Thrombomodulin, von Willebrand factor and E-selectin as plasma markers of endothelial damage/dysfunction and activation in pregnancy induced hypertension

Alterations in the von Willebrand factor/ADAMTS-13 axis in preeclampsia

BACKGROUND

Preeclampsia is a gestational hypertensive disorder characterized by maternal endothelial activation and increased ratio of soluble fms-like tyrosine kinase-1 (sFlt-1) inhibitor to placental growth factor (PlGF). The von Willebrand factor (VWF)/ADAMTS-13 axis is of interest because of the underlying endothelial activation and clinical overlap with pregnancy-associated thrombotic thrombocytopenic purpura.

OBJECTIVES

To assess VWF, ADAMTS-13, and VWF/ADAMTS-13 ratio in preeclampsia and look for associations with sFlt-1/PlGF ratio and clinical features.

METHODS

Thirty-four preeclampsia cases and 48 normal pregnancies were assessed in a case-control study. Twelve normal pregnancies in women with a history of preeclampsia formed an additional comparator group. VWF antigen (VWF:Ag) and VWF activity (VWF:Ac [VWF:glycoprotein IbM]) were measured via automated immunoturbidimetric assay, ADAMTS-13 activity was measured via fluorescence resonance energy transfer-VWF73 assay, and sFlt-1 and PlGF were measured via enzyme-linked immunosorbent assay.

RESULTS

VWF:Ag was higher in preeclampsia than in normal pregnancy (median, 3.07 vs 1.87 IU/mL; P < .0001). ADAMTS-13 activity was slightly lower (median, 89.6 vs 94.4 IU/dL; P = .02), with no severe deficiencies. Significant elevations in VWF:Ac were not observed in preeclampsia, resulting in reduced VWF:Ac/VWF:Ag ratios (median, 0.77 vs 0.97; P < .0001). VWF:Ag/ADAMTS-13 ratios were significantly higher in preeclampsia (median, 3.42 vs 2.06; P < .0001), with an adjusted odds ratio of 19.2 for a ratio of >2.7 (>75th centile of normal pregnancy). Those with a history of preeclampsia had similar ratios to normal pregnant controls. VWF:Ag/ADAMTS-13 and sFlt-1/PlGF were not correlated. However, percentage reduction in platelets correlated positively with VWF:Ac (P = .01), VWF:Ac/VWF:Ag ratio (P = .004), and sFlt-1/PlGF ratio (P = .01).

CONCLUSION

The VWF/ADAMTS-13 axis is significantly altered in preeclampsia. Further investigation of potential clinical utility is warranted.

Decreased Levels of Soluble Developmental Endothelial Locus-1 Are Associated with Thrombotic Microangiopathy in Pregnancy

HELLP (Hemolysis, Elevated Liver enzymes and Low Platelets) syndrome is a life-threatening complication of pregnancy, which is often secondary to preeclampsia. To date, there is no biomarker in clinical use for the early stratification of women with preeclampsia who are under increased risk of HELLP syndrome. Herein, we show that the levels of circulating developmental endothelial locus-1 (DEL-1), which is an extracellular immunomodulatory protein, are decreased in patients with HELLP syndrome compared to preeclampsia. DEL-1 levels are also negatively correlated with the circulating levels of kidney injury molecule-1 (KIM-1), which is a biomarker for disorders associated with kidney damage. Receiver-operating characteristic curve analysis for DEL-1 levels and the DEL-1 to KIM-1 ratio demonstrates that these values could be used as a potential biomarker that distinguishes patients with HELLP syndrome and preeclampsia. Finally, we show that placental endothelial cells are a source for DEL-1, and that the expression of this protein in placenta from patients with HELLP syndrome is minimal. Taken together, this study shows that DEL-1 is downregulated in HELLP syndrome both in the circulation and at the affected placental tissue, suggesting a potential role for this protein as a biomarker, which must be further evaluated.

A novel role of kallikrein-related peptidase 8 in the pathogenesis of diabetic cardiac fibrosis

Rationale: Among all the diabetic complications, diabetic cardiomyopathy, which is characterized by myocyte loss and myocardial fibrosis, is the leading cause of mortality and morbidity in diabetic patients. Tissue kallikrein-related peptidases (KLKs) are secreted serine proteases, that have distinct and overlapping roles in the pathogenesis of cardiovascular diseases. However, whether KLKs are involved in the development of diabetic cardiomyopathy remains unknown.The present study aimed to determine the role of a specific KLK in the initiation of endothelial-to-mesenchymal transition (EndMT) during the pathogenesis of diabetic cardiomyopathy.

