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Thyroid hormones and their placental deiodination in normal and pre-eclamptic pregnancy

Kurlak, L.O.; Mistry, H.D.; Kaptein, E.; Visser, T.J.; Broughton Pipkin, Fiona

Authors

L.O. Kurlak lesia.kurlak@nottingham.ac.uk

H.D. Mistry hiten.mistry@nottingham.ac.uk

E. Kaptein

T.J. Visser

Fiona Broughton Pipkin

Abstract

Pre-eclampsia is associated with lower serum selenium concentrations and glutathione peroxidase expression/activity; total thyroid hormones are also lower.
Objectives, study design and main outcome measures: We hypothesised that the placental selenoprotein deiodinase (D3) will be protected in pre-eclampsia due to the hierarchy of selenoprotein biosynthesis in selenium deficiency. Venous blood and tissue from three standardised placental sites were obtained at delivery from 27 normotensive and 23 pre-eclamptic women. mRNA expression and enzyme activity were assessed for both deiodinases (D2 and D3); protein expression/localisation was also measured for D3. FT4, FT3 and TSH concentrations were measured in maternal and umbilical cord blood.
Results: No significant differences in D3 mRNA or protein expression between normotensive and pre-eclamptic pregnancies. There was a significant effect of sampling site on placental D3 activity only in pre-eclamptic women (P = 0.034; highest activity nearest the cord). A strong correlation between D3 mRNA expression and enzyme activity existed only in the pre-eclamptic group; further strengthened when controlling for maternal selenium (P < 0.002). No significant differences were observed between groups for any of the maternal thyroid hormones; umbilical TSH concentrations were significantly higher in the pre-eclamptic samples (P < 0.001).
Conclusions: D3 mRNA and protein expression appear to be independent of selenium status. Nevertheless, the positive correlation between D3 mRNA expression and activity evident only in pre-eclampsia, suggests that in normotensive controls, where selenium is higher, translation is not affected, but in pre-eclampsia, where selenium is low, enzyme regulation may be altered. The raised umbilical TSH concentrations in pre-eclampsia may be an adaptive fetal response to maximise iodide uptake.

Journal Article Type Article
Publication Date May 1, 2013
Journal Placenta
Print ISSN 0143-4004
Electronic ISSN 1532-3102
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 34
Issue 5
Institution Citation Kurlak, L., Mistry, H., Kaptein, E., Visser, T., & Broughton Pipkin, F. (2013). Thyroid hormones and their placental deiodination in normal and pre-eclamptic pregnancy. Placenta, 34(5), doi:10.1016/j.placenta.2013.02.009
DOI https://doi.org/10.1016/j.placenta.2013.02.009
Publisher URL http://www.sciencedirect.com/science/article/pii/S0143400413001045?via%3Dihub
Copyright Statement Copyright information regarding this work can be found at the following address: http://eprints.nottingh.../end_user_agreement.pdf

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Copyright Statement
Copyright information regarding this work can be found at the following address: http://eprints.nottingham.ac.uk/end_user_agreement.pdf




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