title: Placental 11β-Hydroxysteroid dehydrogenase type 2 expression: Correlations with birth weight and placental metal concentrations.
abstract: BACKGROUND
  Infants born below 2500 g are classified as low birth weight. Excess in utero exposure to cortisol has been linked to restricted fetal growth. Placental production of 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2) inactivates cortisol before passage into the fetus. The present study tested the hypothesis that placental 11β-HSD2 expression is positively correlated with an individualized birth weight centile and raw birth weight, and examines the relationship between metal concentrations in placental tissue and 11β-HSD2 expression.
  
  
  METHODS
  Placentae from 191 births were collected and samples preserved to maintain mRNA profile. Placental 11β-HSD2 expression was measured via qRT-PCR. Addition samples were collected from placental tissues and uniformly dried in order to quantify 18 metals via ICP-MS (n = 160).
  
  
  RESULTS
  A significant, positive correlation between 11β-HSD2 expression and individualized birth weight centile (p = 0.0321) and birth weight (p = 0.0243) was found. Additionally, maternal age and gestational age were positivity correlated with each other (p = 0.0321). Birth weight was significantly different with race, marital status, education and maternal tobacco use. Four metals (Co, Mn, Ni, Zn) demonstrated significant positive correlations (p < 0.05) with 11β-HSD2 expression. Sex specific differences were found; Co, Cu, Fe, Zn, and Ni were positively correlated with 11β-HSD2 expression in males only, no significant correlations were found in the female only sample.
  
  
  CONCLUSIONS
  These data indicate that the growth potential of a fetus is related to the 11β-HSD2 expression in the placenta, and that 11β-HSD2 expression is related to the trace metals status of the mother.
authors.affiliation: Department of Biological and Environmental Sciences, University of Tennessee-Chattanooga, 615 McCallie Ave., Chattanooga, TN 37403, USA. Electronic address: Colleen.mikelson@gmail.com.
authors.forename: C
authors.initials: C
authors.lastname: Mikelson
authors.affiliation: Department of Biological and Environmental Sciences, University of Tennessee-Chattanooga, 615 McCallie Ave., Chattanooga, TN 37403, USA.
authors.forename: M J
authors.initials: MJ
authors.lastname: Kovach
authors.affiliation: Department of Obstetrics and Gynecology, University of Salerno, Italy.
authors.forename: J
authors.initials: J
authors.lastname: Troisi
authors.affiliation: Department of Chemistry, University of Tennessee-Chattanooga, 615 McCallie Ave., Chattanooga, TN 37403, USA.
authors.forename: S
authors.initials: S
authors.lastname: Symes
authors.affiliation: University of Tennessee College of Medicine, Department of Obstetrics and Gynecology, Chattanooga, TN, USA.
authors.forename: D
authors.initials: D
authors.lastname: Adair
authors.affiliation: Department of Obstetrics and Gynecology, University of Rochester, School of Medicine and Dentistry, 601 Elmwood Ave, Box 668 Rochester, NY 14642, USA; Department of Environmental Medicine, University of Rochester, School of Medicine and Dentistry, 601 Elmwood Ave, Box 668 Rochester, NY 14642, USA; Department of Pathology, University of Rochester, School of Medicine and Dentistry, 601 Elmwood Ave, Box 668 Rochester, NY 14642, USA.
authors.forename: R K
authors.initials: RK
authors.lastname: Miller
authors.affiliation: Placental Analytics LLC, Larchmont, NY, USA.
authors.forename: C
authors.initials: C
authors.lastname: Salafia
authors.affiliation: Environmental Sciences Program, Southern Illinois University Edwardsville, Edwardsville, IL 62026, USA.
authors.forename: K
authors.initials: K
authors.lastname: Johnson
authors.affiliation: Environmental Sciences Program, Southern Illinois University Edwardsville, Edwardsville, IL 62026, USA.
authors.forename: Z
authors.initials: Z
authors.lastname: Lin
authors.affiliation: Department of Biological and Environmental Sciences, University of Tennessee-Chattanooga, 615 McCallie Ave., Chattanooga, TN 37403, USA.
authors.forename: S
authors.initials: S
authors.lastname: Richards
mesh_terms: D043209:11-beta-Hydroxysteroid Dehydrogenase Type 2 / Q000378:metabolism*; D000328:Adult; D001724:Birth Weight; D005260:Female; D006801:Humans; D008670:Metals / Q000378:metabolism*; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy
chemical_list: D008670:Metals; D043209:11-beta-Hydroxysteroid Dehydrogenase Type 2; C468387:HSD11B2 protein, human
keywords: 11β-HSD2; Birth weight; Cortisol; Gene expression; Placenta