eclampsia. Both platelet indices are components of the full blood count, a widely available routine test in pregnancy.

METHODS

In this prospective cohort study, 648 healthy pregnant women attending antenatal care at Lagos State University Teaching Hospital and General Hospital Ifako-Ijaiye, Lagos, were recruited between 14-18weeks gestational age. Platelet count (PC), MPV and PDW were measured from their venous blood at recruitment. Participants were monitored until 34weeks of gestation, focusing on the occurrence of early-onset preeclampsia as the outcome of interest. Individuals with chronic medical conditions were excluded from the study. Data analysis involved t-test, Chi-Square and Mann-Whitney U tests, with statistical significance set at a confidence level of 95% and p < 0.05. Sensitivity, specificity, and predictive values were determined using receiver operating characteristics (ROC) curves.

RESULTS

The incidence of early-onset pre-eclampsia in the study was 5.9%. Women who later developed pre-eclampsia had higher median MPV and PDW at 14-18weeks (10.8 fl. and 24.8 fl.) compared to normotensive women (8.1 fl. and 13.3 fl.)(p < 0.001). The median PC was lower in pre-eclamptics (190 × 103/µl) compared to normotensives(264 × 103/µl)(p < 0.001). Using Youden's test, cut-off values identified: PC < 211.5 × 103/µl, MPV > 9.4 fl., and PDW > 21.3 fl., predicted early-onset pre-eclampsia with 96.6% sensitivity and 65.6% specificity for PC; 79.3% sensitivity and 97.7% specificity for PDW; and 82.8% sensitivity and 96.1% specificity for MPV. Cut-offs of PC < 185 × 103/µl, MPV > 10.7 fl., and PDW > 28.3 fl., predicted severe early-onset pre-eclampsia with 100.0% sensitivity and 90.9% specificity for PC, 100.0% sensitivity and 99.4% specificity for MPV, and 100.0% sensitivity and 99.8% specificity for PDW, with corresponding area under the ROC curves of 0.983, 0.996, and 0.998, respectively.

CONCLUSION

The evaluation of MPV and PDW between 14 and 18 weeks of gestation appears to be a reliable predictor of severe early-onset pre-eclampsia.

Integrated metabolomics and machine learning approach to predict hypertensive disorders of pregnancy

BACKGROUND

Hypertensive disorders of pregnancy account for 3% to 10% of maternal-fetal morbidity and mortality worldwide. This condition has been considered one of the leading causes of maternal deaths in developing countries, such as India.

OBJECTIVE

This study aimed to discover hypertensive disorders of pregnancy-specific candidate urine metabolites as markers for hypertensive disorders of pregnancy by applying integrated metabolomics and machine learning approaches.

STUDY DESIGN

The targeted urinary metabolomics study was conducted in 70 healthy pregnant controls and 133 pregnant patients having hypertension as cases. Hypertensive disorders of pregnancy-specific metabolites for disease prediction were further extracted using univariate and multivariate statistical analyses. For machine learning analysis, 80% of the data were used for training (79 for hypertensive disorders of pregnancy and 42 for healthy pregnancy) and validation (27 for hypertensive disorders of pregnancy and 14 for healthy pregnancy), and 20% of the data were used for test sets (27 for hypertensive disorders of pregnancy and 14 for healthy pregnancy).

RESULTS

The statistical analysis using an unpaired t test revealed 44 differential metabolites. Pathway analysis showed mainly that purine and thiamine metabolism were altered in the group with hypertensive disorders of pregnancy compared with the healthy pregnancy group. The area under the receiver operating characteristic curves of the 5 most predominant metabolites were 0.98 (adenosine), 0.92 (adenosine monophosphate), 0.89 (deoxyadenosine), 0.81 (thiamine), and 0.81 (thiamine monophosphate). The best prediction accuracies were obtained using 2 machine learning models (95% for the gradient boost model and 98% for the decision tree) among the 5 used models. The machine learning models showed higher predictive performance for 3 metabolites (ie, thiamine monophosphate, adenosine monophosphate, and thiamine) among 5 metabolites. The combined accuracies of adenosine from all models were 98.6 in the training set and 95.6 in the test set. Moreover, the predictive performance of adenosine was higher than other metabolites. The relative feature importance of adenosine was also observed in the decision tree and the gradient boost model.

CONCLUSION

Among other metabolites, adenosine and thiamine metabolites were found to differentiate participants with hypertensive disorders of pregnancy from participants with healthy pregnancies; hence, these metabolites can serve as a promising noninvasive marker for the detection of hypertensive disorders of pregnancy.

Understanding the Preterm Human Heart: What do We Know So Far?

Globally, preterm birth affects more than one in every 10 live births. Although the short‐term cardiopulmonary complications of prematurity are well known, long‐term health effects are only now becoming apparent. Indeed, preterm birth has been associated with elevated cardiovascular morbidity and mortality in adulthood. Experimental animal models and observational human studies point toward changes in heart morphology and function from birth to adulthood in people born preterm that may contribute to known long‐term risks. Moreover, recent data support the notion of a heterogeneous cardiac phenotype of prematurity, which is likely driven by various maternal, early, and late life factors. This review aims to describe the early fetal‐to‐neonatal transition in preterm birth, the different structural and functional changes of the preterm human heart across developmental stages, as well as potential factors contributing to the cardiac phenotype of prematurity.

Hemodynamic consequences of incomplete uterine spiral artery transformation in human pregnancy, with implications for placental dysfunction and preeclampsia

Normal human pregnancy requires a dramatic increase in uteroplacental blood flow, which is achieved by a transformation in the geometry of uterine spiral arteries, a key element in this blood supply system. The transformation is mediated by trophoblast invasion directed at converting a portion of the spiral artery into an open funnel, thereby greatly reducing resistance to flow. The converted portion lies within the depth of the decidua and part of the myometrium. Insufficient depth of trophoblast invasion in early pregnancy predisposes to inadequate perfusion of the developing placenta and fetus and may lead to preeclampsia, fetal growth restriction, and preterm delivery, sometimes referred to as the "Great Obstetrical Syndromes." We examine the hemodynamic consequences of spiral artery transformation in human pregnancy and the relationship between the degree of transformation and the corresponding change in flow rate and resistance to flow. We identify two key variables in determining the hemodynamic change: the longitudinal converted fraction of the spiral artery and the relative downstream diameter of the open funnel. Our results indicate that there is a critical threshold in the value of the converted fraction required to achieve the marked increase in uteroplacental blood flow in normal pregnancy. This finding validates common clinical observations that the depth of trophoblast invasion reflects the "adequacy" of the increase in uteroplacental blood supply required in normal human pregnancy. Our results provide a quantitative measure of that adequacy and may serve as a future diagnostic marker for high-risk pregnancy.NEW & NOTEWORTHY Human pregnancy requires dramatic increase in uteroplacental blood supply achieved by geometric transformation of uterine spiral arteries and facilitated by trophoblast invasion of these arteries to greatly reduce resistance to flow. Incomplete transformation has been associated with failed pregnancies, preeclampsia, and other pathologies, but a quantitative measure of "incompleteness" has been unavailable so far. We use a mathematical model to obtain a numerical threshold for this measure which may serve as a future diagnostic marker.

