title: Clinical grade vitrification of human ovarian tissue: an ultrastructural analysis of follicles and stroma in vitrified tissue.
abstract: BACKGROUND
  Cancer therapy is one of many conditions which may diminish the ovarian reserve. Banking of human ovarian tissue has become an option for the preservation of female fertility. We have shown that vitrification is an excellent method to cryopreserve ovarian tissue. To carry out vitrification in a clinical setting, we have developed a clinical grade closed system to avoid direct contact of ovarian tissue with liquid nitrogen.
  
  
  METHODS
  Ovarian tissue was obtained by biopsy from 12 consenting women undergoing Caesarean section. Tissues were vitrified in cryotubes, using dimethyl sulphoxide, 1,2-propanediol, ethylene glycol and polyvinylpyrrolidon as cryoprotectants. Non-vitrified and warmed-vitrified tissue was compared by light and electron microscopic morphology of the follicles within the tissues.
  
  
  RESULTS
  We did not see any differences in the light or electron microscopic ultrastructure of oocytes between non-vitrified and vitrified tissues. No irreversible subcellular alterations in vitrified tissues were seen.
  
  
  CONCLUSIONS
  The ultrastructure of follicles within the vitrified human ovarian tissue was well preserved using cryotube in a closed vitrification system to avoid direct contact of liquid nitrogen. The system is compatible with the European tissue directive.
authors.affiliation: Division of Obstetrics and Gynaecology, Department of Clinical, Science, Technology and Intervention, Karolinska Institutet, Karolinska University Hospital Huddinge, Stockholm, Sweden. mona.sheikhi@karolinska.se
authors.forename: Mona
authors.initials: M
authors.lastname: Sheikhi
authors.forename: Kjell
authors.initials: K
authors.lastname: Hultenby
authors.forename: Boel
authors.initials: B
authors.lastname: Niklasson
authors.forename: Monalill
authors.initials: M
authors.lastname: Lundqvist
authors.forename: Outi
authors.initials: O
authors.lastname: Hovatta
mesh_terms: D000328:Adult; D015925:Cryopreservation / Q000379:methods*; D005060:Europe; D005260:Female; D006107:Granulosa Cells / Q000648:ultrastructure; D006801:Humans; D007247:Infertility, Female / Q000628:therapy; D046529:Microscopy, Electron, Transmission; D009865:Oocytes / Q000648:ultrastructure; D009866:Oogenesis; D006080:Ovarian Follicle / Q000648:ultrastructure; D010053:Ovary / Q000648:ultrastructure*; D017154:Stromal Cells / Q000648:ultrastructure; D014015:Tissue Banks / Q000331:legislation & jurisprudence; D046509:Tissue Culture Techniques; D014022:Tissue Survival; D058989:Vitrification; D055815:Young Adult