title: Sildenafil citrate (Viagra) enhances vasodilatation in fetal growth restriction.
abstract: BACKGROUND
  Fetal growth restriction (FGR) affects up to 8% of all pregnancies and has massive short-term (increased fetal morbidity and mortality) and long-term (increased incidence of cardiovascular disease in adulthood) health implications. Doppler waveform analysis of pregnancies complicated by FGR suggests compromised uteroplacental circulation and placental hypoperfusion. Our aim was to determine whether myometrial small artery function was aberrant in FGR and to assess whether sildenafil citrate could improve vasodilatation in FGR pregnancies.
  
  
  METHODS
  Small arteries dissected from myometrial biopsies obtained at cesarean section from normal pregnant women (n = 27) or women whose pregnancies were complicated by FGR (n = 12) were mounted on wire myographs. Vessels were constricted (with arginine vasopressin or U46619) and relaxed (with bradykinin) before and after incubation with a phosphodiesterase-5 inhibitor, sildenafil citrate.
  
  
  RESULTS
  We demonstrated increased myometrial small artery vasoconstriction and decreased endothelium-dependent vasodilatation in vessels from women whose pregnancies were complicated by FGR. Sildenafil citrate significantly reduced vasoconstriction and significantly improved relaxation of FGR small arteries.
  
  
  CONCLUSIONS
  We conclude that sildenafil citrate improves endothelial function of myometrial vessels from women whose pregnancies are complicated by intrauterine growth restriction. Sildenafil citrate may offer a potential therapeutic strategy to improve uteroplacental blood flow in FGR pregnancies.
authors.affiliation: Maternal and Fetal Health Research Centre, The University of Manchester, St. Mary's Hospital, Hathersage Road, Manchester M13 0JH, United Kingdom. mark.wareing@man.ac.uk
authors.forename: Mark
authors.initials: M
authors.lastname: Wareing
authors.forename: Jenny E
authors.initials: JE
authors.lastname: Myers
authors.forename: Maureen
authors.initials: M
authors.lastname: O'Hara
authors.forename: Philip N
authors.initials: PN
authors.lastname: Baker
mesh_terms: D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid / Q000494:pharmacology; D015106:3',5'-Cyclic-GMP Phosphodiesterases / Q000037:antagonists & inhibitors*; D000328:Adult; D001127:Arginine Vasopressin / Q000494:pharmacology; D054706:Cyclic Nucleotide Phosphodiesterases, Type 5; D004730:Endothelium, Vascular / Q000187:drug effects / Q000502:physiology; D005260:Female; D005317:Fetal Growth Retardation / Q000503:physiopathology*; D006801:Humans; D009215:Myometrium / Q000098:blood supply*; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology*; D010879:Piperazines / Q000494:pharmacology*; D011247:Pregnancy; D011687:Purines; D000068677:Sildenafil Citrate; D013450:Sulfones; D014664:Vasodilation / Q000187:drug effects*
chemical_list: D010726:Phosphodiesterase Inhibitors; D010879:Piperazines; D011687:Purines; D013450:Sulfones; D001127:Arginine Vasopressin; D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; D000068677:Sildenafil Citrate; D015106:3',5'-Cyclic-GMP Phosphodiesterases; D054706:Cyclic Nucleotide Phosphodiesterases, Type 5; C517381:PDE5A protein, human