Markers for endothelial injury, clotting and platelet activation in preeclampsia

Platelet count in preeclampsia: a systematic review and meta-analysis

OBJECTIVE

Many studies have reported the association between platelets and preeclampsia. However, sample sizes were small, and their findings were inconsistent. We conducted a systematic review and meta-analysis to evaluate the association in pooled samples and in detail.

DATA SOURCES

A systematic literature search was performed using Medline, Embase, ScienceDirect, Web of Science, Cochrane Library, NICHD-DASH, LILACS, and Scopus from inception to April 22, 2022.

STUDY ELIGIBILITY CRITERIA

Observational studies comparing platelet count between women with preeclampsia and normotensive pregnant women were included.

METHODS

The mean differences with 95% confidence interval in platelet count were calculated. Heterogeneity was assessed using I2 statistics. Sensitivity and subgroup analyses were conducted. Statistical analysis was performed using RevMan 5.3 and ProMeta 3 software.

RESULTS

A total of 56 studies comprising 4892 preeclamptic and 9947 normotensive pregnant women were included. Meta-analysis showed that platelet count was significantly lower in women with preeclampsia than in normotensive controls (overall: mean difference, -32.83; 95% confidence interval, -40.13 to -25.52; P<.00001; I2=92%; mild preeclampsia: mean difference, -18.65; 95% confidence interval, -27.17 to -10.14; P<.00001; I2=84%; severe preeclampsia: mean difference, -42.61; 95% confidence interval, -57.53 to -27.68; P<.00001; I2=94%). Significantly lower platelet count was also observed in the second trimester (mean difference, -28.84; 95% confidence interval, -44.59 to -13.08; P=.0003; I2=93%), third trimester (mean difference, -40.67; 95% confidence interval, -52.14 to -29.20; P<.00001; I2=92%), and before the diagnosis of preeclampsia (mean difference, -18.81; 95% confidence interval, -29.98 to -7.64; P=.009; I2=87%), but not in the first trimester (mean difference, -15.14; 95% confidence interval, -37.71 to 7.43; P=.19; I2=71%). Overall, the pooled sensitivity and specificity of platelet count were 0.71 and 0.77, respectively. The area under the curve was 0.80.

CONCLUSION

This meta-analysis confirmed that platelet count was significantly lower in preeclamptic women, irrespective of severity and presence or absence of associated complications, even before the onset of preeclampsia and in the second trimester of pregnancy. Our findings suggest that platelet count may be a potential marker to identify and predict preeclampsia.

Bioinformatics-based identification of miRNA-, lncRNA-, and mRNA-associated ceRNA networks and potential biomarkers for preeclampsia

This study aimed to identify significantly altered long non-coding RNAs (lncRNAs), microRNAs (miRNAs), mRNAs, pathways in preeclampsia (PE), and to investigate their targeted relationships and biological functions.GSE96985 from Gene Expression Omnibus database was extracted, involving 3 PE and 4 normal tissues. After the differential expression analysis of miRNAs, lncRNAs, and mRNAs using the limma package, protein-protein interaction (PPI) network and module analyses were performed for differentially expressed mRNAs (dif-mRNAs). Combined with the miRanda and miRWalk tools, a regulatory relationship between dif-miRNAs and dif-mRNAs/lncRNAs (dif-mRNAs/dif-lncRNAs) was predicted. Finally, mRNA-miRNA-lncRNA regulatory network construction was performed using Cytoscape software.A total of 511 dif-mRNAs were screened in PE. The top 5 nodes in the PPI networks included up-regulated complement component 3 (C3), C-X-C motif chemokine ligand 8 (CXCL8), and fibronectin 1 (FN1). Three significant network modules were identified for dif-mRNAs. C3 and CXCL8 were identified in module A, and FN1 was identified in module C. A disintegrin and metalloproteinase with thrombospondin motifs 6 (ADAMTS6) was down-regulated by the miR-210-3p. Therefore, lnc-CTD-2383M3.1 functions as a competing endogenous RNA in ADAMTS6 expression regulation by competitively binding to miR-210-3p during the regulation process of PE.C3, CXCL8, FN1, and ADAMTS6 might be involved in the development of PE. The lnc-CTD-2383M3.1-miR-210-3p-ADAMTS6 axis might be a potential regulatory mechanism in PE.