Significance of platelet indices as severity marker in nonthrombocytopenic preeclampsia cases

CONTEXT

Preeclampsia is often asymptomatic, and hence, its detection depends on signs or investigations. The platelet (PLT) parameters, in cases of preeclampsia with normal PLT count, are seldom analyzed. Hence, this study was undertaken to study the PLT parameters in nonthrombocytopenic preeclampsia cases.

AIM

The aim was to evaluate the use of PLT indices as severity markers in nonthrombocytopenic preeclampsia cases.

SUBJECTS AND METHODS

This prospective study was done on 120 cases of severe preeclampsia, 115 cases of preeclampsia without severe features, and 203 normal pregnant women admitted in the obstetrics wards during the study period of 1 year. The PLT indices obtained by analyzing anticoagulated blood were recorded.

STATISTICAL ANALYSIS USED

Analysis of variance test was used to see the significance of association. Receiver operating characteristic (ROC) curve and binary regression analysis was used to estimate the cutoff value and examine the predictive value of the PLT parameters in the disease progression of preeclampsia.

RESULTS

Even in the absence of thrombocytopenia, mean platelet volume (MPV) and PLT distribution width were significantly higher in severe preeclampsia group (P < 0.001) and were also positively correlating with mean arterial pressure (r = 0.38 and 0.20, respectively). ROC curve analysis showed that MPV had the highest area under the curve of 0.78 (95% confidence interval [0.719-0.842]). Cutoff value of >10.95 fl for MPV was found to have significant predictive value for disease progression in preeclampsia.

CONCLUSIONS

Even in the absence of thrombocytopenia, PLT indices, especially MPV, have a good diagnostic significance in detecting severe preeclampsia. Further studies are required to evaluate their role as biomarkers in preeclampsia.

Could circRNA be a new biomarker for pre-eclampsia?

Pre-eclampsia is a devastating complication of pregnancy which is characterized by hypertension and proteinuria in pregnant women. Pre-eclampsia is important as it is the leading cause of death. Moreover, untreated pre-eclampsia might lead to other lethal complications, for both fetus and mother. Pre-eclampsia can also affect the quality of life in affected women. Despite a large number of risk factors for pre-eclampsia, these risk factors are able to detect just 30% of women who are susceptible to pre-eclampsia. Heterogeneous manifestations of pre-eclampsia necessitate the discovery of potential biomarkers required for its early detection. Circular RNAs (circRNAs) are a type of RNA which are more abundant, specific, and highly organized compared with other types of RNA. Accordingly, circRNAs have been suggested as one of the potential biomarkers for different diseases. Recently, researchers have shown interest in the effects of circRNAs in pre-eclampsia, although the current evidence is limited. The majority of obstetricians are probably not aware of circRNAs as a useful biomarker. Here, we aimed to summarize recent supporting evidence and assess the mechanisms by which circRNAs are involved in pre-eclampsia.

The two-stage placental model of preeclampsia: An update

Early-onset preeclampsia has been linked to poor placentation and fetal growth restriction, whereas late-onset preeclampsia was suggested to result from maternal factors. We have proposed an alternative model, suggesting that both early- and late-onset preeclampsia result from placental syncytiotrophoblast stress. This stress represents a common endpoint of several Stage 1 processes, promoting the clinical stage 2 of preeclampsia (new-onset hypertension and proteinuria or other signs of end-organ dysfunction), but the causes and timing of placental malperfusion differ. We have suggested that late-onset preeclampsia, without evidence of poor spiral artery remodelling, may be secondary to intraplacental (intervillous) malperfusion due to mechanical restrictions. As the growing placenta reaches its size limit, malperfusion and hypoxia occurs. This latter pathway reflects what is observed in postmature or multiple pregnancies. Our revised two-stage model accommodates most risk factors for preeclampsia including primiparity, chronic pre-pregnancy disease (e.g. obesity, diabetic-, chronic hypertensive-, and some autoimmune diseases), and pregnancy risk factors (e.g. multiple or molar pregnancies, gestational diabetes or hypertension, and low circulating Placental Growth Factor). These factors may increase the risk of progressing to the second stage of preeclampsia (both early- and late-onset) by affecting one of or both pathways leading to Stage 1, as well as potentially accelerating the steps towards Stage 2, including priming the maternal cardiovascular susceptibility to inflammatory factors shed by the placenta. This paper reviews previous preeclampsia findings and concepts, which fit with the revised two-stage model, and argues that "maternal" preeclampsia does not exist, as all preeclampsia requires a placenta.

Intrapartum mean platelet volume is not a useful predictor of new-onset delayed postpartum pre-eclampsia

OBJECTIVE

To determine whether intrapartum mean platelet volume (MPV) can predict new-onset delayed postpartum pre-eclampsia.

METHODS

In a retrospective study, data were obtained for women with delayed postpartum pre-eclampsia (≥48 hours after delivery) who attended the Detroit Medical Center, Detroit, MI, USA, between January 2002 and July 2010. Patients were divided into two subgroups: new-onset delayed postpartum pre-eclampsia (no history of hypertensive disorder before 48 hours after delivery) and other late-onset/delayed postpartum pre-eclampsia (history of hypertensive disorders). Cases with no hypertensive disorders paired by delivery date were selected as controls. Receiver operating characteristic (ROC) curves were used to determine whether MPV could distinguish between cases and controls.

RESULTS

Data for 130 cases of new-onset delayed postpartum pre-eclampsia, 71 cases of other late-onset/delayed postpartum pre-eclampsia, and 405 controls were collected. MPV was significantly different between the pre-eclampsia subgroups (P=0.007). ROC curves showed that MPV significantly distinguished new-onset delayed postpartum pre-eclampsia cases (area under the curve 0.6, 95% confidence interval 0.5-0.6; P=0.02), with a sensitivity and specificity of 58.1% and 55.4%, respectively.

