Entity

Time filter

Source Type

Lone Tree, CO, United States

Krisher R.L.,National Foundation for Fertility Research | Heuberger A.L.,Colorado State University | Paczkowski M.,National Foundation for Fertility Research | Stevens J.,Fertility Laboratories of Colorado | And 5 more authors.
Reproduction, Fertility and Development | Year: 2015

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. © CSIRO 2015. Source


Surrey E.,Colorado Center for Reproductive Medicine | Keller J.,Exempla Saint Joseph Hospital | Stevens J.,Fertility Laboratories of Colorado | Gustofson R.,Colorado Center for Reproductive Medicine | And 2 more authors.
Reproductive BioMedicine Online | Year: 2010

This retrospective cohort study compared outcomes from transfer of embryos cryopreserved at the pronuclear versus blastocyst stage following 'freeze-all' IVF cycles without fresh transfer for 87 consecutive IVF patients <40 years, who underwent cryopreservation of all viable embryos followed by at least one subsequent frozen embryo transfer (FET) between January 2003 and July 2007. Cryopreservation of all embryos from one oocyte retrieval was performed at either the pronuclear (1.5 mol/l propanediol and 0.1 mol/l sucrose) (group A) or blastocyst (10% glycerol) (group B) stage. Main outcome measures included survival, live birth and implantation rates. A total of 110 FET cycles were analysed. Live birth and implantation rates observed after the first FET were significantly higher (P = 0.025 and P = 0.002) in group B (67.7% and 40.8%) than in group A (41.1% and 21.5%) despite a higher survival rate in group A. After two FET cycles, 32.1% of group A had not conceived despite thaw of all available embryos, compared with 6.5% of group B. When freeze-all is necessary, blastocyst cryopreservation leads to higher implantation and live birth rates compared with pronuclear-stage cryopreservation despite lower survival rates. Prolonged embryo culture may allow for more optimal embryo selection. © 2010, Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved. Source


Herrick J.R.,National Foundation for Fertility Research | Strauss K.J.,National Foundation for Fertility Research | Schneiderman A.,Fertility Laboratories of Colorado | Rawlins M.,Fertility Laboratories of Colorado | And 3 more authors.
Reproduction, Fertility and Development | Year: 2015

In many cell types Mg2+ can antagonise Ca2+-stimulated signalling pathways, but information regarding the effects of these ions on IVF and subsequent embryonic development is limited. Our objectives were to evaluate the effects of Mg2+ in the IVF medium on embryonic development in mice and then determine if similar effects occurred in domestic cats and humans. Oocytes from hybrid and outbred mice, domestic cats and humans were fertilised (IVF, mice and cats; intracytoplasmic sperm injection (ICSI), humans) in the presence of 0.2 or 1.2 (mouse and human) or 1.0 (cat) mM Mg2+ and the resulting embryos were cultured to the blastocyst stage. Decreased concentrations of Mg2+ during IVF increased (P<0.05) cleavage of oocytes from outbred mice (77.9 vs 51.0%), development of embryos from hybrid mice (74.5 vs 51.0% hatching blastocyst per cleaved embryo) and both cleavage (68.4 vs 46.8%) and blastocyst development (53.0 vs 26.2% per cleaved embryo) in cats. Development to the blastocyst stage (52.1 vs 40.2%) was also improved (P<0.05) when ICSI was performed on human oocytes in the presence of 0.2mM Mg2+, compared with a commercial culture medium. Sensitivity to increased (1.0 to 1.2mM) concentrations of Mg2+ in the medium during the oocyte-to-embryo transition appears to be conserved in three different species. © 2015 CSIRO. Source

Discover hidden collaborations