Methods and Results-By screening gene expression profiles of KLKs, it was found that KLK8 was highly induced in the myocardium of mice with streptozotocin-induced diabetes. KLK8 deficiency attenuated diabetic cardiac fibrosis, and rescued the impaired cardiac function in diabetic mice. Small interfering RNA (siRNA)-mediated KLK8 knockdown significantly attenuated high glucose-induced endothelial damage and EndMT in human coronary artery endothelial cells (HCAECs). Diabetes-induced endothelial injury and cardiac EndMT were significantly alleviated in KLK8-deficient mice. In addition, transgenic overexpression of KLK8 led to interstitial and perivascular cardiac fibrosis, endothelial injury and EndMT in the heart. Adenovirus-mediated overexpression of KLK8 (Ad-KLK8) resulted in increases in endothelial cell damage, permeability and transforming growth factor (TGF)-β1 release in HCAECs. KLK8 overexpression also induced EndMT in HCAECs, which was alleviated by a TGF-β1-neutralizing antibody. A specificity protein-1 (Sp-1) consensus site was identified in the human KLK8 promoter and was found to mediate the high glucose-induced KLK8 expression. Mechanistically, it was identified that the vascular endothelial (VE)-cadherin/plakoglobin complex may associate with KLK8 in HCAECs. KLK8 cleaved the VE-cadherin extracellular domain, thus promoting plakoglobin nuclear translocation. Plakoglobin was required for KLK8-induced EndMT by cooperating with p53. KLK8 overexpression led to plakoglobin-dependent association of p53 with hypoxia inducible factor (HIF)-1α, which further enhanced the transactivation effect of HIF-1α on the TGF-β1 promoter. KLK8 also induced the binding of p53 with Smad3, subsequently promoting pro-EndMT reprogramming via the TGF-β1/Smad signaling pathway in HCAECs. The in vitro and in vivo findings further demonstrated that high glucose may promote plakoglobin-dependent cooperation of p53 with HIF-1α and Smad3, subsequently increasing the expression of TGF-β1 and the pro-EndMT target genes of the TGF-β1/Smad signaling pathway in a KLK8-dependent manner.

Conclusions: The present findings uncovered a novel pro-EndMT mechanism during the pathogenesis of diabetic cardiac fibrosis via the upregulation of KLK8, and may contribute to the development of future KLK8-based therapeutic strategies for diabetic cardiomyopathy.

Circulating endothelial cells, circulating endothelial progenitor cells, and von Willebrand factor in pregnancies complicated by hypertensive disorders

PROBLEM

We tested the hypothesis that the number of both CECs and CEPCs as well as the vWf blood plasma concentration are altered in pregnant women with hypertensive disorders.

METHOD OF STUDY

Seventy-five pregnant women were enrolled in our study. We used multicolor flow cytometry for CEC and CEPC analysis and the commercial human VWF ELISA kit to measure vWf blood plasma concentration.

RESULTS

The highest number of CECs was found in the chronic hypertension group and the lowest number in the healthy pregnant control group. The highest number of CEPCs was found in the control group and the lowest number in the chronic hypertension group. The vWf blood plasma concentration was the highest in the pre-eclampsia group. The CEPC/CEC ratio reached its lowest value in the chronic hypertension group and its highest value in the control group.

CONCLUSION

The number of both CECs and CEPCs as well as the vWf blood plasma concentration depends on the type of hypertension complicating the pregnancy.

Is there any relationship between adipocytokines and angiogenesis factors to address endothelial dysfunction and platelet aggregation in untreated patients with preeclampsia?

PURPOSE

Preeclampsia is a multisystem disorder and its etiology remains still unclear. Recent hypotheses rely on imbalance between angiogenic and antiangiogenic factors and disruption of endothelial function of spiral arteries. In addition; increased VTE (venous thromboembolism) risk is still unclear in preeclampsia. Our aim was to investigate the relationship between endothelial dysfunction, adipocytokines, platelet function, and vasculogenesis in preeclampsia.

METHODS

Plasma angiogenic (PlGF, VEGF), antiangiogenic factors (sflt-1, endoglin) with adipocytokines (leptin, adiponectin, ghrelin), endothelial dysfunction markers (vWF, NO), and platelet function markers (ADP and collagen induced platelet aggregation, P-selectin) were examined in 30 early-onset, 22 late-onset preeclampsia, and 27 healthy pregnants. Enzyme-linked immunosorbent assay (ELISA) was used to determine the serum biomarker levels except NO. NO levels were determined using colorimetric method.

RESULTS

Endoglin, leptin, and vWF levels were increased in preeclampsia (P < 0.001), whereas PlGF, P-selectin (P < 0.001), and col-induced platelet aggregation slope (P < 0.05) were decreased in the same counterpart as compared to healthy pregnants. Endoglin also correlated with sflt-1 in preeclamptic patients.

CONCLUSION

Increase in the levels of antiangiogenic factors and leptin herewith decline in the level of other angiogenic factor PlGF, did not affect nitric oxide and platelet aggregation markers significantly. Increased levels of vWF and endoglin might be result of endothelial dysfunction, so our findings suggest that an impaired angiogenesis may address endothelial dysfunction, but not platelet aggregation for preeclampsia.

Donkin psychosis

Donkin psychoses are eclamptic psychoses without seizures. As symptomatic psychoses resulting from cerebral endothelial damage, they may explain the lucid intervals that sometimes occur between eclampsia and the eruption of psychosis. They have the same features as eclamptic psychoses, with onset during pregnancy or the early puerperium, especially in first-time mothers, a short duration and full recovery in most. The clinical picture is usually delirium, but mania is also seen, and some patients have retrograde amnesia or other cognitive defects. Donkin psychosis should be considered in the differential diagnosis of childbearing psychoses, and collaborative research is needed to clarify their differences.

