Plasma P selectin (GMP-140) and glycocalicin are elevated in preeclampsia and eclampsia: their significances

A placenta-on-a-chip model to determine the regulation of FKBPL and galectin-3 in preeclampsia

Preeclampsia is a pregnancy-specific cardiovascular disorder, involving significant maternal endothelial dysfunction. Although inappropriate placentation due to aberrant angiogenesis, inflammation and shallow trophoblast invasion are the root causes of preeclampsia, pathogenic mechanisms are poorly understood, particularly in early pregnancy. Here, we first confirm the abnormal expression of important vascular and inflammatory proteins, FK506-binding protein-like (FKBPL) and galectin-3 (Gal-3), in human plasma and placental tissues from women with preeclampsia and normotensive controls. We then employ a three-dimensional microfluidic placental model incorporating human umbilical vein endothelial cells (HUVECs) and a first trimester trophoblast cell line (ACH-3P) to investigate FKBPL and Gal-3 signaling in inflammatory conditions. In human samples, both circulating (n = 17 controls; n = 30 preeclampsia) and placental (n ≥ 6) FKBPL and Gal-3 levels were increased in preeclampsia compared to controls (plasma: FKBPL, p < 0.0001; Gal-3, p < 0.01; placenta: FKBPL, p < 0.05; Gal-3, p < 0.01), indicative of vascular dysfunction in preeclampsia. In our placenta-on-a-chip model, we show that endothelial cells are critical for trophoblast-mediated migration and that trophoblasts effectively remodel endothelial vascular networks. Inflammatory cytokine tumour necrosis factor-α (10 ng/mL) modulates both FKBPL and Gal-3 signaling in conjunction with trophoblast migration and impairs vascular network formation (p < 0.005). Our placenta-on-a-chip recapitulates aspects of inappropriate placental development and vascular dysfunction in preeclampsia.

Platelet function in preeclampsia - a systematic review and meta-analysis

Preeclampsia is a serious pregnancy-related complication. Platelets are potentially important in the pathogenesis of preeclampsia, and platelet function analyses may prove as sensitive preeclampsia biomarkers. This study aimed to systematically review and summarise the literature on platelet function markers in preeclampsia. This systematic review was conducted according to PRISMA and registered in PROSPERO. Relevant studies were identified through PubMed and Embase on 15/08/17. As platelet function markers platelet activation, platelet aggregation and platelet adhesion markers were included. If possible, relevant data were extracted for each marker to perform a meta-analysis of the mean difference between women with and without preeclampsia. All 69 included articles underwent quality rating. Some platelet activation markers, especially p-selectin and mean platelet volume (MPV), were significantly increased comparing the two groups of women, while others were not. The meta-analysis demonstrated that, overall, women with preeclampsia had significantly higher MPV than in women without preeclampsia. No significant difference was found regarding platelet aggreg`ation comparing the two groups. Platelet adhesion was investigated in noneof the included studies. In conclusion, further studies are warranted to investigate platelet activation markers future role as predictive markers in preeclampsia. MPV is suggested as the most promising biomarker for evaluating platelet function in preeclampsia.

Preeclampsia and the challenge of early prediction: reality or utopia? State of art and critical review of literature

Purpose: The challenge to obtain improved predictive tools, able to identify women destined to develop preeclampsia (PE), is raising the interest of researchers for the attractive chance to allow for timely initiation of prophylactic therapy, appropriate antenatal surveillance, and better-targeted research into preventive interventions. We aimed to gather all the evidence reported up to now in scientific literature relating to all prediction tests for PE.Materials and methods: We searched articles on conventional literature platforms from January 1952 to August 2016, using the terms "preeclampsia," "gestational preeclampsia," and "gestational hypertensive disorders" combined with "predictive test" and "risk assessment." Abstracts/titles identified by the search were screened by three investigators.Results: The search identified 203 citations, of which 154 potentially relevant after the initial evaluation. Among these studies, 20 full articles were excluded, therefore, 134 primary studies met the criteria for inclusion and were analyzed.Conclusions: Current evidence suggests that a combination of several features may provide the best predictive accuracy for the identification of PE. Large-scale, multicenter, multiethnic, prospective trials are required to propose an ideal combination of markers for routine screening.

Clinical Presentation of Preeclampsia and the Diagnostic Value of Proteins and Their Methylation Products as Biomarkers in Pregnant Women with Preeclampsia and Their Newborns

Preeclampsia (PE) is a disorder which affects 1-10% of pregnant women worldwide. It is characterised by hypertension and proteinuria in the later stages of gestation and can lead to maternal and perinatal morbidity and mortality. Other than the delivery of the foetus and the removal of the placenta, to date there are no therapeutic approaches to treat or prevent PE. It is thus only possible to reduce PE-related mortality through early detection, careful monitoring, and treatment of the symptoms. For these reasons the search for noninvasive, blood-borne, or urinary biochemical markers that could be used for the screening, presymptomatic diagnosis, and prediction of the development of PE is of great urgency. So far, a number of biomarkers have been proposed for predicting PE, based on pathophysiological observations, but these have mostly proven to be unreliable and inconsistent between different studies. The clinical presentation of PE and data gathered for the biochemical markers placental growth factor (PlGF), soluble Feline McDonough Sarcoma- (fms-) like tyrosine kinase-1 (sFlt-1), asymmetric dimethylarginine (ADMA), and methyl-lysine is being reviewed with the aim of providing both a clinical and biochemical understanding of how these biomarkers might assist in the diagnosis of PE or indicate its severity.

The profiles of soluble adhesion molecules in the "great obstetrical syndromes". J Matern Fetal Neonatal Med 2018;32:2113-2136. [PMID: 29320948 DOI: 10.1080/14767058.2018.1427058]

OBJECTIVE

The objective of this study was to determine the profiles of maternal plasma soluble adhesion molecules in patients with preeclampsia, small-for-gestational-age (SGA) fetuses, acute pyelonephritis, preterm labor with intact membranes (PTL), preterm prelabor rupture of the membranes (preterm PROM), and fetal death.

