# Evaluation of the effects of a semi-automated vitrification performed before or after in vitro maturation (IVM) on the kinetic of oocyte maturation and chromosome segregation.

Gaëlle Marteil, Chaput L, Sandra Dollet, Bruno Pereira, Eléonore Eymard-Pierre, Melanie Fiot, Charlène Gouhier, Anne Sophie Gremeau, Candice Chauffour, Andrei Tchirkov, et al.

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Gaëlle Marteil, Chaput L, Sandra Dollet, Bruno Pereira, Eléonore Eymard-Pierre, et al. Evaluation of the effects of a semi-automated vitrification performed before or after in vitro maturation (IVM) on the kinetic of oocyte maturation and chromosome segregation. ESHRE 38th Annual Meeting, European Society of Human Reproduction and Embryology (ESHRE), Jul 2022, Milan, Italy. hal-03905773

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Submitted on 19 Dec 2022

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<table><tr><td>Category</td><td>Clinical science</td></tr><tr><td>Topic</td><td>Male and female fertility preservation (incl. medical indications, elective gamete freezing, laboratory techniques)</td></tr><tr><td>Presentation preference</td><td>Oral presentation or poster</td></tr><tr><td>Abstract title</td><td>Evaluation of the effects of a semi-automated vitrification performed before or after in vitro maturation (IVM) on the kinetic of oocyte maturation and chromosome segregation</td></tr><tr><td>Biography</td><td>Gaëlle Marteil, PhD</td></tr></table>

## EDUCATION

2010 PhD in Biology

2007 Master's degree in Biochemistry

2005 Bachelor's degree in Biology

## RESEARCH EXPERIENCE

2018-Present Lecturer in human reproductive biology, IMoST UMR1240 Inserm/University Clermont Auvergne, France

2011 - 2018 Post-doctorate, CCR laboratory, Instituto Gulbenkian de Ciência (IGC), Portugal.

2007 - 2010 PhD Biology, Cell Cycle Team, UMR6061 CNRS- University of Rennes 1, France.

## Last PUBLICATION

2018 G Marteil et al. Over-elongation of Centrioles in Cancer Promotes Centriole Amplification and Chromosome Missegregation. Nature Communications

G. Marteil¹, L. Chaput², S. Dollet¹, B. Pereira³, E. Eymard-Pierre⁴, M. Fiot¹, C. Gouhier², A.S. Grémeau², C. Chauffour², A. Tchirkov⁴, F. Brugnon².

¹IMoST UMR1240 INSERM/UCA, Fertility and Cancer group, Clermont-Ferrand, France.

²CHU Clermont-Ferrand, ART department, Clermont-Ferrand, France.

³CHU Clermont-Ferrand, DRCI "Direction de la Recherche Clinique et Innovations"- biostatistics unit, Clermont-Ferrand, France.

⁴CHU Clermont-Ferrand, Cytogenetics department, Clermont-Ferrand, France.

## Study question:

What are the optimal vitrification method (semi-automated vs. manual)
and oocyte stage for *in vitro*-matured oocyte cryopreservation using
meiosis kinetics and chromosome segregation as readouts?

Summary answer:

The semi-automated vitrification method does not impact oocyte nuclear maturation quality compared with the manual method. Immature oocyte cryopreservation should be performed after IVM.

What is known already:

Fertility preservation using oocyte vitrification should be performed
before oncological treatments. The reference protocol consists in
collecting mature oocytes after ovarian stimulation. Nevertheless, ovarian
stimulation sometimes yields immature oocytes or cannot be performed
(e.g., emergency oncological treatment). An IVM step is therefore
required but it is not clearly demonstrated whether IVM should be
performed before or after vitrification. Oocyte vitrification is usually
performed with manual methods. A semi-automated vitrification device
(Gavi®, Genea Biomedx) showing high performances for embryo was
recently released. To our knowledge, no study has analysed its efficiency
on oocyte vitrification.

Study design, size, duration:

200 immature oocytes collected from ICSI cycles from January 2020 will be used. Oocytes will be divided in five groups (40 oocytes/group): freshly matured oocytes (group 1 control), oocytes vitrified after IVM by a manual technique (group 2a) or by Gavi® (group 2b) and oocytes vitrified prior IVM (groups 3a and 3b). We assess oocyte nuclear maturation quality by evaluating IVM kinetics by time-lapse (Geri®) and the accuracy of homologous chromosomes segregation by CGH array.

Participants/materials, setting, methods:

Since January 2020, 124 out of 200 immature oocytes have been included for this study. These oocytes provide from women under 37 years old without ovulatory disorder after signing an informed consent. The kinetics of meiotic resumption (germinal vesicle breakdown (GVBD) and polar body extrusion (PBE) timings), is determined by time-lapse technology (Geri®, Genea Biomedx). The accuracy of the homologous chromosome segregation during the first meiotic division will be assessed by CGH-Array.

Main results and the role of chance:

The clinico-biological characteristics (age, BMI, smoking and total FSH dose) are comparable between the five groups (p>0.05). No significant difference in post-thawing oocyte survival rate is observed between the two vitrification methods (semi-automated 58% vs. manual 64%). A
significant difference in the overall oocyte survival rate is observed according to the stage of vitrification with a significantly higher survival rate if oocytes are vitrified at the mature stage (93% (2a+2b) vs. 61% (3a+3b), p =0.02). The IVM rate is significantly higher if oocytes are matured freshly (86% in group 1 (fresh IVM, n= 7) and 93% in group 2a+2b (IVM before vitrification, n= 27)) compared to post vitrification (71% in group 3a+3b, n= 28), p=0.03. The vitrification technique does not seem to impact IVM rate since it reached 64% (group 3a, n=11) and 76% (group 3b, n=16) (p=0.4). GVBD and PBE timings are not significantly different between the 5 groups, suggesting that neither the oocyte stage of vitrification nor the vitrification technique affects maturation kinetics. Similarly, our preliminary results of polar bodies and oocytes chromosomal profiles assessed by CGH-Array demonstrate a similar rate of aneuploidy (monosomy or trisomy) between the groups.

Limitations, reasons for caution:

Our preliminary results of CGH array should be confirmed with the
analysis of a larger number of IVM oocytes.

Wider implications of the findings:

Vitrification of immature oocytes should be performed by semi-
automated or manual methods after IVM. Tour knowledge, this is the
first study comparing the efficiency of both semi-automated and manual
vitrification methods on immature and in vitro-matured oocytes.

COI I have no potential conflict of interest to disclose

Keywords
In vitro maturation
fertility preservation
oocyte vitrification
nuclear maturation