Increased VWF antigen levels and decreased ADAMTS13 activity in preeclampsia

This study aimed to assess the von Willebrand factor (VWF) antigen levels and its proteolytic enzyme ADAMTS13 activity in preeclampsia. The study includes 10 non-pregnant women, 50 normal pregnancy, and 110 preeclamptic (PE) women at the same period of pregnancy. For all studied groups plasma ADAMTS13 activities were determined with the FRETs-VWF 73 assay, while VWF antigen levels with an immunoturbometric assay. The plasma ADAMTS13 activity was significantly reduced in PE as compared with normal pregnancy and non-pregnant women (P < 0.01 for both). In contrast, plasma VWF antigen and VWF RCO were significantly elevated in PE, as compared with normal pregnancy group as well as non-pregnant women (P < 0.01 for both). In conclusion, reduction of plasma ADAMTS13 and elevation in VWF might have a role in the pathogenesis of PE.

Maternal ABO blood group and adverse pregnancy outcomes

OBJECTIVE

To determine the relationship between maternal ABO blood group and risk of adverse pregnancy outcomes.

STUDY DESIGN

Data on ABO phenotypes and pregnancy outcomes were collected from medical records of 5320 singleton pregnant women who had ABO blood testing and follow-up care until delivery in our institution. Adverse pregnancy outcomes that were studied in relation to maternal blood group included preeclampsia, gestational diabetes mellitus (GDM), preterm delivery, low birth weight (LBW) and small for gestational age (SGA) infants.

RESULT

Out of 5320 women, 350 (6.6%), 333 (6.3%) and 543 (10.2%) women were diagnosed with preeclampsia, GDM and preterm delivery, respectively. LBW and SGA were, respectively, observed in 394 (7.4%) and 178 (3.3%) infants. By uni- and multivariable analyses, women with A or AB blood types, but not B, were found at increased risk of preeclampsia compared with O type individuals; adjusted relative risks were 1.7 (95% confidence interval (CI), 1.3 to 2.3; P=0.001) for A phenotype and 1.7 (95% CI, 1.1 to 2.6; P=0.01) for AB phenotype. There were no significant relationships between blood types and GDM, preterm delivery, LBW or SGA.

CONCLUSION

Maternal ABO blood group was associated with the risk of preeclampsia, but not with GDM, preterm delivery, LBW or SGA.

Preeclampsia serum upregulates CD40/CD40L expression and induces apoptosis in human umbilical cord endothelial cells

BACKGROUND

The endothelial cell dysfunction observed in preeclampsia (PE) may be induced by CD40/CD40L signaling. This study investigated the role of CD40/CD40L in the pathogenesis of PE by comparing the effect of maternal serum obtained from healthy pregnant women and PE patients on HUVEC cell growth, apoptosis and CD40/CD40L expression.

METHODS

Maternal serum was obtained from 20 patients with PE (PE group) as well as 20 healthy pregnant women (control group). The human umbilical endothelial cell line, CRL1730, was cultured in the presence of maternal serum for 24, 48, and 72 h after which cell growth and apoptosis were assessed by MTT and flow cytometry analysis, respectively. CD40/CD40L expression was determined using flow cytometry and RT-PCR analyses.

RESULTS

As compared to CRL1730 cells treated with control sera, those treated with PE sera had altered morphology, decreased cell growth, increased apoptosis and greater CD40/CD40L protein and mRNA expression. Stimulation of CD40/CD40L protein and mRNA expression by PE sera was greatest at 24 h.

CONCLUSIONS

PE sera may induce endothelial cell damage possibly through increased CD40/CD40L expression in early-onset PE. Further studies are necessary to determine the factor(s) in PE sera responsible for the observed changes in endothelial cell viability.

Von Willebrand factor, ADAMTS13 activity, TNF-α and their relationships in patients with chronic kidney disease

Patients with chronic kidney disease (CKD) often exhibit associated endothelial dysfunction and inflammation. Systemic inflammation may contribute to the endothelial dysfunction and accelerated thrombosis observed in CKD patients. In this study, we assessed the relationships among endothelial dysfunction, a disintegrin-like and metalloprotease with thrombospondin type 1 repeats 13 (ADAMTS13) activity and levels of inflammatory cytokines in CKD patients. CKD patients were classified into three groups: The chronic glomerulonephritis group (CGN; n=31), the idiopathic nephritic syndrome group (NS; n=32) and the lupus nephritis group (LN; n=41). We measured the plasma levels of tumor necrosis factor-α (TNF-α), von Willebrand factor (VWF) antigen (VWF:Ag) and ADAMTS13 activity using an ELISA-based method in CKD patients (n=104) and normal controls (n=32). The ratio of the VWF:Ag levels to ADAMTS13 activity was calculated. The VWF:Ag levels were significantly higher and the ADAMTS13 activities were significantly lower in the disease groups compared to the controls (P<0.01). ADAMTS13 activity was lower in the NS group compared to the CGN and LN groups (P<0.05). The TNF-α levels were higher in the CKD group compared to the control group (P<0.01). TNF-α was positively correlated with the VWF:Ag levels (r=0.242, P=0.013) and negatively correlated with the glomerular filtration rate (GFR) (r=-0.193, P=0.049). ADAMTS13 activity was negatively correlated with the cholesterol levels in CKD patients (r=-0.2, P= 0.042). TNF-α levels in CKD were positively correlated with the VWF:Ag levels and negatively correlated with GFR, which indicates that inflammation may be a major cause of endothelial dysfunction and an index of renal function. The VWF:Ag levels increased and ADAMTS13 activity decreased in CKD patients, which indicates that CKD leads to a prothrombotic state.