MATERIALS AND METHODS

A cross-sectional study was conducted to determine maternal plasma concentrations of sE-selectin, sL-selectin, and sP-selectin as well as sICAM-1, sVCAM-1, and sPECAM-1 in patients with (1) an uncomplicated pregnancy (control, n = 100); (2) preeclampsia (n = 94); (3) SGA fetuses (in women without preeclampsia/hypertension, n = 45); (4) acute pyelonephritis (n = 25); (5) PTL (n = 53); (6) preterm PROM (n = 24); and (7) fetal death (n = 34). Concentrations of soluble adhesion molecules and inflammatory cytokines (tumor necrosis factor (TNF)-α and interleukin (IL)-8) were determined with sensitive and specific enzyme-linked immunoassays.

RESULTS

In comparison to women with a normal pregnancy, (1) women with preeclampsia had higher median concentrations of sE-selectin, sP-selectin, and sVCAM-1, and a lower concentration of sL-selectin (all p values < .001); (2) patients with SGA fetuses had higher median concentrations of sE-selectin, sP-selectin, and sVCAM-1 (all p values < .05); (3) patients with a fetal death had higher median concentrations of sE-selectin and sP-selectin (all p values < .05); (4) patients with acute pyelonephritis had higher median plasma concentrations of sE-selectin, sICAM-1, and sVCAM-1 (all p values < .001); (5) patients with preeclampsia and acute pyelonephritis, plasma concentrations of sVCAM-1, sE-selectin, and sP-selectin correlated with those of the proinflammatory cytokines TNF-α and interleukin (IL)-8 (all p values < .05); (6) patients with PTL had a higher median concentration of sP-selectin and a lower median concentration of VCAM-1 (all p values < .05); and (7) women with preterm PROM had lower median concentrations of sL-selectin and sVCAM-1 (all p values < .05).

CONCLUSIONS

The results of this study show that endothelial cell activation/dysfunction reflected by the plasma concentration of sE-selectin is not specific to preeclampsia but is present in pregnancies complicated by SGA fetuses, acute pyelonephritis, and fetal death. Collectively, we report that each obstetrical syndrome appears to have a stereotypical profile of soluble adhesion molecules in the peripheral circulation.

Combined Screening for Early Detection of Pre-Eclampsia

Although the precise pathophysiology of pre-eclampsia remains unknown, this condition continues to be a major cause of maternal and fetal mortality. Early prediction of pre-eclampsia would allow for timely initiation of preventive therapy. A combination of biophysical and biochemical markers are superior to other tests for early prediction of the development of pre-eclampsia. Apart from the use of parameters in first-trimester aneuploidy screening, cell-free fetal DNA quantification is emerging as a promising marker for prediction of pre-eclampsia. This article reviews the current research of the most important strategies for prediction of pre-eclampsia, including the use of maternal risk factors, mean maternal arterial pressure, ultrasound parameters, and biomarkers.

Preeclampsia and the future risk of hypertension: the pregnant evidence

Cardiovascular death rates continue to rise for women under age 55, underlying the importance of focusing on female-specific conditions that may increase cardiovascular risk, including pregnancy-related disorders. Hypertension complicates about 5-10 % of pregnancies. Preeclampsia, a pregnancy-specific condition, is characterized by hypertension and proteinuria after 20 weeks of gestation and remains one of the major causes of maternal deaths in the United States. In addition, preeclampsia may have an impact on women's health beyond their pregnancies, and has been associated with increased risks for future hypertension and cardiovascular disease, such as coronary heart disease and stroke. In this review, we discuss the evidence supporting the association between preeclampsia and future hypertension; possible mechanisms that underlie this association; current approach to women with a history of preeclampsia; and future research that is needed in this field in order to deliver optimal and timely medical care to the affected women.

A comparative study of vascular cell adhesion molecule-1 and high-sensitive C-reactive protein in normal and preeclamptic pregnancies

BACKGROUND

Preeclampsia is characterized by hypertension, dyslipidemia, and systemic inflammatory response. The aim of this study was to determine the level of serum level of soluble vascular cell adhesion molecule-1 (sVCAM-1) and high-sensitive C-reactive protein (hsCRP) in preeclampsia and to compare normal pregnant, mild preeclamptic, and severe preeclamptic women.

METHODS

A cross-sectional study was conducted to determine the plasma concentrations of sVCAM-1 and hsCRP in peripheral blood obtained from normal pregnant (n = 40), mild preeclamptic (n = 37), and severe preeclamptic women (n = 38). A concentration of soluble adhesion molecule was determined with enzyme-linked immunosorbent assay. hsCRP was measured with immunoturbidometric.

RESULTS

There was significant difference in the means serum hsCRP between normal pregnant women and mild preeclamptic women (P < 0.05). Serum concentration of hsCRP and sVCAM-1 (ng/mL) were significantly higher in severe preeclampsia (P < 0.05) than normal pregnancy. There were also significant differences in hsCRP and sVCAM-1 levels between mild and severe (P < 0.05). There was no difference in the mean sVCAM-1 between normal pregnant and mild preeclamptic women.

CONCLUSION

We have determined the serum concentration of VCAM-1 and hsCRP in normal pregnancy and preeclampsia. sVCAM-1 is elevated in severe preeclampsia compared with normal pregnancy, and hsCRP is elevated in severe preeclampsia compared with mild preeclampsia and normal pregnancy.

Elevated maternal serum sP-selectin levels in preeclamptic pregnancies with and without intrauterine fetal growth restriction, but not in normotensive pregnancies complicated by isolated IUGR

Background

The aim of this study was to show differences of maternal serum sP-selectin levels in pregnancies complicated by intrauterine fetal growth restriction (IUGR) in the course of preeclampsia and to compare the results with normotensive pregnant women with isolated IUGR. These studies were also conducted on preeclamptic pregnancies with appropriate-for-gestational-age weight infants and on the control normotensive pregnant women.

Material/Methods

The study was carried out on 55 patients with pregnancy complicated by fetal growth restriction in the course of preeclampsia, 70 normotensive patients with pregnancies complicated by isolated IUGR, 39 preeclamptic patients with appropriate-for-gestational-age weight fetuses and 54 healthy normotensive pregnant patients with normal fetal growth. Maternal serum levels of sP-selectin were determined using the enzyme-linked immunosorbent assay.