CONCLUSION

Although MPV was significantly lower in women who went on to develop new-onset delayed postpartum pre-eclampsia than among controls, it is not a useful predictor. The low MPV suggests a different mechanism for the development of new-onset delayed postpartum pre-eclampsia.

Association between preeclampsia and the CXC chemokine family (Review)

Preeclampsia is a major cause of maternal and perinatal mortality and morbidity, characterized by gestational hypertension, proteinuria, systemic endothelial cell activation and an exaggerated inflammatory response. The precise cause of preeclampsia is not currently known; however, it is widely accepted that the pathogenesis of preeclampsia involves inadequate trophoblast invasion, leading to generalized endothelial dysfunction and an exaggerated inflammatory response. Chemokines are a superfamily of structurally similar proteins that mediate cell recruitment, angiogenesis, immunity and stem cell trafficking. CXC chemokines are a family of cytokines, unique in their ability to behave in a disparate manner in the regulation of angiogenesis. The CXC chemokine family further divides into two subfamilies; CXC ELR+, which promotes angiogenesis, and CXC ELR-, which inhibits angiogenesis. Furthermore, CXC chemokines are involved in the pathogenesis of various conditions, including malignant tumors, wound repair, chronic inflammation, atherosclerosis and potentially preeclampsia.

Platelet parameters in healthy and pathological pregnancy

Changes in platelet count (PLT) are very important during pregnancy. Many platelet disorders occur during pregnancy and a reduction in PLT is the most common hemostasis abnormality identified, and this has important implications for mother and foetus. Many of these disorders share clinical and laboratory features, making accurate diagnosis difficult. The aim of this study was to establish reference intervals of platelet parameters for some of the more important pathologies associated to pregnancy (pre-eclampsia, gestational diabetes, autoimmune disorders, viral infections) using the automated hematology analyzer Sysmex XE-2100 and to evaluate the difference between healthy and pathological pregnancy. We enrolled in our study 100 pregnant women in the third trimester of pregnancy. The parameters analyzed included PLT, platelet distribution width, and mean platelet volume (MPV). We found statistically significant difference in PLT in pre-eclampsia, autoimmune disorders, and viral infections. Our results demonstrated also a statistically significant difference in MPV in pre-eclampsia and gestational diabetes. Our results allow the clinicians to detect hematologic change by simple complete blood count useful for the management of the pathological pregnancies. In conclusion, the overall picture of platelet disorders is extremely variegated, leading to numerous diagnostic and therapeutic problems whose solutions require close collaboration between clinicians and laboratory specialists.

Endoglin: a critical mediator of cardiovascular health

Endoglin (CD105) is a type III auxiliary receptor for the transforming growth factor beta (TGFβ) superfamily. Several lines of evidence suggest that endoglin plays a critical role in maintaining cardiovascular homeostasis. Seemingly disparate disease conditions, including hereditary hemorrhagic telangiectasia, pre-eclampsia, and cardiac fibrosis, have now been associated with endoglin. Given the central role of the TGFβ superfamily in multiple disease conditions, this review provides a detailed update on endoglin as an evolving therapeutic target in the management of cardiovascular disease.

Nitric oxide and peroxynitrite platelet levels in gestational hypertension and preeclampsia

The aim of the study was to investigate platelet nitric oxide (NO) pathways in women with Gestational Hypertension (GH), Preeclampsia (PE) and Controls. Platelet NO(x) and peroxynitrite (ONOO(-)) levels, inducible (iNOS) and endothelial nitric oxide synthase (eNOS) and Nitrotyrosine expression (N-Tyr) in 30 women with GH, 30 with PE and 30 healthy pregnant controls, age, parity and gestational age-matched, were assessed. Platelet NO(x) and ONOO(-) levels were significantly higher in GH and PE vs. Controls, with higher levels in GH vs. PE. At the same way, iNOS and N-Tyr were significantly higher in GH and PE vs. Controls, with higher levels in GH vs. PE. Since GH expressed higher amount of NO metabolites and higher activation of iNOS compared to PE, we can hypothesize that the severity of hypertensive pathology is almost not related to only NO metabolism, this research confirmed that GH and PE are associated with marked changes in NO pathways; it is not easy to understand if they could be interpreted as causes or consequence of these pathologic states.

The role of serum markers and uterine artery Doppler in identifying at-risk pregnancies

Measures of placental dysfunction, including maternal serum analytes and Doppler studies, have been linked to adverse pregnancy outcomes, although the predictive ability of any single one is poor. Improved knowledge of the multifactorial nature of many of the adverse outcomes of pregnancy has sparked interest in the use of multi-parameter models that combine maternal serum analytes with measures of placental structure and blood flow. The combination of various first-trimester and second-trimester analytes and uterine artery Doppler screening show promise as potential screening tools, but large prospective studies are needed to further define their role in clinical practice.

Causes and mechanisms of intrauterine hypoxia and its impact on the fetal cardiovascular system: a review

Until today the role of oxygen in the development of the fetus remains controversially discussed. It is still believed that lack of oxygen in utero might be responsible for some of the known congenital cardiovascular malformations. Over the last two decades detailed research has given us new insights and a better understanding of embryogenesis and fetal growth. But most importantly it has repeatedly demonstrated that oxygen only plays a minor role in the early intrauterine development. After organogenesis has taken place hypoxia becomes more important during the second and third trimester of pregnancy when fetal growth occurs. This review will briefly adress causes and mechanisms leading to intrauterine hypoxia and their impact on the fetal cardiovascular system.

First-trimester assessment of placenta function and the prediction of preeclampsia and intrauterine growth restriction

Preeclampsia and intrauterine growth restriction (IUGR) are major contributors to perinatal mortality and morbidity worldwide. Both are characterized by impaired trophoblastic invasion of the maternal spiral arteries and their conversion from narrow muscular vessels to wide non-muscular channels. Despite improvement in the understanding of the pathophysiology of these conditions, ability to accurately identify pregnant woman who will develop them is limited. This greatly impairs the development and testing of preventive interventions. While different measures of placental dysfunction have been associated with increased risk for adverse pregnancy outcomes, the ability of any single one to accurately predict these outcomes is poor. Developing predictive tests is further challenged by difficulty in the timing of the measurements, as both the structural and biochemical characteristics of the placenta change with increasing gestational age. The ideal screening test would accurately predict the development of adverse pregnancy outcomes early enough to provide a window for preventive interventions. Improvement in ultrasound technology provides potentially useful novel tools for evaluating placental structure, but measurements need to be standardized in order to be useful. Maternal serum analyte screening is a noninvasive test of placental biochemical function, but present serum marker alone is not sufficiently accurate to suggest its routine use in clinical practice. The use of first trimester biochemical markers in combination with uterine artery Doppler screening is promising as a potential screening tool. Prospective longitudinal studies using standardized methodology are necessary to further evaluate the choice of parameters and strategies of combination to achieve the best predictive models.

