title: Placental vitamin D receptor (VDR) expression is related to neonatal vitamin D status, placental calcium transfer, and fetal bone length in pregnant adolescents.
abstract: The purpose of the study was to identify determinants of placental vitamin D receptor (VDR) expression and placental calcium (Ca) transfer among pregnant adolescents. Placental tissue was obtained in 94 adolescents (≤18 yr) at term. In 12 of these teens, stable Ca isotopes were given intravenously ((42)Ca) and orally ((44)Ca) early in labor. Placental VDR expression was assessed via Western blot and validated by RT-PCR. Maternal-to-fetal Ca transfer was calculated as the enrichment in cord blood at delivery relative to maternal serum enrichment 2 h postdosing. Isotopic study outcomes were examined in relation to fetal long bone length, placental VDR, serum 25-hydroxyvitamin D [25(OH)D], 1,25-dihydroxyvitamin D [1,25(OH)2D], and parathyroid hormone (PTH) in maternal circulation and cord blood at delivery. Placental VDR expression was inversely associated with neonatal 25(OH)D (P=0.012) and positively with neonatal 1,25(OH)2D (P=0.006). Placental VDR was a positive predictor of fetal femur length Z score (P=0.018; R(2)=0.06) and was positively correlated with maternal-to-fetal transfer of intravenous (42)Ca (P=0.004; R(2)=0.62). The fetus may regulate placental VDR expression given the significant associations with neonatal vitamin D metabolites. The association between placental VDR and fetal long bone length may indicate a role for VDR in fetal bone development, potentially by mediating transplacental Ca transfer.
authors.affiliation: 1Department of Nutritional Sciences, Cornell University, 230 Savage Hall, Cornell University, Ithaca, NY 14853, USA. koo4@cornell.edu.
authors.forename: Bridget E
authors.initials: BE
authors.lastname: Young
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: Cooper
authors.forename: Allison W
authors.initials: AW
authors.lastname: McIntyre
authors.forename: Tera
authors.initials: T
authors.lastname: Kent
authors.forename: Frank
authors.initials: F
authors.lastname: Witter
authors.forename: Z Leah
authors.initials: ZL
authors.lastname: Harris
authors.forename: Kimberly O
authors.initials: KO
authors.lastname: O'Brien
mesh_terms: D000284:Administration, Oral; D000293:Adolescent; D001846:Bone Development; D002118:Calcium / Q000378:metabolism*; D002127:Calcium Isotopes / Q000378:metabolism; D015331:Cohort Studies; D004032:Diet; D005260:Female; D005312:Fetal Blood / Q000378:metabolism; D005333:Fetus / Q000378:metabolism; D005786:Gene Expression Regulation; D006801:Humans; D018811:Maternal Exposure; D008431:Maternal-Fetal Exchange; D010281:Parathyroid Hormone / Q000097:blood; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy; D018167:Receptors, Calcitriol / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood / Q000378:metabolism*
chemical_list: D002127:Calcium Isotopes; D010281:Parathyroid Hormone; D018167:Receptors, Calcitriol; D014807:Vitamin D; C097949:1,25-dihydroxyvitamin D; C104450:25-hydroxyvitamin D; D002118:Calcium
keywords: 1,25(OH)2D; 25(OH)D; calcidiol; gestation