title: Applying metabolomic analyses to the practice of embryology: physiology, development and assisted reproductive technology.
abstract: The advent of metabolomics technology and its application to small samples has allowed us to non-invasively monitor the metabolic activity of embryos in a complex culture environment. The aim of this study was to apply metabolomics technology to the analysis of individual embryos from several species during in vitro development to gain an insight into the metabolomics pathways used by embryos and their relationship with embryo quality. Alanine is produced by both in vivo- and in vitro-derived human, murine, bovine and porcine embryos. Glutamine is also produced by the embryos of these four species, but only those produced in vitro. Across species, blastocysts significantly consumed amino acids from the culture medium, whereas glucose was not significantly taken up. There are significant differences in the metabolic profile of in vivo- compared with in vitro-produced embryos at the blastocyst stage. For example, in vitro-produced murine embryos consume arginine, asparagine, glutamate and proline, whereas in vivo-produced embryos do not. Human embryos produce more alanine, glutamate and glutamine, and consume less pyruvate, at the blastocyst compared with cleavage stages. Glucose was consumed by human blastocysts, but not at a high enough level to reach significance. Consumption of tyrosine by cleavage stage human embryos is indicative of blastocyst development, although tyrosine consumption is not predictive of blastocyst quality. Similarly, although in vivo-produced murine blastocysts consumed less aspartate, lactate, taurine and tyrosine than those produced in vitro, consumption of these four amino acids by in vitro-derived embryos with high octamer-binding transcription factor 4 (Oct4) expression, indicative of high quality, did not differ from those with low Oct4 expression. Further application of metabolomic technologies to studies of the consumption and/or production of metabolites from individual embryos in a complete culture medium could transform our understanding of embryo physiology and improve our ability to produce developmentally competent embryos in vitro.
authors.affiliation: National Foundation for Fertility Research, 10290 RidgeGate Circle, Lone Tree, CO 80124, USA.
authors.forename: Rebecca L
authors.initials: RL
authors.lastname: Krisher
authors.affiliation: Proteomics and Metabolomics Facility, Colorado State University, 2021 Campus Delivery, Fort Collins, CO 80523, USA.
authors.forename: Adam L
authors.initials: AL
authors.lastname: Heuberger
authors.affiliation: National Foundation for Fertility Research, 10290 RidgeGate Circle, Lone Tree, CO 80124, USA.
authors.forename: Melissa
authors.initials: M
authors.lastname: Paczkowski
authors.affiliation: Fertility Laboratories of Colorado, 10290 RidgeGate Circle, Lone Tree, CO 80124, USA.
authors.forename: John
authors.initials: J
authors.lastname: Stevens
authors.affiliation: Fertility Laboratories of Colorado, 10290 RidgeGate Circle, Lone Tree, CO 80124, USA.
authors.forename: Courtney
authors.initials: C
authors.lastname: Pospisil
authors.affiliation: Division of Animal Science, University of Missouri, 920 East Campus Drive, Columbia, MO 65211, USA.
authors.forename: Randall S
authors.initials: RS
authors.lastname: Prather
authors.affiliation: Centre for Cardiovascular and Metabolic Research, The Hull York Medical School, University of Hull, Cottingham Road, Kingston Upon Hull, HU6 7RX, UK.
authors.forename: Roger G
authors.initials: RG
authors.lastname: Sturmey
authors.affiliation: National Foundation for Fertility Research, 10290 RidgeGate Circle, Lone Tree, CO 80124, USA.
authors.forename: Jason R
authors.initials: JR
authors.lastname: Herrick
authors.affiliation: Colorado Center for Reproductive Medicine, 10290 RidgeGate Circle, Lone Tree, CO 80124, USA.
authors.forename: William B
authors.initials: WB
authors.lastname: Schoolcraft
mesh_terms: D000596:Amino Acids / Q000378:metabolism*; D000818:Animals; D001755:Blastocyst / Q000378:metabolism*; D002417:Cattle; D003470:Culture Media; D004622:Embryo, Mammalian / Q000378:metabolism*; D047108:Embryonic Development / Q000502:physiology; D005260:Female; D005307:Fertilization in Vitro; D055432:Metabolomics; D051379:Mice; D009028:Morula / Q000378:metabolism*; D027724:Reproductive Techniques, Assisted; D013552:Swine
chemical_list: D000596:Amino Acids; D003470:Culture Media