Changes in coagulation and hemodynamics during pregnancy: a prospective longitudinal study of 58 cases

PURPOSE

To investigate changes and establish reference values in coagulation, anticoagulation, fibrinolysis, anti-fibrinolysis and hemodynamics during normal pregnancy.

METHODS

A total of 58 women with singleton pregnancies were recruited. Blood and ultrasound examinations were performed in the 10th-14th, 20th-24th, and 30th-34th weeks of pregnancy. The same examinations were performed in 50 non-pregnant women who were selected as the control group.

RESULTS

Levels of fibrinogen, thrombin time, fibronectin, prothrombin activated fragments 1+2 and thrombomodulin were higher in early pregnancy than those in the control group (P < 0.05). Fibrinogen, prothrombin time, activated partial thromboplastin time, thrombin time, thromboxane B2, prothrombin activated fragments 1+2, thrombomodulin, D-dimer, and plasminogen activator inhibitor-2 were statistically different between the mid pregnancy and the control group (P < 0.05). Meanwhile, fibrinogen, prothrombin time, activated partial thromboplastin time, thrombin time, fibronectin, thromboxane B2, prothrombin activated fragments 1+2, thrombomodulin, and plasminogen activator inhibitor-2 were obviously elevated in late pregnancy as compared with the control group (P < 0.05). Moreover, fibrinogen, thromboxane B2, prothrombin activated fragment 1+2, D-dimer plasminogen, and activator inhibitor-2 gradually increased during pregnancy with some fluctuation. Prothrombin time, activated partial thromboplastin time, thrombin time, international normalized ratio, and thrombomodulin as well as systolic/diastolic ratio, pulsatility index, and resistance index in uterine arteries showed a tendency to decrease in pregnant women.

CONCLUSIONS

Coagulation, anti-coagulation, fibrinolytic and anti-fibrinolytic activities are enhanced and balanced at a higher level during pregnancy. In addition, uterine artery and umbilical artery hemodynamics become more baby friendly (i.e., high flow and low resistance).

Immunohistochemical expression of von Willebrand factor in the preeclamptic placenta

Preeclampsia is a high-prevalence systemic pregnancy disorder associated with maternal and foetal mortality. Its pathogenesis is unknown, but it is thought that oxidative stress and endothelial dysfunction may play a fundamental role. Von Willebrand factor (vWF), a marker of endothelial cell injury, can be found in different cells and zones of the placenta. To determine the differential immunoexpression of vWF at different tissue types of preeclamptic placenta and endothelial dysfunction markers at maternal serum of preeclamptic pregnancies. A case-control study was performed on a population of pregnant women with preeclampsia (n = 14), and normal pregnancies (n = 8). Placental and blood plasma samples were withdrawn at delivery. Immunohistochemical vWF expression in the placental tissue was determined. Endothelial dysfunction was assessed through plasminogen activator inhibitor (PAI) 1 and 2 ratio and vWF concentration in maternal plasma. P values less than 0.05 were considered statistically significant. Preeclamptic women showed increased plasma PAI-1/PAI-2 ratio (P < 0.05). There was diminished placental vWF expression in syncytiotrophoblast and increased in the intervillous space of preeclamptic placentas (P < 0.05). No significant differences in vWF expression were found in the villous endothelium and stroma, but it was significantly higher in maternal plasma (P < 0.05). In preeclampsia occurs endothelial damage and placental cell injury. Cell damage in syncytiotrophoblast that occurs in preeclampsia could liberate vWF from syncytiotrophoblast to the placental intervillous space, and this may have pathogenic implications.

Angiogenin and hemoxygenase in pregnancy: influence of hypertension

The pathophysiology of hypertension and preeclampsia involves angiogenesis and endothelial damage/dysfunction, as shown by abnormal growth factors (vascular endothelial growth factor [VEGF], and its receptor sFlt-1) and von Willebrand factor (vWf) in the plasma. Angiogenin and hemoxygenase are abnormal in hypertension and angiogenesis but data on pregnancy are scant. We hypothesized altered angiogenin and hemoxygenase in 38 hypertensive pregnant women (HTPW) compared to 38 normotensive pregnant women (NTPW) and 50 nonpregnant controls (NonPCs). Plasma markers were measured by enzyme-linked immunosorbent assay (ELISA). Hypertensive pregnant women had lower VEGF than NonPCs (P < .01), vWf was raised in both pregnant groups (P < .01), but sFlt-1 was no different. Both angiogenin and hemoxygenase were lower in NTPW compared to NonPCs (both p<0.02). In both pregnancy groups, angiogenin correlated with vWf (r > .33, P < .05), but in NonPCs this was not significant (r = .13, P = .367). These changes may reflect differences in endothelial cell physiology and pathology in the hypertension in pregnancy.

