Abstract
In early pregnancy, the O2 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 (PaO2) 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. PaO2 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 ∼60% increase in PB PaO2 (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 PaO2 (r = −0.5, P = 0.008) and also between sFLT-1 and PB PaO2 (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 PaO2 in vivo and inhibin A and sFLT-1 concentrations confirming our hypothesis that specific placental proteins are regulated by intrauterine O2 tension.
Highlights
THE PLACENTA in mammals is the essential interface between the maternal circulation carrying oxygen (O2)-rich blood and nutrients and the fetal circulation
High concentrations of sEng were measured in Maternal serum (MS), placental bed (PB) and placental extracts. sEng levels were significantly (P,0.01) lower in coelomic fluid (CF) than in the other compartments
We found lower concentrations of sEng and PIGF and higher concentrations of s-Flt-1 in the exocoelomic cavity than in the other compartments whereas activin A and inhibin A concentrations were similar in CF and MS but lower than in PB and placental extract
Summary
THE PLACENTA in mammals is the essential interface between the maternal circulation carrying oxygen (O2)-rich blood and nutrients and the fetal circulation. The physiological hypoxia of the early gestational sac protects the developing fetus against the deleterious and teratogenic effects of oxygen free radicals but it is necessary to maintain stem cells in a fully pluripotent state [4] for at physiological levels free radicals regulate a wide variety of molecules, in particular transcription factors [5]. It is well-established that the first-trimester intra-uterine O2 gradient influences trophoblast proliferation and differentiation along the invasive pathway [6] and villous vasculogenesis [7]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