Results

Levels of sP-selectin were higher in women with pregnancy complicated by preeclampsia with and without IUGR; whereas, in the group of normotensive pregnant women with isolated fetal growth restriction, serum sP-selectin levels tended to be lower than in the control subjects, but this difference was not statistically significant. The mean values were 192.05±70.96 ng/mL in the IUGR group, 293.18±222.92 ng/mL in the PI group, 379.78±353.13 ng/mL in the P group and 227.96±134.04 ng/mL in the healthy controls (p<0.001*).

Conclusions

Our findings may suggest that the elevated level of the soluble P-selectin is associated with preeclampsia, and that it may confirm the presence of platelet and endothelial activation, the presence of the hypercoagulant state and may be due to the systemic inflammatory response in this serious pregnancy disorder.

Umbilical sP-selectin levels are different in preeclamptic pregnancies with intrauterine normal growth and growth restricted fetus

OBJECTIVE

The aim of this study was the analysis of the umbilical cord serum sP-selectin levels in pregnancies complicated by severe preeclampsia with and without intrauterine growth restriction and in normotensive pregnancies.

PATIENTS AND METHODS

The study was carried out on 18 patients with singleton pregnancies complicated by severe preeclampsia with appropriate-for-gestational-age weight infants (group P) and 18 pregnant patients with severe preeclampsia complicated by intrauterine fetal growth restriction (IUGR) (group PI). The control group consisted of 34 patients with singleton uncomplicated pregnancies (group C). Umbilical serum sP-selectin concentrations were estimated using a sandwich ELISA assay according to the manufacturer's instruction (ELISA kit Bender MedSystems Vienna, Austria).

RESULTS

Our study revealed different concentrations of soluble P-selectin in the umbilical cord in our both studied groups of preeclamptic women with and without IUGR. The umbilical cord levels of sP-selectin were decreased in the group with preeclampsia complicated by IUGR and increased in the preeclamptic women with the normal intrauterine fetal growth. The mean values of umbilical sP-selectin were 839.008 ± 625.703 ng/ml in group P, 275.873 ± 174.339 ng/ml in group PI, and 288.719 ± 199.039 ng/ml in the control group, respectively.

CONCLUSIONS

Higher levels of the umbilical sP-selectin may confirm the presence of platelet and endothelial cell activation and confirm a hypercoagulant state in preeclamptic disorder, especially in preeclampsia without IUGR.

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.

Physiologic and pathologic changes of platelets in pregnancy

Platelets are key players in haemostasis and thrombus formation. Defects affecting platelets during pregnancy can lead to heterogeneous complications, such as thrombosis, first trimester miscarriage and postpartum haemorrhage. The incidence of complications is increased in women who have heritable platelet function disorders. Modifications of platelet count or platelet functions during normal pregnancy and preeclampsia will be summarized and the management of pregnant women with heritable platelet function disorders will be discussed.

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.

Evidence of maternal platelet activation, excessive thrombin generation, and high amniotic fluid tissue factor immunoreactivity and functional activity in patients with fetal death

OBJECTIVE

Fetal death can lead to disseminated intravascular coagulation or fetal death syndrome. However, currently it is not clear what are the changes in the coagulation system in patients with a fetal death without the fetal death syndrome. This study was undertaken to determine: (1) whether fetal death in the absence of fetal death syndrome is associated with changes in hemostatic markers in maternal plasma and amniotic fluid; and (2) whether maternal hypertension or placental abruption are associated with further changes in the hemostatic profile of these patients.

METHODS

A cross-sectional study included the following: (1) determination of changes in markers of coagulation and platelet activation in patients with a normal pregnancy (n = 71) and patients with fetal demise (FD) without disseminated intravascular coagulation (n = 65); (2) determination of the amniotic fluid (AF)-tissue factor concentration and activity, as well as the concentrations of thrombin-antithrombin III (TAT) complexes in patients with a normal pregnancy (n = 25) and those with a FD (n = 36) who underwent amniocentesis. Plasma and AF concentrations of TAT complexes and TF (an index of thrombin generation), as well as maternal plasma concentrations of sCD40L (a marker of platelet activation), tissue factor pathway inhibitor (TFPI) and prothrombin fragments (PF) 1 + 2 (also an indicator of in vivo thrombin generation) were measured by ELISA. TF and TFPI activity were measured using chromogenic assays.

RESULTS

(1) patients with FD without hypertension had a higher median maternal plasma sCD40L concentration than normal pregnant women (P < 0.001); (2) patients with FD had a higher median maternal plasma TAT III complexes than women with a normal pregnancy (P < 0.001); (3) the median AF-TF concentration and activity were higher in the FD group than in the normal pregnancy group (P < 0.001 for both); (4) patients with preeclampsia and FD had a higher median maternal plasma immunoreactive TF concentration than both normotensive patients with FD and women with normal pregnancies (P < 0.001 and P = 0.001, respectively); (5) the median plasma TF activity was higher in patients with preeclampsia and FD than that of women with normal pregnancies (P = 0.003); (6) among patients with a FD, those with placental abruption had a higher median AF-TAT complexes concentration than those without abruption (P = 0.0004).

CONCLUSIONS

Our findings indicate that: (1) mothers with a FD have evidence of increased in vivo thrombin generation and platelet activation than women with normal pregnancies; (2) patients with a FD and hypertension had a higher degree of TF activation than those with fetal death but without hypertension; (3) the AF of women with a FD had a higher median TF concentration and activity than that of normal pregnant women. AF can be a potential source for tissue factor and it participates in the development of fetal death syndrome in patients with a retained dead fetus.

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.

Potential markers of preeclampsia--a review

Preeclampsia is a leading cause of maternal and fetal/neonatal mortality and morbidity worldwide. The early identification of patients with an increased risk for preeclampsia is therefore one of the most important goals in obstetrics. The availability of highly sensitive and specific physiologic and biochemical markers would allow not only the detection of patients at risk but also permit a close surveillance, an exact diagnosis, timely intervention (e.g. lung maturation), as well as simplified recruitment for future studies looking at therapeutic medications and additional prospective markers. Today, several markers may offer the potential to be used, most likely in a combinatory analysis, as predictors or diagnostic tools. We present here the current knowledge on the biology of preeclampsia and review several biochemical markers which may be used to monitor preeclampsia in a future, that, we hope, is not to distant from today.

