Juan L. Delgado

2-methoxyestradiol plasma levels are associated with clinical severity indices and biomarkers of preeclampsia.

We investigated whether clinical severity indices and biomarkers for preeclampsia (PE) are associated with low plasmatic 2-methoxyestradiol (2ME) in the third trimester of gestation. Blood was collected from 53 women with PE and 73 control pregnant women before parturition. The concentration of 2ME was significantly higher in controls than in patients with PE (2906.43 ± 200.69 pg/mL vs 1818.41 ± 189.25 pg/mL). The risk of PE decreased as 2ME levels increased. The 2ME values were negatively correlated with systolic peak arterial pressure and proteinuria in PE. Additionally, those women with PE with lower 2ME had a more serious clinical situation and needed a more aggressive therapy. Finally, 2ME levels (in patients with PE and total population) were significantly correlated with concentrations of soluble fms-like tyrosine kinase 1 and placental growth factor . Summarizing, patients with PE had lower 2ME levels that were correlated with different clinical indices and biomarkers of severity, indicating that 2ME could be taken into account for the clinical management of this syndrome.

Reliability of examining the external iliac artery with Doppler ultrasound in the first trimester and its relationship with maternal blood pressure and uterine artery blood flow

OBJECTIVE To explore the reliability of examining the external iliac artery (EIA) at 11+0 to 13+6 weeks of gestation with Doppler ultrasound and its relationship with maternal characteristics and uterine artery blood flow. STUDY DESIGN Cross-sectional study of 451 pregnant women undergoing an ultrasound scan in the first trimester. Mean pulsatility index (PI) of both EIAs was correlated to maternal characteristics (maternal age, parity, body mass index and mean arterial blood pressure (MAP)) and ultrasound parameters (crown-rump length (CRL) and mean uterine artery PI). Mean EIA-PI was logarithmically transformed to perform multiple linear regression analysis. The intra- and inter-observer reproducibilities of EIA-PI were examined. RESULTS Satisfactory flow velocity waveforms were obtained from both EIA in all patients. There is a significant negative correlation between mean EIA pulsatility index and maternal blood pressure. Multiple linear regression analysis showed an independent contribution of MAP to log EIA-PI (mean) (standardized regression coefficient = -0.20, 95% CI: -0.005 to -0.002). The intra-class correlation coefficients (ICCs) for intraobserver and interobserver reproducibility were 0.94 (95% CI, 0.88-0.97) and 0.87 (0.76-0.94) respectively. CONCLUSIONS Examining blood flow in the external iliac artery using Doppler ultrasound in the first trimester is feasible and reproducible. There is a negative correlation between mean EIA-PI and maternal blood pressure.

Hemodynamic effect of 17β-estradiol in absence of NO in ovariectomized rats: role of angiotensin II

Previous reports correlate plasma levels of estrogen with increased nitric oxide (NO) production. To investigate whether the hemodynamic effects of estrogens are mediated by NO, we compared the hemodynamic changes induced by 17β-estradiol (100 μg/kg) in the absence and presence of the NO synthesis inhibitor N ω-nitro-l-arginine methyl ester (l-NAME). All protocols were performed in ovariectomized, conscious rats. Estradiol alone resulted in no significant changes in cardiac index (CI) or mean arterial pressure (MAP). However, in the presence ofl-NAME, estradiol induced a significant increase in total peripheral resistance (TPR) of 37.3 ± 11.7% and a decrease in CI of 27 ± 4.9%, without changes in MAP. Previous blockade of angiotensin II AT1 receptors with losartan prevented any change in CI and TPR induced by 17β-estradiol in the presence of l-NAME. These observations suggest that NO is necessary to offset a vasoconstrictor action of angiotensin II, which is stimulated by estradiol administration.

sFlt-1/PlGF for early-onset pre-eclampsia prediction: STEPS (Study of Early Pre-eclampsia in Spain)

A high ratio of soluble fms‐like tyrosine kinase‐1 (sFlt‐1) to placental growth factor (PlGF) has been linked to pre‐eclampsia (PE). We evaluated the sFlt‐1/PlGF ratio as a predictive marker for early‐onset PE in women at risk of PE.

Fetal Val108/158Met catechol-O-methyltransferase (COMT) polymorphism and placental COMT activity are associated with the development of preeclampsia.

OBJECTIVE To evaluate the association between fetal and maternal catechol-O-methyltransferase (COMT) Val158Met and methyl tetrahydrofolate reductase (MTHFR) C677T functional polymorphisms and preeclampsia, examining its influence on placental COMT and in maternal 2-methoxyestradiol (2-ME) plasma levels. DESIGN Prospective case-control study. SETTING University hospital. PATIENT(S) A total of 53 preeclamptic and 72 normal pregnant women. INTERVENTION(S) Maternal and cord blood samples and placental tissue samples were obtained. MAIN OUTCOME MEASURE(S) Maternal and fetal COMT and MTHFR polymorphisms were genotyped. Maternal plasma 2-ME and homocysteine levels, and expression and activity of placental COMT were measured. RESULT(S) The odds ratio for the risk of preeclampsia for fetal COMT Met/Met was 3.22, and it increased to 8.65 when associated with fetal MTHFR TT. Placental COMT activity and expression were influenced by genotype, but COMT activity in preeclamptic placentas did not differ from control pregnancies. There was no association between any genotypes and maternal 2-ME. Homocysteine levels were higher in women with preeclampsia than in normal pregnancies, and were inversely correlated with 2-ME plasma levels, indicating that its altered metabolism may lower COMT activity in vivo. CONCLUSION(S) Fetal Met-Met COMT genotype reduces COMT placental expression and activity in vitro and increases preeclampsia, risk but it does not explain the difference in maternal 2-ME levels between preeclamptic and normal pregnancies. However, the preeclamptic patients had elevated homocysteine levels that correlated inversely with 2-ME, indicating that an altered methionine-homocysteine metabolism may contribute to reduce COMT activity in vivo and explain the decreased levels of 2-ME in preeclamptic women.

