Circulating Angiogenic Factors in the Pathogenesis and Prediction of Preeclampsia

Predictive value of angiogenic factors, clinical risk factors and uterine artery Doppler for pre-eclampsia and fetal growth restriction in second and third trimester pregnancies in an Ecuadorian population

OBJECTIVE

To evaluate the performance of angiogenic factors, maternal risks and uterine artery Doppler (UAD) in the prediction of pre-eclampsia (PE) and fetal growth restriction (FGR) in a high-risk Ecuadorian population.

METHODS

Patients with singleton pregnancies (n = 346) were investigated at two clinical visits (18-25 weeks and 28-32 weeks). Mean uterine artery (UA), pulsatility index (PI) and maternal biomarkers (soluble fms-like tyrosine kinase-1, placental growth factor, sFlt-1/PLGF ratio) were obtained. The main endpoints were PE and FGR. UA PI and angiogenic factor levels were compared for the groups with PE (n = 34), FGR (n = 26), PE & FGR (n = 14) and controls (n = 272). Multivariable stepwise logistic regression was used to construct prediction models.

RESULTS

Pregnancies with either FGR or PE & FGR exhibited in the second trimester a significantly higher mean UA PI and sFlt-1/PLGF ratio and lower PLGF values compared to controls. In the third trimester, all groups with adverse outcome demonstrated significantly lower PLGF levels and a higher sFlt-1/PLGF ratio compared to normal pregnancies. Differences were most pronounced for pregnancies that developed PE and FGR for both time intervals. The combination of UAD and sFlt-1/PLGF ratio improved the predictive capacity for PE and FGR compared to each parameter alone. The best performance was obtained by integrating anamnestic risk factors, resulting in an area under the receiver operating curve for PE of 0.85 and 0.89 and for FGR of 0.79 and 0.77 in the second and third trimester, respectively.

CONCLUSION

In a high-altitude Ecuadorian population, angiogenic factors and UA PI were useful tools in the prediction of PE and/or FGR. The highest performance was achieved by the combination of these factors, including obstetric and medical history.

Serum endocan concentration in women with pre-eclampsia

PURPOSE

To investigate serum endocan levels in pregnant subjects with and without pre-eclampsia.

METHODS

This cross-sectional study was conducted on 49 pregnant women with pre-eclampsia and 32 healthy pregnant women matched for gestational age. Maternal levels of serum endocan were measured with the use of an enzyme-linked immunosorbent assay kit.

RESULTS

Mean endocan levels were not significantly different among groups (10.7 ± 4.5 vs. 10.3 ± 3.2 ng/mL, p 0.763). Mean uterine artery PI and RI were higher in the pre-eclampsia group (p < 0.001, p < 0.001). Mean endocan levels were negatively correlated with BMI at the time of blood sampling (r = -0.247, p = 0.044). There was no correlations between mean endocan levels and all the others parameters.

CONCLUSION

These findings suggest that the role of endocan in the pathogenesis of pre-eclampsia was not related to pre-eclampsia; hence, further studies are needed to investigate the role of endocan in the pathogenesis of pre-eclampsia.

In vivo experiments reveal the good, the bad and the ugly faces of sFlt-1 in pregnancy

Objective

Soluble fms-like tyrosine kinase (sFlt)-1-e15a, a primate-specific sFlt-1-isoform most abundant in the human placenta in preeclampsia, can induce preeclampsia in mice. This study compared the effects of full-length human (h)sFlt-1-e15a with those of truncated mouse (m)sFlt-1(1-3) used in previous preeclampsia studies on pregnancy outcome and clinical symptoms in preeclampsia.

Methods

Mice were injected with adenoviruses or fiber-mutant adenoviruses overexpressing hsFlt-1-e15a, msFlt-1(1-3) or control GFP under the CMV or CYP19A1 promoters on gestational day 8 (GD8) and GD11. Placentas and pups were delivered by cesarean section, and dams were monitored postpartum. Blood pressure was telemetrically recorded. Urine samples were collected with cystocentesis and examined for albumin/creatinine ratios. Tissue specimens were evaluated for transgene as well as endogenous mFlt-1 and msFlt-1-i13 expression. H&E-, Jones- and PAS-stained kidney sections were histopathologically examined. Placental GFP expression and aortic ring assays were investigated with confocal microscopy.

Results

Mean arterial blood pressure (MAP) was elevated before delivery in hsFlt-1-e15a-treated mice compared to controls (GD18: ΔMAP = 7.8 mmHg, p = 0.009), while ΔMAP was 12.8 mmHg (GD18, p = 0.005) in msFlt-1(1-3)-treated mice. Urine albumin/creatinine ratio was higher in hsFlt-1-e15a-treated mice than in controls (GD18, p = 0.04; PPD8, p = 0.03), and msFlt-1(1-3)-treated mice had marked proteinuria postpartum (PPD8, p = 4×10⁻⁵). Focal glomerular changes were detected in hsFlt-1-e15a and msFlt-1(1-3)-treated mice. Aortic ring microvessel outgrowth was decreased in hsFlt-1-e15a (p = 0.007) and msFlt-1(1-3)-treated (p = 0.02) mice. Full-length msFlt-1-i13 expression was unique for the placenta. In hsFlt-1-e15a-treated mice, the number of pups (p = 0.046), total weight of living pups (p = 0.04) and maternal weights (p = 0.04) were higher than in controls. These differences were not observed in truncated msFlt-1(1-3)-treated mice.