P-selectin in placenta and gestational myometrium: its measurements and hypothetical role in hemostasis of placental bed after labor

AIM

P-selectin is a member of selectin family (E, L- and P-selectins) which plays a crucial role in reproduction and hemostasis as well as in pathogenesis of preeclampsia. There are no regular studies on P-selectin in placenta and it is not clear whether it is present in gestational myometrium. In the present study, we have asked whether P-selectin is present in placenta and myometrium and in what concentration.

MATERIAL AND METHODS

The study group consisted of 33 healthy pregnant women at term and/or at the beginning of labor who delivered by cesarean section because of fetal distress or elective reasons. Strips of placenta and myometrium as well as venous blood were obtained during the operation. P-selectin was measured in tissue extracts and plasma with the use of immunoenzymatic assays (ELISA).

RESULTS

The median of the level of P-selectin in placenta was 31.65 ng/mg P (total protein), quartiles (Q1-Q3): 24.54-43.35 ng/mg P, and in myometrium 25.54 ng/mg P, quartiles (Q1-Q3): 21.83-35.65 ng/mg P, whereas the median and quartiles (Q1-Q3) of soluble P-selectin in the mother's plasma was 1.14: 0.76-1.63 ng/mg P. The plasma/tissue ratio for placenta was 1:30, and for myometrium -1:25.

CONCLUSIONS

P-selectin is present in placenta and gestational myometrium; its concentration is relatively high - respectively 30- and 25-times higher than in plasma. On the basis of our studies, we hypothesize about the role of placental and myometrial P-selectin in hemostasis of placental bed after labor.

Preeclampsia and future cardiovascular risk: formal risk factor or failed stress test?

It is estimated that 10% of pregnancies are affected by hypertension worldwide. Approximately one-half of all hypertensive pregnancy disorders are due to preeclampsia, a pregnancy-specific disorder, its distinctive feature being either sudden onset, or worsening of pre-existing proteinuria. It has become increasingly recognized that women with a history of preeclampsia are at increased risk for future cardiovascular disease (CVD), but the mechanisms of this increase in risk are unclear. One possible explanation is that these two conditions share several common metabolic abnormalities as risk factors, including obesity, insulin resistance, and lipid abnormalities that may lead to preeclampsia and CVD at different times of a woman's life. Recent studies have revealed that, similar to CVD, several mediators of endothelial cell dysfunction are up-regulated in preeclampsia. Free radical derived oxidative stress, various inflammatory markers, including neutrophil response, C-reactive protein, and leukocyte adhesion, may contribute to endothelial dysfunction in both preeclampsia and coronary atherosclerosis. Alternatively, preeclampsia itself may induce metabolic and vascular changes that may increase the overall future risk for CVD in affected women. Therefore, at present, it remains unclear whether preeclampsia is a formal risk factor for CVD, or identifies women at increased risk for CVD later in life. Pending large-scale studies aiming to examine the causality of this association, women with a history of preeclampsia should be counseled regarding their increased risks for hypertension and other cardiovascular sequelae later in life, followed closely and treated aggressively for modifiable CVD risk factors.

Premature labor: a state of platelet activation?

OBJECTIVE

This study was undertaken to determine whether premature labor is associated with changes in the maternal plasma concentration of soluble CD40 ligand (sCD40L), a marker of platelet activation.

METHODS

A cross-sectional study included patients in the following groups: 1) non-pregnant (n=21); 2) normal pregnancy (n=71); 3) normal pregnancy at term with (n=67) and without labor (n=88); 4) preterm labor (PTL) with intact membranes (n=136) that was divided into the following sub-groups: 4a) PTL who delivered at term (n=49); 4b) PTL without intra-amniotic infection and/or inflammation (IAI) who delivered preterm (n=54); and 4c) PTL with IAI who delivered preterm (n=33). sCD40L concentrations were measured by ELISA.

RESULTS

The median maternal plasma sCD40L concentration was higher in pregnant than non-pregnant women (P=0.017). Patients with PTL had a higher median maternal plasma sCD40L concentration than women with normal pregnancies, regardless of the presence or absence of IAI and gestational age at delivery (P<0.001 for all comparisons). IAI was not associated with a higher median maternal plasma concentration of sCD40L.

CONCLUSIONS

Normal pregnancy is a state in which there is a physiologic increase of sCD40L. PTL was associated with an increased median maternal plasma sCD40L concentration that could not be accounted for by IAI. Thus, our findings suggest that platelet activation occurs during an episode of preterm labor.

Method of diagnosing pre-eclampsia

Pre-eclampsia is a pregnancy-specific disorder that causes a high degree of maternal and fetal morbidity and mortality. Despite many recent advances in the field, the diagnosis, treatment and prevention of pre-eclampsia remain elusive. The current patent application provides evidence for a marker of pre-eclampsia, a 26.6-kDa polypeptide, which is present in pre-eclamptic women and absent in normal controls. The prospect of developing a laboratory test for the diagnosis of pre-eclampsia is exciting, as is the possibility for risk-stratification and potential therapies.

Microparticle-associated P-selectin reflects platelet activation in preeclampsia

Platelet activation in preeclampsia is reflected by elevated levels of platelets exposing P-selectin. In plasma, a non-cell bound (soluble) form of P-selectin is present. Elevated levels of this soluble form have been reported in preeclampsia. Plasma P-selectin may consist of two fractions: microparticle (MP)--associated P-selectin and non-MP--associated P-selectin. In the present cross-sectional study, we investigated to which extent plasma P-selectin is MP--associated and whether such MP are elevated in preeclamptic patients. Preeclamptic patients (n=10) were matched with normotensive pregnant women (n=10) and non-pregnant controls (n=10). Plasma P-selectin was measured by ELISA. MP were isolated, double labelled with anti-CD61 (GPIIIa) and anti-CD62P (P-selectin) and subsequently analyzed with flowcytometry. Plasma P-selectin concentration was elevated in preeclamptic patients compared to non-pregnant controls (p=0.007), but not compared to normotensive pregnant women (p=0.210). Plasma P-selectin is partially MP--associated (3-5%). In pregnancy, the fraction of P-selectin exposing platelet-derived MP (PMP) (10.9%) was increased compared to non-pregnant controls (8%). This fraction further increased in preeclamptic patients (15.4%), and significantly differed from normotensive pregnant women (p=0.02). A minor fraction of plasma P-selectin is associated with PMP. The fraction of PMP exposing P-selectin is increased in preeclamptic patients and to a lesser extent in normotensive pregnancy. Because MP associated P-selectin exclusively originates from platelets, this fraction indicates platelet activation. Platelet activation is prominent in preeclampsia and this study proves that at least a part of the plasma P-selectin originates from platelets.

