title: Is serum-soluble vascular endothelial growth factor receptor-1 of importance in unexplained infertility?
abstract: OBJECTIVE
  To analyze the role of vascular endothelial growth factor (VEGF) and its naturally occurring circulating antagonist, soluble VEGF receptor-1 (sVEGFR-1), in infertility. VEGF is a key angiogenic factor in the endometrial and ovarian cyclic processes that are crucial for fertility and sVEGFR-1 impairs its function and fertility in animals - less is known as regards human fertility.
  
  
  METHODS
  Case-control study.
  
  
  METHODS
  University Central Hospital, a tertiary referral center.
  
  
  METHODS
  Women with unexplained infertility (n=15) and fertile controls (n=10) had serial blood samples collected during their natural cycles, and the infertile women during a subsequent in vitro fertilization (IVF) cycle.
  
  
  METHODS
  Enzyme-linked immunosorbent assay was used for this study.
  
  
  METHODS
  Concentrations of VEGF and sVEGFR-1 in the natural cycles and of sVEGFR-1 during a subsequent IVF cycle.
  
  
  RESULTS
  Plasma VEGF concentrations showed no cyclicity in fertile women, but were higher in the infertile group at the midluteal phase. Serum sVEGFR-1 concentrations were similar between the groups and between natural and IVF cycles. However, in infertile women, concentrations of sVEGFR-1 increased from the follicular phase to the luteal phase. In the follicular phase infertile women had a high ratio of VEGF/sVEGFR-1, which was decreased in the luteal phase. Both findings were associated with failure to achieve pregnancy in subsequent IVF cycles.
  
  
  CONCLUSIONS
  One cause of unexplained infertility may be unbalanced secretion of sVEGFR-1 with concomitant changes in free VEGF during the transition from the follicular to the luteal phase. This aberration may be related to impaired implantation.
authors.affiliation: Departments of Obstetrics and Gynaecology, Helsinki University Central Hospital, Finland. katja-anneli.wathen@helsinki.fi
authors.forename: Katja-Anneli
authors.initials: KA
authors.lastname: Wathén
authors.forename: Leila
authors.initials: L
authors.lastname: Unkila-Kallio
authors.forename: Rita
authors.initials: R
authors.lastname: Isaksson
authors.forename: Aila
authors.initials: A
authors.lastname: Tiitinen
authors.forename: Ulf-Håkan
authors.initials: UH
authors.lastname: Stenman
authors.forename: Piia
authors.initials: P
authors.lastname: Vuorela
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D007247:Infertility, Female / Q000097:blood*; D008597:Menstrual Cycle / Q000097:blood; D040281:Vascular Endothelial Growth Factor Receptor-1 / Q000097:blood*
chemical_list: D040281:Vascular Endothelial Growth Factor Receptor-1