title: First trimester vitamin D status and placental epigenomics in preeclampsia among Northern Plains primiparas.
abstract: OBJECTIVE
  As maternal vitamin D status has been associated with preeclampsia, the purpose of this study was to determine variations in DNA methylation patterns and associated protein expression in placental genes regulating vitamin D metabolism.
  
  
  METHODS
  A convenience sample of 48 pregnant nulliparous women, including 11 later diagnosed with preeclampsia, were recruited in this prospective study. Using a case-control design in two groups of women, we administered a food frequency questionnaire to determine vitamin D dietary intake. Laboratory measures included serum vitamin D levels (25[OH]D), DNA methylation patterns and protein expression in placental genes regulating vitamin D metabolism (1α-hydroxylase, CYP27B1; vitamin D receptor, VDR; retinoid X receptor, RXR) from placental tissue collected at delivery among those diagnosed with preeclampsia and those who remained normotensive throughout pregnancy.
  
  
  RESULTS
  There were no significant differences in vitamin D dietary intake or mean serum 25[OH]D levels, although the proportion of women with deficient 25[OH]D levels was higher in the preeclampsia group (46%) than the normotensive group (20%). Placenta samples from women with preeclampsia also had increased DNA methylation of CYP27B1, VDR and RXR genes with lower protein expression levels limited to RXR.
  
  
  CONCLUSIONS
  Hypermethylation of key placental genes involved in vitamin D metabolism suggests uncoupling of processes that may interfere with placentation and availability of vitamin D at the maternal-fetal interface.
authors: College of Nursing, The Ohio State University, Columbus, OH, United States. Electronic address: anderson.2765@osu.edu.
authors: Cindy M
authors: CM
authors: Anderson
authors: College of Nursing and Professional Disciplines, University of North Dakota, Grand Forks, ND, United States.
authors: Jody L
authors: JL
authors: Ralph
authors: Grand Forks Human Nutrition Research Center, Grand Forks, ND, United States.
authors: LuAnn
authors: L
authors: Johnson
authors: Grand Forks Human Nutrition Research Center, Grand Forks, ND, United States.
authors: Angela
authors: A
authors: Scheett
authors: Virginia Commonwealth University, Richmond, VA, United States.
authors: Michelle L
authors: ML
authors: Wright
authors: Yale School of Nursing, Orange, CT, United States.
authors: Jacquelyn Y
authors: JY
authors: Taylor
authors: School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, United States.
authors: Joyce E
authors: JE
authors: Ohm
authors: Grand Forks Human Nutrition Research Center, Grand Forks, ND, United States.
authors: Eric
authors: E
authors: Uthus
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D019175:DNA Methylation / Q000502:physiology*; D057890:Epigenomics / Q000379:methods; D005260:Female; D005786:Gene Expression Regulation / Q000502:physiology*; D006801:Humans; D009658:North Dakota; D010298:Parity / Q000502:physiology*; D010920:Placenta / Q000378:metabolism*; D011225:Pre-Eclampsia / Q000378:metabolism*; D011247:Pregnancy; D011256:Pregnancy Outcome; D014807:Vitamin D / Q000008:administration & dosage / Q000097:blood*
chemical_list: D014807:Vitamin D
keywords: DNA methylation; Gestational hypertension; Vitamin D