Endothelial dysfunction in hypertension in pregnancy: associations between circulating endothelial cells, circulating progenitor cells and plasma von Willebrand factor

BACKGROUND

Endothelial damage/dysfunction has been related to hypertension in pregnancy, with implications in pregnancy outcomes. We hypothesised abnormal levels of circulating endothelial cells (CECs), circulating progenitor cells (CPCs) and plasma von Willebrand factor (vWf, a marker of endothelial damage/dysfunction) in pregnant women with hypertension, when compared to pregnant normotensives and non pregnant healthy controls.

METHODS

Our study groups were 3rd trimester hypertensive pregnant women, 40 age matched normotensive pregnant women and 50 non pregnant healthy controls. CECs were measured by immunomagnetic separation using anti-CD146 monoclonal antibody coated beads. CPCs were defined using flow cytometry as CD133+/CD34+/CD45-. vWf was measured by ELISA.

RESULTS

Hypertensive pregnant women had significantly higher CECs compared to normotensive pregnant women and non pregnant healthy controls (p < 0.001). CPCs were raised in the normotensive pregnant group compared with hypertensive pregnant and non pregnant healthy controls (p < 0.05). Both pregnant women groups had significantly higher vWF than the non pregnant controls. CEC levels correlated with both systolic and diastolic BP (r = 0.28, p < 0.005 and r = 0.31, p < 0.001, respectively). vWf correlated with CECs (r = 0.39, p < 0.0001). Multiple linear regression analysis revealed hypertension in pregnancy as an independent predictor of CEC levels (p < 0.0001).

CONCLUSIONS

Hypertension in pregnancy is characterised by abnormalities in the vascular endothelium, with abnormal CECs and vWf that correlate with BPs. This may reflect dysfunctional processes that are counteracted with reparative attempts at restoring endothelial integrity.

Soluble FLT1 sensitizes endothelial cells to inflammatory cytokines by antagonizing VEGF receptor-mediated signalling

Aims

Pre-eclampsia affects 5–7% of pregnancies, and is a major cause of maternal and foetal death. Elevated serum levels of placentally derived splice variants of the vascular endothelial growth factor (VEGF) receptor, soluble fms-like tyrosine kinase-1 (sFLT1), are strongly implicated in the pathogenesis but, as yet, no underlying mechanism has been described. An excessive inflammatory-like response is thought to contribute to the maternal endothelial cell dysfunction that characterizes pre-eclampsia. We hypothesized that sFLT1 antagonizes autocrine VEGF-A signalling, rendering endothelial cells more sensitive to pro-inflammatory factors also released by the placenta. We tested this by manipulating VEGF receptor signalling and treating endothelial cells with low doses of tumour necrosis factor-α (TNF-α).

Methods and results

Application of recombinant sFLT1 alone did not activate human umbilical vein endothelial cells (HUVECs). However, antagonizing the autocrine actions of endothelial VEGF-A and/or placenta growth factor (PlGF) by pre-incubation with recombinant sFLT1, anti-FLT1, anti-VEGF receptor 2 (KDR), anti-VEGF-A, VEGF receptor tyrosine kinase inhibitor SU5614, or knocking-down FLT1 or KDR transcripts rendered cells more sensitive to low doses of TNF-α. Each treatment increased activation, as measured by increases in endothelial intercellular adhesion molecule 1 (ICAM1), vascular cell adhesion molecule 1 (VCAM1), endothelin 1 (ET-1), von Willebrand factor (vWF), and leucocyte adhesion, and led to reduction in AKT Ser⁴⁷³ and endothelial nitric oxide synthase (eNOS) Ser¹¹⁷⁷ phosphorylation.

Conclusions

Our data describe a mechanism by which sFLT1 sensitizes endothelial cells to pro-inflammatory factors, providing an explanation for how placental stress may precipitate the pre-eclamptic syndrome.

Plasma osteopontin concentrations in preeclampsia - is there an association with endothelial injury?

Abstract Background: It has been previously reported that plasma osteopontin (OPN) concentrations are increased in cardiovascular disorders. The goal of the present study was to determine plasma OPN concentrations in healthy pregnant women and preeclamptic patients, and to investigate their relationship to the clinical characteristics of the study subjects and to markers of inflammation [C-reactive protein (CRP)], endothelial activation [von Willebrand factor antigen (VWF:Ag)] or endothelial injury (fibronectin), oxidative stress [malondialdehyde (MDA)] and trophoblast debris (cell-free fetal DNA).