Trophoblast function in normal and preeclamptic pregnancy

Preeclampsia (PE) is a common disease of pregnancy that affects women particularly in their first pregnancies. Current estimates suggest that between 7 and 10% of pregnancies may be complicated by PE. Despite considerable research and medical efforts, the incidence of the disease has not changed substantially in the last century. In severe cases the disease may be life-threatening and is associated with high neonatal mortality and morbidity. Furthermore, therapy is often ineffective and at best treats the disease symptoms rather than the aetiology. One reason for the lack of progress may be that while the disease is generally agreed by most to be due to abnormal implantation and development of the placenta (events which happen in the first trimester) most research efforts have focused on managing and understanding the maternal disease. Since the disease typically appears in the last trimester, many weeks after the likely start of the pathology, it has been difficult to understand the progression of events. However, this picture has improved recently. The purpose here is to review how placental development is affected in PE and describe new insights into the causes. It is hoped that an understanding of the pathogenesis of the placental defects in PE will lead to new efforts towards early diagnosis, before the onset of clinical symptoms, as well as new treatments for these lesions.

Inhibition of VEGF or TGF-{beta} signaling activates endothelium and increases leukocyte rolling

OBJECTIVE

Motivated by the central roles that vascular endothelial growth factor (VEGF) and transforming growth factor (TGF)-beta play in the assembly and maintenance of the vasculature, we examined the impact of systemic VEGF or TGF-beta signal inhibition on endothelial activation as detected by leukocyte-endothelial interactions.

METHODS AND RESULTS

VEGF or TGF-beta inhibition, accomplished using adenovirus expression of soluble Flt1 (Ad-sFlt1) or soluble endoglin (Ad-sEng), resulted in a significant increase in the number of leukocytes rolling along the mesenteric venous endothelium and a significant decrease in rolling velocity in Ad-sEng mice. Neutralization of VEGF or TGF-beta resulted in endothelial surface expression of P-selectin and impaired peripheral vasodilatation. Neither inhibition of VEGF nor TGF-beta was associated with platelet or leukocyte activation, as detected by the activation markers platelet P-selectin and the active integrin alphaIIbbetaIII, or by leukocyte expression of L-selectin. Soluble vascular cell adhesion molecule (VCAM)-1 and E-selectin were increased in sEng-expressing mice, indicating higher levels of these adhesion receptors.

CONCLUSIONS

VEGF or TGF-beta neutralization leads to impaired endothelium-mediated vasodilatation and elevated expression of surface adhesion molecules, resulting in increased leukocyte adhesion. These results indicate an essential role for both VEGF and TGF-beta in maintaining the endothelium in a nonactivated state and have implications for therapeutic approaches that neutralize VEGF or TGF-beta.

Antiangiogenic Effect of Soluble Vascular Endothelial Growth Factor Receptor-1 in Placental Angiogenesis

Differential splicing of the flt-1 mRNA generates soluble variant of vascular endothelial growth factor (VEGF) receptor-1 (sVEGFR-1, also known as sFlt-1). The action of VEGF is antagonized by sVEGFR-1. Soluble VEGFR-1 binds to VEGF with a high affinity and therefore works to modulate VEGF and VEGF signaling pathway. In this study, the authors tested the hypothesis that VEGF-mediated endothelial cell angiogenesis is tightly modulated by the release of sVEGFR-1 and placental expression of sVEGFR-1 is upregulated by hypoxia. Immunolocalization studies showed progressively intense staining for sVEGFR-1 and VEGF in the trophoblast of placental villous explants throughout gestation. Endothelial cell migration studies using a modified Boyden's chamber showed a significant increase in cell migration in response to VEGF that was significantly attenuated in the presence of exogenous sVEGFR-1. Furthermore, stimulation of endothelial cells with VEGF led to a dose-dependent increase in the release of sVEGFR-1 as determined by enzyme-linked immunosorbent assay (ELISA). Exposure of normal placental villous explants to hypoxia (1% pO2) increased trophoblast expression of sVEGFR-1 when compared with tissue normoxia (5% pO2). In addition, conditioned media from hypoxia treated placental villous explants induced a significant increase in endothelial cell migration that was significantly reduced in presence of sVEGFR-1. Our study demonstrates that hypoxia positively regulates sVEGFR-1 protein expression in ex vivo trophoblasts, which control VEGF-driven angiogenesis.

Disseminated intravascular coagulation in obstetric disorders and its acute haematological management

As activation of the coagulation pathway is a physiological response to injury, the development of disseminated intravascular coagulation (DIC) is a warning signal to the clinician that the primary pathological disease state is decompensating. In pregnancy, DIC can occur in several settings, which include emergencies such as placental abruption and amniotic fluid embolism as well as complications such as pre-eclampsia. Whilst the acuteness of the event and the proportionality in the coagulant and fibrinolytic responses may vary between these different conditions, a common theme for pregnancy-associated DIC is the pivotal role played by the placenta. Removal of the placenta is the linchpin to treatment in most cases but appropriate blood product support is also key to management. This is necessary because DIC itself can have pathological consequences that translate clinically into a worse prognosis for affected patients. This article will describe how pregnancy-associated DIC can be diagnosed promptly and how treatment should be managed strategically. It also discusses the latest developments in our understanding of haemostatic mechanisms within the placenta and how these may have relevance to new diagnostic approaches as well as novel therapeutic modalities.

Critical care management of severe pre-eclampsia

Severe pre-eclampsia is a common disorder in developing countries but still remains a significant problem in developed societies. The management of severe pre-eclampsia in developing countries is frequently hampered by lack of adequate facilities; paradoxically those countries with sufficient resources have a lower incidence of the disease and consequently lack experience in the treatment of severe pre-eclampsia. The management of these patients is further compromised because obstetricians generally lack the necessary knowledge and skills in critical care and conversely critical care specialists may lack appreciation and knowledge of pregnancy physiology and pathophysiology. Patients with severe pre-eclampsia therefore present an interdisciplinary challenge to obstetricians and physicians, who need to be familiar with pregnancy physiology and the current concepts in the pathogenesis and pathophysiology of severe pre-eclampsia. Patients who develop multisystem disease are most appropriately managed by an experienced obstetrician in an obstetric intensive care unit with a physician in consultation.

