title: Vitrification of in vitro matured oocytes collected from antral follicles at the time of ovarian tissue cryopreservation.
abstract: BACKGROUND
  In the past few years, cryopreservation of ovarian tissue has become an established procedure proposed in many centers around the world and transplantation has successfully resulted in full-term pregnancies and deliveries in human. This prospective study aims to evaluate the feasibility of vitrifying in vitro matured oocytes (IVM) isolated at the time of ovarian tissue cryopreservation to improve the efficiency of fertility preservation programs.
  
  
  METHODS
  Oocyte-cumulus complexes were retrieved from freshly collected ovarian cortex by aspirating antral follicular fluid, and were matured in vitro for 24-48 h prior to vitrification. Oocytes were matured in an IVM commercial medium (Copper Surgical, USA) supplemented with 75 mIU/ml FSH and 75 mIU/ml LH and vitrified using a commercial vitrification kit (Irvine Scientific, California) in high security vitrification straws (CryoBioSystem, France). Oocyte collection and IVM rates were evaluated according to the age, the cycle period and the amount of tissue collected.
  
  
  RESULTS
  Immature oocyte retrieval from ovarian tissue was carried out in 57 patients between 8 and 35 years of age, undergoing ovarian tissue cryopreservation. A total of 266 oocytes were isolated, 28 of them were degenerated, 200 were at germinal vesicle stage (GV), 35 were in metaphase I (MI) and 3 displayed a visible polar body (MII). The number of oocytes collected was positively correlated with the amount of tissue cryopreserved (p < 0.001) and negatively correlated with the age of the patients (p = 0.005). Oocytes were obtained regardless of menstrual cycle period or contraception. A total maturation rate of 31% was achieved, leading to the vitrification of at least one mature oocyte for half of the cohort.
  
  
  CONCLUSIONS
  The study showed that a significant number of immature oocytes can be collected from excised ovarian tissue whatever the menstrual cycle phases and the age of the patients, even for prepubertal girls.
authors: Research Laboratory on Human Reproduction, Faculty of Medicine, Campus Erasme, Université Libre de Bruxelles, 1070 Brussels, Belgium. Giovanna.Fasano@erasme.ulb.ac.be
authors: Giovanna
authors: G
authors: Fasano
authors: Federica
authors: F
authors: Moffa
authors: Julie
authors: J
authors: Dechène
authors: Yvon
authors: Y
authors: Englert
authors: Isabelle
authors: I
authors: Demeestere
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D015925:Cryopreservation / Q000379:methods*; D005240:Feasibility Studies; D005260:Female; D059247:Fertility Preservation / Q000379:methods; D005640:Follicle Stimulating Hormone / Q000494:pharmacology; D006801:Humans; D007986:Luteinizing Hormone / Q000494:pharmacology; D009865:Oocytes / Q000166:cytology* / Q000187:drug effects / Q000254:growth & development; D006080:Ovarian Follicle / Q000166:cytology*; D010053:Ovary / Q000166:cytology*; D011446:Prospective Studies; D015203:Reproducibility of Results; D013997:Time Factors; D055815:Young Adult
chemical_list: D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone