Poster Presentation ESA-SRB-ANZBMS 2024 in conjunction with ENSA

The impact of varying IVF procedures on embryo metabolism (#426)

Megan Lim 1 2 3 , Cheow Yuen (Tiffany) Tan 1 2 , Wenyu Li 1 , Kishan Dholakia 2 3 4 , Kylie R Dunning 1 2
  1. Robinson Research Institute, School of Biomedicine, The University of Adelaide, Adelaide, South Australia, Australia
  2. The Centre of Light for Life, School of Biological Sciences, Faculty of Sciences, Engineering, and Technology, The University of Adelaide , Adelaide, South Australia, Australia
  3. School of Biological Sciences, The University of Adelaide, Adelaide, South Australia, Australia
  4. Scottish Universities Physics Alliance, School of Physics and Astronomy, University of St Andrews, North Haugh, Scotland

For decades, IVF success rates have seen minimal improvement. A crucial determinant of IVF success is embryo quality, however, an approach to assess this remains elusive. We previously demonstrated that capturing metabolic information from embryos, using light-based approaches, is a marker of embryo quality. The development of a metabolic-based tool requires understanding how in vitro conditions may alter embryo metabolism – this is yet to be explored.

Here, we investigated the impact of varying IVF procedures on murine embryo metabolism by: (1) culturing embryos in different culture media (in-house “Research Cleave”, G1-PLUS™/G2-PLUS™, or SAGE 1-Step™); and (2) utilising different recovery durations post-cryopreservation (2, 4, 6, or 24h). Blastocyst-stage embryos were evaluated for metabolic activity by capturing autofluorescence from metabolic cofactors (NAD(P)H and FAD) and calculating the resultant optical redox ratio (ORR). Allocation of cells to the divergent cell lineages: inner cell mass and trophectoderm, was also assessed.

Culturing embryos in different media resulted in alterations to metabolism and cell lineage allocation. Embryos cultured in G1/G2 media had significantly higher NAD(P)H levels (P<0.0001) and lower ORR compared to embryos cultured in Research Cleave (P<0.0001) or SAGE medium (P<0.05). These embryos also had increased numbers of cells in the inner cell mass and trophectoderm than those cultured in Research Cleave (P<0.05).

Recovery time post-cryopreservation also impacted embryo metabolic activity and cell allocation to divergent cell lineages. Non-cryopreserved embryos had significantly elevated NAD(P)H levels, whereas embryos recovered for 24h had lower FAD levels compared to all other groups (P<0.001). Embryos recovered for 6h had significantly fewer inner cell mass cells compared to non-cryopreserved embryos (P<0.05), and embryos recovered for 24h had a significantly elevated number of trophectoderm cells compared to all groups (P<0.0001).

Our research reveals how IVF procedures influence embryo metabolism, informing future development of a metabolic-based tool for embryo quality assessment.