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.

Quantitative distribution of a panel of circulating mRNA in preeclampsiaversus controls

OBJECTIVE

The aim of this study was to evaluate whether the quantitative distribution of a panel of circulating mRNAs from maternal whole blood of normal pregnancies is statistically different from those complicated with preeclampsia (PE) with or without intrauterine growth restriction (IUGR).

METHODS

Maternal whole blood of six subjects with mild or severe PE with or without IUGR and 30 matched controls (1:5 match for gestational age) were retrospectively examined for circulating mRNA markers. Seven specific mRNA markers were identified and chosen based on previous microarray mRNA expressions performed on placental tissue from normal and PE patients. They were human placental lactogen (hPL), inhibin A, KISS-1, pregnancy-associated plasma protein-A (PAPP-A), plasminogen activator inhibitor type 1 (PAI-1), selectin-P and vascular endothelial growth factor receptor (VEGFR), which were therefore quantified for statistical purposes.

RESULTS

Median gestational age was 229 (178-283) and 232 (194-262) days for controls and cases respectively. All mRNA markers but PAPP-A, showed statistically different median values. They were hPL, inhibin A, KISS-1, PAI-1, Selectin-P, and VEGFR. Inhibin A, Selectin-P and VEGFR showed higher values than expected for controls. Instead, hPL, KISS-1 and PAI-1 values of PE patients were lower than those of controls. Selectin-P was the marker with the most aberrant difference, followed by VEGFR and KISS-1.

CONCLUSION

This preliminary analysis revealed that the median values of a panel of mRNAs from the maternal blood of PE patients were different from those of the same gestational age control group at the third trimester. If prospective studies at the second trimester could detect a related marker sufficiently able to discriminate between affected and unaffected patients and thus detect the disease before its clinical onset, then a screening project using a panel of mRNAs would be feasible.

Surface expression of neutrophil adhesion molecules in pregnant women at risk for hypertensive complications

OBJECTIVE

To determine if neutrophil activation is a pathogenetic factor in hypertensive disorders in pregnancy, the neutrophil expression of adhesion molecules was prospectively investigated in pregnant women at risk, prior to the development of hypertensive complications.

METHODS

Two neutrophil activation parameters, beta2-integrin (CD11b) and l-selectin (CD62L), were assessed at admission between 14 and 24 weeks of gestation in 82 pregnant women at risk of preeclampsia and other hypertensive complications. Results were compared to those in 20 healthy normotensive women.

RESULTS

Of the 82 women at risk, 23 (28%) developed hypertensive complications: 9 (11%) preeclampsia and 14 (17%) others, such as intrauterine growth restriction (n = 6), fetal or neonatal loss (n = 8), and preterm delivery (< or = 30 weeks of gestation) (n = 8). All pregnancy outcome measures were significantly worse in the patients with complications than in those at risk but without complications or the healthy controls. Expression of beta2-integrin was significantly higher in early stages of pregnancy in the women who eventually developed complications than the women who did not, P =.019, or the healthy controls, P =.049.

CONCLUSIONS

Surface expression of beta2-integrin is increased in pregnant women at risk for hypertensive complications before the clinical manifestations of the disorder.

Women with preeclampsia have increased serum levels of pregnancy-associated plasma protein A (PAPP-A), inhibin A, activin A and soluble E-selectin

OBJECTIVE

Poor placentation in early pregnancy is thought to lead to an excessive maternal systemic inflammatory response, which causes the maternal syndrome of preeclampsia. The aims of this retrospective study were to confirm old reports of increased blood levels of pregnancy-associated plasma protein A (PAPP-A) in preeclampsia and how its levels correlate with the levels of other placental and endothelial proteins that are reported to be elevated in preeclampsia.

METHODS

Nineteen women with preeclampsia symptoms were matched with 19 normal pregnant controls for gestational age, maternal age, and parity. PAPP-A, placental pregnancy-specific beta1-glycoprotein (SP1), inhibin A, activin A, and sE-selectin were measured in serum using specific ELISAs.

RESULTS

Maternal serum levels of PAPP-A, inhibin A, activin A and sE-selectin were increased in women with preeclampsia (mean 157.7 vs. 76.85 mIU/mL, p=0.005; 3.08 vs. 1.51 ng/mL, p=0.002, 32.36 vs. 3.77 ng/mL, p<0.001 and 62.15 vs. 46.37 ng/mL, p=0.02 respectively), compared to controls. Serum levels of SP1 were not altered in preeclampsia. PAPP-A (r=0.636, p<0.01) had a positive correlation with sE-selectin in patients with preeclampsia. Serum inhibin A and activin A had a significant positive correlation with each other in preeclampsia.

CONCLUSIONS

Raised levels of PAPP-A in preeclampsia confirm earlier reports. Activin A showed the highest increase over the controls and is thus likely to be a better serum marker for this pathology than the other markers that were tested.

Predictive Value of Routine Circulating Soluble Endothelial Cell Adhesion Molecule Measurements during Pregnancy

Background: The present study was aimed at determining whether routine prenatal measurements of circulating soluble intercellular adhesion molecule (sICAM-1; CD54) and soluble vascular cell adhesion molecule (sVCAM-1; CD106) in midgestation have predictive value for the identification of pregnant women destined to develop preeclampsia or other complications of pregnancy during late gestation.

Methods: Plasma sICAM-1 and sVCAM-1 were analyzed between weeks 22 and 29 of gestation in 1543 pregnant women and related to the outcome of pregnancy in a prospective longitudinal study.

