Endothelial microparticles and the antiangiogenic state in preeclampsia and the postpartum period

Relationship between proteinuria and changes in antepartum and postpartum choroidal thickness in patients with pre-eclampsia

Pre-eclampsia (PE) is a hypertensive disorder characterised by systemic vascular resistance and endothelial dysfunction. It is known to influence choroidal thickness (CT). No previous studies have explored the antepartum and postpartum changes in CT with respect to the protein-creatinine ratio (PCR), a measure of proteinuria that is a clinical hallmark of PE. This study evaluated the correlations between antepartum and postpartum CT and the PCR in patients with PE. In this retrospective study, sixty-six eyes (66 patients) were analysed. The patients were divided into two groups according to the median PCR value (2.36 mg/mg): low PCR group (< 2.36 mg/mg) and high PCR group (≥ 2.36 mg/mg). Ophthalmologic clinical data were collected and assessed. We observed higher antepartum CT and higher mean arterial pressure in high PCR group than in low PCR group. Moreover, postpartum CT decreased significantly in high PCR group. In the multivariate analysis, CT changes were correlated with antepartum CT and antepartum PCR after logarithm transformation. In conclusion, a greater decrease in CT was observed in high PCR group than in low PCR group. Further, the antepartum PCR showed a correlation with the extent of CT reduction.

Prenatal Low-Dose Aspirin Use Associated with Reduced Incidence of Postpartum Hypertension among Women with Preeclampsia

OBJECTIVE

Postpartum hypertension (PP-HTN), defined as systolic/diastolic blood pressure (SBP/DBP) ≥140/90, on two occasions at least 4 hours apart after delivery occurs in up to 50% of preeclamptic pregnancies, and is associated with adverse maternal outcomes. Excessive production of antiangiogenic factors (i.e., soluble fms-like tyrosine kinase 1 [sFLT1]) and reduced levels of proangiogenic factors (i.e., placental growth factor [PlGF]) are associated with preeclamptic pregnancies. The aim of this study was to identify clinical risk factors and/or serum biomarkers associated with PP-HTN in preeclampsia.

STUDY DESIGN

Preeclamptic women (n = 82, aged ≥18 years) were prospectively enrolled in an observational study. Serial blood pressures were obtained through the labor course and until 48 hours postpartum, and serum was obtained within 24 hours postpartum. Statistical analysis was performed by using Student's two-tailed t-test and Fisher's exact test.

RESULTS

Baseline comorbidities and antihypertensive use were similar among those who developed PP-HTN and those who did not. Among preeclamptic patients, 33% developed PP-HTN; these had significantly more severe preeclampsia features versus no PP-HTN (96 vs. 78%, p = 0.05). PP-HTN was associated with higher re-hospitalization rates (26 vs. 6%, p = 0.01). Among those taking low-dose aspirin (ASA) for preeclampsia prophylaxis (n = 12), PP-HTN was significantly less frequent versus those not taking low-dose ASA (0 vs. 22%, p = 0.007). Low-dose ASA use was associated with significantly lower peripartum sFLT1 levels (4,650 ± 2,335 vs. 7,870 ± 6,282 pg/mL, p = 0.03) and sFLT1/PlGF ratio (397 ± 196 vs. 1,527 ± 2,668, p = 0.03).

CONCLUSION

One-third of women with preeclampsia develop PP-HTN; these patients have more severe preeclampsia and have higher re-hospitalization rates. Prenatal low-dose ASA use was associated with significantly lower incidence of PP-HTN, reduced levels of antiangiogenic factors, and lower 6-week re-hospitalization rates. These findings, if replicated, may have clinical implications on the use of low-dose ASA during pregnancy to reduce incidence of postpartum HTN.

KEY POINTS

· Postpartum hypertension is common in preeclampsia.. · Prenatal aspirin may reduce postpartum hypertension.. · Prenatal aspirin may reduce sFLT1 levels..

Preeclampsia and the Kidney: Pathophysiology and Clinical Implications

Preeclampsia and other hypertensive disorders of pregnancy are major contributors to maternal morbidity and mortality worldwide. This group of disorders includes chronic hypertension, gestational hypertension, preeclampsia, preeclampsia superimposed on chronic hypertension, and eclampsia. The body undergoes important physiological changes during pregnancy to allow for normal placental and fetal development. Several mechanisms have been proposed that may lead to preeclampsia, including abnormal placentation and placental hypoxia, impaired angiogenesis, excessive pro-inflammatory response, immune system imbalance, abnormalities of cellular senescence, alterations in regulation and activity of angiotensin II, and oxidative stress, ultimately resulting in upregulation of multiple mediators of endothelial cell dysfunction leading to maternal disease. The clinical implications of preeclampsia are significant as there are important short-term and long-term health consequences for those affected. Preeclampsia leads to increased risk of preterm delivery and increased morbidity and mortality of both the developing fetus and mother. Preeclampsia also commonly leads to acute kidney injury, and women who experience preeclampsia or another hypertensive disorder of pregnancy are at increased lifetime risk of chronic kidney disease and cardiovascular disease. An understanding of normal pregnancy physiology and the pathophysiology of preeclampsia is essential to develop novel treatment approaches and manage patients with preeclampsia and hypertensive disorders of pregnancy. © 2023 American Physiological Society. Compr Physiol 13:4231-4267, 2023.

HDAC5 inactivates CYR61-regulated CD31/mTOR axis to prevent the occurrence of preeclampsia

Our study was to pinpoint the significance of histone deacetylase 5 (HDAC5) affecting the pathogenesis of preeclampsia (PE) via CD31/mammalian target of rapamycin (mTOR) axis by regulating cysteine-rich angiogenic inducer 61 (CYR61). Expression of HDAC5, CYR61, and CD31/mTOR in placental tissues of patients with PE and trophoblast cells HTR-8/SVneo cells was determined first followed by their interaction analysis. Following different transfection, the significance of HDAC5 in cell functions was assayed in relation to CYR61 and CD31/mTOR. An in vivo PE mouse model was constructed for further validation. The clinical tissue and in vitro cell experimentations discovered that HDAC5 was downregulated in placental tissues of PE patients and trophoblast cells, while CYR61, CD31, mTOR, and p-mTOR displayed upregulation. After overexpression of HDAC5, trophoblast cell functions were enhanced. HDAC5 reduced the acetylation enrichment of H3K27 to inhibit the expression of CYR61. Furthermore, CYR61 promoted the activation of CD31/mTOR axis, thereby inhibiting HTR-8/SVneo cell functions. The in vivo rat model confirmed the above alterations. Taken together, HDAC5 contributes to downregulation of CYR61 through histone deacetylation, inactivating CD31/mTOR axis, which prevents the occurrence and development of PE.

Differential and targeted vesiculation: pathologic cellular responses to elevated arterial pressure

Extracellular vesicles are small membrane-enclosed particles released during cell activation or injury. They have been investigated for several decades and found to be secreted in various diseases. Their pathogenic role is further supported by the presence of several important molecules among their cargo, including proteins, lipids, and nucleic acids. Many studies have reported enhanced and targeted extracellular vesicle biogenesis in diseases that involve chronic or transient elevation of arterial pressure resulting in endothelial dysfunction, within either the general circulatory system or specific local vascular beds. In addition, several associated pathologic processes have been studied and reported. However, the role of elevated pressure as a common pathogenic trigger across vascular domains and disease chronicity has not been previously described. This review will therefore summarize our current knowledge of the differential and targeted biogenesis of extracellular vesicles in major diseases that are characterized by elevated arterial pressure leading to endothelial dysfunction and propose a unified theory of pressure-induced extracellular vesicle-mediated pathogenesis.