METHODS

Forty-four patients with preeclampsia and 44 healthy pregnant women matched for age and gestational age were involved in this case-control study. Plasma OPN concentrations were measured with ELISA. Serum CRP concentrations were determined with an autoanalyzer using the manufacturer's reagents. Plasma VWF:Ag was quantified by ELISA, while plasma fibronectin concentrations were measured by nephelometry. Plasma MDA concentrations were estimated by the thiobarbituric acid-based colorimetric assay. The amount of cell-free fetal DNA in maternal plasma was determined by quantitative real-time PCR analysis of the sex-determining region Y (SRY) gene. For statistical analyses, non-parametric methods were applied.

RESULTS

Serum levels of CRP, as well as plasma concentrations of VWF:Ag, fibronectin, MDA and cell-free fetal DNA were significantly higher in preeclamptic patients than in healthy pregnant women. There was no significant difference in plasma OPN concentrations between controls and the preeclamptic group. However, preeclamptic patients with plasma fibronectin concentrations in the upper quartile had significantly higher plasma OPN concentrations than those below the 75th percentile, as well as healthy pregnant women [median (interquartile range): 9.38 (8.10-11.99) vs. 7.54 (6.31-9.40) and 7.40 (6.51-8.80) ng/mL, respectively, p<0.05 for both]. Furthermore, in preeclamptic patients, plasma OPN concentrations showed a significant positive linear association with plasma fibronectin (Spearman R=0.38, standardized regression coefficient (beta)=0.41, p<0.05 for both).

CONCLUSIONS

Plasma OPN concentrations are increased in preeclamptic patients with extensive endothelial injury. However, further studies are warranted to explore the relationship between OPN and endothelial damage. Clin Chem Lab Med 2010;48:181-7.

Markers of endothelial cell activation in elderly men at high risk for coronary heart disease

OBJECTIVE

Circulating cell adhesion molecules (CAMS) are regarded as inflammatory markers related to the process of atherosclerosis and cardiovascular disease (CVD). In the haemostatic system, elevated levels of thrombomodulin (TM), von Willebrand factor (vWF) and tissue-type plasminogen activator antigen (tPAag) have likewise been associated with atherothrombotic cardiovascular disease states.

MATERIAL AND METHODS

Levels of these circulating markers were investigated in a cross-sectional study including 563 men aged 70 (64-76) years characterized as hypercholesterolaemic in 1972, as related to the following clinical entities: cardiovascular morbidity (28%), diabetes (15%), hypertension (70%) and smoking habits (34%) after 24 years.

RESULTS

In patients presenting with CVD, significantly higher levels of tPAag were encountered (12.9 versus 12.0 ng/ml, p = 0.02). In smokers, levels of sICAM-1 were significantly higher (331 versus 298 ng/ml, p < 0.001), whereas levels of sVCAM-1 and sTM were lower compared with those in non-smokers (543 versus 582 ng/ml, p = 0.01, 40.6 versus 44.5 ng/ml, p < 0.01, respectively). In diabetics, levels of sE-selectin and tPAag were significantly higher than those in non-diabetics (55.9 versus 45.7 ng/ml, p < 0.001, 13.6 versus 12.0, p = 0.001, respectively). In subjects with hypertension, levels of TM were elevated (44.0 versus 40.8 ng/ml, p = 0.03). In multivariate regression analyses, tPAag remained significantly associated with the presence of CVD (p = 0.03), sE-selectin with diabetes (p=0.004), sTM with hypertension (p = 0.02) and sVCAM-1, sICAM-1 and sTM with smoking, (p = 0.01, p < 0.001, p < 0.001, respectively).

CONCLUSIONS

The present results may contribute to the understanding of the multitude of factors influencing these endothelial markers and their evaluation in various disease entities.

Von Willebrand factor, red cell fragmentation, and disease activity in systemic lupus erythematosus

This study sought to determine whether the plasma levels of Von Willebrand factor (vWf) and the degree of red blood cell (RBC) fragmentation on peripheral smear correlate with disease activity in systemic lupus erythematosus (SLE). Forty consecutive patients who fulfilled the criteria for SLE were studied prospectively for 1 year. Patients were categorized according to the SLE Disease Activity Index (SLEDAI) as either active (>2) or inactive disease and followed up monthly (active) or quarterly (inactive). At each visit, patients were examined fully and had complete blood count, tests on antibodies to double-stranded DNA, C3, and C4 levels, and urinalysis. Citrated plasma was analyzed for vWf antigen by standard enzyme-linked immunosorbent assay. A Wright's stained blood smear was obtained and schistocytes were quantitated on blood smear. The number of schistocytes per 500 RBCs was determined and a schistocyte index (SI) was calculated. At baseline, vWf correlated with SLEDAI (r = 0.64, p < 0.01), SI correlated with SLEDAI (r = 0.62, p < 0.01), and vWf and SI correlated with each other (r = 0.41, p = 0.01). There was an inverse correlation between baseline C3 levels and vWf (r = 0.49, p = 0.0013) and C3 levels and SI (r = 0.40, p = 0.01). Over time, there was also a correlation of SLEDAI with vWf (r = 0.53, p = 0.002) and SI (r = 0.57;p = 0.002). The relation of vWf with SI approached but did not reach statistical significance (r = 0.37, p = 0.06). We found that the plasma levels of vWf and the degree of RBC fragmentation correlate with lupus disease activity over time. Therefore, inflammation in SLE may be associated with endothelial injury.

