Placental 11β-Hydroxysteroid dehydrogenase type 2 expression: Correlations with birth weight and placental metal concentrations

Abstract

IntroductionInfants 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. MethodsPlacentae 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). ResultsA 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. ConclusionThese 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.