title: Concentration of free vascular endothelial growth factor and its soluble receptor, sFlt-1 in the maternal and fetal circulations of normal term pregnancies at high and low altitudes.
abstract: OBJECTIVE
  Vascular endothelial growth factor (VEGF) is regulated by hypoxia that is essential for placental development. It is antagonized by a soluble form of its receptor (sFlt-1). The purpose of this study was to measure these factors in the maternal and the cord bloods, at low and high altitude.
  
  
  METHODS
  Samples were collected from full term births normal pregnant women. Free (unbound) VEGF and sFlt-1 levels were measured in plasma samples from cord and maternal blood for each subject by enzyme-linked immunosorbent assay (ELISA) using commercially available kits from R&D systems, UK (Cat # DVE00 and Cat # SVR100B, respectively).
  
  
  RESULTS
  At high altitude, the average maternal free VEGF in pg/ml was significantly (p < 0.001) lower than that of the cord level (71.30 ± 282.14 and 431.35 ± 424.31, respectively). On the other hand, the average maternal sFlt-1 was significantly (p < 0.001) higher than that of the cord level (8205.41 ± 6244.72 and 1811.74 + 3469.30, respectively). At low altitude, the average maternal free VEGF was significantly lower than that of the cord level (0.47 ± 0.89 and 483.44 ± 457.31, respectively, p < 0.001). On the other hand, the average maternal sFlt-1 was significantly higher than that of the cord level (9267.82 ± 6345.68 and 958.66 ± 1359.92, respectively, p < 0.001). There were no significant differences by altitude.
  
  
  CONCLUSIONS
  Secretion of sFlt-1 appears to be polarized, in that concentrations are higher in the maternal compartment than on the fetal side at both high and low altitudes. This may be a normal physiological phenomenon to permit angiogenesis in the placenta and fetus while protecting the mother. Chronic exposure to hypobaric hypoxia at high altitude does not affect these distributions.
authors.affiliation: Department of Anatomy, College of Medicine, King Khalid University, Abha, Saudi Arabia. kzaki50@yahoo.com
authors.forename: Kamal Z M
authors.initials: KZ
authors.lastname: Ali
authors.forename: Graham J
authors.initials: GJ
authors.lastname: Burton
authors.forename: Ali M
authors.initials: AM
authors.lastname: Al-Binali
authors.forename: Mamdoh A
authors.initials: MA
authors.lastname: Eskandar
authors.forename: Awad A
authors.initials: AA
authors.lastname: El-Mekki
authors.forename: Riyad A
authors.initials: RA
authors.lastname: Moosa
authors.forename: Salah A
authors.initials: SA
authors.lastname: Abd-Alla
authors.forename: Ali G A
authors.initials: AG
authors.lastname: Salih
authors.forename: Abulqasim M B
authors.initials: AM
authors.lastname: Sideeg
authors.forename: Ahmed A
authors.initials: AA
authors.lastname: Mahfouz
mesh_terms: D000328:Adult; D000531:Altitude; D015415:Biomarkers / Q000097:blood; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005312:Fetal Blood / Q000378:metabolism*; D006801:Humans; D007231:Infant, Newborn; D049590:Postpartum Period; D011247:Pregnancy / Q000097:blood*; D012529:Saudi Arabia; D042461:Vascular Endothelial Growth Factor A / Q000097:blood*; D040281:Vascular Endothelial Growth Factor Receptor-1 / Q000097:blood*
chemical_list: D015415:Biomarkers; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; C501162:FLT1 protein, human; D040281:Vascular Endothelial Growth Factor Receptor-1