title: Brain-derived neurotrophic factor is expressed in rat and human placenta and its serum levels are similarly regulated throughout pregnancy in both species.
abstract: OBJECTIVE
  Pregnancy is characterized by several metabolic changes that promote fat gain and later onset of insulin resistance. As Brain-derived neurotrophic factor (BDNF) decreases hyperglycaemia and hyperphagia, we aimed to investigate the potential role of placental and circulating BDNF levels in these pregnancy-related metabolic changes in rats and humans.
  
  
  METHODS
  We identified the mRNA and protein expression of placental BDNF and its receptor TrkB using real-time PCR, Western blot and immunohistochemical approaches in both rat and humans. Serum BDNF was measured by ELISA. We also did a longitudinal prospective cohort study in 42 pregnant women to assess BDNF levels and correlations with other metabolic parameters.
  
  
  RESULTS
  We found that BDNF and TrkB are expressed in both rat and human placenta. In rat, both placental mRNA and serum levels are increased throughout pregnancy, whereas their protein levels are significantly decreased at the end of gestation. Serum BDNF levels in pregnant women are significantly lower in the first trimester when compared to the second and third trimester (P < 0·0148, P < 0·0012, respectively). Serum BDNF levels were negatively correlated with gestational age at birth and fasting glucose levels.
  
  
  CONCLUSIONS
  Our findings suggest that both BDNF and its receptor TrkB are expressed in rodent and human placenta being regulated during pregnancy. Taken together, these findings support a role of BDNF in the regulation of several metabolic functions during pregnancy.
authors.affiliation: Department of Physiology, School of Medicine, Universidad Nacional de Colombia, Bogotá, Colombia.
authors.forename: María F
authors.initials: MF
authors.lastname: Garcés
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Sanchez
authors.forename: Alejandra L
authors.initials: AL
authors.lastname: Torres-Sierra
authors.forename: Ariel I
authors.initials: AI
authors.lastname: Ruíz-Parra
authors.forename: Edith
authors.initials: E
authors.lastname: Angel-Müller
authors.forename: Juan P
authors.initials: JP
authors.lastname: Alzate
authors.forename: Ángel Y
authors.initials: ÁY
authors.lastname: Sánchez
authors.forename: Martín A
authors.initials: MA
authors.lastname: Gomez
authors.forename: Ximena C
authors.initials: XC
authors.lastname: Romero
authors.forename: Zoila E
authors.initials: ZE
authors.lastname: Castañeda
authors.forename: Estrella
authors.initials: E
authors.lastname: Sanchez-Rebordelo
authors.forename: Carlos
authors.initials: C
authors.lastname: Diéguez
authors.forename: Rubén
authors.initials: R
authors.lastname: Nogueiras
authors.forename: Jorge E
authors.initials: JE
authors.lastname: Caminos
mesh_terms: D000818:Animals; D019208:Brain-Derived Neurotrophic Factor / Q000097:blood* / Q000235:genetics / Q000378:metabolism*; D005260:Female; D006801:Humans; D007120:Immunochemistry; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy; D012333:RNA, Messenger; D051381:Rats; D017208:Rats, Wistar; D060888:Real-Time Polymerase Chain Reaction; D020813:Receptor, trkB / Q000097:blood / Q000235:genetics / Q000378:metabolism
chemical_list: D019208:Brain-Derived Neurotrophic Factor; D012333:RNA, Messenger; D020813:Receptor, trkB