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.

Early onset preeclampsia is associated with an elevated mean platelet volume (MPV) and a greater rise in MPV from time of booking compared with pregnant controls: results of the CAPE study

OBJECTIVE

To characterise Mean platelet volume (MPV) in patients with early onset preeclampsia (EOPE) and unaffected controls from time of first antenatal visit until the postpartum.

MATERIALS AND METHODS

Retrospective secondary analysis of an observational study in an Irish tertiary referral centre with 9000 deliveries annually. The MPV of 27 women with EOPE was compared to 19 unaffected controls. The inclusion criteria for the disease state was the development of EOPE defined by the National Institute for Health and Care Excellence (NICE) guideline, as new onset hypertension presenting after 20 weeks and prior to 34 weeks with significant proteinuria. Between October 2013 and July 2015 we recruited 27 women with EOPE and 19 pregnant controls. Statistical analysis was performed using paired T-test of Mann-Whitney test where appropriate and a P-value <0.05 was deemed significant.

RESULTS

At time of diagnosis and late in the third trimester MPV was significantly increased to 9.0 (±0.3) fL in cases of EOPE in comparison to 8.5 (±0.6) fL in normotensive controls (P<0.05). There was no significant difference during the first trimester or postpartum when comparing the MPV in EOPE to controls.

CONCLUSION

Despite an increased MPV at time of diagnosis of EOPE this study did not demonstrate a potential use for increased MPV as a first trimester screening tool.

Maternal ophthalmic artery Doppler velocimetry in pre-eclampsia in Southwestern Nigeria

BACKGROUND

Pre-eclampsia (PE) poses a serious challenge to maternal and fetal health in Africa. It is associated with hemodynamic changes that may affect the internal carotid/ophthalmic artery circulation with consequent neuro-ophthalmic manifestations. Ophthalmic artery Doppler (OAD) ultrasound is an important tool that can be used to detect hemodynamic changes in PE and monitor its severity. In this study, we evaluated hemodynamic changes on OAD ultrasound in the ophthalmic arteries of pre-eclamptic women and compared these with values in healthy pregnant women.

METHODS

OAD parameters, such as, peak systolic velocity, peak diastolic velocity, end diastolic velocity, pulsatility index, and peak ratio, were measured on transorbital triplex ultrasound scan with a 7-10 MHz multifrequency linear transducer in 42 consenting pre-eclamptic patients and 41 pregnant controls matched for maternal age, gestational age, and parity at the Department of Radiology, University College Hospital, Ibadan. Univariate, bivariate, and receiver operating characteristic curve data analyses were performed. P<0.05 was considered to be statistically significant.

RESULTS

Mean resistivity index, pulsatility index, and peak systolic velocity were significantly lower in pre-eclamptic patients than in the controls. Mean peak diastolic velocity, end diastolic velocity, and peak ratio were significantly higher in the pre-eclamptic group. The receiver operating characteristic curve showed that the resistivity index (sensitivity 75%, specificity 77.8%) could distinguish mild from severe PE while the peak ratio (sensitivity 90.5%, specificity 81.3%) could accurately detect PE.

CONCLUSION

OAD ultrasound can be used to monitor patients with PE for early detection of progression to severe forms before cerebral complications develop. OAD screening of patients at high risk for PE can also detect early changes of hemodynamic derangement.

Platelet distribution width (PDW): A putative marker for threatened preterm labour

Objective: To determine the alterations of mean platelet volume (MPV), platelet distribution width (PDW), platelet level and hemoglobin level in pregnancies with threatened preterm labor (TPL).

Methods: The retrospective analysis of 201 pregnant women with threatened preterm labour admitted to our clinic between 2009 and 2013 and 192 healthy pregnancies was conducted. The data regarding the maternal age, hemoglobin level, platelet count, mean platelet volume (MPV), platelet distribution width (PDW) was evaluated.

Results: The mean MPV and hemoglobin levels were significantly lower in TPL group (p=0.001 and p=0.01, respectively). PDW levels were significantly higher in TPL group (p=0.05). (p=0.01). Regarding the platelet count, there was no statistically significant difference between the TPL and control groups. ROC curve analysis for PDW revealed an area under curve (AUC) 66.8%. By using a cut-off value 16.15 for PDW, sensitivity was 76.1% and specificity was 43.5% for TPL.

