title: Preeclampsia is associated with low placental transthyretin levels.
abstract: OBJECTIVE
  To investigate the relationship between placental transthyretin (TTR) level and preeclampsia.
  
  
  METHODS
  Placental tissues from uncomplicated and preeclamptic pregnancies were analyzed using immunohistochemistry and image analysis. We measured the mean optical density (OD) of immunohistochemical staining of TTR across multiple sections using Image Pro Plus 6.0. To avoid bias, we used placental tissue array, which contained preeclamptic placentas (n=8) and the control placentas (n=6) on the same slide.
  
  
  RESULTS
  The mean TTR OD of the syncytiotrophoblast layer of placentas (95% confidence interval) from the first trimester was higher than those from the second/third trimester, and term placentas [0.149 (0.014-0.285) for the 1(st) trimester, 0.037 (0.000-0.073) for the 2(nd)/3(rd) trimester, and 0.011 (0.035-0.056) for term; p<0.01]. Although the OD of the second/third trimester placentas appeared greater than that of term placentas, this was not statistically significant. The mean TTR OD of the syncytiotrophoblast layer of the severe preeclampsia group was lower than that of controls [0.010 (0.005-0.016) vs. 0.027 (0.013-0.041), p<0.05].
  
  
  CONCLUSIONS
  The immunohistochemical expression of TTR in the syncytiotrophoblast layer of the placenta decreased significantly after 12 weeks of gestation, paralleling the changing demands of thyroid hormone uptake into the placenta. The reduced TTR expression in the syncytiotrophoblast layer of the preeclamptic placenta might impair thyroid hormone uptake and contribute to the pathophysiology of the disease.
authors.affiliation: Beijing Chaoyang Hospital Affiliated Capital Medical University, Beijing, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Zhu
authors.affiliation: Research Centre for Women's and Infants' Health at the Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Dora
authors.initials: D
authors.lastname: Baczyk
authors.affiliation: Research Centre for Women's and Infants' Health at the Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada; Department of Obstetrics and Gynecology, Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada. Electronic address: lye@lunenfeld.ca.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Lye
authors.affiliation: Beijing Chaoyang Hospital Affiliated Capital Medical University, Beijing, China. Electronic address: zhenyuzhangcn@126.com.
authors.forename: Zhenyu
authors.initials: Z
authors.lastname: Zhang
mesh_terms: D005260:Female; D005865:Gestational Age; D006801:Humans; D010920:Placenta / Q000737:chemistry*; D011225:Pre-Eclampsia / Q000378:metabolism*; D011228:Prealbumin / Q000032:analysis*; D011247:Pregnancy; D011264:Pregnancy Trimesters; D046888:Tissue Array Analysis; D014327:Trophoblasts / Q000737:chemistry
chemical_list: D011228:Prealbumin
keywords: preeclampsia; thyroid hormone; transthyretin