Results: Plasma sICAM-1 and sVCAM-1 in uncomplicated pregnancies were normally distributed and varied over a small range (sICAM-1, SD = 22.5%; sVCAM-1, SD = 25.5%). Of all analyzed uncomplicated pregnancies, 54 (3.95%) were identified with concentrations of sICAM-1 or sVCAM-1 above the mean + 2 SD. In contrast, of 177 pregnancies with complications (prevalence, 11.5%), 97 (55%) had sICAM-1 or sVCAM-1 concentrations above the same cutoffs weeks before the onset of disease. The sensitivities of sICAM-1 and sVCAM-1 measurements were 66% for preeclampsia and hemolysis, elevated liver enzymes, and low platelets (HELLP syndrome), 42% for gestational hypertension, 50% for fetal retardation, 46% for preterm labor, 50% for gestational diabetes mellitus, 67% for gestational proteinuria, and 70% for infections during pregnancy. Taken together, routine prenatal sICAM-1 and sVCAM-1 measurements had an overall predictive value of 64%.

Conclusions: Midgestation measurements of circulating sICAM-1 and sVCAM-1 have a high predictive value (area under the curve of combined sICAM-1 and sVCAM-1 measurements determined by ROC analysis, 0.85) and may identify up to 55% of pregnant women who will later develop a severe pregnancy-related complication.

Soluble adhesion molecule profile in normal pregnancy and pre-eclampsia

OBJECTIVE

An exaggerated inflammatory response has been implicated as the cause of endothelial cell dysfunction and the maternal syndrome of pre-eclampsia. Adhesion molecules play a central role in the adherence of leukocytes to endothelial cells and the subsequent migration of white blood cells into perivascular tissue. Cellular forms of adhesion molecules mediate specific steps of leukocyte-endothelial cell interaction, and have been implicated in the pathophysiology of preeclampsia. Soluble forms of these molecules can be detected in plasma, and their concentrations are thought to reflect the degree of activation of a particular cell type. Elevations in soluble P-selectin (sP-selectin) reflect platelet activation; changes in soluble L-selectin (sL-selectin) suggest leukocyte activation; and an increase in soluble forms of E-selectin (sE-selectin), vascular cell adhesion molecule 1 (sVCAM-1), intercellular adhesion molecule 1 (sICAM-1) and platelet endothelial cell adhesion molecule (sPECAM-1) indicate endothelial cell activation/dysfunction. The objective of this study was to determine whether normal pregnancy and pre-eclampsia were associated with changes in the concentrations of soluble selectins and members of the immunoglobulin superfamily of adhesion molecules.

STUDY DESIGN

A cross-sectional study was conducted to determine the plasma concentrations of sL-selectin, sE-selectin, sP-selectin, sVCAM-1, sICAM-1 and sPECAM-1 in peripheral blood obtained from non-pregnant women (n = 20), normal pregnant women (n = 100) and patients with pre-eclampsia (n = 55). Concentrations of soluble adhesion molecules were determined with enzyme-linked immunoassays. Parametric statistics were used for data analysis.

RESULTS

Normal pregnancy was associated with a significant increase in the maternal plasma concentration of sP-selectin, a decrease in sL-selectin, and no change in sE-selectin, sVCAM-1, sICAM-1 and sPECAM-1. In contrast, pre-eclampsia was associated with a significant increase in sP-selectin, sE-selectin and sVCAM-1, a decrease in sL-selectin, but no change in sICAM-1 and sPECAM-1 concentrations.

CONCLUSIONS

The increased concentration of sP-selectin and decreased sL-selectin, as well as the lack of change in endothelial cell-associated soluble adhesion molecules suggest that pregnancy is associated with platelet and leukocyte activation, but not endothelial cell activation. In contrast, pre-eclampsia appears to be characterized by activation of platelets, leukocytes and endothelial cells.

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.

Annexin V inhibits phosphatidylserine-induced intrauterine growth restriction in mice

To investigate the role of phosphatidylserine (PS) derived from the activated platelets in placental circulation, we established an artificial PS-induced intrauterine growth restriction (IUGR) model in mice and examined whether annexin V, a PS-binding anticoagulant protein, could prevent the development of IUGR in the animal experiments. The ICR mice were injected in the tail vein on days 8, 11 and 14 of pregnancy with filtered PS/phosphatidylcholine (PC) microvesicles (<0.3 microm in maximal diameter). The microvesicles have a procoagulant activity which was inhibited by annexin V in a dose-dependent fashion. The mice were killed on day 18 of pregnancy and the placental and fetal weights were measured. The placental tissue specimens were examined microscopically. PS/PC vesicles induced significant reductions in fetal weights compared with PC vesicles alone. The placental tissue revealed severe congestion with fibrin depositions although the lung and kidney tissue specimens showed minimal histological changes. PS/PC microvesicles with recombinant annexin V showed no significant reductions in fetal weights in mice with PS/PC vesicles alone. These results suggest that PS from the activated platelets induces IUGR by enhancing the coagulation cascade in the placental circulation and that annexin V from the villous trophoblast prevents the development of IUGR.

Elevated soluble adhesion molecules in women with pre-eclampsia. Do cytokines like tumour necrosis factor-alpha and interleukin-1beta cause endothelial activation

OBJECTIVE

The purpose of the present study was to evaluate the clinical significance of tumour necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) for endothelial cell activation in pre-eclampsia. Therefore, we determined and compared the correlations between these cytokines and circulating adhesion molecules in the sera of pre-eclamptic pregnant women, normotensive pregnant women and nonpregnant women.

METHODS

The soluble adhesion molecules VCAM-1, ICAM-1, E-selectin, and P-selectin were determined in the serum of 38 pre-eclamptic pregnant women and 40 normotensive pregnant and nonpregnant controls using ELISA-techniques. We correlated these serum concentrations with the serum levels of TNF-alpha and IL-1beta, respectively, also determined by ELISA.

RESULTS

Elevated serum levels of VCAM-1 and E-selectin could be detected in pre-eclamptic patients, with and without HELLP-syndrome. In contrast, no increased serum concentration of ICAM-1, P-selectin, TNF-alpha and IL-1beta were found in these patients. While significant correlation between VCAM-1 and E-selectin could be determined (r=0.604; p<0.001) no unambiguous correlations, however, were found between TNF-alpha or between IL-1beta and the examined adhesion molecules or the selectins.