Conclusion: MPV seems to be lower in threatened preterm deliveries, whereas PDW levels were increased suggesting the possible high grade inflammation and platelet activation in the pathology. Anemia occurs more frequently in threatened preterm delivery. Increased PDW levels especially > 16.15 may alert the obstetrician for the risk of the preterm delivery. However, further studies are needed to state the usefulness of the platelet indices in the diagnosis and clinical follow-up of preterm labor.

Uterine NK cells are critical in shaping DC immunogenic functions compatible with pregnancy progression

Dendritic cell (DC) and natural killer (NK) cell interactions are important for the regulation of innate and adaptive immunity, but their relevance during early pregnancy remains elusive. Using two different strategies to manipulate the frequency of NK cells and DC during gestation, we investigated their relative impact on the decidualization process and on angiogenic responses that characterize murine implantation. Manipulation of the frequency of NK cells, DC or both lead to a defective decidual response characterized by decreased proliferation and differentiation of stromal cells. Whereas no detrimental effects were evident upon expansion of DC, NK cell ablation in such expanded DC mice severely compromised decidual development and led to early pregnancy loss. Pregnancy failure in these mice was associated with an unbalanced production of anti-angiogenic signals and most notably, with increased expression of genes related to inflammation and immunogenic activation of DC. Thus, NK cells appear to play an important role counteracting potential anomalies raised by DC expansion and overactivity in the decidua, becoming critical for normal pregnancy progression.

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.

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.

Evaluation of natural coagulation inhibitor levels in various hypertensive states of pregnancy

OBJECTIVE

To evaluate the role of natural coagulation inhibitors in various classifications of pregnancy associated hypertension in Turkish population living in Trakya region of Turkey.

STUDY DESIGN

Serum uric acid levels, plasma protein C (PC), protein S (PS), antithrombin III (AT III) activities and activated protein C resistance (APCR) were measured in 80 pregnant women with hypertension (preeclampsia, n = 32; severe preeclampsia, n = 25; eclampsia, n = 14; chronic hypertension, n = 9) and 58 healthy pregnant women. Tukey and Tamhane multiple comparison tests, Kruskal-Wallis, chi2 and Fisher's exact tests were performed for comparison of means and/or medians.

RESULTS

Serum uric acid levels were significantly elevated in women with preeclampsia and severe preeclampsia, but PS activity decreased in women with severe preeclampsia (33.2 +/- 18.9% versus 50.4 +/- 22.7%, p = 0.015) and chronic hypertension (29.5 +/- 14.5% versus 50.4+ /- 22.7%, p = 0.045) compared to healthy controls. There was no significant difference in APCR, and PC or AT III activity between the groups. Platelet counts were significantly lower in women with severe preeclampsia, compared to controls and women with chronic hypertension.

CONCLUSION(S)

Serum uric acid levels and plasma protein S activity may be useful as indices of severity of pathology in pregnancy associated hypertension.

Mechanisms of Disease: pre-eclampsia

Pre-eclampsia, a syndrome of pregnant women, is one of the leading causes of maternal and fetal morbidity and mortality. Despite active research, the etiology of this disorder remains an enigma. Recent work has, however, provided promising explanations for the causation of the disorder and some of its phenotypes. Evidence indicates that the symptoms of hypertension and proteinuria, upon which the diagnosis of pre-eclampsia is based, have several underlying causes. Nevertheless, the treatment of pre-eclampsia has not changed significantly in over 50 years. This review describes the most recent insights into the pathophysiology of pre-eclampsia from both basic and clinical research, and attempts to provide a unifying hypothesis to reconcile the abnormalities at the feto-placental level and the clinical features of the maternal syndrome. The novel findings outlined in this review provide a rationale for potential future prophylactic and therapeutic interventions for pre-eclampsia.