Acute activation of the endothelium results in increased levels of active von Willebrand factor in hemolysis, elevated liver enzymes and low platelets (HELLP) syndrome

BACKGROUND

HELLP (hemolysis, elevated liver enzymes and low platelets) syndrome is a severe complication of pre-eclampsia in pregnancy, characterized by microvascular platelet thrombi. Activation of the endothelium is thought to play a key role in pre-eclampsia and HELLP syndrome. Activation of endothelial cells may lead to release of von Willebrand factor (VWF) multimers, which are highly reactive with platelets. Normally, newly released multimers are cleaved by ADAMTS13, resulting in less reactive derivatives.

OBJECTIVE

We hypothesized that HELLP syndrome is characterized by increased amounts of active VWF compared with healthy pregnancy and pre-eclampsia, due to acute activation of endothelial cells. This might contribute to thrombocytopenia and thrombotic microangiopathy.

METHODS

Active VWF and ADAMTS13 activity were measured in healthy pregnant volunteers (n = 9), patients with pre-eclampsia (n = 6) and patients with HELLP syndrome (n = 14) at similar gestational ages. To study the role of endothelial cell activation, the propeptide/mature VWF ratio was determined, and VWF released by cultured endothelial cells was analyzed.

RESULTS

Active VWF levels were increased 2.1-fold in HELLP syndrome compared with healthy pregnant volunteers (P < 0.001) and 1.6-fold compared with patients with pre-eclampsia (P = 0.001). ADAMTS13 activity was moderately decreased in patients with HELLP syndrome compared with healthy pregnant volunteers (P < 0.004), but not compared with patients with pre-eclampsia. The propeptide/mature VWF ratio was increased 1.7-fold compared with healthy pregnant volunteers (P < 0.001) and 1.5-fold compared with patients with pre-eclampsia (P < 0.05). A significant correlation was found between this ratio and the activation factor of VWF (r = 0.68, P < 0.001). The amount of active VWF was increased 1.4-fold in medium of stimulated endothelial cells when compared with non-stimulated cells (P < 0.05).

CONCLUSION

Acute endothelial cell activation in HELLP syndrome and decreased ADAMTS13 activity result in increased amounts of active VWF. This might explain the consumptive thrombocytopenia and thrombotic microangiopathy associated with HELLP syndrome. Inhibition of circulating active VWF could be a potential new approach in the treatment of patients with HELLP syndrome.

Factor VIII levels and the risk of pre-eclampsia, HELLP syndrome, pregnancy related hypertension and severe intrauterine growth retardation

OBJECTIVE

Recently, acquired as well as genetic prothrombotic factors are associated with thrombotic events. These factors have also been related to conditions of uteroplacental insufficiency such as pre-eclampsia, HELLP syndrome and severe intrauterine growth restriction (IUGR). The aim of this study was to determine whether elevated factor VIII levels are associated with uteroplacental insufficiency, in particular pre-eclampsia, HELLP syndrome or pregnancy-induced hypertension and intrauterine growth retardation.

METHODS

Plasma samples of 75 women with a history of pregnancy complicated by pre-eclampsia, HELLP syndrome, pregnancy induced hypertension or intrauterine growth restriction were tested for factor VIII:C (FVIII:C) levels at a minimum of 10 weeks post-partum. Laboratory results were compared to factor VIII:C levels found in a healthy control group of 272 women.

RESULTS

Mean factor VIII:C levels were similar at 123 IU/dl in both the patient group and the controls. In a logistic regression model, after adjusting for age and blood group, no effect of factor VIII:C levels on the risk of pregnancy complications was observed, with the exception of IUGR with (OR 2.9, CI 1.0-8.7) or without hypertension (OR 2.0, CI 0.7-6.4).

CONCLUSION

If the elevated level of factor VIII would be the sole factor responsible for the increased risk observed, one would expect to find an effect of blood group on risk as well (blood group being an important determinant of FVIII:C). While no such effect could be shown a causal relationship between elevated levels of factor VIII and conditions of uteroplacental insufficiency such as pre-eclampsia, HELLP syndrome, pregnancy-induced hypertension and IUGR is not very likely.

Molecular evidence of placental hypoxia in preeclampsia

BACKGROUND

Oxygen plays a central role in human placental pathologies including preeclampsia, a leading cause of fetal and maternal death and morbidity. Insufficient uteroplacental oxygenation in preeclampsia is believed to be responsible for the molecular events leading to the clinical manifestations of this disease.

DESIGN

Using high-throughput functional genomics, we determined the global gene expression profiles of placentae from high altitude pregnancies, a natural in vivo model of chronic hypoxia, as well as that of first-trimester explants under 3 and 20% oxygen, an in vitro organ culture model. We next compared the genomic profile from these two models with that obtained from pregnancies complicated by preeclampsia. Microarray data were analyzed using the binary tree-structured vector quantization algorithm, which generates global gene expression maps.