Extracellular Vesicles From Women With Severe Preeclampsia Impair Vascular Endothelial Function

BACKGROUND

Preeclampsia (PE) manifesting as hypertension and organ injury is mediated by vascular dysfunction. In biological fluids, extracellular vesicles (EVs) containing microRNA (miRNA), protein, and other cargo released from the placenta may serve as carriers to propagate injury, altering the functional phenotype of endothelial cells. PE has been consistently correlated with increased levels of placenta-derived EVs (pEVs) in maternal circulation. However, whether pEVs impaired endothelial cell function remains to be determined. In this study, we hypothesize that pEVs from pregnant women with severe PE (sPE) impair endothelial function through altered cell signaling.

METHODS

We obtained plasma samples from women with sPE (n = 14) and normotensive pregnant women (n = 15) for the isolation of EVs. The total number of EV and pEV contribution was determined by quantifying immunoreactive EV-cluster of designation 63 (CD63) and placental alkaline phosphatase (PLAP) as placenta-specific markers, respectively. Vascular endothelial functional assays were determined by cell migration, electric cell-substrate impedance sensing in human aortic endothelial cells (HAECs), and wire myography in isolated blood vessels, preincubated with EVs from normotensive and sPE women.

RESULTS

Plasma EV and pEV levels were increased in sPE when compared to normotensive without a significant size distribution difference in sPE (108.8 ± 30.2 nm) and normotensive-EVs (101.3 ± 20.3 nm). Impaired endothelial repair and proliferation, reduced endothelial barrier function, reduced endothelial-dependent vasorelaxation, and decreased nitrite level indicate that sPE-EVs induced vascular endothelial dysfunction. Moreover, sPE-EVs significantly downregulated endothelial nitric oxide synthase (eNOS and p-eNOS) when compared to normotensive-EV.

CONCLUSIONS

EVs from sPE women impair endothelial-dependent vascular functions in vitro.

Phosphatidylserine Exposing Extracellular Vesicles in Pre-eclamptic Patients

Background: Pre-eclampsia (P-EC) is associated with systemic inflammation, endothelial dysfunction and hypercoagulability. The role of extracellular vesicles (EVs) in coagulation disturbances affecting the development and severity of P-EC remains elusive. We aimed to evaluate the concentration of EVs expressing phosphatidylserine (PS) and specific markers in relation to the thrombin and fibrin formation as well as fibrin clot properties, in pregnant women with P-EC in comparison to healthy pregnant women of similar gestational age.

Methods: Blood samples of 30 pregnant women diagnosed with P-EC were collected on the morning following admission to hospital and after delivery (mean duration 5 days). The concentration of the PS-exposing EVs (PS+ EVs) from platelets (CD42a⁺, endothelial cells (CD62E⁺), and PS+ EVs expressing tissue factor (TF) and vascular cell adhesion molecule 1 (VCAM-1) were measured by flow cytometry. Further phenotyping of EVs also included expression of PlGF. Markers of maternal haemostasis were correlated with EVs concentration in plasma.

Results: Preeclamptic pregnancy was associated with significantly higher plasma levels of PS+ CD42a⁺ EVs and PS+ VCAM-1⁺ EVs in comparison with normotensive pregnancy. P-EC patients after delivery had markedly elevated concentration of PS+ CD42a⁺ EVs, CD62E⁺ EVs, TF⁺ EVs, and VCAM-1⁺ EVs compared to those before delivery. Inverse correlation was observed between EVs concentrations (PS+, PS+ TF⁺, and PlGF⁺) and parameters of overall haemostatic potential (OHP) and fibrin formation, while PS+ VCAM-1⁺ EVs directly correlated with FVIII activity in plasma.

Conclusion: Increased levels of PS+ EVs subpopulations in P-EC and their association with global haemostatic parameters, as well as with fibrin clot properties may suggest EVs involvement in intravascular fibrin deposition leading to subsequent microcirculation disorders.

Subfoveal Choroidal Thickness and Associated Changes of Angiogenic Factors in Women with Severe Preeclampsia

OBJECTIVE

Severe preeclampsia complicates roughly 1% of all pregnancies. One defining feature of severe preeclampsia is new onset visual disturbance. The accessibility of the choroid to high-resolution, noninvasive imaging makes it a reasonable target of investigation for disease prediction, stratification, or monitoring in preeclampsia. This study aimed to compare subfoveal choroidal thickness between women with severe preeclampsia and those with normotensive pregnancies, and to investigate associations between such findings and other indicators of disease severity, including gestational age and serum angiogenic factors.

STUDY DESIGN

We designed a case-control study comprised of 36 women diagnosed with severe preeclampsia (cases) matched to 37 normotensive women (controls) by race/ethnicity and parity, all diagnosed in the postpartum period. All patients underwent enhanced depth imaging spectral-domain optical coherence tomography and serum analysis.

RESULTS

Cases showed no difference in subfoveal choroidal thickness compared with controls (p = 0.65). Amongst cases, subfoveal choroidal thickness and gestational age at delivery were inversely related (r = 0.86, p < .001). There was a positive association of placental growth factor with subfoveal choroidal thickness amongst cases (r = 0.54, p = 0.002).

CONCLUSION

This study suggests a relationship between the degree of disease severity and the magnitude of choroidal thickening. We also show an association between this index and placental growth factor level in the postpartum period.

Overview of extracellular vesicles in the pathogenesis of preeclampsia†

Preeclampsia (PE) is a leading cause of maternal and fetal-neonatal deaths, and its pathogenesis has been linked to the involvement of extracellular vesicles (EVs). EVs are a heterogeneous group of cell-originated membranous vesicles including exosomes, microvesicles, and apoptotic bodies. EVs transport various bioactive cargos such as lipids, proteins, or nucleic acids, and thus mediate cellular communication and contribute to the proper functioning of cells, organs and processes, including normal pregnancy. Numerous studies have reported that EVs are associated with abnormal levels of soluble fms-like tyrosine kinase-1 (sFlt-1), soluble endoglin (sEng), and placental growth factor (PlGF) in PE. EVs isolated from preeclamptic women have been implicated in trophoblast dysfunction and have been reported to activate endothelium, monocytes, and platelets, and to be involved in defective placentation, imbalanced angiogenesis, and intravascular inflammation. When injected into pregnant rodents, these EVs induced hypertension, proteinuria, and adverse fetal outcomes. Deciphering the contribution of EVs to PE will advance our current understanding of this disorder and may lead to more clinical strategies for the management of PE. Of note, the composition of EV cargos may be characteristic of the status and stages of gestation, providing researchers the possibility of one day using EVs as novel, noninvasive, biomarkers for early screening of PE. Herein, we reviewed the latest research into EVs with emphasis on their role in the pathogenesis of PE and their applications as biomarkers in the early screening of this pregnancy-specific disorder.