Conclusions

Truncated msFlt-1(1-3) simulated the preeclampsia-promoting effects of full-length hsFlt-1. MsFlt-1(1-3) had strong effect on maternal endothelium but not on placentas and embryos. In contrast, hsFlt-1-e15a induced preeclampsia-like symptoms; however, it also increased litter size. In accord with the predominant placental expression of hsFlt-1-e15a and msFlt-1-i13, full-length sFlt-1 may have a role in the regulation of embryonic development. These observations point to the difference in the biological effects of full-length and truncated sFlt-1 and the changes in the effect of full-length sFlt-1 during pregnancy, and may have important implications in the management of preeclampsia.

Early disturbed placental ischemia and hypoxia creates immune alteration and vascular disorder causing preeclampsia

Preterm preeclampsia (PE) remains a leading cause of maternal death and perinatal morbidity. The pathophysiological process that underlies PE has been proposed to occur in two episodes, the first is a reduced placental perfusion and then the maternal clinical syndrome. Placental ischemia/hypoxia is believed to result in the release of a variety of placental factors such as cytokines including TNF-α and interleukin 6, activated circulating immune cells and autoantibodies that have profound effects on blood flow and arterial pressure regulation. PE is also associated with decreased formation of vasodilators such as nitric oxide and prostacyclin. It is accompanied by widespread maternal vascular dysfunction and a chronic inflammatory response. Additionally, anti-angiogenic peptides are released, inhibiting vascular remodeling essential for increased blood flow to the growing uteroplacental unit. Although these factors accompany the clinical syndrome of PE, it is suggested that they are secondary to the maternal decrease in placental blood flow. Experimental evidence has demonstrated the importance of these soluble factors to increase blood pressure and stimulate the production of such anti-angiogenic factors, thereby eliciting a vicious cycle existing within the maternal vasculature as well as within the placental unit. These alterations in vascular function not only lead to hypertension but to multi-organ dysfunction. The quantitative importance of the various endothelial and humoral factors that mediate vascular dysfunction and hypertension during PE remains to be elucidated.

Influence of maternal pre-eclampsia on VEGF/PlGF heterodimer levels in preterm infants

OBJECTIVE

To measure VEGF/PlGF heterodimer levels in preterm infants born to mothers with preeclampsia.

METHODS

Neonates with birth weight <2000 g and gestational age ≤34 weeks were divided into two groups: born to mothers with Preeclampsia (PE) and controls. Neonates transferred from outside after the 72nd hour of life, death before blood collection, major congenital malformations or inborn errors of metabolism, and mothers with multiple pregnancies, STORCH complex infections, HIV or autoimmune conditions were excluded. Blood was collected within 72 h of birth and again at 28 days. VEGF/PlGF heterodimer levels were measured by ELISA.

RESULTS

We included 73 neonates (24 born to mothers with PE and 49 without PE). Mean gestational age was 30.32 ± 2.88 weeks and mean birth weight was 1288.62 ± 462.22 g. Median VEGF/PlGF levels were significantly higher in infants born to mothers with PE. VEGF/PlGF levels were inversely proportional to birth weight. There were no between-group differences in blood samples collected at age 28 days.

CONCLUSION

Higher VEGF/PlGF levels were higher in neonates exposed to PE, and there was a significant negative correlation between birth weight and VEGF/PlGF levels. Further studies to elucidate the role of this substance in the fetal and neonatal period are needed.

The first trimester: prediction and prevention of the great obstetrical syndromes

A number of groups are currently examining the potential of screening for pre-eclampsia and gestational diabetes at 12 weeks' gestation. This can be performed at the time of combined first-trimester screening for aneuploidy using a similar method of regression analysis to combine multiple demographic and investigative factors. At present, research into the prediction of pre-eclampsia is more robust and is associated with the potential for therapeutic intervention that can reduce the prevalence of early-onset pre-eclampsia and improve maternal and neonatal outcomes.

Carbon monoxide prevents hypertension and proteinuria in an adenovirus sFlt-1 preeclampsia-like mouse model

Preeclampsia (PE) remains a leading cause of maternal and neonatal morbidity and mortality worldwide. Smoking cigarettes is associated with a decreased incidence of PE. Based on this observation and previous work, we hypothesize that women who smoke have a lower risk of developing PE because of elevated levels of carbon monoxide (CO) in their blood. The objective of this study was to determine if low-dose CO in ambient air could attenuate the late pregnancy hypertension (HTN) and proteinuria in the Adenovirus (Ad) sFlt-1 PE-like mouse model. Continuous low-dose CO treatment (250 ppm) was started on E10.5 and maintained until E17.5. Compared to control and Ad empty vector, AdsFlt-1 mice displayed late- gestation HTN (E14.5–17.5) (P<0.05), proteinuria (P<0.05) and reduced Bowman's space which were all prevented with CO treatment. Use of the Ad (with/without sFlt-1) or CO had no effect (p>0.05) on litter size, fetal resorption numbers and fetal or placental weights. This study shows that treatment with CO can prevent HTN and proteinuria in a mouse model of PE. It provides a possible mechanism for the reduced incidence of PE in smoking women, and supports the possibility of using CO as a future treatment for PE.

Elevated maternal C-reactive protein and increased risk of schizophrenia in a national birth cohort

OBJECTIVE

The objective of the present study was to investigate an association between early gestational C-reactive protein, an established inflammatory biomarker, prospectively assayed in maternal sera, and schizophrenia in a large, national birth cohort with an extensive serum biobank.

METHOD

A nested case-control design from the Finnish Prenatal Study of Schizophrenia cohort was utilized. A total of 777 schizophrenia cases (schizophrenia, N=630; schizoaffective disorder, N=147) with maternal sera available for C-reactive protein testing were identified and matched to 777 control subjects in the analysis. Maternal C-reactive protein levels were assessed using a latex immunoassay from archived maternal serum specimens.