Performance of a panel of maternal serum markers in predicting preeclampsia at 11–15 weeks' gestation

OBJECTIVE

We evaluated whether a discriminant model of prediction based on quantitative distribution of a panel of biomolecules in maternal serum can discriminate normal pregnancies from those who will develop preeclampsia (PE) prior to onset of clinical symptoms at 11-15 weeks' gestation.

METHODS

Case control study encompassing 56 women destined to develop PE cases matched 1:3 for gestational age with 168 controls. After multiple of median (MoM) conversion of all available markers, comprising total Activin A (t-activin A), P-selectin, and vascular endothelial growth factor receptor (VEGFR) the combined likelihood ratios generated for each marker were used to calculate, for each patient enrolled in the study, the odds of being affected given a positive results (OAPR) of developing PE. For all the analyses performed, the type II error was < 20% with a type I error fixed at 5%.

RESULTS

Data were expressed in MoM of controls. P-selectin was identified as the marker with the best discriminant ability between controls and PE, followed by (t-activin A). No significant differences in VEGFR were observed between cases and controls. By using a 3% prevalence of PE (or, about 1:33) we found that the median OAPR of developing PE for the 56 cases was 1:9 or 10% (1:1-1:417). The median OAPR of PE for controls was 1:40 or 2.5% (range, 1:6-1:4205). Detection rate of the statistical model, with a 5% false-positive rate was 59%.

CONCLUSION

This analysis revealed that maternal serum markers assessed at the first and second trimester of pregnancy in asymptomatic patients can improve the early detection of cases at higher risk of developing PE.

Lipid Peroxidation and Ca-ATPase Activity of Basal Plasma Membranes of Syncytiotrophoblast from Normotensive Pregnant Women

BACKGROUND

The Ca-ATPase activity of the plasma membranes of several tissues of preeclamptic pregnant women is significantly reduced when compared with the values of normotensive pregnant women. This has been explained considering the raise in the level of lipid peroxidation of the plasma membranes with preeclampsia. In this work we studied the effect of lipid peroxidation of syncytiotrophoblast basal (fetal facing) plasma membranes from normotensive pregnant women, on their level of Ca-ATPase activity.

METHODS

The syncytiotrophoblast basal (fetal facing) plasma membranes from normotensive pregnant women were isolated and irradiated with ultraviolet (UV) light (254 nm). The membranes were then assayed for Ca-ATPase activity and lipid peroxidation by TBARS.

RESULTS

The UV irradiation raises the level of lipid peroxidation of the membranes, producing a concomitant inhibition of their Ca-ATPase activity. Presence of the antioxidant butylated hydroxytoluene during the UV irradiation of the membranes prevents increase in their level of lipid peroxidation and hence the inhibition of their Ca-ATPase activity.

CONCLUSION

These results give a strong support to the hypothesis that the lowered Ca-ATPase activity already described for plasma membranes of several tissues of preeclamptic women is the consequence of the increased level of lipid peroxidation shown by these membranes.

The effect of pre-eclampsia on complete blood count, platelet count and mean platelet volume

Pre-eclampsia is a condition observed during pregnancy and threatens the life of both mother and foetus. There are studies, which suggest platelets play a major role in the pathogenesis of pre-eclampsia. The aim of this study is to compare the complete blood count (CBC) parameters, especially platelet count and mean platelet volume (MPV), in pre-eclamptic and normal pregnant women and to evaluate whether these parameters have a prognostic significance in determining the severity of eclampsia. The study and control groups consist of 56 pre-eclamptic and 43 normal pregnant women, respectively. There was no statistically significant difference according to CBC, platelet count and MPV when pre-eclamptic and severely pre-eclamptic patients were compared with controls. As a result, we observed no prognostic significance of CBC, platelet count and MPV on the presence and/or severity of pre-eclamptic condition. There are conflicting results especially on the significance of MPV in the literature, and possibly this confliction is due to the difference between methods and/or equipments used for automated blood count.

Pre-eclampsia

Pre-eclampsia is a major cause of maternal mortality (15-20% in developed countries) and morbidities (acute and long-term), perinatal deaths, preterm birth, and intrauterine growth restriction. Key findings support a causal or pathogenetic model of superficial placentation driven by immune maladaptation, with subsequently reduced concentrations of angiogenic growth factors and increased placental debris in the maternal circulation resulting in a (mainly hypertensive) maternal inflammatory response. The final phenotype, maternal pre-eclamptic syndrome, is further modulated by pre-existing maternal cardiovascular or metabolic fitness. Currently, women at risk are identified on the basis of epidemiological and clinical risk factors, but the diagnostic criteria of pre-eclampsia remain unclear, with no known biomarkers. Treatment is still prenatal care, timely diagnosis, proper management, and timely delivery. Many interventions to lengthen pregnancy (eg, treatment for mild hypertension, plasma-volume expansion, and corticosteroid use) have a poor evidence base. We review findings on the diagnosis, risk factors, and pathogenesis of pre-eclampsia and the present status of its prediction, prevention, and management.

Elevated placental soluble vascular endothelial growth factor receptor-1 inhibits angiogenesis in preeclampsia

Preeclampsia is an inflammatory disorder in which serum levels of vascular endothelial growth factor (VEGF) and its soluble receptor-1 (sVEGFR-1, also known as sFlt-1) are elevated. We hypothesize that VEGF and placenta growth factor (PlGF) are dysregulated in preeclampsia due to high levels of sVEGFR-1, which leads to impaired placental angiogenesis. Analysis of supernatants taken from preeclamptic placental villous explants showed a four-fold increase in sVEGFR-1 than normal pregnancies, suggesting that villous explants in vitro retain a hypoxia memory reflecting long-term fetal programming. The relative ratios of VEGF to sVEGFR-1 and PlGF to sVEGFR-1 released from explants decreased by 53% and 70%, respectively, in preeclampsia compared with normal pregnancies. Exposure of normal villous explants to hypoxia increased sVEGFR-1 release compared with tissue normoxia (P<0.001), as did stimulation with tumor necrosis factor-alpha (P<0.01). Conditioned medium (CM) from normal villous explants induced endothelial cell migration and in vitro tube formation, which were both attenuated by pre-incubation with exogenous sVEGFR-1 (P<0.001). In contrast, endothelial cells treated with preeclamptic CM showed substantially reduced angiogenesis compared with normal CM (P<0.001), which was not further decreased by the addition of exogenous sVEGFR-1, indicating a saturation of the soluble receptor. Removal of sVEGFR-1 by immunoprecipitation from preeclamptic CM significantly restored migration (P<0.001) and tube formation (P<0.001) to levels comparable to that induced by normal CM, demonstrating that elevated levels of sVEGFR-1 in preeclampsia are responsible for inhibiting angiogenesis. Our finding demonstrates the dysregulation of the VEGF/PlGF axis in preeclampsia and offers an entirely new therapeutic approach to its treatment.