Extracellular vesicles and their potential role inducing changes in maternal insulin sensitivity during gestational diabetes mellitus

Gestational diabetes mellitus (GDM) is one of the most common endocrine disorders during gestation and affects around 15% of all pregnancies worldwide, paralleling the global increase in obesity and type 2 diabetes. Normal pregnancies are critically dependent on the development of maternal insulin resistance balanced by an increased capacity to secrete insulin, which allows for the allocation of nutrients for adequate foetal growth and development. Several factors including placental hormones, inflammatory mediators and nutrients have been proposed to alter insulin sensitivity and insulin response and underpin the pathological outcomes of GDM. However, other factors may also be involved in the regulation of maternal metabolism and a complete understanding of GDM pathophysiology requires the identification of these factors, and the mechanisms associated with them. Recent studies highlight the potential utility of tissue-specific extracellular vesicles (EVs) in the diagnosis of disease onset and treatment monitoring for several pregnancy-related complications, including GDM. To date, there is a paucity of data defining changes in the release, content, bioactivity and diagnostic utility of circulating EVs in pregnancies complicated by GDM. Placental EVs may engage in paracellular interactions including local cell-to-cell communication between the cell constituents of the placenta and contiguous maternal tissues, and/or distal interactions involving the release of placental EVs into biological fluids and their transport to a remote site of action. Hence, the aim of this review is to discuss the biogenesis, isolation methods and role of EVs in the physiopathology of GDM, including changes in maternal insulin sensitivity during pregnancy.

Extracellular Vesicles and Preeclampsia: Current Knowledge and Future Research Directions

Preeclampsia (PE) is associated with long-term morbidity in mothers and lifelong morbidities for their children, ranging from cerebral palsy and cognitive delay in preterm infants, to hypertension, diabetes and obesity in adolescents and young adults. There are several processes that are critical for development of materno-fetal exchange, including establishing adequate perfusion of the placenta by maternal blood, and the formation of the placental villous vascular tree. Recent studies provide persuasive evidence that placenta-derived extracellular vesicles (EVs) represent a significant intercellular communication pathway, and that they may play an important role in placental and endothelial cell (both fetal and maternal) function. These functions are known to be altered in PE. EVs can carry and transport a wide range of bioactive molescules that have potential to be used as biomarkers and therapeutic delivery tools for PE. EV content is often parent cell specific, thus providing an insight or "thumbprint" of the intracellular environment of the originating cell (e.g., human placenta). EV have been identified in plasma under both normal and pathological conditions, including PE. The concentration of EVs and their content in plasma has been reported to increase in association with disease severity and/or progression. Placenta-derived EVs have been identified in maternal plasma during normal pregnancy and PE pregnancies. They contain placenta-specific proteins and miRNAs and, as such, may be differentiated from maternally-derived EVs. The aim of this review, thus, is to describe the potential roles of EVs in preecmpatic pregnancies, focussing on EVs secreted from placental cells. The biogenesis, specificity of placental EVs, and methods used to characterise EVs in the context of PE pregnancies will be also discussed.

Placental Findings in Postpartum Preeclampsia: A Comparative Retrospective Study

OBJECTIVE

Preeclampsia is a multifactorial placental disease that can occur after delivery. The pathophysiology of postpartum preeclampsia remains unknown. The objective was to describe placental findings in postpartum preeclampsia.

STUDY DESIGN

This is a case-control study, comparing the placental histologic findings in four groups of 30 patients with postpartum preeclampsia, early-onset preeclampsia, late-onset preeclampsia, and normotensive controls.

RESULTS

Placentas of postpartum preeclampsia had a mean placental weight not different from that of late-onset preeclampsia at a similar gestational age (479.0 ± 152.7 vs. 521.3 ± 144.1 g, p = 0.07); they showed a higher rate of acute deciduitis of 42.4% than early preeclampsia (5.7%, p < 0.01) or in controls (3.2%, p < 0.01); 18.2% had decidual arteriolopathy, with no significant difference with other groups. These placentas had fewer villous infarcts as compared with early preeclampsia (9.1 vs. 62.9%, p < 0.01) and less accelerated maturation of villi (24.2 vs. 74.3%, p < 0.01).

CONCLUSION

There were no significant differences for decidual arteriolopathy and villous infarcts among postpartum preeclampsia, late-onset preeclampsia, and the controls. This suggests that postpartum preeclampsia is more of a maternal disease in which the placenta may act as a priming effect in predisposed mothers and becomes clinically apparent after delivery.

Exosomes From Women With Preeclampsia Induced Vascular Dysfunction by Delivering sFlt (Soluble Fms-Like Tyrosine Kinase)-1 and sEng (Soluble Endoglin) to Endothelial Cells

Preeclampsia is a unique multiple system disorder that affects 5% to 8% of pregnancies. Exosomes, membrane-encapsulated vesicles that are released into the extracellular environment by many cell types, can carry signals to the recipient cells to affect inflammation, apoptosis, and angiogenesis. We hypothesize that exosomes from women with preeclampsia complications impair vascular development by delivering antiangiogenic factors to endothelial cells. In the current study, plasma samples from gestational age-matched preeclampsia and normal pregnancies were used to isolate circulating exosomes by commercial kits. Next, application of transwell and matrigel tube formation assays showed that exosomes from preeclampsia patients impaired angiogenesis of human umbilical vein endothelial cells. We found that exosomes from preeclampsia expressed abundant sFlt-1 (soluble fms-like tyrosine kinase-1) and sEng (soluble endoglin). Considering the possibility that extracellular sFlt and sEng were horizontally transferred to human umbilical vein endothelial cells, we successfully collected exosomes containing high levels of sFlt-1 and sEng by overexpressing them in human embryonic kidney 293 cells. Furthermore, we demonstrated that these exosomes can attenuate the proliferation, migration, and tube formation of human umbilical vein endothelial cells in vitro. In a mouse model, exosomes from preeclampsia patients caused vascular dysfunction directly resulted in adverse preeclampsia-like birth outcomes. Thus, we proposed that exosomes mediated efficient transfer of sFlt-1 and sEng to endothelial cells to damage vascular functions and induce complications in preeclampsia patients.

Deletion of Prl7d1 causes placental defects at mid-pregnancy in mice

Prolactin family 7, subfamily d, member 1 (Prl7d1), a member of the expanding prolactin family, is mainly expressed in the placental junctional zone (including trophoblast giant cells and spongiotrophoblast cells) with peak expression observed at 12 days postcoitum (dpc) in mice. Previous studies have shown that PRL7D1 is a key mediator of angiogenesis in vitro; however, its physiological roles in placental development in vivo have not been characterized. To address this issue, we deleted Prl7d1 in mice and demonstrated that its absence results in reduced litter size and fertility. Histologically, Prl7d1 mutants exhibited striking placental abnormalities at 12.5 dpc, including a reduction in the proportion of labyrinth layers and a significant increase in decidual natural killer cells, glycogen trophoblasts, and trophoblast giant cells in the junctional zone. Moreover, placentas from Prl7d1-null mice displayed a thickened decidual spiral artery. Notably, these negative effects were more pronounced in male fetuses. Further RNA-sequencing analysis showed that Prl7d1 deletion results in significant differences in the placental transcriptome profile between the two sexes of fetuses. Together, this study demonstrates that Prl7d1 possesses antiangiogenic properties in deciduas and inhibits the development of junctional zone, which potentially alters the functional capacity of the placenta to support optimal fetal growth. Moreover, of note, the role of Prl7d1 in the placenta is regulated in a fetal sex-specific manner.