RESULTS

Increasing maternal C-reactive protein levels, classified as a continuous variable, were significantly associated with schizophrenia in offspring (adjusted odds ratio=1.31, 95% confidence interval=1.10-1.56). This finding remained significant after adjusting for potential confounders, including maternal and parental history of psychiatric disorders, twin/singleton birth, urbanicity, province of birth, and maternal socioeconomic status.

CONCLUSIONS

This finding provides the most robust evidence to date that maternal inflammation may play a significant role in schizophrenia, with possible implications for identifying preventive strategies and pathogenic mechanisms in schizophrenia and other neurodevelopmental disorders.

Progesterone supplementation attenuates hypertension and the autoantibody to the angiotensin II type I receptor in response to elevated interleukin-6 during pregnancy

OBJECTIVE

Preeclampsia is a multisystem disorder recognized as hypertension with proteinuria developing >20 weeks' gestation. Preeclampsia is associated with chronic immune activation characterized by increased T and B lymphocytes, cytokines, and antibodies activating the angiotensin II type I receptor (AT1-AA). Hypertension in response to elevated interleukin (IL)-6 during pregnancy occurs with increased renin activity and AT1-AA, and reduced kidney function.

STUDY DESIGN

We aim to determine whether 17-alpha-hydroxyprogesterone caproate (17-OHPC), progesterone, improved inflammatory pathways during elevated IL-6 in pregnant rats. IL-6 (5 ng/d) was infused via miniosmotic pumps into normal pregnant (NP) rats beginning on day 14 of gestation and 17-OHPC (3.32 mg/kg) was diluted in normal saline and injected on day 18. Blood pressure (mean arterial pressure [MAP]) determination and serum collection were performed on day 19 of gestation.

RESULTS

MAP in NP was 100 ± 3 mm Hg, which increased with IL-6 to 112 ± 4 mm Hg (P < .05). Pregnant rats given 17-OHPC alone had a MAP of 99 ± 3 mm Hg and MAP increased to 103 ± 2 mm Hg in IL-6+17-OHPC. AT1-AA was 1.2 ± 0.5 bpm in NP rats, increased to 17 ± 9 bpm with IL-6 infusion but administration of 17-OHPC significantly blunted AT1-AA to 4 ± 0.8 bpm in NP+IL-6+17-OHPC. Total circulating nitrate/nitrite was significantly decreased and placental Ser(1177)-phosporylated-eNOS/eNOS was lowered with IL-6 infusion. Supplementation of 17-OHPC significantly improved placental Ser(1177)-phosporylated-eNOS/eNOS however, circulating nitrate/nitrite was unchanged with 17-OHPC supplementation.

CONCLUSION

This study illustrates that 17-OHPC attenuated hypertension, decreased AT1-AA activity, and improved placental nitric oxide in response to elevated IL-6 during pregnancy and could lend hope to a new potential therapeutic for preeclampsia.

MiR-101 regulates apoptosis of trophoblast HTR-8/SVneo cells by targeting endoplasmic reticulum (ER) protein 44 during preeclampsia

To investigate a possible association between miR-101 and apoptosis of human trophoblast cells mediated by endoplasmic reticulum protein 44 (ERp44) in preeclampsia (PE), we explored the expression of miR-101 in PE placentas (n=30) compared with normotensive pregnant placentas (n=30) and the correlation between miR-101 and ERp44 was also analyzed. Furthermore, both the apoptotic rate of trophoblast cells and the ER stress-induced apoptotic proteins were assayed when the HTR-8/SVneo cells were treated with miR-101 mimics or inhibitors in vitro. We found a lower expression of miR-101 and an inverse correlation between miR-101 and ERp44 protein in PE placentas. Upregulation of miR-101 expression could inhibit trophoblast HTR-8/SVneo cell apoptosis and repress ER stress-induced apoptotic proteins by targeting ERp44 in vitro, whereas inhibition of miR-101 could induce HTR-8/SVneo cell apoptosis. Our findings indicated that overexpression of miR-101 could downregulate ERp44 and suppress apoptosis in trophoblast cells during PE. Therefore, loss of miR-101 expression could contribute to ER stress-induced trophoblast cell apoptosis by targeting ERp44.

The effect of Silymarin on VEGF, VEGFR-1 and IL-1α levels in placental cultures of severe preeclamptic women

OBJECTIVE

The purpose of this study was to evaluate the effects of Silymarin on vascular endothelial growth factor (VEGF), soluble VEGF Receptor-1 (sVEGFR-1) and Interleukin-1 alpha (IL-1α) levels in placental tissue samples of severely preeclamptic women.

MATERIAL AND METHODS

We conducted an in vitro study in Başkent University Faculty of Medicine, Ankara, Turkey between September 2008 and May 2009. A total of 16 placental tissue samples (8 from severe preeclamptic, and 8 from controls) were analysed. Placental samples were incubated, and VEGF, sVEGFR-1, and IL1-α were measured in culture media using an ELISA kit. The effect of Silymarin on these levels was investigated. Descriptive statistics were initially performed, followed by Mann Whitney U-test and Kruskal-Wallis test to compare means between groups. P values less than 0.05 were considered statistically significant.

RESULTS

Eight patients were included in the severe preeclampsia (SP) group, whereas the remaining 8 patients were included in the control group. There were no significant correlations between gestational age and placental VEGF, sVEGFR-1 and IL-1α after 48 or 72 hours of incubation. Basal VEGF levels were lower in the SP group; however, it did not reach statistical significance. sVEGFR-1 and IL-1α levels were also similar between the SP and control groups (p>0.05). After 48 and 72 hours of incubation, sVEGFR-1 levels in Silymarin-added SP and control placental cultures were lower than in the samples without Silymarin addition; however, this difference also did not reach significance.

CONCLUSION

Although we could not demonstrate a significant effect on placental cytokines, considering the role of vasospasm, inflammation, angiogenesis, endothelial cell activation, and oxidative stress in preeclampsia, the potential benefits of Silymarin should be evaluated in future trials with a larger sample size.

Examination of intrarenal resistance indices indicate the involvement of renal pathology as a significant diagnostic classifier of preeclampsia

BACKGROUND

Preeclampsia (PE) is a hypertensive disorder during pregnancy with endotheliosis leading to occlusion of renal perfusion with an impact on the glomerular filtration barrier. We therefore analyzed the role of intrarenal resistance indices in the renal interlobular arteries measured by Doppler ultrasound as a diagnosis of PE.

METHODS

Women with preeclampsia (n = 24; mean blood pressure/24 h = 145 ± 11/ 93 ± 7 mm Hg; mean proteinuria = 5.63 ± 1.0 g/24 h) were compared against a group of healthy pregnant women (n = 24). All patients underwent a Doppler ultrasound of the intrarenal arteries between the 24th week of gestation and the 5th week postpartum. Several risk factors for PE, as well as the arterial resistive indices of the Arteriae uterinae and the Arteria umbilicalis, were monitored in parallel.

RESULTS

The intrarenal resistive index (mean ± SD = 0.63 ± 0.05 in women with preeclampsia vs. 0.59 ± 0.056 in healthy pregnant women; P < 0.003), the pulsatile index (mean ± SD = 1.15 ± 0.19 in women with preeclampsia vs. 0.92 ± 0.13 in healthy pregnant women; P < 0.0001), and the end diastolic flow velocity (mean ± SD = 14.16 ± 4.75 cm/s in women with preeclampsia vs. 10.67 ± 2.68 cm/s in healthy pregnant women, P < 0.006) were elevated in patients with PE, as were the arterial resistive indices of the Aa. uterinae and A. umbilicalis. The intrarenal resistive indices correctly classified 84.2% of the women as having PE.

CONCLUSIONS

Intrarenal resistive indices are a significant classifier of PE, providing the possibility to predict nephropathy. They could be a prognostic tool for cardiovascular comorbidity in PE patients even after delivery.

Altered matrix metalloproteinase-2 and -9 expression/activity links placental ischemia and anti-angiogenic sFlt-1 to uteroplacental and vascular remodeling and collagen deposition in hypertensive pregnancy

Preeclampsia is a complication of pregnancy manifested as maternal hypertension and often fetal growth restriction. Placental ischemia could be an initiating event, but the linking mechanisms leading to hypertension and growth restriction are unclear. We have shown an upregulation of matrix metalloproteinases (MMPs) during normal pregnancy (Norm-Preg). To test the role of MMPs in hypertensive-pregnancy (HTN-Preg), maternal and fetal parameters, MMPs expression, activity and distribution, and collagen and elastin content were measured in uterus, placenta and aorta of Norm-Preg rats and in rat model of reduced uteroplacental perfusion pressure (RUPP). Maternal blood pressure was higher, and uterine, placental and aortic weight, and the litter size and pup weight were less in RUPP than Norm-Preg rats. Western blots and gelatin zymography revealed decreases in amount and gelatinase activity of MMP-2 and MMP-9 in uterus, placenta and aorta of RUPP compared with Norm-Preg rats. Immunohistochemistry confirmed reduced MMPs in uterus, placenta and aortic media of RUPP rats. Collagen, but not elastin, was more abundant in uterus, placenta and aorta of RUPP than Norm-Preg rats. The anti-angiogenic factor soluble fms-like tyrosine kinase-1 (sFlt-1) decreased MMPs in uterus, placenta and aorta of Norm-Preg rats, and vascular endothelial growth factor (VEGF) reversed the decreases in MMPs in tissues of RUPP rats. Thus placental ischemia and anti-angiogenic sFlt-1 decrease uterine, placental and vascular MMP-2 and MMP-9, leading to increased uteroplacental and vascular collagen, and growth-restrictive remodeling in HTN-Preg. Angiogenic factors and MMP activators may reverse the decrease in MMPs and enhance growth-permissive remodeling in preeclampsia.

Ion channels in the endometrium: regulation of endometrial receptivity and embryo implantation

BACKGROUND

Although embryo implantation is a prerequisite for human reproduction, it remains a poorly understood process. The molecular mechanisms regulating endometrial receptivity and/or embryo implantation are still largely unclear.

METHODS

Pubmed and Medline literature databases were searched for articles in English published up to December 2013 with relevant keywords including 'endometrium', 'Na(+), Cl(-), K(+), or Ca(2+) channels', 'ion channels', 'endometrial receptivity', 'blastocyst implantation' and 'embryo implantation'.

RESULTS

At the time of writing, more than 14 types of ion channels, including the cystic fibrosis transmembrane conductance regulator, epithelial sodium channel and various Ca(2+) and K(+) channels, had been reported to be expressed in the endometrium or cells of endometrial origin. In vitro and/or in vivo studies conducted on different species, including rodents, pigs and humans, demonstrated the involvement of various ion channels in the process of embryo implantation by regulating: (i) uterine luminal fluid volume; (ii) decidualization; and (iii) the expression of the genes associated with implantation. Importantly, abnormal ion channel expression was found to be associated with implantation failure in IVF patients.

CONCLUSIONS

Ion channels in the endometrium are emerging as important players in regulating endometrial receptivity and embryo implantation. Abnormal expression or function of ion channels in the endometrium may lead to impaired endometrial receptivity and/or implantation failure. Further investigation into the roles of endometrial ion channels may provide a better understanding of the complex process of embryo implantation and thus reveal novel targets for diagnosis and treatment of implantation failure.