The G20210A prothrombin-gene mutation and the plasminogen activator inhibitor (PAI-1) 5G/5G genotype are associated with early onset of severe preeclampsia

Hereditary risk determinants of venous thrombosis have been reported to be associated with severe preeclampsia. So far there are no data to support whether these risk determinants are related to the time of onset of severe preeclampsia. We used a case-control design, studying 97 women with severe preeclampsia in previous pregnancies and 277 normal women, to assess hereditary risk factors of venous thrombosis as risk determinants for severe preeclampsia. A case-only design comprising solely the 97 women with a history of preeclampsia was used to evaluate these risk factors as risk determinants for early onset of severe preeclampsia. Using the case-control design, there was no significant risk association of the hereditary risk factors with severe preeclampsia [factor V Leiden, odds ratio (OR) 0.9, 95% confidence interval (CI) 0.4, 2.2; prothrombin mutation, OR 1.9, 95% CI 0.5, 7.0; methylentetrahydrofolate reductase 677TT genotype, OR 0.8, 95% CI 0.4, 1.8; plasminogen activator inhibitor (PAI-1) 4G/4G genotype, OR 1.2, 95% CI 0.7, 2.1; PAI-1 5G/5G genotype, OR 1.0, 95% CI 0.5, 1.8]. However, the onset of severe preeclampsia was significantly earlier in women with the G20210A prothrombin gene mutation (24.5 weeks vs. 30.1 weeks, P = 0.046) and in women with the PAI-1 5G/5G genotype (25.7 weeks vs. 30.8 weeks, P = 0.024). Hereditary risk factors for venous thrombosis do not predispose for severe preeclampsia. However, women who are carriers of the G20210A prothrombin gene mutation and the PAI-1 5G/5G genotype are at risk for early onset of severe preeclampsia. It appears that these risk factors do not induce the pathomechanism but accelerate the course of preeclampsia.

Coagulation inhibitors in preeclamptic pregnant women

OBJECTIVE

Our objective was to detect clinical evaluation of coagulation inhibitors in preeclamptic and normotensive pregnant women and to determine their important role in pathogenesis of preeclampsia.

METHODS

A total of 20 mild, 20 severe preeclamptic and 45 normotensive pregnant women were included in this study. The plasma value of antithrombin III (AT-III) activity, proteins C and S activity, PT, PTT, fibrinogen and platelet counts were determined.

RESULTS

The values AT-III were lower in women with severe preeclampsia than in controls (p<0.05). In all groups, there was no significantly difference in the concentration of protein C activity, protein S and fibrinogen (p>0.05). The plasma thrombocyte counts were significantly lower in severe preeclamptic women than in normotensive women (p<0.05). There was no significant difference in the prothrombin time value in all groups, but a significantly difference with regard to partial thromboplastin time between severe preeclamptic and the control group (p<0.0001). It was longer than the control.

CONCLUSION

The markers of hemostasis activation such as protein S, protein C activity together with fibrinogen levels are not useful tools but the reduction of AT-III and platelet counts would seem useful in different pathological situations in pregnancy to predict and monitor the severity of the condition.

Changes in plasma endothelin-1 after elective cesarean section in women with preeclampsia and the relationship to thrombocytopenia

OBJECTIVE

The aim of this study was to clarify the time course of plasma endothelin-1 levels and platelet counts after elective cesarean section in women with preeclampsia, and to investigate the relationship between them postoperatively.

METHODS

We studied 20 patients with preeclampsia and 25 healthy pregnant women without preeclampsia who underwent cesarean section and 20 women without preeclampsia who had vaginal deliveries. The plasma endothelin-1 and platelet counts were measured serially after cesarean section.

RESULTS

1) In patients with preeclampsia, plasma endothelin-1 levels peaked on postoperative day 0 (p<0.05), and remained high, then fell to the preoperative level from day 5. The concentration was lower in healthy pregnant women undergoing cesarean section than in patients with preeclampsia before surgery, but showed a gradual significant increase from postoperative day 0 to postoperative day 3 (p<0.05) before falling. The women who underwent vaginal delivery showed a peak level of endothelin-1 on the day of delivery but this fell rapidly between day 3. 2) Women with preeclampsia showed a negative correlation between plasma endothelin-1 levels and platelet counts after cesarean section (r=0.46, p<0.01), while women without preeclampsia undergoing cesarean and vaginal deliveries did not.

CONCLUSION

Endothelin-1 production is stimulated after cesarean section, which is paralleled with postpartal thrombocytopenia only in patients with preeclampsia.

