Placental Aromatase Is Deficient in Placental Ischemia and Preeclampsia.

INTRODUCTION: Preeclampsia is a maternal hypertensive disorder with uncertain etiology and a leading cause of maternal and fetal mortality worldwide, causing nearly 40% of premature births delivered before 35 weeks of gestation. The first stage of preeclampsia is characterized by reduction of utero-placental blood flow which is reflected in high blood pressure and proteinuria during the second half of pregnancy. In human placenta androgens derived from the maternal and fetal adrenal glands are converted into estrogens by the enzymatic action of placental aromatase. This implies that alterations in placental steroidogenesis and, subsequently, in the functionality or bioavailability of placental aromatase may be mechanistically involved in the pathophysiology of PE. METHODS: Serum samples were collected at 32-36 weeks of gestation and placenta biopsies were collected at time of delivery from PE patients (n = 16) and pregnant controls (n = 32). The effect of oxygen tension on placental cells was assessed by incubation JEG-3 cells under 1% and 8% O2 for different time periods, Timed-mated, pregnant New Zealand white rabbits (n = 6) were used to establish an in vivo model of placental ischemia (achieved by ligature of uteroplacental vessels). Aromatase content and estrogens and androgens concentrations were measured. RESULTS: The protein and mRNA content of placental aromatase significantly diminished in placentae obtained from preeclamptic patients compared to controls. Similarly, the circulating concentrations of 17-ß-estradiol/testosterone and estrone/androstenedione were reduced in preeclamptic patients vs. controls. These data are consistent with a concomitant decrease in aromatase activity. Aromatase content was reduced in response to low oxygen tension in the choriocarcinoma JEG-3 cell line and in rabbit placentae in response to partial ligation of uterine spiral arteries, suggesting that reduced placental aromatase activity in preeclamptic patients may be associated with chronic placental ischemia and hypoxia later in gestation. CONCLUSIONS: Placental aromatase expression and functionality are diminished in pregnancies complicated by preeclampsia in comparison with healthy pregnant controls.

NFAT5 Is Up-Regulated by Hypoxia: Possible Implications in Preeclampsia and Intrauterine Growth Restriction.

During gestation, low oxygen environment is a major determinant of early placentation process, while persistent placental hypoxia leads to pregnancy-related complications such as preeclampsia (PE) and intrauterine growth restriction (IUGR). PE affects 5%-8% of all pregnancies worldwide and is a cause of maternal and fetal morbidity and mortality. During placental development, persistent hypoxia due to poor trophoblast invasion and reduced uteroplacental perfusion leads to maternal endothelial dysfunction and clinical manifestation of PE. Here we hypothesized that nuclear factor of activated T cells-5 (NFAT5), a well-known osmosensitive renal factor and recently characterized hypoxia-inducible protein, is also activated in vivo in placentas of PE and IUGR complications as well as in the in vitro model of trophoblast hypoxia. In JAR cells, low oxygen tension (1% O2) induced NFAT5 mRNA and increased its nuclear abundance, peaking at 16 h. This increase did not occur in parallel with the earlier HIF1A induction. Real-time PCR and Western blot analysis confirmed up-regulation of NFAT5 mRNA and NFAT5 nuclear content in human preeclamptic placentas and in rabbit placentas of an experimentally induced IUGR model, as compared with the control groups. In vitro lambda protein phosphatase (lambda PPase) treatment revealed that increased abundance of NFAT5 protein in nuclei of either JAR cells (16 h of hypoxia) or PE and IUGR placentas is at least partially due to NFAT5 phosphorylation. NFAT5 downstream targets aldose reductase (AR) and sodium-myo-inositol cotransporter (SMIT; official symbol SLC5A3) were not significantly up-regulated either in JAR cells exposed to hypoxia or in placentas of PE- and IUGR-complicated pregnancies, suggesting that hypoxia-dependent activation of NFAT5 serves as a separate function to its tonicity-dependent stimulation. In conclusion, we propose that NFAT5 may serve as a novel marker of placental hypoxia and ischemia independently of HIF1A.

Levels of key enzymes of methionine-homocysteine metabolism in preeclampsia.