CONCLUSIONS

In contrast to in vitro investigations on cultured umbilical vein endothelium, our experimental results indicate that the cytokines TNF-alpha and IL-1beta can not explain endothelial cell activation, and that their measurement in serum is not useful for the detection of pre-eclampsia.

Platelet surface p-selectin, platelet-granulocyte heterotypic aggregates, and plasma-soluble p-selectin during plateletpheresis

BACKGROUND

Plateletpheresis components have been shown to contain p-selectin-positive platelets after collection and storage. P-selectin mediates binding of activated platelets to granulocytes and monocytes. This study was undertaken to assess platelet activation, granulocyte activation, platelet-granulocyte heterotypic aggregate formation, and the plasma-soluble p-selectin level during plateletpheresis performed on a particular instrument (MCS+, Haemonetics).

STUDY DESIGN AND METHODS

Flow cytometry was used to assay platelet surface p-selectin, granulocyte iC3b receptor, and platelet-granulocyte aggregates in the platelet component, residual blood in the disposable polycarbonate bowl of the MCS+, and in the donor blood with and without the addition of in vitro agonists before, during, and after plateletpheresis. The plasma-soluble p-selectin levels in the platelet component, disposable bowl, and donor venous blood were measured by an enzyme-linked immunosorbent assay.

RESULTS

Levels of p-selectin-positive platelets, activated granulocytes, and platelet-granulocyte aggregates were greater in the disposable bowl than in the preapheresis donor blood. Levels of p-selectin-positive platelets, activated granulocytes, and platelet-granulocyte aggregates in the postapheresis donor blood were similar to those in the preapheresis donor blood. The platelet components contained no activated granulocytes or detectable platelet-granulocyte heterotypic aggregates, and only about 10-percent activated platelets. The plasma-soluble p-selectin level in the platelet component was significantly greater than that in the preapheresis donor blood, the residual blood in the disposable bowl, or the postapheresis donor blood.

CONCLUSIONS

Measurements of platelet surface p-selectin, platelet-granulocyte heterotypic aggregates, and plasma-soluble p-selectin can be used to detect platelet activation during plateletpheresis.

P-selectin deficiency exacerbates experimental glomerulonephritis: a protective role for endothelial P-selectin in inflammation

P-selectin is a leukocyte adhesion receptor present in endothelial cells and platelets. We examined the role of P-selectin in the autologous phase of an accelerated model of anti-glomerular basement membrane (GBM) glomerulonephritis using P-selectin-deficient mice and chimeric mice expressing P-selectin only in platelets or endothelial cells. P-selectin-deficient mice exhibited more severe glomerular damage with increased interstitial mononuclear leukocytic infiltrates, and had significantly increased proteinuria and mortality when compared to wild-type mice. P-selectin on the endothelium was predominantly responsible for protection from the exacerbated disease, because chimeric mice with endothelial P-selectin, and not mice with platelet P-selectin, showed glomerular injury similar to that in wild-type animals. Levels of soluble circulating P-selectin were increased in nephritic wild-type mice and in chimeric mice with endothelial P-selectin, but not platelet P-selectin. Levels of soluble P-selectin, which has been shown to be anti-inflammatory in vitro, were inversely associated with the severity of disease. P-selectin was not expressed in the endothelium of the glomerulus or interstitium. Thus, the protective effect in wild-type mice may be accounted for, in part by soluble P-selectin shed by non-renal endothelial cells, although other endothelial P-selectin-dependent mechanisms cannot be ruled out.

The role of soluble adhesion molecules in evaluating endothelial cell activation in preeclampsia

OBJECTIVE

Adhesion molecules, such as vascular cell adhesion molecule 1, are known to be increased in the serum of patients with preeclampsia, indicating that these molecules are possible markers of endothelial cell activation. We investigated the influence of serum from women with preeclampsia on the expression of adhesion molecules by cultured endothelial cells.

STUDY DESIGN

Human umbilical vein endothelial cells were cultured in Ham/Iscove modified Dulbecco's medium containing 20% pooled human serum, l -glutamine (200 mmol/L), penicillin, and streptomycin. We stimulated these cells for 24 hours with sera from patients with preeclampsia and then determined the levels of vascular cell adhesion molecule 1, intercellular cell adhesion molecule 1, E-selectin, and P-selectin in the supernatant and in the maternal serum by means of enzyme-linked immunosorbent assay. These results were compared with those of sera obtained from normotensive pregnant and nonpregnant women. In addition, the expressions of these adhesion molecules on the endothelial surface were determined by immunofluo-rescence microscopy.

RESULTS

Only for vascular cell adhesion molecule 1 and E-selectin were elevated plasma levels found in hypertensive patients, whereas intercellular cell adhesion molecule 1 and P-selectin showed similar plasma levels in all the patients. No differences in the levels of the adhesion molecules were found between the supernatants of endothelial cell cultures after stimulation with sera from patients with preeclampsia and those after stimulation with normotensive control sera. In contrast, with immunofluorescence microscopy we could detect higher amounts of vascular cell adhesion molecule 1, intercellular cell adhesion molecule 1, and E-selectin on the endothelial surface after stimulation with sera from women with preeclampsia.

CONCLUSION

Although vascular cell adhesion molecule 1 and E-selectin were elevated in maternal serum samples from women with preeclampsia and on the endothelial surface after stimulation with such sera, there were no detectable increases in the levels of both of these adhesion molecules in the supernatant of cultured endothelial cells. We therefore assume that sera from women with preeclampsia may cause endothelial cell activation. Because we could not detect elevated concentrations of any of the investigated adhesion molecules in the supernatant of endothelial cells, we believe that factors other than sera from women with preeclampsia seem to play a major role in the release of soluble forms of adhesion molecules from the endothelial membrane.