The Prediction of Adverse Maternal Outcomes in Preeclampsia

OBJECTIVES

(1) To evaluate whether clinical variables reflecting the multiorgan dysfunctions of preeclampsia can predict adverse maternal outcomes of preeclampsia; (2) to determine the usefulness of the mean platelet volume (MPV):platelet ratio as a novel measure of platelet consumption in predicting the severity of preeclampsia.

METHOD

A retrospective chart review was conducted of cases of preeclampsia seen in 3 tertiary level units from January 2001 to December 2001. Candidate predictors of adverse maternal outcome were gestational age (GA) on admission to hospital, blood pressure, proteinuria, urine output, uric acid, creatinine, aspartate transaminase (AST), lactate dehydrogenase, bilirubin, albumin, fraction of inspired oxygen:oxygen saturation (FIO2:SaO2) ratio, platelet count, MPV, MPV:platelet ratio, fibrinogen, and seizures. The combined adverse maternal outcomes included maternal death; 1 or more of hepatic failure, hematoma, or rupture; Glasgow coma scale <13; stroke; 2 or more seizures; cortical blindness; positive inotrope support; myocardial infarction; infusion of any third antihypertensive; dialysis; renal transplantation; > or =50% FIO2 for >1 hour; intubation; or transfusion of > or =10 units of blood products. Descriptive, univariable, and multivariable analyses were performed, with significance set at P < .05.

RESULTS

Of a total of 594 women with preeclampsia, 60 (10.1%) developed at least 1 element of the combined adverse outcome; 1 of these 60 women died. The most common outcomes were increased oxygen requirements, the use of a third infused antihypertensive, and transfusion >10 units. In women who developed an adverse outcome, GA and fibrinogen were lower, and total leukocyte count, creatinine, and AST were greater. Multivariable logistic regression revealed that admission GA (odds ratio [OR], 0.91), dipstick protein (OR, 1.31), and MPV:platelet ratio (OR, 391.0) independently predicted the outcome.

CONCLUSIONS

Several promising markers were identified: admission GA, dipstick proteinuria, and the MPV:platelet ratio. MPV:platelet ratio also showed promise as a marker of platelet consumption. A prospective study is required to develop a clinical prediction model for preeclampsia.

Platelet Activation, Sympathetic Tone, and Plasma Volume in Nulligravid Women of Reproductive Age

OBJECTIVE

Preeclampsia is associated with increased platelet activation, increased sympathetic activity, and decreased plasma volume. We sought to estimate the relationship of plasma volume, sympathetic activity, or both to platelet activation in nonpregnant nulligravid women.

METHODS

We studied 37 healthy nulligravid subjects during the follicular phase of the menstrual cycle. After intravenous access was obtained, subjects rested in the supine position for 15 minutes. Blood was drawn without venous constriction for measurement of plasma catecholamines (epinephrine and norepinephrine) and complete blood count. Antigenic markers of platelet activation, CD63 and CD61-CD14 (platelet-monocyte aggregates), were measured with flow cytometry. Plasma volume was estimated in the supine position by using Evans blue dye and is expressed in milliliters and corrected for body mass index (BMI). We compared data from the lowest plasma volume/BMI quartile with the 2 middle quartiles combined and with the upper quartile. Data are expressed as mean +/- standard deviation. P <.05 was considered significant.

RESULTS

Subjects were aged 26.5 +/- 5.0 years, BMI was 24.0 +/- 3.0 kg/m(2), and plasma volume was 2,685 +/- 429 mL. We identified no significant relationship of platelet concentration to plasma volume/BMI between quartile groups (P =.944). However, there was a significant difference between quartiles for %CD63 expression (P =.013) and for CD61/CD14 expression (P =.018), with the lowest quartile demonstrating elevated platelet activation.

CONCLUSIONS

We found evidence that enhanced platelet activation is associated with reduced plasma volume, but not with plasma catecholamine concentrations. There was no association of platelet concentration with reduced plasma volume. We speculate that elements of the clinical syndrome of preeclampsia coexist as a subclinical phenotype before pregnancy.

Inherited thrombophilia and gestational vascular complications

The most common causes of inherited thrombophilia, the factor V Leiden and the factor II A20210 mutations, confer a higher risk of venous thromboembolism. Moreover, several studies have suggested that they can have a role in the occurrence of gestational vascular complications in otherwise unexplained recurrent fetal losses, hypertensive disorders of pregnancy and fetal growth restriction. Observational and case-control studies addressing these issues are available in literature. However, longitudinal, perspective studies are lacking. Mild hyperhomocysteinaemia can be due partly to inherited susceptibility--as the homozygous carriership of the T677 variant in the gene encoding 5,10-methylenetetrahydrofolate reductase (MTHFR). Case-control studies have been carried out on a possible association between unexplained fetal losses and mild hyperhomocysteinaemia. Although case-control and perspective studies are available on hyperhomocysteinaemia and other gestational vascular complications the data are conflicting.Intervention studies have been carried out to prevent adverse obstetric outcomes in women with factor V Leiden or factor II A20210 mutations and previous adverse outcomes. Although these are not randomized controlled trials, all have found significantly better outcomes in treated pregnancies compared to those of untreated pregnancies in the same women.

Maternal serum of women with pre-eclampsia reduces trophoblast cell viability: evidence for an increased sensitivity to Fas-mediated apoptosis

OBJECTIVE

Pre-eclampsia or 'toxemia of pregnancy' has been attributed to the presence of a circulating 'toxin' which disappears from peripheral blood after delivery of the placenta. However, the presence, nature and effects of this toxin have eluded characterization. Increased trophoblast apoptosis has been observed in the placenta of women with pre-eclampsia, and it is possible that this biological phenomenon is important for the genesis of the disease and mediated through a soluble factor(s) present in maternal blood. This study was designed to test the hypothesis that serum from women with pre-eclampsia changes trophoblast viability. Moreover, we sought to examine whether this effect could be mediated through changes in sensitivity to Fas/Fas ligand-mediated apoptosis.