Umbilical artery Doppler at 19 to 22 weeks of gestation in the prediction of adverse pregnancy outcomes.

The aim of this study was to determine the clinical utility of Doppler assessment of the umbilical artery in the second trimester scan for predicting adverse pregnancy outcomes.

sFlt‐1/PlGF for prediction of early‐onset pre‐eclampsia: STEPS (Study of Early Pre‐eclampsia in Spain)

A high ratio of soluble fms‐like tyrosine kinase‐1 (sFlt‐1) to placental growth factor (PlGF) has been linked to pre‐eclampsia (PE). We evaluated the sFlt‐1/PlGF ratio as a predictive marker for early‐onset PE in women at risk of PE.

Uterine and umbilical artery Doppler at 28 weeks for predicting adverse pregnancy outcomes in women with abnormal uterine artery Doppler findings in the early second trimester

The objective of this study was to determine the contribution of uterine (UtA) and umbilical arteries (UA) Doppler examination at 28 weeks to predict adverse pregnancy outcomes in women who had increased resistance in UtA in the early second trimester.

Down Regulation of the Munc18b-syntaxin-11 Complex and β1-tubulin Impairs Secretion and Spreading in Neonatal Platelets

Neonatal platelets are hyporeactive and show impaired agonist-induced secretion despite no obvious abnormalities in their granules. Here, we examined, for the first time, the ultrastructure of neonatal and adult platelets following agonist activation. Under resting conditions, neonatal and adult platelets appeared ultrastructurally identical. Following agonist stimulation, however, noticeable degranulation occurred in adult platelets, while granules in neonatal platelets remained clearly visible and apparently unable to centralize or fuse. To investigate the underlying mechanisms, we first examined the expression levels of the main SNARE proteins, which mediate the membrane fusion events required for exocytosis. Neonatal platelets showed significantly reduced levels of syntaxin-11 and its regulator, Munc18b. Since granule centralization depends on contraction of the microtubule ring, we also examined the expression of its main component, β1-tubulin. Noteworthy, we found decreased TUBB1 mRNA and protein levels in neonatal platelets, while TUBB2A and TUBB isoforms were overexpressed, partially compensating for that deficiency. Finally, supporting the functional consequences of defective exocytosis, adhesion kinetic assays, performed in plasma-free medium, demonstrated delayed adhesion and spreading of neonatal platelets. This is the first report showing marked reductions of syntaxin-11-Munc18b complex and β1-tubulin in neonatal platelets, indicating that these proteins, required for platelet degranulation, are developmentally regulated.

Significant Hypo-Responsiveness to GPVI and CLEC-2 Agonists in Pre-Term and Full-Term Neonatal Platelets and following Immune Thrombocytopenia.

Neonatal platelets are hypo-reactive to the tyrosine kinase-linked receptor agonist collagen. Here, we have investigated whether the hypo-responsiveness is related to altered levels of glycoprotein VI (GPVI) and integrin α2β1, or to defects in downstream signalling events by comparison to platelet activation by C-type lectin-like receptor 2 (CLEC-2). GPVI and CLEC-2 activate a Src- and Syk-dependent signalling pathway upstream of phospholipase C (PLC) γ2. Phosphorylation of a conserved YxxL sequence known as a (hemi) immunotyrosine-based-activation-motif (ITAM) in both receptors is critical for Syk activation. Platelets from human pre-term and full-term neonates display mildly reduced expression of GPVI and CLEC-2, as well as integrin αIIbβ3, accounted for at the transcriptional level. They are also hypo-responsive to the two ITAM receptors, as shown by measurement of integrin αIIbβ3 activation, P-selectin expression and Syk and PLCγ2 phosphorylation. Mouse platelets are also hypo-responsive to GPVI and CLEC-2 from late gestation to 2 weeks of age, as determined by measurement of integrin αIIbβ3 activation. In contrast, the response to G protein-coupled receptor agonists was only mildly reduced and in some cases not altered in neonatal platelets of both species. A reduction in response to GPVI and CLEC-2, but not protease-activated receptor 4 (PAR-4) peptide, was also observed in adult mouse platelets following immune thrombocytopenia, whereas receptor expression was not impaired. Our results demonstrate developmental differences in platelet responsiveness to GPVI and CLEC-2, and also following immune platelet depletion leading to reduced Syk activation. The rapid generation of platelets during development or following platelet depletion is achieved at the expense of signalling by ITAM-coupled receptors.