P-Selectin and Platelet Clearance

P-selectin is an adhesion receptor for leukocytes expressed by activated platelets and endothelial cells. To assess a possible role of P-selectin in platelet clearance, we adapted an in vivo biotinylation technique in mice. Wild-type and P-selectin–deficient mice were infused with N-hydroxysuccinimido biotin. The survival of biotinylated platelets was followed by flow cytometry after labeling with fluorescent streptavidin. Both wild-type and P-selectin–deficient platelets presented identical life spans of about 4.7 days, suggesting that P-selectin does not play a role in platelet turnover. When biotinylated platelets were isolated, activated with thrombin, and reinjected into mice, the rate of platelet clearance was unchanged. In contrast, storage of platelets at 4°C caused a significant reduction in their life span in vivo but again no significant differences were observed between the two genotypes. The infused thrombin-activated platelets rapidly lost their surface P-selectin in circulation, and this loss was accompanied by the simultaneous appearance of a 100-kD P-selectin fragment in the plasma. This observation suggests that the platelet membrane P-selectin was shed by cleavage. In conclusion, this study shows that P-selectin, despite its binding to leukocytes, does not mediate platelet clearance. However, the generation of a soluble form of P-selectin on platelet activation may have biological implications in modulating leukocyte recruitment or thrombus growth.

P-Selectin and Platelet Clearance

P-selectin is an adhesion receptor for leukocytes expressed by activated platelets and endothelial cells. To assess a possible role of P-selectin in platelet clearance, we adapted an in vivo biotinylation technique in mice. Wild-type and P-selectin–deficient mice were infused with N-hydroxysuccinimido biotin. The survival of biotinylated platelets was followed by flow cytometry after labeling with fluorescent streptavidin. Both wild-type and P-selectin–deficient platelets presented identical life spans of about 4.7 days, suggesting that P-selectin does not play a role in platelet turnover. When biotinylated platelets were isolated, activated with thrombin, and reinjected into mice, the rate of platelet clearance was unchanged. In contrast, storage of platelets at 4°C caused a significant reduction in their life span in vivo but again no significant differences were observed between the two genotypes. The infused thrombin-activated platelets rapidly lost their surface P-selectin in circulation, and this loss was accompanied by the simultaneous appearance of a 100-kD P-selectin fragment in the plasma. This observation suggests that the platelet membrane P-selectin was shed by cleavage. In conclusion, this study shows that P-selectin, despite its binding to leukocytes, does not mediate platelet clearance. However, the generation of a soluble form of P-selectin on platelet activation may have biological implications in modulating leukocyte recruitment or thrombus growth.

Fetal plasma levels of circulating endothelial cell adhesion molecules in normal and preeclamptic pregnancies

OBJECTIVE

Circulating levels of endothelial cell adhesion molecules are elevated in women with preeclampsia. The aim of the present study was to determine levels of these molecules in the fetal circulation of normal pregnancies and pregnancies complicated by preeclampsia.

STUDY DESIGN

Fetal plasma samples from the umbilical vein and peripheral maternal plasma and serum sample were collected at delivery from women with preeclampsia and women with normal pregnancy. Women with non-proteinuric pregnancy-induced hypertension (PIH) were excluded from the study. A sandwich ELISA technique was employed to quantitate concentrations of soluble ICAM-1 (CD54), VCAM-1 (CD106), and E-selectin (CD62E).

RESULTS

The normal values of soluble endothelial cell adhesion molecules in the fetal circulation were determined as 162+/-45 ng/ml for ICAM-1, 1612+/-582 ng/ml for VCAM-1, and 154+/-58 ng/ml for E-selectin. They were found to markedly differ from the corresponding normal values in the maternal circulation (sICAM-1: 247+/-65 ng/ml; sVCAM-1: 715+/-170 ng/ml; sE-selectin: 34+/-14 ng/ml). The concentrations of sICAM-1, sVCAM-1, and sE-selectin were significantly elevated in women with preeclampsia compared to healthy control pregnant women. In contrast, there was no difference in the circulating fetal concentrations of these molecules between normal pregnancies and pregnancies complicated by preeclampsia.

CONCLUSIONS

Normal values of sICAM-1, sVCAM-1, and sE-selectin in fetal circulation are markedly different from the values obtained for healthy adults. Plasma concentrations of these molecules are elevated in women with preeclampsia but not in the fetal circulation of preeclamptic pregnancies suggesting that based on the analysis of soluble adhesion molecules the fetal circulation may not be affected by the factor(s) that lead to disturbed endothelial cell function in women with preeclampsia.

Circulating endothelial cell adhesion molecules as diagnostic markers for the early identification of pregnant women at risk for development of preeclampsia

OBJECTIVE

The aim of the current study was to determine levels of circulating endothelial cell adhesion molecules during preeclampsia and to assess their predictive value as diagnostic markers for the early identification of pregnant women at risk of developing preeclampsia.

STUDY DESIGN

Plasma samples were obtained from women with preeclampsia; the syndrome of hemolysis, elevated liver enzymes, and low platelets; uncomplicated pregnancy-induced hypertension; and women with normal pregnancy. In addition, longitudinal plasma profiles of pregnant women were randomly collected to determine individual profiles of circulating endothelial cell adhesion molecules. A sandwich enzyme-linked immunosorbent assay technique was used to quantitate concentrations of soluble intercellular adhesion molecule-1 (CD54), vascular cell adhesion molecule-1 (CD106), E-selectin (CD62E), platelet endothelial cell adhesion molecule (CD31), and P-selectin (CD62P).

RESULTS

Plasma levels of intercellular adhesion molecule-1, vascular cell adhesion molecule-1, E-selectin, and platelet endothelial cell adhesion molecule-1 were significantly elevated in women with preeclampsia compared with healthy control pregnant women. Longitudinal analysis of soluble plasma intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 levels during pregnancy revealed that these molecules (1) show little variation in healthy pregnant women, (2) do not vary during normal pregnancy, and (3) are significantly elevated in women with preeclampsia and the syndrome of hemolysis, elevated liver enzymes, and low platelets compared with control pregnant women and those with uncomplicated pregnancy-induced hypertension. Analysis of soluble intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 levels in longitudinal profiles of pregnant women identified significantly elevated levels of these molecules in the plasma of preeclampsia-prone women 3 to 15 weeks before the onset of clinical symptoms.

CONCLUSION

Elevated soluble intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 measurements during pregnancy can be considered as major risk factors. Elevated levels of these substances in the plasma of pregnant women with preeclampsia support the concept of a primary endothelial cell involvement in the pathogenesis of preeclampsia. Although currently based on a limited database, significantly elevated levels of soluble intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 in the plasma of otherwise healthy pregnant women suggest a very high predictive value of these molecules for the earliest identification of women at risk of developing preeclampsia.