Relationships between TGFβ Proteins and Oxygen Concentrations Inside the First Trimester Human Gestational Sac

UCL EGA Institute for Women's Health, University College London, London, United Kingdom.
PLoS ONE (Impact Factor: 3.23). 06/2008; 3(6):e2302. DOI: 10.1371/journal.pone.0002302
Source: PubMed


In early pregnancy, the O(2) gradient between the maternal circulation and the gestational sac tissues modulates trophoblast biological functions. The aim was to evaluate if placental partial pressure of oxygen (PaO(2)) modulates in vivo synthesis of specific placental proteins inside the first trimester gestational sac. Matched samples of peripheral venous blood, blood from the placental bed (PB), coelomic fluid (CF) and placental tissue were obtained in 37 normal pregnancies at 6-12 weeks gestation. PaO(2) was measured in PB and CF using an IRMA blood gas monitor. Inhibin A, activin A, sEng, PlGF, sFlt-1 and free VEGF concentrations were measured in all samples. HSP 70 was measured in placental extracts. ANOVA showed approximately 60% increase in PB PaO(2) (P = 0.02) between after 10 weeks gestation. Unpaired Student's T-test between two groups (6-9 weeks vs 9-12 weeks) shows a significant increase in MS Activin A (P = 0.001), CF activin A (P<0.001), MS P1GF (P = 0.001), CF PlGF (P<0.001), MS sFLT-1 (P = 0.03), CF sFLT-1 (P = 0.01), HSP 70 in placental extracts (P = 0.04) and a significant decrease in PB inhibin A levels (P<0.001) and PB sFLT-1 (P = 0.02) . Multiple correlation analysis showed a significant negative correlation between PB inhibin A levels and gestation (r = -0.45, P<0.05) and PB PaO(2) (r = -0.5, P = 0.008) and also between sFLT-1 and PB PaO(2) (P = 0.03). There was a positive correlation (P<0.01) between PlGF, sEng and VEGF levels in the placental extracts. Our results indicate a direct relationship in the early intrauterine PaO(2) in vivo and inhibin A and sFLT-1 concentrations confirming our hypothesis that specific placental proteins are regulated by intrauterine O(2) tension.