Prenatal screening, epidemiology, diagnosis, and management of preeclampsia

The cause of preeclampsia remains unknown. The disease manifests itself across a broad clinical spectrum from mild to severe, conferring vastly different morbidities and suggesting possibly different disease processes. Oxidative stress, endothelial dysfunction, maternal-fetal immune incompatibility, and abnormal placental implantation are among the suggested causes. The need for a marker or set of markers that allow for definitive diagnosis and assessment of future risk of preeclampsia is tremendous. Ultrasound techniques and several markers have been identified that are increased among patients with preeclampsia, but no test is highly sensitive. In the future, a combination of markers likely will be used to assess risk and, establish the diagnosis, and test treatment strategies. Such an approach would allow for more refined treatment studies of patients who are at highest risk for preeclampsia.

Pre-eclampsia: fluids, drugs, and anesthetic management

Severe pre-eclampsia is a complex disease, which taxes the expertise of even the most experienced obstetric anesthesiologist. The treatment should focus on stabilization of blood pressure, optimization of fluid status, and prevention of convulsions. Neuraxial blocks for labor and delivery offer many benefits to the mother and her infant. For cesarean section, there is unequivocal evidence of superiority of neuraxial anesthesia over general anesthesia. If general anesthesia is needed, careful preanesthetic preparation and meticulous airway management is essential. The successful and safe peripartum management of the pre-eclamptic patient and her infant is a team effort among the anesthesiologist, obstetrician, and neonatologist.

Preeclampsia. Part 1: clinical and pathophysiologic considerations

Preeclampsia-eclampsia is still one of the leading causes of maternal and fetal morbidity and mortality. Despite active research for many years, the etiology of this disorder exclusive to human pregnancy is an enigma. Recent evidence suggests there may be several underlying causes or predispositions leading to the signs of hypertension, proteinuria, and edema, findings that allow us to make the diagnosis of the "syndrome" of preeclampsia. Despite improved prenatal care, severe preeclampsia and eclampsia still occur. Although understanding of the pathophysiology of these disorders has improved, treatment has not changed significantly in over 50 years. Although postponement of delivery in selected women with severe preeclampsia improves fetal outcome to a degree, this is not done without risk to the mother. In the United States, magnesium sulfate and hydralazine are the most commonly used medications for seizure prophylaxis and hypertension in the intrapartum period. The search for the underlying cause of this disorder and for a clinical marker to predict those women who will develop preeclampsia-eclampsia is ongoing, with its prevention the ultimate goal. This review begins with the clinical and pathophysiologic aspects of preeclampsia-eclampsia (Part 1). In Part 2, the experimental observations, the search for predictive factors, and the genetics of this disorder will be reviewed.

Evidence of in vivo generation of thrombin in patients with small-for-gestational-age fetuses and pre-eclampsia

OBJECTIVE

Thrombotic lesions in the maternal or fetal compartments are frequently observed in the placentas of patients with small-for-gestational-age (SGA) fetuses and in pre-eclampsia. The objective of this study was to determine whether there was evidence of in vivo generation of thrombin, the rate-limiting enzyme responsible for the formation of fibrin. The plasma concentrations of thrombin-antithrombin (TAT) complexes were used as an index of thrombin generation.

METHODS

TAT complexes were measured in the plasma from 68 women from the following groups: normal pregnancy (n = 29); pre-eclampsia (n = 26); and SGA (defined as estimated fetal weight below the 10th centile for gestational age, which was confirmed by neonatal birth weight) (n = 13). TAT complex plasma concentrations were determined with a specific and sensitive immunoassay. Statistical analysis was performed with non-parametric statistics.

RESULTS

The median plasma TAT complex concentrations were significantly higher in patients who delivered SGA neonates than in normal pregnant women (SGA, median 24.2 microg/l; range 11.9-788.7 vs. normal pregnancy, median: 14.4 microg/l; range 6.8-26.9; p = 0.001). Patients with pre-eclampsia had a higher median plasma TAT complex concentration than normal pregnant women (pre-eclampsia, median 18.1 microg/l; range 10.0-75.2 vs. normal pregnancy, median 14.4 microg/l; range 6.8-26.9; p = 0.02).

CONCLUSION

In vivo generation of thrombin, determined by the plasma concentrations of TAT complexes, is higher in patients with SGA fetuses and patients with pre-eclampsia than in normal pregnancy.