Vitamin D suppresses oxidative stress-induced microparticle release by human umbilical vein endothelial cells

Endothelial microparticle (MP) release was increased in numerous cardiovascular diseases including preeclampsia. Oxidative stress is a potent inducer of endothelial dysfunction. In this study, we aimed to investigate if vitamin D could protect endothelial cells (ECs) from MP release induced by oxidative stress. Endothelial cell (from human umbilical vein) oxidative stress was induced by cultivation of cells under lowered oxygen condition (2%O2) for 48 h and cells cultured under standard condition (21%O2) served as control. 1,25(OH)2D3 was used as bioactive vitamin D. Using annexin-V as a marker of released MP assessed by flow cytometry and cytochrome c reduction assay to measure EC superoxide generation, we found that MP release and superoxide generation were significantly increased when cells were cultured under 2%O2, which could be significantly inhibited by 1,25(OH)2D3. To study the potential mechanisms of 1,25(OH)2D3 protective effects on ECs, EC expression of endothelial nitric oxide synthase (eNOS), p-eNOSSer1177, p-eNOSThr495, caveolin-1, extracellular signal-regulated kinase (ERK), p-ERK, Akt, p-AktSer473, Rho-associated coiled-coil protein kinase 1 (ROCK1), and vitamin D receptor were determined. Microparticle expression of eNOS and caveolin-1 were also determined. We found that under lowered oxygen condition, 1,25(OH)2D3 could upregulate EC eNOS, p-eNOSSer1177, and p-AktSer473 expression, but inhibit cleaved ROCK1 expression. The upregulatory and inhibitory effects induced by 1,25(OH)2D3 were dose dependent. Strikingly, we also found that oxidative stress-induced decrease in ratio of eNOS and caveolin-1 expression in MP could be attenuated when 1,25(OH)2D3 was present in culture. These results suggest that upregulation of eNOSSer1177 and AktSer473 phosphorylation and inhibition of ROCK1 cleavage in EC and modulation of eNOS and caveolin-1 expression in MP could be plausible mechanisms of vitamin D protective effects on ECs.

Vitamin D suppresses oxidative stress-induced microparticle release by human umbilical vein endothelial cells

Endothelial microparticle (MP) release was increased in numerous cardiovascular diseases including preeclampsia. Oxidative stress is a potent inducer of endothelial dysfunction. In this study, we aimed to investigate if vitamin D could protect endothelial cells (ECs) from MP release induced by oxidative stress. Endothelial cell (from human umbilical vein) oxidative stress was induced by cultivation of cells under lowered oxygen condition (2%O2) for 48 h and cells cultured under standard condition (21%O2) served as control. 1,25(OH)2D3 was used as bioactive vitamin D. Using annexin-V as a marker of released MP assessed by flow cytometry and cytochrome c reduction assay to measure EC superoxide generation, we found that MP release and superoxide generation were significantly increased when cells were cultured under 2%O2, which could be significantly inhibited by 1,25(OH)2D3. To study the potential mechanisms of 1,25(OH)2D3 protective effects on ECs, EC expression of endothelial nitric oxide synthase (eNOS), p-eNOSSer1177, p-eNOSThr495, caveolin-1, extracellular signal-regulated kinase (ERK), p-ERK, Akt, p-AktSer473, Rho-associated coiled-coil protein kinase 1 (ROCK1), and vitamin D receptor were determined. Microparticle expression of eNOS and caveolin-1 were also determined. We found that under lowered oxygen condition, 1,25(OH)2D3 could upregulate EC eNOS, p-eNOSSer1177, and p-AktSer473 expression, but inhibit cleaved ROCK1 expression. The upregulatory and inhibitory effects induced by 1,25(OH)2D3 were dose dependent. Strikingly, we also found that oxidative stress-induced decrease in ratio of eNOS and caveolin-1 expression in MP could be attenuated when 1,25(OH)2D3 was present in culture. These results suggest that upregulation of eNOSSer1177 and AktSer473 phosphorylation and inhibition of ROCK1 cleavage in EC and modulation of eNOS and caveolin-1 expression in MP could be plausible mechanisms of vitamin D protective effects on ECs.

Circulating microparticles: challenges and perspectives of flow cytometric assessment

Circulating blood microparticles are likely to play a significant role as messengers of biological information. Their accurate quantification and characterisation is challenging and needs to be carefully designed with preferable usage of fresh minimally-processed blood samples. Utilisation of flow cytometers specifically designed for analysis of small-size particles is likely to provide considerable methodological advantages and should be the preferable option. This viewpoint manuscript provides a critical summary of the key methodological aspects of microparticle analysis.

Note: The review process for this viewpoint article was fully handled by Christian Weber, Editor in Chief.

Association between angiogenic factors and signs of arterial aging in women with pre-eclampsia

OBJECTIVE

Pre-eclampsia (PE) is associated with an increased risk of cardiovascular disease later in life. In cases with PE there is a substantial increase in levels of the antiangiogenic factor soluble fms-like tyrosine kinase-1 (sFlt-1) and decreased levels of the proangiogenic factor placental growth factor (PlGF). Elevated levels of sFlt-1 are also found in individuals with cardiovascular disease. The aims of this study were to assess levels of sFlt-1, PlGF and the sFlt-1/PlGF ratio and their correlation with signs of arterial aging by measuring the common carotid artery (CCA) intima and media thicknesses and their ratio (I/M ratio) in women with and without PE.

METHODS

Serum sFlt-1 and PlGF levels were measured using commercially available enzyme-linked immunosorbent assay kits, and CCA intima and media thicknesses were estimated using high-frequency (22-MHz) ultrasonography in 55 women at PE diagnosis and in 64 women with normal pregnancy at a similar gestational age, with reassessment at 1 year postpartum.

RESULTS

During pregnancy, higher levels of sFlt-1, lower levels of PlGF, a thicker intima, a thinner media and a higher I/M ratio of the CCA were found in women with PE vs controls (all P < 0.0001). Further, sFlt-1 and the sFlt-1/PlGF ratio were positively correlated with intima thickness and I/M ratio (all P < 0.0001). At 1 year postpartum, levels of sFlt-1 and the sFlt-1/PlGF ratio had decreased in both groups; however, their levels in the PE group were still higher than in the controls (P = 0.001 and < 0.0001, respectively). Levels of sFlt-1 and the sFlt-1/PlGF ratio remained positively correlated with intima thickness and I/M ratio at 1 year postpartum.

CONCLUSIONS

Higher sFlt-1 levels and sFlt-1/PlGF ratio in women with PE were positively associated with signs of arterial aging during pregnancy. At 1 year postpartum, sFlt-1 levels and the sFlt-1/PlGF ratio were still higher in the PE group and were associated with the degree of arterial aging. © 2016 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of the International Society of Ultrasound in Obstetrics and Gynecology.

Tissue factor activity in women with preeclampsia or SGA: a potential explanation for the excessive thrombin generation in these syndromes

OBJECTIVE

The aim of this study was to determine whether the activity of tissue factor (TF) and tissue factor pathway inhibitor (TFPI) in the plasma of women with preeclampsia (PE) and small for gestational age (SGA) neonate differ from that of normal pregnant women and whether they are related to specific placental lesions.

METHODS

This cross-sectional study included the following groups: (1) normal pregnancy (n = 68); (2) PE (n= 128); and (3) SGA (n = 56). Maternal plasma TF and TFPI activity was determined with chromogenic assays.

RESULTS

(1) The median maternal plasma TF activity, but not TFPI activity, differed among the study groups (p < .0001 and p = .4, respectively); (2) patients with PE had a higher median maternal plasma TF activity than women with normal pregnancies (p < .0001) and mothers with SGA fetuses (p = .002); (3) among patients with PE, those with distal villous hypoplasia had a higher median maternal TF activity than those without these placental lesions (p = .018); and (4) following adjustment for confounding variables, maternal plasma TF and TFPI activity were not associated with an SGA neonate.

CONCLUSIONS

Plasma TF activity is higher in women with PE than in those with SGA or normal pregnancies. We propose that these changes may be responsible, at least in part, for the increased in-vivo thrombin generation observed in this obstetrical syndrome.