Clinical syndromes associated with acquired antithrombin deficiency via microvascular leakage and the related risk of thrombosis

Antithrombin (AT) is a 65kDa glycoprotein belonging to a group of inhibitory factors known as serpins (serine protease inhibitors). It plays a critical role in the inhibition of coagulation and inflammation processes within the environment of the vascular endothelium. Inadequate levels of functional AT in plasma results in an increased risk of thrombotic events, both venous and arterial. AT deficiency can be inherited or acquired. Congenital AT deficiency is the most severe inherited thrombophilic condition with an odds ratio of 20 for the increased risk of venous thrombosis. Acquired AT deficiency occurs in a variety of physiologic and pathologic medical conditions with similar risks of increased thrombosis. In this article, we review clinical settings characterized by an acquired AT deficiency largely or partly subsequent to protein microvascular leakage. Other different mechanisms of AT depletion are implied in some clinical conditions together with endothelial loss, and, therefore, outlined. In addition, we provide a description of the current knowledge on the specific mechanisms underlying endothelial AT leakage and on the consequences of this protein decrease, specifically looking at thrombosis. We identify potential directions of research that might prove useful in patients with acquired AT deficiency.

Elevated maternal C-reactive protein and autism in a national birth cohort

Autism is a complex neuropsychiatric syndrome with a largely unknown etiology. Inflammation during pregnancy may represent a common pathway by which infections and other insults increase risk for the disorder. Hence, we investigated the association between early gestational C-reactive protein (CRP), an established inflammatory biomarker, prospectively assayed in maternal sera, and childhood autism in a large national birth cohort with an extensive serum biobank. Other strengths of the cohort included nearly complete ascertainment of pregnancies in Finland (N=1.2 million) over the study period and national psychiatric registries consisting of virtually all treated autism cases in the population. Increasing maternal CRP levels, classified as a continuous variable, were significantly associated with autism in offspring. For maternal CRP levels in the highest quintile, compared with the lowest quintile, there was a significant, 43% elevated risk. This finding suggests that maternal inflammation may have a significant role in autism, with possible implications for identifying preventive strategies and pathogenic mechanisms in autism and other neurodevelopmental disorders.

Recent insights into the pathophysiology of preeclampsia

Preeclampsia, characterized by new-onset gestational hypertension and proteinuria, is a common and serious complication of pregnancy. Evidence from both animal and human studies has implicated placental ischemia and hypoxia as a central causative factor in the etiology of the disorder. The ischemic placenta in turn initiates a cascade of secondary effector mechanisms, including altered proangiogenic and antiangiogenic factor balance, increase in maternal oxidative stress and endothelial and immunological dysfunction. The full elucidation of these mechanisms will hopefully lead to a more complete understanding of the etiology of preeclampsia and lead to successful therapeutic intervention through the targeted disruption of new and novel pathways.

An Elevated Maternal Plasma Soluble fms-Like Tyrosine Kinase-1 to Placental Growth Factor Ratio at Midtrimester Is a Useful Predictor for Preeclampsia

Background. To assess the ability of mid-trimester sFlt-1/PlGF ratio for prediction of preeclampsia in two different Arabic populations. Methods. This study measured levels of sFlt-1, PlGF, and sFlt-1/PlGF ratio at midtrimester in 83 patients who developed preeclampsia with contemporary 250 matched controls. Results. Women subsequently developed preeclampsia had significantly lower PlGF levels and higher sFlt-1 and sFlt-1/PlGF ratio levels than women with normal pregnancies (P < 0.0001 for all). Women who with preterm preeclampsia had significantly higher sFlt-1 and sFlt-1/PlGF ratio than term preeclamptic women (P = 0.01, 0.003, resp.). A cutoff value of 3198 pg/mL for sFlt-1 was able to predict preeclampsia with sensitivity, specificity, and accuracy of 88%, 83.6%, and 84.7%, respectively, with odds ratio (OR) 37.2 [95% confidence interval (CI) 17.7-78.1]. PIGF at cutoff value of 138 pg/mL was able to predict preeclampsia with sensitivity, specificity, and accuracy of 85.5%, 77.2%, and 79.3%, respectively, with OR 20 [95% CI, 10.2-39.5]. The sFlt-1/PIGF ratio at cutoff value of 24.5 was able to predict preeclampsia with sensitivity, specificity, and accuracy of 91.6%, 86.4%, and 87.7%, respectively with OR 67 [95% CI, 29.3-162.1]. Conclusion. Midtrimester sFlt-1/PlGF ratio displayed the highest sensitivity, specificity, accuracy, and OR for prediction of preeclampsia, demonstrating that it may stipulate more effective prediction of preeclampsia development than individual factor assay.

Upregulation of long noncoding RNA SPRY4-IT1 modulates proliferation, migration, apoptosis, and network formation in trophoblast cells HTR-8SV/neo

SPRY4-IT1 has been reported to have extremely high expression in normal placenta tissues. It is a Long noncoding RNA (lncRNA), which is associated with cell growth, migration, invasion, and apoptosis in melanoma. A 2.8-fold increase of SPRY4-IT1 expression was validated by Real-time reverse transcription-polymerase chain reaction (qRT-PCR) in severe preeclamptic placenta as compared with that of the normal ones (n=25) in this study. Furthermore, the role of SPRY4-IT1 in proliferation, migration, apoptosis, and network formation ability of trophoblast cells HTR-8/SVneo was assessed. Suppression of SPRY4-IT1 using siRNA treatment and its overexpression using plasmid targeting SPRY4-IT1 were performed in order to explore the biological function of SPRY4-IT1 in the development and progression of trophoblast cells HTR-8/SVneo, in vitro. The results showed that SPRY4-IT1 knockdown enhanced the cell migration and proliferation, and reduced the response of cells to apoptosis. However, exogenous SPRY4-IT1 overexpression significantly decreased the cell migration and proliferation, while increased cell apoptosis. Our study showed for the first time that aberrant expression of lncRNA SPRY4-IT1 might contribute to the abnormal condition of trophoblast cells HTR-8/SVneo. Therefore, we proposed SPRY4-IT1 as a novel lncRNA molecule, which might be associated with the pathogenesis of preeclampsia and might provide a new target for its early diagnosis and treatment.