OBJECTIVE: To evaluate the role of key enzymes in the methionine-homocysteine metabolism (MHM) in the physiopathology of preeclampsia (PE). METHODS: Plasma and placenta from pregnant women (32 controls and 16 PE patients) were analyzed after informed consent. Protein was quantified by western blot. RNA was obtained with RNA purification kit and was quantified by reverse transcritase followed by real-time PCR (RT-qPCR). Identification of the C677T and A1298C methylenetetrahydrofolate reductase (MTHFR) single-nucleotide polymorphisms (SNPs) and A2756G methionine synthase (MTR) SNP was performed using PCR followed by a high-resolution melting (HRM) analysis. S-adenosyl methionine (SAM) and S-adenosyl homocysteine (SAH) were measured in plasma using high-performance liquid chromatography-tandem mass spectrometry (HPLC/MS/MS). The SNP association analysis was carried out using Fisher's exact test. Statistical analysis was performed using a Mann-Whitney test. RESULTS: RNA expression of MTHFR and MTR was significantly higher in patients with PE as compared with controls. Protein, SAM, and SAH levels showed no significant difference between preeclamptic patients and controls. No statistical differences between controls and PE patients were observed with the different SNPs studied. CONCLUSION: The RNA expression of MTHFR and MTR is elevated in placentas of PE patients, highlighting a potential compensation mechanism of the methionine-homocysteine metabolism in the physiopathology of this disease.

First trimester prediction of early onset preeclampsia using demographic, clinical, and sonographic data: a cohort study.

OBJECTIVE: The aim of this research was to evaluate the performance of a predictive model for early onset preeclampsia (PE) during early gestation. METHOD: Prospective multicenter cohort study was performed in women attending 11-14 weeks ultrasound. Medical history and biometrical variables were recorded and uterine artery Doppler was performed. All patients were followed until postpartum period. Constructed predictive models were compared using the area under the associated receiver operating characteristic curve. Sensitivity, specificity, and likelihood ratios were estimated for each outcome. RESULTS: A total of 627 patients were enrolled. Sixty-five (10.4%) developed gestational hypertension, of which 29 developed PE (4.6% of the total sample) and nine occurred before 34 weeks (1.5% of total sample). Prediction model generated for early onset PE (ePE) with 5% false positive achieve sensitivity of 62.5% and specificity of 95.5%. The positive and negative likelihood ratios for ePE were 13.9 and 0.39, respectively. Development of ePE was significantly associated with history of preterm labor (p = 0.002) and diabetes mellitus (p = 0.02). CONCLUSIONS: This study confirms the advantage of combining multiple variables for prediction of ePE.

Low 2-methoxyestradiol levels at the first trimester of pregnancy are associated with the development of pre-eclampsia.

OBJECTIVE: To determine whether maternal plasma levels of 2-methoxyestradiol (2-ME) are decreased early in pregnancies that subsequently develop pre-eclampsia (PE) and whether this difference could be attributed to the presence of Val158Met catechol-O-methyltransferase (COMT) polymorphism in the placenta. METHODS: Clinical characteristics and plasma samples were collected at 11 to 14 weeks prospectively in a cohort of patients. From them, 13 PE and 72 control pregnant women were chosen. Plasma soluble fms-like tyrosine kinase1 and placental growth factor levels were measured by electrochemiluminescence and 2-ME was measured by high-performance liquid chromatography with mass spectrometry/mass spectrometry detection. At delivery, placental tissue was collected and the Val158Met COMT polymorphism was determined by restriction fragment length polymorphism-PCR. RESULTS: At 11 to 14 weeks, patients who would develop PE have significantly lower plasma levels of 2-ME than controls [1.9 ± 2 standard error of the mean (SEM) vs 61.7 ± 27 pg/mL, P < 0.05]. The Val158Met polymorphism was more frequent in controls than in PE patients and the placental presence of COMT polymorphism was associated with a decreased risk of developing PE [PE: 23.1% vs control: 66.6%; χ(2) = 10.9, p = 0.0041]. CONCLUSIONS: Lower plasma concentrations of 2-ME during early pregnancy in patients who subsequently develop PE were found. Presence of placental Val158Met COMT polymorphism is associated with a decreased risk to develop PE, suggesting a protective role against PE.

Cerebral venous blood flow in growth restricted fetuses with an abnormal blood flow in the umbilical artery before 32 weeks of gestation.