Endothelial Extracellular Vesicles-Promises and Challenges

Extracellular vesicles, including exosomes, microparticles, and apoptotic bodies, are phospholipid bilayer-enclosed vesicles that have once been considered as cell debris lacking biological functions. However, they have recently gained immense interest in the scientific community due to their role in intercellular communication, immunity, tissue regeneration as well as in the onset, and progression of various pathologic conditions. Extracellular vesicles of endothelial origin have been found to play a versatile role in the human body, since they are on the one hand known to contribute to cardiovascular diseases, but on the other hand have also been reported to promote endothelial cell survival. Hence, endothelial extracellular vesicles hold promising therapeutic potential to be used as a new tool to detect as well as treat a great number of diseases. This calls for clinically approved, standardized, and efficient isolation and characterization protocols to harvest and purify endothelial extracellular vesicles. However, such methods and techniques to fulfill stringent requirements for clinical trials have yet to be developed or are not harmonized internationally. In this review, recent advances and challenges in the field of endothelial extracellular vesicle research are discussed and current problems and limitations regarding isolation and characterization are pointed out.

Syncytiotrophoblast extracellular vesicles - Circulating biopsies reflecting placental health

The ability to directly monitor the status of the placenta throughout pregnancy would be a major advance in both general and personalized obstetric care, allowing treatments to be tailored to the dynamic changes that can occur in gestation. Syncytiotrophoblast extracellular vesicles (STBEV) are membrane bound vesicles, released from the surface of the placenta directly into the maternal circulation, in the form of exosomes, microvesicles and apoptotic bodies. They carry many syncytiotrophoblast derived factors such as proteins, lipids, glycans and nucleic acids, which together could dynamically signal to the mother the status of the placenta. We review STBEV research and discuss the potential for STBEV to be used as circulating syncytiotrophoblast biopsies, accessible via a simple blood sample throughout pregnancy, giving a real-time readout of syncytiotrophoblast health. We also highlight advances in the use of extracellular vesicles as circulating tumour derived biopsies in the field of cancer research, which could prove beneficial to obstetric care.

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Syncytiotrophoblast release extracellular vesicles (STBEV) directly into the maternal circulation, during normal pregnancy and in increased amounts in preeclampsia, in the form of exosomes, microvesicles and apoptotic bodies.

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STBEV carry many syncytiotrophoblast derived factors such as proteins, lipids, glycans and nucleic acids, the composition of which can change with syncytiotrophoblast stress.

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Circulating STBEV are therefore placental “biopsies” accessible throughout gestation, giving a real-time readout of syncytiotrophoblast health.

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STBEV have great potential as biomarkers for monitoring heterogeneous syndromes such as PE and other forms of placental compromise/stress.

Preeclampsia and Extracellular Vesicles

Preeclampsia is a hypertensive pregnancy disorder characterized by development of hypertension and proteinuria after 20 weeks of gestation that remains a leading cause of maternal and neonatal morbidity and mortality. While preeclampsia is believed to result from complex interactions between maternal and placental factors, the proximate pathophysiology of this syndrome remains elusive. Cell-to-cell communication is a critical signaling mechanism for feto-placental development in normal pregnancies. One mechanism of cellular communication relates to activated cell-derived sealed membrane vesicles called extracellular vesicles (EVs). The concentrations and contents of EVs in biological fluids depend upon their cells of origin and the stimuli which trigger their production. Research on EVs in preeclampsia has focused on EVs derived from the maternal vasculature (endothelium, vascular smooth muscle) and blood (erythrocytes, leukocytes, and platelets), as well as placental syncytiotrophoblasts. Changes in the concentrations and contents of these EVs may contribute to the pathophysiology of preeclampsia by accentuating the pro-inflammatory and pro-coagulatory states of pregnancy. This review focuses on possible interactions among placental- and maternal-derived EVs and their contents in the initiation and progression of the pathogenesis of preeclampsia. Understanding the contributions of EVs in the pathogenesis of preeclampsia may facilitate their use as diagnostic and prognostic biomarkers.

Systemic and placental α-klotho: Effects of preeclampsia in the last trimester of gestation

INTRODUCTION

α-klotho is an anti-aging protein, potentially important in preeclampsia (PE). Produced by kidney, brain and placenta, and by mRNA splicing is both a full-length membrane-bound and a truncated soluble protein in the circulation. The membrane-bound protein is an obligate co-receptor for fibroblast growth factor 23 (FGF23) and its action on receptor (FGFR), but ADAM proteinases also cause its shedding. The aims of this study were to investigate levels of maternal plasma, placental, and fetal membrane α-Klotho and their association with placental accelerated villous maturation (AVM) in PE. In addition, placental and membrane levels of ADAM17 and FGFR were measured in the same patients.

METHODS

Maternal blood, placenta and fetal membranes from 61 women (31 with PE and 30 controls) between 32 and 40 weeks gestation were collected. Plasma α-klotho was measured by ELISA, and quantitative immunohistochemistry used for α-klotho, ADAM17 and FGFR1 in tissues. Placental AVM was histologically assessed.

RESULTS

Maternal plasma levels of α-Klotho were higher in PE compared to controls (p = 0.01) and patients with the highest levels had significantly less AVM (p = 0.03). α-Klotho, ADAM17, and FGFR were all present in syncytiotrophoblast and cytotrophoblast of membranes. Between 32 and 40 weeks gestation, all placental levels decreased in controls respectively (p = 0.04, p = 0.004, p = 0.05), but not in PE. Fetal membrane levels were unchanged.

DISCUSSION

Maternal plasma α-Klotho was increased in PE and its levels associated with reduced placental AVM. Changes in placental α-Klotho, ADAM17, and FGFR suggest their involvement in the pathophysiology of PE.

Analyses of Endothelial Cells and Endothelial Progenitor Cells Released Microvesicles by Using Microbead and Q-dot Based Nanoparticle Tracking Analysis

Accurate analysis of specific microvesicles (MVs) from biofluids is critical and challenging. Here we described novel methods to purify and detect MVs shed from endothelial cells (ECs) and endothelial progenitor cells (EPCs) by combining microbeads with fluorescence quantum dots (Q-dots) coupled nanoparticle tracking analysis (NTA). In the in vitro screening systems, we demonstrated that 1) anti-CD105 (EC marker) and anti-CD34 (EPC marker) conjugated-microbeads had the highest sensitivity and specificity for isolating respective MVs, which were confirmed with negative controls, CD41 and CD235a; 2) anti-CD144 (EC marker) and anti-KDR (EPC marker) conjugated-Q-dots exhibited the best sensitivity and specificity for their respective MV NTA detection, which were confirmed with positive control, anti-Annexin V (MV universal marker). The methods were further validated by their ability to efficiently recover the known amount of EC-MVs and EPC-MVs from particle-depleted plasma, and to detect the dynamical changes of plasma MVs in ischemic stroke patients, as compared with traditional flow cytometry. These novel methods provide ideal approaches for functional analysis and biomarker discovery of ECs- and EPCs- derived MVs.

Circulating endothelial cell number and markers of endothelial dysfunction in previously preeclamptic women

OBJECTIVE

Patients with preeclampsia (PE) have endothelial dysfunction and an increased future risk of cardiovascular (CV) mortality. The number of circulating endothelial cells (CECs) is markedly increased in conditions associated with a high degree of endothelial cell activation/injury including PE. We hypothesized that the number of CECs continues to be increased in women with a history of PE, reflecting ongoing endothelial cell activation/injury.

STUDY DESIGN

CECs, flow-mediated vasodilation, levels of adhesion molecules and soluble vascular endothelial growth factor receptor-1 (sVEGFR1), and urine albumin/creatinine ratio were determined in 21 healthy women with ongoing normal pregnancy, 24 healthy currently nonpregnant women with a history of normal pregnancy, a total of 17 women with currently active mild (n = 11) or severe (n = 6) PE without hemolysis, elevated liver enzymes, and low platelet count (HELLP) syndrome, and 16 currently nonpregnant women with a history of mild (n = 10) or severe (n = 6) PE.

