Erik Ernst

Improving the maturation rate of human oocytes collected ex vivo during the cryopreservation of ovarian tissue

Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaperJournal articleResearchpeer-review

  • Dmitry Nikiforov, University of Copenhagen, University of Teramo
  • ,
  • Cheng Junping, University of Copenhagen, People’s Hospital of Guangxi Autonomous Region
  • ,
  • Jesus Cadenas, University of Copenhagen
  • ,
  • Vallari Shukla, Kobenhavns Universitet
  • ,
  • Robert Blanshard, Illumina UK Ltd., University of Sussex
  • ,
  • Susanne Elisabeth Pors, University of Copenhagen
  • ,
  • Stine Gry Kristensen, University of Copenhagen
  • ,
  • Kirsten Tryde Macklon, Rigshospitalet
  • ,
  • Lotte Colmorn, Rigshospitalet
  • ,
  • Erik Ernst
  • Anne Mette Bay-Bjørn
  • ,
  • Zeinab Ghezelayagh, University of Copenhagen
  • ,
  • Yu Wakimoto, University of Copenhagen, Hyogo College of Medicine
  • ,
  • Marie Louise Grøndahl, Gentofte Hospital
  • ,
  • Eva Hoffmann, Kobenhavns Universitet
  • ,
  • Claus Yding Andersen, Laboratory of Reproductive Biology, University of Copenhagen

Purpose: The aim of the present study was to improve the in vitro maturation (IVM) procedure using oocytes from surplus ovarian tissue after fertility preservation. Methods: Twenty-five patients aged 17–37 years were included in the study. Maturation was compared between oocytes collected in HEPES-buffered medium or saline, and we determined whether transport on ice prior to oocyte collection affected maturation. Two different IVM media were used that were supplemented with and without recombinant human midkine. Mature oocytes were assessed for aneuploidy using next-generation sequencing (NGS). Results: On average, 36 immature oocytes were collected from each patient (range 7–90, N = 895). Oocytes recovered from HEPES-buffered medium matured at a higher rate than oocytes recovered from saline (36% vs 26%, p < 0.01). Ovarian transportation on ice prior to the procedure negatively affected maturation compared with non-transported samples (42% vs 27%, p < 0.01). The addition of midkine improved maturation rate (34% vs 27%, p < 0.05). On average, 11 MII oocytes were obtained per patient (range 1–30). NGS of 53 MII oocytes and their first polar bodies indicated that 64% were euploid. Conclusions: The study demonstrated unexpectedly high number of immature oocytes collected from surplus ovarian tissue without any stimulation. The overall MII rate was one in three, resulting in a total number of MII oocytes that was similar to the number obtained after ovarian stimulation. If these MII oocytes prove suitable for IVF, they will provide a substantial improvement in fertility preservation for patients and advance IVM as an interesting platform for further improvements in assisted reproduction.

Original languageEnglish
JournalJournal of Assisted Reproduction and Genetics
Pages (from-to)891-904
Number of pages14
Publication statusPublished - 2020

    Research areas

  • Fertility preservation, Human immature oocytes, In vitro maturation, Oocyte diameter, Ovarian cryopreservation

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