Predictive markers of pre-eclampsia in hypertensive disorders of pregnancy

OBJECTIVE

The aim of this work is to assess the most widespread methods currently proposed and two new markers for predicting the development of pre-eclampsia in pregnant women with hypertension.

METHODS

The study involved 212 pregnant Caucasian women: 104 normotensive, 68 pregnancy-induced hypertensive and 40 chronic hypertensive. Blood and urine were sampled between 28 and 30 weeks gestation. All 108 hypertensive pregnant women, at the time of sampling, demonstrated proteinuria below 0.3 g/24 h. The following laboratory tests were performed: fibronectin, antithrombin-III, alpha-1-microglobulin, U-N-acetyl-beta-glucosaminidase, uric acid and albumin excretion rate. Student's t-test, discriminant analysis and chi2 (chi-square) test were used as statistical methods. A P value less than 0.05 was considered significant.

RESULTS

After discriminating analysis, only three of the six variables analyzed were able to discriminate patients who would develop pre-eclampsia from the remaining hypertensive pregnant women: microalbuminuria, uric acid and fibronectin (chi2 = 29.122, P < 0.01).

CONCLUSIONS

In agreement with previous studies, albumin excretion rate appeared to be the best predictive test for pre-eclampsia in hypertensive pregnant women, giving a higher positive predictive value and specificity (87.5 and 98.9%, respectively).

Prediction of preeclampsia

The onset of preeclampsia at or near to term is associated with low maternal and neonatal morbidity and mortality. In contrast, those patients (1%) who suffer early onset preeclampsia engender significant maternal and perinatal morbidity and mortality. Therefore, because of the lack of proven prophylaxis for preeclampsia, prediction of risk or identification of subclinical disease is desirable to identify patients for more intensive observation. There are certain at-risk groups of patients such as those with chronic hypertension, pregestational diabetes, multifetal gestation, and previous preeclampsia. These patients account for the majority of cases of preeclampsia in multiparas, yet only account for 14% of preeclampsia in nulliparous women. Thus, the majority of cases of preeclampsia arises from nulliparous women without medical complications at low risk. Differences in the time of onset, severity, and organ system involvement suggest there may be different underlying etiologies that ultimately lead to preeclampsia manifested as the triad of maternal hypertension, proteinuria, and edema. Distinct markers therefore may identify subgroups of at-risk patients with separate underlying causes. These markers ultimately could be used for diagnosis of disease before the clinical appearance of maternal disease (hypertension, proteinuria, and edema). Based on data from patients with established disease, with the involvement of various organ systems, potential candidate markers would include renal function (kallikrein-creatinine); coagulation and fibrinolytic systems and platelet activation (platelet volume); markers of vascular function (fibronectin, prostacyclin, thromboxane) and oxidant stress (lipid peroxides, 8-isoprostane, antioxidants, anticardiolipin antibodies, hemoglobin, iron, transferrin, homocysteine, hypertriglyceridemia, albumin isoforms); placental peptide hormones (CRH, CRHbp, activin, inhibin, hCG); vascular resistance (uteroplacental flow velocity waveforms); genetic markers; insulin resistance; and glucose intolerance. Although cross-sectional studies have identified these potential markers, they need to be evaluated in prospective longitudinal studies with rigorous definition of outcome to determine if they are useful in predicting preeclampsia and whether they can identify different subgroups of patients.

