title: Ultrastructure of preimplantation genetic diagnosis-derived human blastocysts grown in a coculture system after vitrification.
abstract: OBJECTIVE
  To evaluate ultrastructural features of preimplantation genetic diagnosis (PGD) blastocysts before and after vitrification.
  
  
  METHODS
  Descriptive study of both vitrified and fresh hatching blastocysts.
  
  
  METHODS
  PGD program at the Instituto Universitario, Instituto Valenciano de Infertilidad.
  
  
  METHODS
  Patients undergoing PGD donated their abnormal embryos for research (n = 26).
  
  
  METHODS
  Biopsied embryos were cultured in the presence of human endometrial cells until day 6. Sixteen blastocysts were vitrified. A total of 11 high-scored hatching blastocysts, 6 warmed and 5 fresh, were fixed for ultrastructure.
  
  
  METHODS
  The cytoskeleton structure, type of intercellular junctions, and basic intracellular organelles in trophoectoderm cells and the inner cell mass were analyzed.
  
  
  RESULTS
  Ten of 16 blastocysts (62%) survived the warming process. Six of these showed no signs of cell degeneration and light microscopy revealed similar ultrastructural characteristics to those of controls. However, in trophoectoderm cells from both fresh and cryopreserved blastocysts, a reduced number of tight junctions and the presence of degradation bodies were detected.
  
  
  CONCLUSIONS
  The particular ultrastructural features observed in PGD-derived blastocysts could be related to embryo manipulation and culture conditions. Vitrification does not seem to alter blastocysts, as those that survive hatching do not display detectable cellular alterations when observed through electron microscopy.
authors.affiliation: Instituto Universitario IVI, Valencia, Spain. mjescriba@ivi.es
authors.forename: María-José
authors.initials: MJ
authors.lastname: Escribá
authors.forename: Carmen
authors.initials: C
authors.lastname: Escobedo-Lucea
authors.forename: Amparo
authors.initials: A
authors.lastname: Mercader
authors.forename: María-José
authors.initials: MJ
authors.lastname: de los Santos
authors.forename: Antonio
authors.initials: A
authors.lastname: Pellicer
authors.forename: José
authors.initials: J
authors.lastname: Remohí
mesh_terms: D001755:Blastocyst / Q000648:ultrastructure*; D002478:Cells, Cultured; D018920:Coculture Techniques / Q000379:methods*; D015925:Cryopreservation / Q000379:methods*; D020732:Cytogenetic Analysis; D006801:Humans; D019836:Preimplantation Diagnosis / Q000379:methods*