RESULTS

Blood samples from women with active preeclampsia had higher CECs (9.9 ± 7.9 cells/mL) than healthy pregnant women (3.0 ± 4.1 cells/mL; P < .001), healthy nonpregnant women with a history of normal pregnancy (3.4 ± 4.0 cells/mL; P < .001), or women with a history of preeclampsia (2.4 ± 2.0 cells/mL; P < .001). The number of CECs were similar between women with a history of preeclampsia and healthy nonpregnant women with a history of normal pregnancy. Patients with active preeclampsia had significantly higher soluble vascular cell adhesion molecule-1, soluble E-selectin, sVEGFR1, and urinary albumin/creatinine ratio than healthy pregnant women. However, soluble vascular cell adhesion molecule-1, soluble E-selectin, urinary albumin/creatinine ratio were similar in women with a history of preeclampsia and healthy nonpregnant women with a history of normal pregnancy. However, women with a history of preeclampsia had higher sVEGFR1 levels than women with a history of normal pregnancy (P < .05).

CONCLUSION

Markers of endothelial activation, dysfunction, and damage were increased in patients with PE. After the delivery, this activation status is similar to the age-matched nonpregnant women with a history of normal pregnancy. However, sVEGFR-1 levels remain higher in women with a history of preeclampsia compared with women without a history of preeclampsia.

Inflammation-induced endothelial cell-derived extracellular vesicles modulate the cellular status of pericytes

Emerging lines of evidence have shown that extracellular vesicles (EVs) mediate cell-to-cell communication by exporting encapsulated materials, such as microRNAs (miRNAs), to target cells. Endothelial cell-derived EVs (E-EVs) are upregulated in circulating blood in different pathological conditions; however, the characteristics and the role of these E-EVs are not yet well understood. In vitro studies were conducted to determine the role of inflammation-induced E-EVs in the cell-to-cell communication between vascular endothelial cells and pericytes/vSMCs. Stimulation with inflammatory cytokines and endotoxin immediately induced release of shedding type E-EVs from the vascular endothelial cells, and flow cytometry showed that the induction was dose dependent. MiRNA array analyses revealed that group of miRNAs were specifically increased in the inflammation-induced E-EVs. E-EVs added to the culture media of cerebrovascular pericytes were incorporated into the cells. The E-EV-supplemented cells showed highly induced mRNA and protein expression of VEGF-B, which was assumed to be a downstream target of the miRNA that was increased within the E-EVs after inflammatory stimulation. The results suggest that E-EVs mediate inflammation-induced endothelial cell-pericyte/vSMC communication, and the miRNAs encapsulated within the E-EVs may play a role in regulating target cell function. E-EVs may be new therapeutic targets for the treatment of inflammatory diseases.

Evaluation of plasma endothelial microparticles in pre-eclampsia

Objective

To compare the antepartum and postpartum plasma concentrations of endothelial microparticles (EMPs) in patients with pre-eclampsia with those of healthy control subjects with normal pregnancies.

Methods

Plasma concentrations of EMPs were measured using specific antibody labelling and flow cytometry prior to delivery by caesarean section (antepartum), and again at 24 h and 72 h postpartum. The correlations between EMP concentration and mean arterial pressure (MAP), and between EMP concentration and 24-h urine protein were analysed.

Results

A total of 59 patients with pre-eclampsia and 60 healthy control subjects participated in the study. The antepartum plasma EMP concentration was significantly higher in patients with pre-eclampsia than in healthy control subjects with normal pregnancies (2863.5 ± 1543.1 versus 1703.0 ± 592.2 EMPs/ml, respectively); similar findings were observed at 24 h postpartum (1836.7 ± 1153.8 versus 1421.8 ± 760.2 EMPs/ml, respectively). There was no significant difference between the two groups at 72 h postpartum. The antepartum plasma EMP concentration in patients with pre-eclampsia demonstrated a significant positive correlation with MAP ( r = 0.716) and with 24-h urine protein ( r = 0.770).

Conclusion

Plasma EMP concentration might serve as a biomarker to evaluate the severity of pre-eclampsia in the future.

Placenta-derived microparticles

Microparticles (MPs), sub-micron membrane vesicles, participate in the placental and maternal crosstalk in normal pregnancies as well as in gestational vascular complications (GVC). The article will review the effects of MPs on placental physiological processes, including hemostasis, trophoblast migration, invasion, placental vasculature and their involvement in pathologic states such as thrombosis, inflammation and endothelial dysfunction, resulting in GVC.

Microvesicles of women with gestational hypertension and preeclampsia affect human trophoblast fate and endothelial function

Microvesicles shedding from cell membrane affect inflammation, apoptosis, and angiogenesis. We hypothesize that microvesicles of women with gestational vascular complications reflect pathophysiological state of the patients and affect their endothelial and trophoblast cell function. Microvesicles of healthy pregnant women, women with gestational hypertension, mild, or severe preeclampsia/toxemia, were characterized, and their effects on early-stage or term trophoblasts and endothelial cells were evaluated using apoptosis, migration, and tube formation assays. Patient subgroups differed significantly only in proteinuria levels, therefore their microvesicles were assessed as 1 group, demonstrating higher levels of inflammatory and angiogenic proteins compared with those of healthy pregnant women. In endothelial cells, microvesicles of healthy pregnant women reduced caspase 3/7 activity, increased migration, and induced tube formation. These processes were suppressed by microvesicles of women with gestational vascular complications. In early-stage trophoblasts, microvesicles of healthy pregnant women decreased apoptosis compared with untreated cells (6±5% versus 13.8±5.8%; P<0.001) and caspase 3/7 activity and induced higher migration (39.7±10.1 versus 20.3±8.3 mm2; P<0.001). This effect was mediated through extracellular signal-regulated kinase pathway. Conversely, microvesicles of women with gestational vascular complications increased term trophoblast apoptosis compared with cells exposed to microvesicles of healthy pregnant women (15.1±3.3% versus 6.5±2.1%; P<0.001) and inhibited early-stage trophoblasts migration (21.4±18.5 versus 39.7±10.1 mm2; P<0.001). In conclusion, microvesicle content and effects on endothelial and trophoblast cells vary according to the physiological/pathological state of a pregnant woman. Microvesicles seem to play a pivotal role in the course of pregnancy, which could potentially result in gestational vascular complications.

Differences and similarities in the transcriptional profile of peripheral whole blood in early and late-onset preeclampsia: insights into the molecular basis of the phenotype of preeclampsiaa

OBJECTIVE

Preeclampsia (PE) can be sub-divided into early- and late-onset phenotypes. The pathogenesis of these two phenotypes has not been elucidated. To gain insight into the mechanisms of disease, the transcriptional profiles of whole blood from women with early- and late-onset PE were examined.

METHODS

A cross-sectional study was conducted to include women with: i) early-onset PE (diagnosed prior to 34 weeks, n=25); ii) late-onset PE (after 34 weeks, n=47); and iii) uncomplicated pregnancy (n=61). Microarray analysis of mRNA expression in peripheral whole blood was undertaken using Affymetrix microarrays. Differential gene expression was evaluated using a moderated t-test (false discovery rate <0.1 and fold change >1.5), adjusting for maternal white blood cell count and gestational age. Validation by real-time qRT-PCR was performed in a larger sample size [early PE (n=31), late PE (n=72) and controls (n=99)] in all differentially expressed genes. Gene ontology analysis and pathway analysis were performed.

