title: Non-invasive amino acid turnover predicts human embryo developmental capacity.
abstract: BACKGROUND
  IVF is limited by low success rates and a confounding high multiple birth rate contributing to prematurity, increased neonatal mortality and child handicap. These problems could be overcome if single embryos of known developmental competence could be selected for transfer on day 2/3 of development, but current methods, which rely on morphological appearance, are poor predictors of viability.
  
  
  METHODS
  We have measured non-invasively the depletion/appearance (i.e. turnover) of a physiological mixture of 18 amino acids by single human embryos during in-vitro culture using high performance liquid chromatography.
  
  
  RESULTS
  From the time of transfer (day 2/3), embryos with future competence to develop to the blastocyst stage (day 5/6) exhibit amino acid flux patterns distinct from those of embryos with similar morphological appearance which arrest. Significantly, the profiles of Ala, Arg, Gln, Met and Asn flux predict blastocyst potentiality at >95%. The amino acid most consistently depleted throughout development by those embryos which form blastocysts was leucine. Of the amino acids which were produced, the most striking was alanine, which appeared in increasing amounts throughout development.
  
  
  CONCLUSIONS
  Non-invasive amino acid profiling has the potential to select developmentally competent single embryos for transfer, thereby increasing the success rate and eliminating multiple births in IVF.
authors.affiliation: Department of Biology, University of York, PO Box 373, York YO10 5YW, UK. fdh1@york.ac.uk
authors.forename: Franchesca D
authors.initials: FD
authors.lastname: Houghton
authors.forename: Judith A
authors.initials: JA
authors.lastname: Hawkhead
authors.forename: Peter G
authors.initials: PG
authors.lastname: Humpherson
authors.forename: Jan E
authors.initials: JE
authors.lastname: Hogg
authors.forename: Adam H
authors.initials: AH
authors.lastname: Balen
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Rutherford
authors.forename: Henry J
authors.initials: HJ
authors.lastname: Leese
mesh_terms: D000596:Amino Acids / Q000378:metabolism*; D001755:Blastocyst / Q000502:physiology; D004622:Embryo, Mammalian / Q000166:cytology / Q000378:metabolism*; D005314:Embryonic and Fetal Development / Q000502:physiology*; D005307:Fertilization in Vitro; D005544:Forecasting; D006801:Humans; D009028:Morula / Q000502:physiology; D013997:Time Factors
chemical_list: D000596:Amino Acids