Endothelial adhesion molecules and leukocyte integrins in preeclamptic patients

Endothelial cell activation is important in the pathogenesis of preeclampsia; however, the nature of the activation is unknown. We investigated 22 patients with preeclampsia. 29 normotensive pregnancies, and 18 nonpregnant women to test the hypothesis that serum from preeclamptic patients induces expression of intercellular adhesion molecule-1 (ICAM-1) and vascular adhesion molecule-1 (VCAM-1) and stimulates intracellular free calcium concentrations [Ca2+]i in cultured endothelial cells. We then asked whether the corresponding integrin adhesive counter receptors lymphocyte function-associated antigen-1 (CD11a/CD18), macrophage-1 antigen (CD11b/CD18), p150,95 (CD11c/CD18), and very late activation antigen-4 (CD49/CD29) are increased in patients with preeclampsia. In the pregnant women, the measurements were conducted both before and after delivery. Integrin expression was measured by fluorescent antibody cell sorting analysis using monoclonal antibodies. ICAM-1 and VCAM-1 were analyzed on endothelial cells by enzyme-linked immunosorbent assay. [Ca2+]i was measured with fura 2. Serum from preeclamptic patients increased endothelial cell ICAM-1 expression but not VCAM-1 expression. Preeclamptic patients' serum also increased [Ca2+]i in endothelial cells compared with serum from normal nonpregnant or normal pregnant women. Endothelial cell [Ca2+]i concentrations were correlated with the ICAM-1 expression in preeclamptic patients (r = .80, P < .001) before but not after delivery. Expression of the integrin counter receptors on leukocytes was similarly increased in preclampsia and normal pregnancy compared with the nonpregnant state. The expression decreased significantly after delivery in both groups. Our results demonstrate that serum from preeclamptic women induces increased ICAM-1 surface expression on endothelial cells, while the expression of the integrin counterreceptors was not different. The effect on endothelial cells may be related to an increase in [Ca2+]i. The effect on cultured endothelial cells and the rapid decrease after delivery suggests the presence of a circulating serum factor which increases endothelial cell [Ca2+]i and enhances adhesion molecule expression.

Fibronectin and antithrombin as markers of pre-eclampsia in pregnancy

INTRODUCTION

The differential diagnosis between pre-eclampsia and chronic hypertension is not easy, but is essential to proper management of a pregnancy. Patients presenting pre-pregnancy hypertension can be treated conservatively, if not a superimposed pre-eclampsia occurs, controlling pressure pharmacologically and completing the pregnancy with a natural delivery. In pre-eclampsia, hypertension is merely the visible sign of a process of endothelial damage and coagulation cascade activation which is often destined to emerge clinically on a dramatic scale.

MATERIALS AND METHODS

The study involved 18 women with physiological pregnancies, 19 with pre-eclampsia and 13 with chronic hypertension since superimposed pre-eclampsia. The following laboratory tests were performed: PT, PTT, AT-III, proteins C and S, platelet count, D-dimer, fibrinogen and plasma fibronectin. The three groups were compared using the Kruskall Wallis test, the median test and, for multiple comparisons, the Mann-Whitney test. A 'P' value of < 0.01 was considered as statistically significant.

RESULTS

The values for plasma fibronectin were higher in the pre-eclampsia group (410 mg/l (253-727)) than in controls (262 mg/l (183-385)) (P < 0.01) and values for AT-III were lower in the pre-eclampsia group (73% (40-100)) than in controls (93% (80-126) (P < 0.01) (Table 2). The groups with chronic hypertension revealed no such significant differences, however, in relation to the control group (fibronectin = 296 mg/l (198-530), AT-III = 86% (75-103)).

CONCLUSIONS

Measuring antithrombin and fibronectin to monitor any onset of pre-eclampsia can help the obstetrician to avoid important diagnostic and therapeutic errors.

Fibronectin fragments cause an underestimation of plasma fibronectin levels in severe pre-eclampsia

Elevated fibronectin (Fn) concentrations in plasma from pregnant women have been suggested to be predictive for the development of pre-eclampsia. However, reported correlations between Fn concentration with gestational age or disease severity appear to be confounded by several variables. Our finding of degradation products of Fn in plasma from patients with severe pre-eclampsia led to a study of whether their presence could influence immunological and functional measurements of intact plasma Fn. Plasma samples (10 control pregnant and 10 severe pre-eclampsia patients) were studied for the presence of intact Fn and fragments by SDS-PAGE and Western blotting. Percentages of immunoreactive Fn fragmentation in control plasma (9.37 +/- 6.7%) and severe pre-eclampsia plasma (62.57 +/- 7.0%) were determined by densitometric scanning. Immunoassays by ELISA were performed on normal plasma samples and on purified Fn in the absence or presence of plasma digests of pure Fn. Artefactual underestimations of Fn concentration occurred in the presence of Fn fragments. The percentage underestimation increased with increasing digestion times (1 h, 46.52 +/- 3.69%; 3 h, 77.5 +/- 7.18%; 4 h, 100%) and with increasing concentrations of Fn digest products (1h) added to normal plasma samples (n = 10) (40 micrograms, 23 +/- 8.1%; 125 micrograms, 36.33 +/- 5.1%; 250 micrograms, 43.66 +/- 6.5%). The underestimation of Fn concentration in the presence of Fn fragments suggests that ELISAs for Fn may be unreliable and thus lose their predictive value in these patients. Opsonic activities of control pregnant and severe pre-eclamptic plasma were determined by gelatin-latex agglutination assay. The ratios of opsonic activity to Fn concentration in plasma from patients with pre-eclampsia were significantly lower than those of control pregnant plasma samples (p < 0.008). The impaired gelatin-latex agglutination of Fn in pre-eclamptic plasma suggests that Fn fragmentation could have biological sequelae in vivo.