RESULTS

i) 43 and 28 genes were differentially expressed in early- and late-onset PE compared to the control group, respectively; ii) qRT-PCR confirmed the microarray results for early and late-onset PE in 77% (33/43) and 71% (20/28) of genes, respectively; iii) 20 genes that are involved in coagulation (SERPINI2), immune regulation (VSIG4, CD24), developmental process (H19) and inflammation (S100A10) were differentially expressed in early-onset PE alone. In contrast, only seven genes that encoded proteins involved in innate immunity (LTF, ELANE) and cell-to-cell recognition in the nervous system (CNTNAP3) were differentially expressed in late-onset PE alone. Thirteen genes that encode proteins involved in host defense (DEFA4, BPI, CTSG, LCN2), tight junctions in blood-brain barrier (EMP1) and liver regeneration (ECT2) were differentially expressed in both early- and late-onset PE.

CONCLUSION

Early- and late-onset PE are characterized by a common signature in the transcriptional profile of whole blood. A small set of genes were differentially regulated in early- and late-onset PE. Future studies of the biological function, expression timetable and protein expression of these genes may provide insight into the pathophysiology of PE.

The anti-aging factor α-klotho during human pregnancy and its expression in pregnancies complicated by small-for-gestational-age neonates and/or preeclampsia

OBJECTIVE

α-klotho, a protein with anti-aging properties, has been involved in important biological processes, such as calcium/phosphate metabolism, resistance to oxidative stress, and nitric oxide production in the endothelium. Recent studies have suggested a role of α-klotho in endocrine regulation of mineral metabolism and postnatal growth in infants. Yet, the role of α-klotho during pregnancy remains largely unknown. The aim of this study was to determine whether maternal plasma concentration of α-klotho changes during pregnancy and evaluate its expression in pregnancies complicated by small for gestational age (SGA) and/or preeclampsia (PE).

STUDY DESIGN

This cross-sectional study included patients in the following groups: (1) non pregnant women (n = 37); (2) uncomplicated pregnancy (n = 130); (3) PE without an SGA neonate (PE; n = 58); (4) PE with an SGA neonate (PE and SGA; n = 52); and (5) SGA neonate without PE (SGA; n = 52). Plasma concentrations of α-klotho were determined by ELISA.

RESULTS

The median plasma α-klotho concentration was higher in pregnant than in non-pregnant women. Among women with an uncomplicated pregnancy, the median plasma concentration of α-klotho increased as a function of gestational age (Spearman Rho = 0.2; p = 0.006). The median (interquartile range) plasma concentration of α-klotho in women with PE and SGA [947.6 (762-2013) pg/mL] and SGA without PE [1000 (585-1567) pg/mL] were 21% and 17% lower than that observed in women with an uncomplicated pregnancy [1206.6 (894-2012) pg/mL], (p = 0.005 and p = 0.02), respectively. Additionally, there were no significant differences in the median plasma concentration of α-klotho between uncomplicated pregnancies and women with PE without an SGA neonate (p = 0.5).

CONCLUSION

Maternal plasma concentration of α-klotho was higher during pregnancy than in a non-pregnant state. Moreover, the median maternal plasma concentration of α-klotho was lower in mothers who delivered an SGA neonate than in those with an uncomplicated pregnancy regardless of the presence or absence of PE.

Maternal plasma soluble TRAIL is decreased in preeclampsia

OBJECTIVE

Preeclampsia (PE) is characterized by systemic intravascular inflammation. Women who develop PE are at an increased risk for cardiovascular disease in later life. Tumor necrosis factor related apoptosis-inducing ligand (TRAIL) has anti-atherosclerotic effects in endothelial cells and can mediate neutrophil apoptosis. Low soluble TRAIL (sTRAIL) and high C-reactive protein (CRP) concentrations are associated with an increased risk of future cardiovascular disease in non-pregnant individuals. The aim of this study was to determine whether maternal plasma concentrations of sTRAIL and CRP differ between women with PE and those with uncomplicated pregnancies.

METHOD

This cross-sectional study included women with an uncomplicated pregnancy (n = 93) and those with PE (n = 52). Maternal plasma concentrations of sTRAIL and CRP concentrations were determined by ELISA.

RESULTS

1) The median plasma sTRAIL concentration (pg/mL) was significantly lower and the median plasma CRP concentration was significantly higher in women with PE than in those with an uncomplicated pregnancy (25.55 versus 29.17; p = 0.03 and 8.0 versus 4.1; p = 0.001, respectively); 2) the median plasma concentration sTRAIL/CRP ratio was two-fold lower in women with PE than in those with an uncomplicated pregnancy (p < 0.001); and 3) women with plasma sTRAIL and CRP ratio in the lowest quartile were 8 times more likely to have PE than women with concentrations in the upper three quartiles (OR 8.9; 95% CI: 2.8-27.8).

CONCLUSION

Maternal plasma sTRAIL concentrations are lower (while those of CRP are higher) in women with PE than in those with uncomplicated pregnancies. These findings are consistent with the evidence of intravascular inflammation in this disorder.

Plasma concentrations of angiogenic/anti-angiogenic factors have prognostic value in women presenting with suspected preeclampsia to the obstetrical triage area: a prospective study

OBJECTIVE

To prospectively determine the prognostic value of maternal plasma concentrations of placental growth factor (PlGF), soluble endoglin (sEng) and soluble vascular endothelial growth factor receptors-1 and -2 (sVEGFR-1 and -2) in identifying patients with suspected preeclampsia (PE), who require preterm delivery (PTD) or develop adverse outcomes.

STUDY DESIGN

This prospective cohort study included 85 consecutive patients who presented to the obstetrical triage area at 20-36 weeks with a diagnosis of "rule out PE." Patients were classified as: 1) those who remained stable until term (n = 37); and 2) those who developed severe PE and required PTD (n = 48). Plasma concentrations of PlGF, sEng and sVEGFR-1 and -2 were determined by ELISA.

RESULTS

Patients with PlGF/sVEGFR-1 ≤0.05 multiples of the median (MoM) or PlGF/sEng ≤0.07 MoM were more likely to deliver preterm due to PE [adjusted odd ratio (aOR) 7.4 and 8.8], and to develop maternal (aOR 3.7 and 2.4) or neonatal complications (aOR 10.0 and 10.1). Among patients who presented <34 weeks of gestation, PlGF/sVEGFR-1 ≤ 0.035 MoM or PlGF/sEng ≤0.05 MoM had a sensitivity of 89% (16/18), specificity of 96% (24/25) and likelihood ratio for a positive test of 22 to identify patients who delivered within 2 weeks. The addition of the PlGF/sVEGFR-1 ratio to standard clinical tests improved the sensitivity at a fixed false-positive rate of 3% (p = 0.004) for the identification of patients who were delivered due to PE within 2 weeks. Among patients who had a plasma concentration of PlGF/sVEGFR-1 ratio ≤0.035 MoM, 0.036-0.34 MoM and ≥0.35 MoM, the rates of PTD <34 weeks were 94%, 27% and 7%, respectively.

CONCLUSIONS

The determination of angiogenic/anti-angiogenic factors has prognostic value in patients presenting to the obstetrical triage area with suspected PE for the identification of those requiring preterm delivery and at risk for adverse maternal/neonatal outcomes.

