title: Maternal vitamin D status in preeclampsia: seasonal changes are not influenced by placental gene expression of vitamin D metabolizing enzymes.
abstract: Preeclampsia, a hypertensive disorder in pregnancy develops in 2-8% of pregnancies worldwide. Winter season and vitamin D deficiency have been associated with its onset.
  
  
  OBJECTIVE
  To investigate the influence of season on maternal vitamin D status and placental vitamin D metabolism.
  
  
  METHODS
  25-OH vitamin D and 1,25-(OH)2 vitamin D were measured in maternal serum obtained during the winter or summer months from 63 pregnant women at delivery (43 healthy, 20 preeclampsia). In a subgroup, mRNA expression of CYP24A1 (24-hydroxylase), CYP27B1 (1α-hydroxylase) and VDR (vitamin D receptor) were quantified by real time PCR in placental samples of 14 women with normal pregnancies and 13 with preeclampsia.
  
  
  RESULTS
  In patients with preeclampsia,25-OH vitamin D levels were lower, but differed significantly from controls only in summer (18.21±17.1 vs 49.2±29.2 ng/mL, P<0.001), whereas 1,25-(OH)2 vitamin D levels were significantly lower only in winter (291±217 vs 612.3±455 pmol/mL, P<0.05). A two-factorial analysis of variance produced a statistically significant model (P<0.0001) with an effect of season (P<0.01) and preeclampsia (P = 0.01) on maternal 25-OH vitamin D levels, as well as a significant interaction between the two variables (P = 0.02). Placental gene expression of CYP24A1, CYP27B1, and VDR did not differ between groups or seasons. A negative correlation between placental gene expression of CYP24A1 and CYP27B1 was observed only in healthy controls (r = -0.81, P<0.0001).
  
  
  CONCLUSIONS
  Patients with preeclampsia displayed lower vitamin D serum levels in response to seasonal changes.The regulation of placental CYP24A1, but not of the VDR or CYP27B1 might be altered in preeclampsia.
authors.affiliation: Department of Pediatric Endocrinology and Diabetology, Kinderklinik II, Universitätsklinikum-Essen and the University of Duisburg-Essen, Essen, Germany.
authors.forename: Carolin
authors.initials: C
authors.lastname: Lechtermann
authors.affiliation: Department of Pediatric Endocrinology and Diabetology, Kinderklinik II, Universitätsklinikum-Essen and the University of Duisburg-Essen, Essen, Germany.
authors.forename: Berthold P
authors.initials: BP
authors.lastname: Hauffa
authors.affiliation: Department of Pediatric Endocrinology and Diabetology, Kinderklinik II, Universitätsklinikum-Essen and the University of Duisburg-Essen, Essen, Germany; Department of Neonatology, Kinderklinik I, Universitätsklinikum -Essen and the University of Duisburg-Essen, Essen, Germany.
authors.forename: Ralf
authors.initials: R
authors.lastname: Herrmann
authors.affiliation: Department of Pediatric Oncology and Hematology, Kinderklinik III, Universitätsklinikum -Essen and the University of Duisburg-Essen, Essen, Germany.
authors.forename: Michael M
authors.initials: MM
authors.lastname: Schündeln
authors.affiliation: Institute of Molecular Biology, Universitätsklinikum -Essen and the University of Duisburg-Essen, Essen, Germany.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Gellhaus
authors.affiliation: Department of Gynecology and Obstetrics, Klinikum Duisburg and the University of Duisburg-Essen, Duisburg, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Schmidt
authors.affiliation: Department of Pediatric Endocrinology and Diabetology, Kinderklinik II, Universitätsklinikum-Essen and the University of Duisburg-Essen, Essen, Germany.
authors.forename: Corinna
authors.initials: C
authors.lastname: Grasemann
mesh_terms: D015090:25-Hydroxyvitamin D3 1-alpha-Hydroxylase / Q000235:genetics / Q000378:metabolism; D000328:Adult; D002118:Calcium / Q000097:blood / Q000378:metabolism; D016022:Case-Control Studies; D005260:Female; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D010920:Placenta / Q000378:metabolism; D011225:Pre-Eclampsia / Q000235:genetics / Q000378:metabolism*; D011247:Pregnancy; D018167:Receptors, Calcitriol / Q000235:genetics / Q000378:metabolism; D012621:Seasons; D014807:Vitamin D / Q000097:blood / Q000378:metabolism*; D065668:Vitamin D3 24-Hydroxylase / Q000235:genetics / Q000378:metabolism
chemical_list: D018167:Receptors, Calcitriol; D014807:Vitamin D; D065668:Vitamin D3 24-Hydroxylase; D015090:25-Hydroxyvitamin D3 1-alpha-Hydroxylase; D002118:Calcium