Comparison of maternal serum PlGF and sFlt-1 between pregnancies with and without fetal hemoglobin Bart's disease

OBJECTIVE

The aim of this study was to compare the levels of maternal serum placental growth factor (PlGF) and soluble fms-like tyrosine kinase-1 (sFlt-1) between pregnancies with fetal hemoglobin (Hb) Bart's disease and unaffected pregnancies.

METHODS

Ninety-one pregnancies at risk for fetal Hb Bart's disease scheduled for cordocentesis at 18-22 weeks were recruited into the study. Maternal serum PlGF and sFlt-1 concentrations were measured before cordocentesis. Fetal blood samples were collected for thalassemia diagnosis based on fetal Hb typing using high-performance liquid chromatography. PlGF, sFlt-1, and sFlt-1/PlGF ratio were compared between the fetal Hb Bart's group and the non-Hb Bart's group (normal Hb typing or α-thalassemia-1 carrier).

RESULTS

Maternal serum concentration of PlGF was significantly higher in women with fetal Hb Bart's disease (18 cases) than those with unaffected fetuses (71 cases) (P = 0.008), whereas the concentration of sFlt-1 was not significantly different (P = 0.139). However, the sFlt-1/PlGF ratio was significantly lower in women with fetal Hb Bart's disease than those with unaffected fetuses (P = 0.001).

CONCLUSION

Placental growth factor may help differentiate affected from unaffected fetuses among pregnancies at risk, though further studies are needed to confirm its usefulness. In addition, preeclampsia prediction using these markers may be unreliable in pregnancies with placental dysfunction secondary to severe fetal anemia.

Changes in retinal microvascular caliber precede the clinical onset of preeclampsia

Preeclampsia is a leading cause of maternal morbidity and mortality. The degree of maternal cardiovascular dysfunction that precedes the onset of preeclampsia is largely unknown. This prospective cohort study aimed to characterize differences in vivo in retinal microvascular caliber and blood pressure throughout pregnancy in relation to preeclampsia development. Women were recruited from Royal Prince Alfred Hospital, Sydney, Australia, of which 92 women were included in the study. Retinal images and blood pressures were collected at 13, 19, 29, and 38 weeks of gestation. Retinal vessels were analyzed as the central retinal arteriolar equivalent corrected for mean arterial blood pressure and the central retinal venular equivalent corrected for mean arterial blood pressure, using generalized linear models adjusted for age and body mass index. The preeclampsia group were significantly older (P=0.002) and had a significantly higher mean body mass index (P=0.005). The central retinal arteriolar equivalent corrected for mean arterial blood pressure was significantly reduced at 13 (P=0.03), 19 (P=0.007), and 38 (P=0.03) weeks of gestation in the preeclampsia group. The central retinal venular equivalent corrected for mean arterial blood pressure was also significantly lower at 13 (P=0.04) and 19 (P=0.001) weeks of gestation in the women who progressed to preeclampsia. This study directly documents increased peripheral resistance in vivo, observed as the combination of constricted retinal arterioles or venules and elevated blood pressure, in women who later developed preeclampsia. This difference preceded the clinical signs of preeclampsia.

Microvascular remodelling in preeclampsia: quantifying capillary rarefaction accurately and independently predicts preeclampsia

BACKGROUND

Preeclampsia is a major cause of maternal and neonatal mortality and morbidity. The incidence of preeclampsia seems to be rising because of increased prevalence of predisposing disorders, such as essential hypertension, diabetes, and obesity, and there is increasing evidence to suggest widespread microcirculatory abnormalities before the onset of preeclampsia. We hypothesized that quantifying capillary rarefaction could be helpful in the clinical prediction of preeclampsia.

METHODS

We measured skin capillary density according to a well-validated protocol at 5 consecutive predetermined visits in 322 consecutive white women, of whom 16 subjects developed preeclampsia.

RESULTS

We found that structural capillary rarefaction at 20-24 weeks of gestation yielded a sensitivity of 0.87 with a specificity of 0.50 at the cutoff of 2 capillaries/field with the area under the curve of the receiver operating characteristic value of 0.70, whereas capillary rarefaction at 27-32 weeks of gestation yielded a sensitivity of 0.75 and a higher specificity of 0.77 at the cutoff of 8 capillaries/field with area under the curve of the receiver operating characteristic value of 0.82. Combining capillary rarefaction with uterine artery Doppler pulsatility index increased the sensitivity and specificity of the prediction. Multivariable analysis shows that the odds of preeclampsia are increased in women with previous history of preeclampsia or chronic hypertension and in those with increased uterine artery Doppler pulsatility index, but the most powerful and independent predictor of preeclampsia was capillary rarefaction at 27-32 weeks.

CONCLUSIONS

Quantifying structural rarefaction of skin capillaries in pregnancy is a potentially useful clinical marker for the prediction of preeclampsia.