Maternal plasma concentrations of sST2 and angiogenic/anti-angiogenic factors in preeclampsia

OBJECTIVES

Angiogenic/anti-angiogenic factors have emerged as one of the promising biomarkers for the prediction of preeclampsia. Since not all patients with preeclampsia can be identified by these analytes, the search for additional biomarkers continues. The soluble form of ST2 (sST2), a protein capable of binding to interleukin (IL)-33 and thus contributing to a Th1-biased immune response, has been reported to be elevated in maternal plasma of women with preeclampsia. The aims of this study were to examine: (1) differences in maternal plasma concentrations of sST2 and IL-33 between women diagnosed with preeclampsia and those having uncomplicated pregnancies; (2) the relationship between sST2, umbilical and uterine artery Doppler velocimetry, and the severity of preeclampsia; and (3) the performance of sST2 and angiogenic/anti-angiogenic factors in identifying patients with preeclampsia at the time of diagnosis.

METHODS

This cross-sectional study included women with preeclampsia (n = 106) and women with an uncomplicated pregnancy (n = 131). Plasma concentrations of sST2, IL-33, soluble vascular endothelial growth factor receptor (sVEGFR)-1, soluble endoglin (sEng) and placental growth factor (PlGF) were determined by enzyme linked immune sorbent assay. Area under the receiver operating characteristic curve (AUC) for the identification of preeclampsia was examined for each analyte.

RESULTS

(1) Patients with preeclampsia had a higher mean plasma concentrations of sST2 than those with an uncomplicated pregnancy (p < 0.0001), while no significant difference in the mean plasma concentration of IL-33 between the two groups was observed; (2) the magnitude of this difference was greater in early-onset, compared to late-onset disease, and in severe compared to mild preeclampsia; (3) sST2 plasma concentrations did not correlate with the results of uterine or umbilical artery Doppler velocimetry (p = 0.7 and p = 1, respectively) among women with preeclampsia; (4) sST2 correlated positively with plasma concentrations of sVEGFR1-1 and sEng (Spearman's Rho = 0.72 and 0.63; each p < 0.0001), and negatively with PlGF (Spearman's Rho = -0.56, p < 0.0001); and (5) while the AUC achieved by sST2 and angiogenic/anti-angiogenic factors in identifying women with preeclampsia at the time of diagnosis were non-significantly different prior to term (<37 weeks of gestation), thereafter the AUC achieved by sST2 was significantly less than that achieved by angiogenic/anti-angiogenic factors.

CONCLUSIONS

Preeclampsia is associated with increased maternal plasma concentrations of sST2. The findings that sST2 concentrations do not correlate with uterine or umbilical artery Doppler velocimetry in women with preeclampsia suggest that elevated maternal plasma sST2 concentrations in preeclampsia are not related to the increased impedance to flow in the utero-placental circulation. The performance of sST2 in identifying preeclampsia at the time of diagnosis prior to 37 weeks of gestation was comparable to that of angiogenic/anti-angiogenic factors. It remains to be elucidated if an elevation of maternal plasma sST2 concentrations in pregnancy is specific to preeclampsia.

Maternal plasma 25-hydroxyvitamin D levels, angiogenic factors, and preeclampsia

OBJECTIVE

The objective of the study was to examine the associations of maternal plasma levels of 25-hydroxyvitamin D [25(OH)D] with angiogenesis and endothelial dysfunction indicators: soluble fms-like tyrosine kinase-1 (sFlt-1), placental growth factor (PlGF), intercellular adhesion molecule-1 (ICAM-1), vascular adhesion molecule-1 (VCAM-1), and risk of preeclampsia.

STUDY DESIGN

In this prospective cohort study (n = 697), maternal plasma 25(OH)D levels were measured at 12-18 and 24-26 weeks; sFlt-1, PlGF, ICAM-1, and VCAM-1 levels were measured at 24-26 weeks.

RESULTS

Maternal PlGF levels were significantly lower in women with 25(OH)D less than 50 nmol/L at 12-18 weeks (median, 449.5 vs 507.9 pg/mL, P = 0.04) and 24-26 weeks (median, 450.4 vs 522.5 pg/mL, P = 0.007). Both maternal 25(OH)D and PlGF levels were inversely associated with the risk of preeclampsia (both P < .05). However, based on a test of interaction, there was no evidence that the association between vitamin D and preeclampsia depended on the level of PlGF.

CONCLUSION

Maternal vitamin D deficiency is associated with low PlGF levels and increased preeclampsia risk. However, our data do not support the hypothesis that the association between vitamin D deficiency and preeclampsia is mediated by impaired angiogenesis.

Preeclampsia is a biomarker for vascular disease in both mother and child: the need for a medical alert system

This paper reviews the literature pertaining to the impact of preeclampsia not only on the mother but particularly on the children. The review points to the higher blood pressure in children born to preeclamptic mothers compared to controls, their increased tendency to suffer strokes, the reduction in their cognitive ability, and their vulnerability to depression. Mechanisms that may induce these changes are emphasized, particularly the placental vascular insufficiency and the resulting hypoxic and proinflammatory environments in which the fetus develops. The hypothesis proposed is that these changes in the fetal-placental environment result in epigenetic programming of the child towards a higher propensity for vascular disease. The review's main recommendation is that, within ethical boundaries, the medical records of individuals born to preeclamptic mothers should clearly indicate this event and should be made available to the affected individuals so that preventive measures against vascular complications and lifestyle changes that may mitigate the latter can be instituted.

Maternal plasma concentrations of angiogenic/antiangiogenic factors in the third trimester of pregnancy to identify the patient at risk for stillbirth at or near term and severe late preeclampsia

OBJECTIVE

To determine whether maternal plasma concentrations of placental growth factor (PlGF), soluble endoglin (sEng), and soluble vascular endothelial growth factor receptor-1 (sVEGFR-1) at 30-34 weeks of gestation can identify patients at risk for stillbirth, late preeclampsia, and delivery of small-for-gestational-age (SGA) neonates.

STUDY DESIGN

A prospective cohort study included 1269 singleton pregnant women from whom blood samples were obtained at 30-34 weeks of gestation and who delivered at >34 weeks of gestation. Plasma concentrations of PlGF, sEng, and sVEGFR-1 were determined by enzyme-linked immunosorbent assay.

RESULTS

The prevalence of late (>34 weeks of gestation) preeclampsia, severe late preeclampsia, stillbirth, and SGA was 3.2% (n = 40), 1.8% (n = 23), 0.4% (n = 5), and 8.5% (n = 108), respectively. A plasma concentration of PlGF/sEng <0.3 MoM was associated with severe late preeclampsia (adjusted odds ratio, 16); the addition of PlGF/sEng to clinical risk factors increased the area under the receiver-operating characteristic curve from 0.76 to 0.88 (P = .03). The ratio of PlGF/sEng or PlGF/sVEGFR-1 in the third trimester outperformed those obtained in the first or second trimester and uterine artery Doppler velocimetry at 20-25 weeks of gestation for the prediction of severe late preeclampsia (comparison of areas under the receiver-operating characteristic curve; each P ≤ .02). Both PlGF/sEng and PlGF/sVEGFR-1 ratios achieved a sensitivity of 74% with a fixed false-positive rate of 15% for the identification of severe late preeclampsia. A plasma concentration of PlGF/sVEGFR-1 <0.12 MoM at 30-34 weeks of gestation had a sensitivity of 80%, a specificity of 94%, and a likelihood ratio of a positive test of 14 for the identification of subsequent stillbirth. Similar findings (sensitivity 80%; specificity 93%) were observed in a separate case-control study.

CONCLUSION

Risk assessment for stillbirth and severe late preeclampsia in the third trimester is possible with the determination of maternal plasma concentrations of angiogenic and antiangiogenic factors at 30-34 weeks of gestation.