RESULTS

Our results highlight a striking global gene expression similarity between 3% O(2)-treated explants, high-altitude placentae, and importantly placentae from preeclamptic pregnancies. We demonstrate herein the utility of explant culture and high-altitude placenta as biologically relevant and powerful models for studying the oxygen-mediated events in preeclampsia.

CONCLUSION

Our results provide molecular evidence that aberrant global placental gene expression changes in preeclampsia may be due to reduced oxygenation and that these events can successfully be mimicked by in vivo and in vitro models of placental hypoxia.

Activated platelets induce Weibel-Palade-body secretion and leukocyte rolling in vivo: role of P-selectin

The presence of activated platelets and platelet-leukocyte aggregates in the circulation accompanies major surgical procedures and occurs in several chronic diseases. Recent findings that activated platelets contribute to the inflammatory disease atherosclerosis made us address the question whether activated platelets stimulate normal healthy endothelium. Infusion of activated platelets into young mice led to the formation of transient platelet-leukocyte aggregates and resulted in a several-fold systemic increase in leukocyte rolling 2 to 4 hours after infusion. Rolling returned to baseline levels 7 hours after infusion. Infusion of activated P-selectin-/- platelets did not induce leukocyte rolling, indicating that platelet P-selectin was involved in the endothelial activation. The endothelial activation did not require platelet CD40L. Leukocyte rolling was mediated solely by the interaction of endothelial P-selectin and leukocyte P-selectin glycoprotein ligand 1 (PSGL-1). Endothelial P-selectin is stored with von Willebrand factor (VWF) in Weibel-Palade bodies. The release of Weibel-Palade bodies on infusion of activated platelets was indicated by both elevation of plasma VWF levels and by an increase in the in vivo staining of endothelial P-selectin. We conclude that the presence of activated platelets in circulation promotes acute inflammation by stimulating secretion of Weibel-Palade bodies and P-selectin-mediated leukocyte rolling.

Transcriptional response of human umbilical vein endothelial cells to low doses of ionizing radiation

We used cDNA microarray hybridization technology to monitor the transcriptional response of Human Umbilical Vein Endothelial (HUVEC) cells to x-rays doses ranging from 2 to 200 cGy. An early time window from irradiation (4h) was selected in order to minimize the effects of the cell cycle blockage eventually induced at high doses of irradiation. Three different gene-clustering algorithms have been used to group the 4134 monitored ORF based on their transcriptional response in function of the irradiation dose. The results show that while few genes exhibit a typical dose-dependent modulation with a variable threshold, most of them have a different modulation pattern, peaking at the two intermediate doses. Strikingly even the lowest dose used (2 cGy) seems to be very effective in transcriptional modulation. These results confirm the physiological relevance of sublethal-dose exposures of endothelial cells and strengthens the hypothesis that alternative dose-specific pathways of radioadaptive response exist in the mammalian cells. 111 genes were found to be modulated at all doses of irradiation. These genes were functionally classified by cellular process or by molecular function. Genes involved in coagulation and peroxidase activity and structural constituent of ribosomes were over-represented among the up-regulated genes as compared with their expected statistical occurrence. Three genes coding for regulatory kinase activities (CDK6; PRCKB1 and TIE) are found down-regulated at all doses of irradiation.

Predictors of the rise in vWF after ST elevation myocardial infarction: implications for treatment strategies and clinical outcome

AIMS

Prior studies suggest that acute coronary syndromes (ACSs) are associated with endothelial activation and that this is of prognostic significance. We hypothesized that endothelial activation, as measured by a rise in von Willebrand Factor (DeltavWF), was influenced by the thrombolysis in myocardial infarction flow grade (TFG), the corrected TIMI frame count (CTFC) and the choice of anticoagulant therapy after fibrinolysis in ST elevation myocardial infarction (STEMI).

METHODS AND RESULTS

Data were drawn from the enoxaparin and tenecteplase tissue plasminogen activator (TNK-tpa) with or without GPIIb/IIIa inhibitor as the reperfusion strategy in the STEMI trial (ENTIRE-TIMI 23). Three hundred and fourteen patients had serial measurements of vWF (baseline and 48-72 h) and angiographic data available. TFG<3 (P=0.0042) or CTFC>/=40 at 60 min (P=0.0035) were associated with a higher DeltavWF. DeltavWF >/=75th percentile was associated with a higher incidence of death or myocardial infarction (MI) at 30 days, compared with <75th percentile (11.2 vs. 4.1%, P=0.027). Enoxaparin independently reduced the DeltavWF (P=0.019) and also the composite of death or MI (OR 0.33, 95% CI 0.12-0.91, P=0.03) compared with unfractionated heparin.

CONCLUSION

In STEMI treated by fibrinolysis, coronary flow at 60 min and choice of adjunctive anticoagulant appear to be independent determinants of DeltavWF. Enoxaparin is independently associated with a reduction in DeltavWF and a reduction in death or MI. The clinical benefits of enoxaparin as an adjunctive treatment in STEMI may be mediated in part by a reduction in vWF release.