Proceedings of The Physiological Society
University of Edinburgh (2007) Proc Physiol Soc 6, C7
Differences in serum selenium concentrations between normal and pre-eclamptic human pregnancies
H. Mistry1, V. Wilson1, M. M. Ramsay1, F. Broughton Pipkin1, M. E. Symonds1
1. Centre for Reproduction and Early Life, School of Human Development, University of Nottingham, Queen's Medical Centre, Nottingham, United Kingdom.
Pre-eclampsia (PE) is a pregnancy specific condition that affects 2-3% of women. The main pathological features are impaired placentation, with inadequate invasion of the spiral arteries by syncytiotrophoblast, and systemic endothelial damage. This not only contributes to increased neonatal and maternal morbidity and mortality but may have life time consequences for the fetus in terms of greater predisposition to adult cardiovascular disease. Selenium (Se), acting through selenoproteins, such as glutathione peroxidase (GPx), has a critical role in angiogenesis, and in regulating antioxidant status . Recent reports strongly implicate poor maternal selenium status as a nutritional factor predisposing the mother to PE  but the fetus and placenta have not been studied in tandem. We have now measured maternal and umbilical venous serum Se concentrations in Caucasian PE women and matched normotensive controls (NC) by graphite furnace atomic absorption spectroscopy (GFAAS) . The study was approved by the Queen’s Medical Centre Ethical Committee; informed, written consent was obtained from all subjects. In 22 maternal NC samples, mean ± s.e.m. [Se] was 58.3 ± 3.8 µg/L compared to 36.8 ± 2.6 µg/L in 21 maternal PE samples (P < 0.001). Mean umbilical venous concentrations in 21 NC babies were 39.8 ± 2.4 µg/L compared to 29.3 ± 2.5 µg/L in 16 PE samples (P = 0.005). There was a significant association between maternal and umbilical serum [Se] in PE samples (r2 = 0.182; P = 0.035) but not in NC samples (r2 = 0.028; P > 0.2). Body mass index (BMI) and age have been reported to be correlated with serum [Se] outside pregnancy. However, analysis of variance (ANOVA) showed no such effect in these women (BMI, P>0.7; age, P>0.2). There was no effect of gestation age on [Se] in maternal (P>0.2) or umbilical (P>0.1) serum. A low dietary intake of Se might predispose to PE, as it does to other forms of cardiovascular disease, if selenoprotein synthesis were reduced. Conversely, enhanced tissue synthesis of GPx, as has been reported for PE decidua, might lower serum [Se] by utilising such Se as is available. Tissue selenoprotein concentration response to supplementation is known to vary with tissue in the same individual. We are currently analysing the family of GPx proteins and specific factors influencing synthesis in serum and placental tissue to try to determine their primary or secondary role in PEAcknowledgements: We thank all patients who consented to take part in the study and the midwives of the Queen’s Medical Centre, without whose support this research would not have been possible. John Corrie and Darren Hepworth of The School of Biosciences, University of Nottingham, provided invaluable and expert instruction and technical support with GFAAS technology. Finally, we would like to acknowledge BBSRC funding for this research.Reference 1 : Arthur, J.R., The glutathione peroxidases. Cell Mol Life Sci, 2000. 57(13-14): p. 1825-35.Reference 2 : Rayman, M.P., P. Bode, and C.W. Redman, Low selenium status is associated with the occurrence of the pregnancy disease preeclampsia in women from the United Kingdom. Am J Obstet Gynecol, 2003. 189(5): p. 1343-9.Reference 3 : Sanders, J., Selenium in Serum measured by Zeeman GFAAS. Varian AA Instruments at Work, 1995. AA-122.
Where applicable, experiments conform with Society ethical requirements