Matrix metalloproteinases as drug targets in preeclampsia

Preeclampsia is an important syndrome complicating pregnancy. While the pathogenesis of preeclampsia is not entirely known, poor placental perfusion leading to widespread maternal endothelial dysfunction is accepted as a major mechanism. It has been suggested that altered placental expression of matrix metalloproteinases (MMPs) may cause shallow cytotrophoblastic invasion and incomplete remodeling of the spiral arteries. MMPs are also thought to link placental ischemia to the cardiovascular alterations of preeclampsia. In fact, MMPs may promote vasoconstriction and surface receptors cleavage affecting the vasculature. Therefore, the overall goal of this review article is to provide an overview of the pathophisiology of preeclampsia, more specifically regarding the role of MMPs in the pathogenesis of preeclampsia and the potential of MMP inhibitors as therapeutic options.

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.

Influence of maternal and cord blood C-reactive protein on childhood respiratory symptoms and eczema

BACKGROUND

Inflammatory processes during pregnancy might affect fetal lung development and immune responses. We examined the associations of maternal and cord blood C-reactive protein levels with respiratory symptoms and eczema in preschool children.

METHODS

This study was embedded in a population-based prospective cohort study of 4984 children. Generalized estimating equations were used to assess the effect of C-reactive protein levels on respiratory symptoms or eczema. C-reactive protein levels were measured during early pregnancy and at birth. Wheezing, lower respiratory tract infections, and eczema until the age of 4 yr were annually obtained by questionnaires.

RESULTS

Maternal C-reactive protein was not associated with the risks of wheezing and lower respiratory tract infections. Compared to children with maternal C-reactive protein in the lowest quarter, children in the highest quarter had increased risks of eczema OR 1.20 (1.03, 1.40). Compared to children with cord blood C-reactive protein lower than 0.20 mg/l, those with levels higher than 0.20 mg/l had increased risks of wheezing, OR 1.21 (1.07, 1.36), and lower respiratory tract infections, OR 1.21 (1.05, 1.39), but not of eczema.

CONCLUSIONS

Our results suggest that elevated maternal C-reactive protein in pregnancy is associated with a higher risk of eczema, and C-reactive protein in cord blood with a higher risk of wheezing and lower respiratory tract infections in the first 4 yrs.

Placental expression of VEGF is increased in pregnancies with hydatidiform mole: possible association with developing very early onset preeclampsia

BACKGROUND

Hydatidiform mole is an abnormal pregnancy with over-proliferation of the placenta, which causes the dysfunction of placenta. Although more than 80% of hydatidiform moles are benign with good outcome, hydatidiform moles are associated with developing very early onset preeclampsia. However the association between hydatidiform mole and very early onset preeclampsia is unclear. Preeclampsia is associated with altered levels of angiogenic factors, like vascular endothelial growth factor (VEGF) and soluble endoglin.

AIM

The aim of this study is to investigate the levels of VEGF and endoglin in hydatidiform molar placenta.

STUDY DESIGN

21 placentas from complete hydatidiform mole, 9 placentas from partial hydatidiform mole and 18 placentas from gestation matched placenta were collected in this study.

SUBJECTS

The subjects of this study are human placentas.

OUTCOME MEASURES

The protein levels and mRNA levels of VEGF and endoglin were measured using immunohistochemistry, western blotting and real time PCR.

RESULTS

The protein levels of VEGF measured by immunohistochemistry and western blotting were significant increased, as well as mRNA levels of VEGF quantified by real time PCR in hydatidiform molar placenta in comparison to normal controls. There was no difference in the protein levels of VEGF between complete and partial hydatidiform moles. In contrast, the levels of protein and mRNA in endoglin were no difference between hydatidiform molar placenta and normal controls.

CONCLUSION

In this study our data show that hydatidiform moles produce more VEGF than normal early pregnant placenta. The increased levels of angiogenic factors VEGF in hydatidiform moles may link to the mechanism of developing very early onset preeclampsia.

Nanotoxicity: a growing need for study in the endocrine system

Nanomaterials (NMs) are engineered for commercial purposes such as semiconductors, building materials, cosmetics, and drug carriers, while natural nanoparticles (NPs) already exist in the environment. Due to their unique physicochemical properties, they may interact actively with biological systems. Some of these interactions might be detrimental to human health, and therefore studies on the potential 'nanotoxicity' of these materials in different organ systems are warranted. The purpose of developing the concept of nanotoxicity is to recognize and evaluate the hazards and risks of NMs and evaluate safety. This review will summarize and discuss recent reports derived from cell lines or animal models concerning the effects of NMs on, and their application in, the endocrine system of mammalian and other species. It will present an update on current studies of the effects of some typical NMs-such as metal-based NMs, carbon-based NMs, and dendrimers-on endocrine functions, in which some effects are adverse or unwanted and others are favorable or intended. Disruption of endocrine function is associated with adverse health outcomes including reproductive failure, metabolic syndrome, and some types of cancer. Further investigations are therefore required to obtain a thorough understanding of any potential risk of pathological endocrine disruption from products containing NMs. This review aims to provide impetus for further studies on the interactions of NMs with endocrine functions.

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.

Circulating Vascular Growth Factor (VEGF) Angiopoietin-1 (Angi-1) and Soluble Tie-2 Receptor in Pregnancy Complicated with Pre-eclampsia: A Prospective Study

BACKGROUND

Preeclampsia is a leading cause of maternal and fetal/neonatal mortality and morbidity worldwide. Although the etiology of preeclampsia (PE) is still unclear, recent studies suggest that its major phenotypes, high blood pressure and proteinuria, are due in part to the disturbed angiogenic process.

STUDY DESIGN

This study included the following groups: (1) women with normal pregnancies (n = 150), (2) patients with PE (n = 88), and (3) patients who delivered small growth for date (SGA) neonate (n = 50). Maternal serum concentrations of VEGF, Angi-1, and sTie-2 were measured by a sensitive immunoassay. Non-parametric statistics were used for analysis.

