MICRO-MAGNETIC RESONANCE SPECTROSCOPY OF INDIVIDUAL MAMMALIAN EMBRYOS: A CUTTING-EDGE, NON-INVASIVE TOOL FOR IDENTIFYING THE MOST VIABLE EMBRYOS

Problem statement: Assisted reproductive techniques (ART) have undergone enormous technological improvements, yet the live birth rates per transfer remains around 25% worldwide. Non-invasive metabolic assessment of embryos has been proposed via analysis of culture medium or label-free fluorescence imaging. However, a new non-invasive technology for embryo characterization based on identifying metabolic markers via micro-magnetic resonance (micro-MRS) has been developed by Annaida technologies. In this study, the aim was to explore metabolic markers obtained using our innovative device to predict cryopreservation and developmental potential of embryos in different mammalian species.

Methods: The study involved bovine and porcine embryos that were shipped cryopreserved to the lab and thawed before analysis with our proprietary micro-MRS device. The study involved identifying distinct spectral peaks mainly originating from lipids, which serve as biomarkers for a novel non-invasive MRS-based embryo screening tool. Micro-MRS measurements were performed during 50 minutes per sample. Statistical analysis was performed using GraphPad Software V9.0, with statistical significance set at p<0.05.

Results: The study examined bovine embryos and identified up to six markers, of which five were significantly higher expressed (p<0.05) in late-arrested versus early-arrested embryos (n=32 embryos). To further investigate lipid-biomarkers, we analysed porcine embryos that were delipidated to improve cryo-preservation. The observed signal spread correlated with the embryo`s ability to cryopreserve, with 80% of the observed embryos correctly identified in alive and dead samples post-thawing through Sat lipid marker (n=18) (p<0.05). Readily detectable lipid markers were also confirmed in rabbit blastocysts and human oocytes. These represent the first model where a single mammalian cell could be analysed with micro-MRS.

Conclusion: The main findings involve lipid biomarkers across different mammalian species showing that the micro-MRS-based device can be informative about embryo viability and cryotolerance. The study highlights the potential of micro-MRS for embryo screening, which could contribute to identify the most viable embryos for transfer.

EU Horizon 2020 research and innovation program supported this work under grant agreement No 959600.