Coagulation and plasma fibronectin parameters in HELLP syndrome

OBJECTIVES

HELLP syndrome (hemolysis, elevated liver enzymes and low platelets) has a high fetal mortality and maternal morbidity, partly due to its late diagnosis. In order to facilitate earlier diagnosis, we studied the changes occurring in natural coagulation inhibitors, fibronectin and haptoglobin as potential early markers of endothelial damage, coagulation cascade activation and intravascular hemolysis.

METHODS

The study compared antithrombin (AT-III), protein C and S activity, plasma fibronectin, 'prothrombin time' and 'partial prothrombin time' (AST, ALT), lactate dehydrogenase (LDH), bilirubin and serum haptoglobin in 17 asymptomatic controls, 19 preeclampsia patients and 11 HELLP syndrome patients.

RESULTS

HELLP syndrome patients had higher fibronectin and D-dimer values, lower AT-III and protein C activity, a lower platelet count and higher LDH than healthy controls; only 25% had raised bilirubin. Serum haptoglobin was lower in HELLP syndrome.

CONCLUSIONS

Early on in HELLP syndrome, there is probably a pro-coagulatory imbalance in the placental microcirculation. Endothelial damage causes tissue thromboplastin release and coagulation cascade activation due to collagen exposure; the vascular lesion increases thromboplastin in the bloodstream and triggers distant coagulation processes, suggesting compensated disseminated intravascular coagulopathy. Measuring plasma fibronectin and coagulation inhibitors should be supported by testing haptoglobin as a marker of intravessel hemolysis to differentiate conventional preeclampsia from HELLP.

Clotting inhibitors and fibronectin as potential markers in preeclampsia

OBJECTIVES

As conventional laboratory tests fail to identify early preeclampsia, the aim of this study was to seek a marker of endothelial injury and select more sensitive tests for monitoring the activation of the coagulation cascade.

METHODS

Using routine blood sampling methods, PT, PTT, AT-III, proteins C and S, platelets, fibrinogen and fibronectin were measured in 18 preeclamptic patients and 17 controls with a normal pregnancy.

RESULTS

Preeclampsia was associated with higher fibronectin and lower AT-III, protein C and protein S. The platelet count, fibrinogen and PT were similar. PTT was longer in preeclampsia.

CONCLUSION

As AT-III revealed compensated coagulopathy and fibronectin demonstrated preeclamptic vascular lesions before these were apparent from routine tests, measuring these elements could contribute to the earlier diagnosis and better treatment of chronically-altered coagulation in preeclampsia.

Hemostasis and diagnosis of preeclampsia

The diagnosis of preeclampsia, with all of its consequences, is at times difficult to establish, especially when the patient has underlying chronic hypertension and is not known from prior prenatal care visits. Many screening tests have been proposed. These should be sensitive, relatively specific, easy to perform, of low cost, and have a reasonable interval from prediction to disease onset. Laboratory assays would obviously be useful. We evaluated hemostasis tests for the diagnosis of preeclampsia, and compared fibronectin, antithrombin III and alpha 2-antiplasmin in 48 preeclamptics and 86 control nulliparas. Receive operator characteristic (ROC) curve analysis suggested that fibronectin is the most effective of these tests. A similar analysis comparing the results of previous studies using serum iron, angiotensin infusion, urinary calcium/creatinine ratio, the rollover test and uric acid suggested a possible role for fibronectin in the diagnosis of preeclampsia. While not ideal, there seems to be, at present, no other, easy to perform laboratory test that outperforms fibronectin in predicting preeclampsia.