OBJECTIVE: To evaluate the brain venous circulation in fetuses with severe intrauterine growth restriction (IUGR) before 32 weeks of gestation. STUDY DESIGN: Fifty fetuses with severe IUGR diagnosed between 27 and 32 weeks of gestation and 50 appropriate-for-gestational age (AGA) fetuses matched by gestational age were evaluated. IUGR fetuses were classified according to their hemodynamic deterioration pattern in relation to the Doppler examination of the umbilical artery (UA), middle cerebral artery (MCA) and ductus venosus (DV). The fetal venous brain blood flow was evaluated in the vein of Galen (VG), superior sagittal (SS), straight and transverse venous sinuses. RESULTS: Only the transverse sinus (TS) showed a significant reduction in the pulsatility index (PI) values in IUGR fetuses. All other veins showed similar PI values between IUGR and AGA fetuses. All cerebral veins of IUGR fetuses showed significantly increased maximum and mean velocities. All these findings did not change in relation to the hemodynamic IUGR deterioration. In nearly all normal and all IUGR fetuses, a pulsatile blood flow pattern was observed in the straight and transverse sinuses, whereas an increased pulsatile pattern in the VG and in the SS was noted in IUGR fetuses. CONCLUSION: Brain venous blood flow in IUGR fetuses shows an increment in the maximum and mean velocities of all veins and a reduction in the PI in the transverse sinus.

[Normal reference values of the pulsatility index and peak systolic velocity in the fetal middle cerebral artery during normal pregnancy]. / Valores de referencia del índice de pulsatilidad y de la velocidad máxima en la arteria cerebral media fetal durante el embarazo normal.

OBJECTIVE: To establish the normal reference values of the fetal middle cerebral artery (MCA) pulsatility index (PI) and MCA peak systolic velocity (PSV) during normal pregnancy. PARTICIPANTS AND METHODS: A total of 727 normally grown fetuses were evaluated with pulsed Doppler ultrasound between 20 and 40 weeks of gestation. The MCA was located in a transverse view of the fetal head 1 cm after its origin from the Willis vascular circle. The insonation angle was always kept as close as possible to 0. The PI and PSV were measured in 5 consecutive and uniform cardiac cycles and the mean considered as the representative for each case. Normal reference values for each gestational week were constructed. Reproducibility and agreement were analyzed for the MCA PI estimation. RESULTS: There was a significant correlation between MCA PSV and gestational age (GA) (PSV = -13.81+1.96 X GA, r2 = 0.59, p=0.001). The correlation between MCA PI and GA showed an initial increment until week 30 with a further reduction towards the end of the pregnancy (MCA PI = 2.44 + -0.02 X EG, r2 = 0.09). Reproducibility analysis of the MCA PI estimation showed an intra-class and inter-class correlation coefficients of 0.89 (95%CI 0.65-0.97) and 0.87 (95% CI 0.63-0.93), respectively. Agreement evaluation showed a mean difference between observers of 0.03 (standard deviation 0.19), with 95% limits of agreement of -0.41 a 0.35. CONCLUSION: The normal reference values obtained in this study confirm the diagnostic and prognostic capacity of the fetal MCA PI and the MCA PSV evaluation in high risk pregnancies.

[Normal reference values of the pulsatility index from the uterine and umbilical arteries during pregnancy]. / Valores de referencia del índice de pulsatilidad de las arterias uterina y umbilical durante el embarazo.

OBJECTIVE: To establish the normal reference values of the pulsatility index in the uterine (UtA PI) and umbilical (UmA PI) arteries during pregnancy. PATIENTS AND METHODS: A total of 2081 normal pregnancies with normal growth fetuses were evaluated with pulsed Doppler ultrasound (US) between 20 and 40 weeks of gestation (WG). Both, UtA and UmA, were located with color Doppler US and PI measured in 5 consecutive and uniform cardiac cycles. In the uterine arteries, mean PI from the left and right arteries (Mean UtAPI) was calculated and the prevalence of unilateral or bilateral "notch" documented. Normal reference values for each gestational week were constructed, and reproducibility analyzed. RESULTS: There was a negative correlation between the gestational age and PI values from both arteries (Mean UtAPI = 1.57 + -0.02 X WG, r2= 0.07; PI UmA = 1.56 + -0.02 X WG, r2= 0.15). The prevalence of unilateral and bilateral "notch" in the uterine arteries was (median) 5% (range 3-10%), and 17% (range 4-23%), respectively. Reproducibility analysis for calculation of the Mean UtAPI showed an intraclass and interclass correlation coefficients of 0.87 (95% confidence intervals [CI] 0.74 - 0.93) and 0.78 (95% CI 0.59-0.88), respectively, and for UmAPI, 0.97 (95% CI 0.93-0.98) and 0.94 (95% Cl 0.88-0.97), respectively. Agreement analysis between observers for the calculation of the Mean UtAPI showed a mean difference of 0.01 (SD, 0.13) (95% limits of agreement [95% LA] -0.27-0.28) and for the UmAPI mean difference of 0.04 (SD 0.16) (95% LA, -0.29 - 0.36). CONCLUSION: The reference values here obtained of the mean UtA PI and UmAPI can be applied in the clinical surveillance of normal and complicated pregnancies.