STUDY DESIGN

H8 trophoblast cells were cultured with serum obtained from normal pregnant women (n = 48) and patients with pre-eclampsia (n = 12). Cell viability was determined by the Cell Titer 96 assay. Fas sensitivity was determined by treating the cells with an agonist anti-Fas antibody or a blocking anti-Fas ligand antibody.

RESULTS

Serum from normal pregnant women did not affect trophoblast cell viability. In contrast, serum from pre-eclamptic women reduced trophoblast viability, and this was enhanced by treatment with an anti-Fas antibody. This effect was reversed by the treatment with a blocking anti-Fas ligand antibody.

CONCLUSION

Serum from women with pre-eclampsia induces the cytotoxicity of a first-trimester trophoblast cell line (H8). This effect appears to be related to changes in trophoblast sensitivity to Fas-mediated apoptosis. These findings suggest that a factor present in the maternal blood of patients with pre-eclampsia may have a role in the genesis of the syndrome.

The management of thrombophilia during pregnancy: a Canadian survey

OBJECTIVE

To determine current Canadian practice patterns in the management of pregnant women with thrombophilia.

METHODS

Physician members of the Society of Obstetricians and Gynaecologists of Canada (SOGC) who provide obstetrical care were invited to complete a closed-ended questionnaire in which they were presented 5 clinical scenarios involving thrombophilic pregnancies and asked to give their management recommendations. The 5 scenarios presented in the survey were of a pregnant woman with (1) asymptomatic factor V Leiden (FVL), (2) asymptomatic FVL and a family history of venous thromboembolism (VTE), (3) FVL and recurrent fetal loss, (4) FVL and a previous VTE, or (5) antiphospholipid antibody syndrome and recurrent fetal loss.

RESULTS

Of the 1448 eligible SOGC members invited, 18 had moved with no forwarding address, and 662 (46.3% of the remainder) responded. The majority (65%) of the respondents were obstetricians and 51% of them had a university-affiliated practice. In scenario 1, 26% of physicians indicated they would recommend some form of antepartum thromboprophylaxis, whereas in the remaining four scenarios, 58% to 84% would definitely recommend antepartum thromboprophylaxis.

CONCLUSION

Most clinicians favour intervening with thromboprophylaxis in pregnant thrombophilic women rather than observing without prophylaxis. This tendency spans a wide range of clinical scenarios, despite a lack of evidence to support such decisions. This survey highlights the need to provide clinicians and women with evidence for the safety and effectiveness of prophylaxis, before these interventions become the default recommendation by clinicians caring for this prevalent group of women.

Activated protein C in normal human pregnancy and pregnancies complicated by severe preeclampsia: a therapeutic opportunity?

OBJECTIVES

Given the efficacy and safety of recombinant human activated protein C (rhAPC) in the systemic inflammatory response syndrome, this study was designed to review the evidence for a role for APC in the pathogenesis of preeclampsia. Preeclampsia is a proinflammatory and procoagulant state, and it is a pregnancy-specific condition that mimics the systemic inflammatory response syndrome. rhAPC reduces mortality in patients with systemic inflammatory response syndrome and could potentially have a role as disease-modifying therapy in preeclampsia. To determine which patients would be offered rhAPC, the literature pertaining to fetal/neonatal outcomes for preeclampsia remote from term, transplacental transport of protein C, and pregnancy experience with the compound were reviewed.

DATA SOURCES

MEDLINE, review papers, hand searches of relevant nonindexed journals, and the bibliographies of relevant textbooks and articles reviewed.

STUDY SELECTION

Randomized controlled trials were considered to provide the best quality of clinical data. Case-control series were considered over uncontrolled data. Some data were not available in the published literature (e.g., neonatal outcomes at various gestational ages and birthweights after a hypertensive pregnancy; and transplacental transfer of protein C), and these data were determined by us.

DATA EXTRACTION

Data were extracted by systematic review onto data collection sheets. Because of the quality of the data, this review is primarily qualitative.

DATA SYNTHESIS

APC levels fall during normal gestation, returning to normal values by 6 wks postpartum. Limited data suggest that early onset preeclampsia is a state of further, and inappropriate, reduction in APC. Preeclampsia resembles systemic inflammatory response syndrome in this regard. After hypertensive pregnancies, neonates have a 50% chance of intact survival if delivered after 27 + 0 wks of gestation with a birthweight of >600 g. It would seem ethical to offer women with preeclampsia with <50% chance of intact perinatal survival novel and potentially disease-modifying therapy such as rhAPC, especially as there is no transplacental transfer of protein C. Limited evidence would support the use of rhAPC in women with severe postpartum preeclampsia.

CONCLUSIONS

Sufficient data exist to support the use of rhAPC in phase II clinical studies for women with either early onset preeclampsia or severe or deteriorating postpartum disease.

Identification of a functional Na+/Mg2+ exchanger in human trophoblast cells

BACKGROUND

Ionized magnesium levels are elevated in fetal blood compared with maternal blood, suggesting that the placenta may possess an active transport mechanism for magnesium. In the present study, we sought to determine the existence of an active transport mechanism for magnesium in the placenta using cultured trophoblast cells.

METHODS

Using choriocarcinoma cells as a model system, we attempted to demonstrate the presence of a functional Na+/Mg2+ exchanger. Human choriocarcinoma JEG-3 cells cultured on glass coverslips were loaded with MAG-Fura 2-AM (5 micromol/L x 30 min) to spectrofluorometrically assess kinetics of intracellular magnesium ([Mg2+]i). Cells were superfused with various concentrations of Na+, Mg2+, Ca2+ and imipramine, a blocker of erythrocyte Na/Mg exchange. [Mg2+]i calibration was determined via Triton X-100 and EDTA.

RESULTS

Sequential lowering of extracellular Na+ caused progressively larger, transient increases in [Mg2+]i. These transient changes in [Mg2+]i were completely dependent on [Mg]o but was independent of extracellular calcium ([Ca]o). Although acute imipramine did not alter basal [Mg2+]i, imipramine eliminated the return-to-basal phase of the [Mg2+]i transient induced by low sodium medium. Increasing extracellular magnesium ([Mg]o) caused stepwise increases in [Mg2+]i.