RESULTS

The median maternal serum concentration of sVEGF and sAngi-1 was lower in normal pregnant women as compared to that in PE and SGA and the differences were statistically significant (P < 0.01). In contrast, there is a significant reduction in sTie-2 levels in PE and SGA groups as compared to that in normal pregnancy group (P < 0.01). Serum VEGF and Angi-1 were significantly higher in the late onset PE subgroup as compared to that in the early onset PE (P < 0.01), but sTie-2 was not significantly different in the 2 subgroups (P > 0.05). Serum VEGF, sAngi-1, and sTie-2 were significantly higher and Tie-2 was significantly lower in the severe PE subgroup as compared to that of the milder PE subgroup (P < 0.01 for all).

CONCLUSION

Patients with PE and those with SGA fetuses have lower median serum concentrations of sTie-2 and higher sVEGF and sAngi-1 than women with normal pregnancies. These findings lend support to the hypothesis that circulating angiogenic proteins may have an important biologic role in PE.

Expression of genes coding for proangiogenic factors and their receptors in human placenta complicated by preeclampsia and intrauterine growth restriction

The aim of the study was to investigate the expression of genes coding for vascular endothelial growth factor (VEGF) and placenta growth factor (PlGF) as well as their receptors, fms-like tyrosine kinase receptor 1 (VEGFR-1/Flt-1) and VEGF receptor 2 (VEGFR-2/KDR) in the placentae of patients with pregnancies complicated by preeclampsia (PE) and intrauterine growth restriction (IUGR). Tissue samples were collected from placentae of women with PE (n=31) and IUGR syndrome (n=25) as well as of healthy control women (n=31). Total RNA was extracted and purified, mRNA reversely transcribed, and amplified using real-time PCR. Expression of the examined genes was normalized to β-actin. Higher levels of PlGF (p<0.001) and Flt-1 (p<0.05) transcription were found in PE placentae compared to normal ones. A positive correlation between PlGF and Flt-1 expression was revealed in the PE patients. In conclusion, the presented data indicate the upregulation of both PlGF and Flt-1 in placentae of women with PE, which could be induced by a pathological process possibly due to endothelial dysfunction.

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.

NADPH oxidase 2-derived superoxide downregulates endothelial KCa3.1 in preeclampsia

Endothelial dysfunction is associated with KCa3.1 dysfunction and contributes to the development of hypertension in preeclampsia. However, evidence of endothelial KCa3.1 dysfunction in the vascular system from women with preeclampsia is still lacking. Therefore, we examined whether endothelial KCa3.1 dysfunction occurs in vessels from women with preeclampsia. We compared KCa3.1 and NADPH oxidase (NOX) expression in umbilical vessels and primary cultured human umbilical vein endothelial cells (HUVECs) from normal (NP; n=17) and preeclamptic pregnancy (PE; n=19) and examined the effects of plasma from NP or PE on KCa3.1 and NOX2 expression in primary cultured HUVECs from NP or human uterine microvascular endothelial cells. The endothelial KCa3.1 was downregulated, and NOX2 was upregulated, in umbilical vessels and HUVECs from PE, compared with those from NP. In addition, HUVECs from PE showed a significant decrease in KCa3.1 current. Plasma from PE induced KCa3.1 down regulation, NOX2 upregulation, phosphorylated-p38 mitogen-activated protein kinase downregulation, and superoxide generation, and these effects were prevented by antioxidants (tempol or tiron), NOX2 inhibition, or anti-lectin-like oxidized low-density lipoprotein (LDL) receptor 1 (LOX1) antibody. Oxidized LDL and the superoxide donor xanthine/xanthine oxidase mixture induced KCa3.1 downregulation. In contrast, plasma from PE did not generate hydrogen peroxide, and the hydrogen peroxide donor tert-butylhydroperoxide induced KCa3.1 upregulation. These results provide the first evidence that plasma from PE generates superoxide via a LOX1-NOX2-mediated pathway and downregulates endothelial KCa3.1, which may contribute to endothelial dysfunction and vasculopathy in preeclampsia. This suggests KCa3.1as a novel target for patients with preeclampsia.

Mechanisms of implantation: strategies for successful pregnancy

Physiological and molecular processes initiated during implantation for pregnancy success are complex but highly organized. This review primarily highlights adverse ripple effects arising from defects during the peri-implantation period that perpetuate throughout pregnancy. These defects are reflected in aberrations in embryo spacing, decidualization, placentation and intrauterine embryonic growth, manifesting in preeclampsia, miscarriages and/or preterm birth. Understanding molecular signaling networks that coordinate strategies for successful implantation and decidualization may lead to approaches to improve the outcome of natural pregnancy and pregnancy conceived from in vitro fertilization.

Pathogenesis and promising non-invasive markers for preeclampsia

Preeclampsia is one of the leading causes of maternal mortality/morbidity and preterm delivery in the world, affecting 3% to 5% of pregnant women. The pathophysiology of preeclampsia likely involves both maternal and fetal/placental factors. Abnormalities in the development of placental vessels early in pregnancy may result in placental hypoperfusion, hypoxia, or ischemia. Hypoperfusion, hypoxia, and ischemia are critical components in the pathogenesis of preeclampsia because the hypoperfused placenta transfers many factors into maternal vessels that alter maternal endothelial cell function and lead to the systemic symptoms of preeclampsia. There are several hypotheses to explain the pathogenesis of preeclampsia, including altered angiogenic balance, circulating angiogenic factors (such as marinobufagenin, a bufadienolide trigger), and activation of the renin-angiotensin system. Epigenetically-modified cell-free nucleic acids that circulate in plasma and serum might be novel markers with promising non-invasive clinical applications in the diagnosis of preeclampsia.