There has been considerable focus on identifying quantifiable biomarkers of optimal developmental
and viability to improve the selection of preimplantation embryos produced using IVF, in order to
improve success rates and reduce multiple pregnancies. Examples of predictive biomarkers of
embryo viability include quantifying carbohydrate metabolism, amino acid metabolism and time-lapse
analysis of embryo kinetics. Independently, these biomarkers have been used to predict embryo
viability; however, their inter-relationship has not been previously investigated, especially on the same
embryo. It was hypothesized that developmental events, such as timing of cleavage divisions, rely on
optimal metabolic control for all cellular processes. Results demonstrated, for the first time, that
kinetically different cleavage stage mouse embryos develop into blastocysts with significantly different
carbohydrate and global amino acid profiles. Importantly, these kinetically different embryos
correspond with different viability outcomes, despite appearing morphologically similar. Interestingly,
aspartate consumption levels were significantly different between kinetically different embryos, which
suggests that aspartate is a quantifiable biomarker of viability. To investigate this, a novel
ultramicrofluorescence assay was developed to quantitate aspartate metabolism at the single
blastocyst level. It was demonstrated that embryo consumption of aspartate was positively correlated
to culture media aspartate concentration, with a proportional increase in glucose consumption.
However, lactate production was not different, suggesting that the additional glucose consumed was
not used for aerobic glycolysis. Overall, results strongly suggest that glucose and amino acid
metabolism of the embryo are biologically linked to developmental morphokinetics, and may be used
to predict viability. Additionally, a potential new biomarker, quantification of aspartate metabolism has
been identified. In combination, these parameters will facilitate the development of more reliable
embryo selection methods to increase the accuracy and power of embryo viability assessments, to
improve the success of clinical IVF outcomes, especially for single embryo transfers.