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Available from: Eric Jauniaux, Feb 09, 2014
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    • "We have previously shown that the first trimester human placenta syncytiotrophoblast is acutely sensitive to O2-mediated damage [38] and that the changes in intra-placental O2 concentration during the first half of pregnancy are essential for trophoblast differentiation and placental development [39], [40]. Furthermore, we recently found a direct relationship in the early intrauterine PaO2 in vivo and inhibin A and sFLT-1 concentrations in placental bed blood confirming our hypothesis by intrauterine O2 tension play a role in the placental proteins synthesis [41]. It has also been recently suggested that the oxidative status of the trophoblast may regulate glycosylation of proteins and thereby modulate major trophoblast cell functions [42]. "
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    ABSTRACT: IntroductionAntihypertensive drugs lower the maternal blood pressure in pre-eclampsia (PE) by direct or central vasodilatory mechanisms but little is known about the direct effects of these drugs on placental functions.ObjectiveThe aim of our study is to evaluate the effect of labetolol, hydralazine, α-methyldopa and pravastatin on the synthesis of placental hormonal and angiogenic proteins know to be altered in PE.DesignPlacental villous explants from late onset PE (n = 3) and normotensive controls (n = 6) were cultured for 3 days at 10 and 20% oxygen (O2) with variable doses anti-hypertensive drugs. The levels of activin A, inhibin A, human Chorionic Gonadotrophin (hCG), soluble fms-like tyrosine kinase-1 (sFlt-1) and soluble endoglin (sEng) were measured in explant culture media on day 1, 2 and 3 using standard immunoassays. Data at day 1 and day 3 were compared.ResultsSpontaneous secretion of sEndoglin and sFlt-1 were higher (p<0.05) in villous explants from PE pregnancies compared to controls. There was a significant time dependant decrease in the secretion of sFlt-1 and sEndoglin in PE cases, which was seen only for sFlt-1 in controls. In both PE cases and controls the placental protein secretions were not affected by varying doses of anti-hypertensive drugs or the different O2 concentration cultures, except for Activin, A which was significantly (p<0.05) higher in controls at 10% O2.InterpretationOur findings suggest that the changes previously observed in maternal serum hormones and angiogenic proteins level after anti-hypertensive treatment in PE could be due to a systemic effect of the drugs on maternal blood pressure and circulation rather than a direct effect of these drugs on placental biosynthesis and/or secretion.
    Full-text · Article · Sep 2014 · PLoS ONE
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    • "However the mechanism involved in the other 50% of RSAs remains unexplained (Unexplained RSA) [4,5]. Recent studies have indicated that placental ischemia/hypoxia and endothelial dysfunction may contribute to cases of RSA [6,7]. Yet the pathogenesis has not been fully elucidated and is still a matter of debate. "
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    ABSTRACT: Recurrent spontaneous abortion (RSA) is a health problem that affects approximately 1% to 5% reproductive age woman. Yet, in around half of these patients, the mechanism for RSA is unexplained. Recent studies have indicated that placental ischemia/hypoxia and endothelial dysfunction are important factors in miscarriage. Other studies have indicated that the level and expression of soluble FMS-like tyrosine kinase-1 (sFlt1) is increased under a hypoxic environment. However, decreased sFlt-1 in the maternal circulation during the first trimester has recently been proposed as a potential marker for identifying risk of pregnancy loss. In this prospective study clinical samples were obtained within a short time after the fetal death, protein expression and maternal serum levels of sFlt1 were assessed and compared to samples taken from those with normal pregnancies. Our results indicate that levels of VEGF and sFlt-1 are both increased in women during early pregnancy compared women that are not pregnant (p<0.05) indicating that VEGF and sFlt-1 are both associated with pregnancy. More importantly, we detected a significant (p<0.05) increase in sFlt1 and VEGF levels and expression in the RSA patients who suffered subsequent miscarriages compare to controls. These results demonstrate that there is likely a relationship between VEGF, sFlt-1 and RSA suggesting that the high levels and over expression of sFlt-1 and VEGF might be associated with the pathogenesis of RSA.
    Preview · Article · Sep 2013 · PLoS ONE
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    • "Two studies [11], [22] have recently flagged sFlt1 and PlGF as potential biomarkers of early pregnancy loss using samples collected from women presenting with symptoms of miscarriage such as abdominal pain or vaginal bleeding. In agreement with these, our analysis of MoMs clearly indicated a decline in sFlt1 in samples from pregnancies that went on to miscarry compared to those who went on to produce live offspring. "
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    ABSTRACT: Miscarriage is the most common complication of pregnancy. Pre-clinical miscarriage has an estimated incidence of 30%, whilst clinical miscarriage has an incidence of 12-15%. Two thirds of pregnancies lost to miscarriage are believed to be attributable to defective placentation, thus a number of studies have sought to identify markers of defective placentation that could be used as clinical biomarkers of miscarriage. Decreased soluble FMS-like tyrosine kinase-1 (sFlt1), placental growth factor (PlGF), and soluble endoglin (sEng) in the maternal circulation during the first trimester have recently been proposed as potential markers of pregnancy loss. However, in these studies clinical samples were only obtained once women had presented with symptoms of miscarriage. In this study we prospectively screened serum samples collected from asymptomatic women with a viable fetus. We assessed maternal serum levels of sFlt1, PlGF and sEng across the first trimester of normal pregnancy and compared levels between women who continued to a live birth, to those who subsequently miscarried. Both sFlt1 and PlGF significantly (p≤0.05) increased across gestation in normal pregnancy with serum levels rising from 0.65±0.12 ng/ml at 6 weeks to 1.85±0.24 ng/ml at 12 weeks for sFlt1, and 57.2±19.2 pg/ml to 106±22.7 pg/ml for PlGF. sEng remained unchanged throughout the the first trimester. Importantly we detected a significant (35%, p≤0.05) decrease in sFlt1 levels between our control and miscarriage cohort, however there was significant overlap between cases and controls, suggesting serum sFlt1 is unlikely to be useful as a clinical biomarker in asymptomatic women. Nevertheless, our data suggests a dysregulation of angiogenic factors may be involved in the pathophysiology of miscarriage.
    Full-text · Article · Feb 2012 · PLoS ONE
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