CONCLUSIONS

The JEG-3 cells appear to possess a functional Na/Mg exchanger that functions to maintain low [Mg2+]i in cytotrophoblast cells. In addition, [Mg2+]i is acutely regulated by [Mg]o. Because placental trophoblasts are sites of maternal-fetal ion exchange, and [Mg]o is altered in preeclampsia, derangements in or modulation of this exchanger may contribute to complications of pregnancy such as pregnancy-induced hypertension, pre-eclampsia, and preterm labor.

Mechanisms involved in agonist-induced hyperaggregability of platelets from normal pregnancy

There is substantial evidence of increased platelet reactivity in vivo and in vitro during pregnancy. Platelet activation occurs in pregnancy with a risk of the development of preeclampsia. In this study, platelet behavior was studied during 28-40 weeks of gestation in a group of women who remained normotensive and a group of nonpregnant female controls. Platelet aggregation and ATP release stimulated by agonists (i.e. collagen and adenosine 5'-diphosphate) were markedly enhanced in washed platelets from pregnant subjects. Furthermore, the collagen-evoked increase in intracellular Ca(2+) ([Ca(2+)](i)) mobilization in fura-2-AM-loaded platelets was also enhanced in pregnant subjects. Moreover, the binding activity of fluorescein isothiocyanate-triflavin toward the platelet glycoprotein IIb/IIIa complex did not significantly differ between the nonpregnant and pregnant groups. In addition, the amount of thromboxane A(2) (TxA(2)) formation from pregnant subjects was significantly greater than that from nonpregnant subjects in both resting and collagen-activated platelets. On the other hand, prostaglandin E(2) formation in the presence of imidazole in either resting or arachidonic acid (100 microM)-treated platelets did not significantly differ between these two groups. The levels of cyclic AMP formation in both resting and prostaglandin E(1) (10 microM)-treated platelets from pregnant subjects were significantly lower than those in nonpregnant subjects. Nitric oxide production was measured by a chemiluminescence detection method in this study. The extent of nitrate production in either resting or collagen-stimulated platelets from pregnant subjects did not significantly differ from that of platelets from the nonpregnant group. We conclude that the agonist-induced hyperaggregability of platelets from normal pregnancy may be due, at least partly, to an increase in TxA(2) formation and a lowering of the level of cyclic AMP formation, which leads to increased [Ca(2+)](i) mobilization and finally to enhanced platelet aggregation and ATP release.

Plasma P-selectin is elevated in the first trimester in women who subsequently develop pre-eclampsia

OBJECTIVE

To report plasma concentrations of the adhesion cell molecule P-selectin during pregnancy to determine the effect of subsequent development of hypertension and pre-eclampsia.

DESIGN

A longitudinal study.

METHODS

A longitudinal study involving 70 women followed up from early pregnancy; 20 who subsequently developed pre-eclampsia were compared with 24 who developed gestational hypertension and 26 normotensive women with normal obstetric outcome. The determination of citrate plasma soluble P-selectin levels throughout pregnancy was performed using a commercial quantitative sandwich immunoassay kit. The temporal course of plasma P-selectin in the three groups of subjects was analysed.

RESULTS

There was no significant difference in mean plasma P-selectin concentration between normotensive and gestational hypertensive subjects at any stage of pregnancy. Using a cutoff level of 60 ng/mL, P-selectin concentration at 10-14 weeks had a negative predictive value for pre-eclampsia of almost 99%. Mean plasma P-selectin concentrations were significantly elevated by 10-14 weeks in women who later developed pre-eclampsia (P < 0.001).

CONCLUSIONS

Our data support an inflammatory model for pre-eclampsia whereby endothelial cell activation may be secondary to a primary inflammatory response. Plasma P-selectin has significant potential as a first trimester clinical marker of pre-eclampsia.

Plasma P-selectin is elevated in the first trimester in women who subsequently develop pre-eclampsia

OBJECTIVE

To report plasma concentrations of the adhesion cell molecule P-selectin during pregnancy to determine the effect of subsequent development of hypertension and pre-eclampsia.

DESIGN

A longitudinal study.

METHODS

A longitudinal study involving 70 women followed up from early pregnancy; 20 who subsequently developed pre-eclampsia were compared with 24 who developed gestational hypertension and 26 normotensive women with normal obstetric outcome. The determination of citrate plasma soluble P-selectin levels throughout pregnancy was performed using a commercial quantitative sandwich immunoassay kit. The temporal course of plasma P-selectin in the three groups of subjects was analysed.

RESULTS

There was no significant difference in mean plasma P-selectin concentration between normotensive and gestational hypertensive subjects at any stage of pregnancy. Using a cutoff level of 60 ng/mL, P-selectin concentration at 10-14 weeks had a negative predictive value for pre-eclampsia of almost 99%. Mean plasma P-selectin concentrations were significantly elevated by 10-14 weeks in women who later developed pre-eclampsia (P < 0.001).

CONCLUSIONS

Our data support an inflammatory model for pre-eclampsia whereby endothelial cell activation may be secondary to a primary inflammatory response. Plasma P-selectin has significant potential as a first trimester clinical marker of pre-eclampsia.

Pathophysiology of preeclampsia and the role of serotonin

Hypertensive disorders constitute the most common medical complications of pregnancy. In normal pregnancy, impressive physiological changes take place in the maternal cardiovascular system. Morphological changes are the result of invasion of migratory trophoblast cells into the walls of the spiral arteries. After destruction of elastic, muscular and neural tissue in the media, the trophoblast cells get incorporated into the vessel wall and the endothelial lining of the spiral arteries is restored. The physiological changes create a low-resistance, low-pressure, high-flow system with the absence of maternal vasomotor control. Biochemical adaptations in maternal vasculature include changes in the prostaglandin system, the renin-angiotensin-aldosteron system and the kallikrein-kinin system. In preeclampsia, physiological changes in the spiral arteries are confined to the decidual portion of the arteries. Myometrial segments remain anatomically intact and fail to dilate. In addition, the adrenergic nerve supply is left intact. The cause of this impaired endovascular trophoblast invasion is not yet elucidated. But in combination with the imbalance between vasodilator and vasoconstrictor eicosanoids, it gives rise to reduced perfusion of the intervillous space. In the absence of an adequate production of antiaggregatory prostacyclin (PGI(2)), nitric oxide, or both, surface-mediated platelet activation is supposed to occur on the surface of the spiral arteries. Because platelets are the principal source of circulating serotonin, the increased platelet aggregation in preeclampsia causes an increase in serotonin levels. Interaction of serotonin with serotonin(1)- or serotonin(2)-receptors depends on the state of the endovascular trophoblast or endothelium in the spiral arteries and has opposite effects with regard to vasodilating and vasoconstrictive influences.