NCT02000349.

Massively parallel genome sequencing, also known as next-generation sequencing (NGS), is the latest approach for preimplantation genetic diagnosis. The purpose of this study was to determine whether NGS can accurately detect aneuploidy in human embryos. Low coverage genome sequencing was applied to trophectoderm biopsies of embryos at the blastocyst stage of development. Sensitivity and specificity of NGS was determined by comparison of results with a previously validated platform, array-comparative genomic hybridization (aCGH). In total, 156 samples (116 were blindly assessed) were tested: 40 samples were re-biopsies of blastocysts where the original biopsy specimen was previously tested for aCGH; four samples were re-biopsies of single blastomeres from embryos previously biopsied at the cleavage stage and tested using aCGH; 18 samples were single cells derived from well-characterized cell lines; 94 samples were whole-genome amplification products from embryo biopsies taken from previous preimplantation genetic screening cycles analysed using aCGH. Per embryo, NGS sensitivity was 100% (no false negatives), and 100% specificity (no false positives). Per chromosome, NGS concordance was 99.20%. With more improvement, NGS will allow the simultaneous diagnosis of single gene disorders and aneuploidy, and may have the potential to provide more detailed insight into other aspects of embryo viability.

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Pyruvate is added to all media used for human in vitro fertilization and embryo culture, but its function(s) in the early embryo is unknown. We tested the possibility that pyruvate can act as an oxidizable energy source by measuring the consumption of pyruvate and oxygen by Day 2 and Day 3 human embryos, using microfluorometric techniques. Oxygen consumption (19.6 pmol/embryo per hour) could account for the oxidation of only 56% of the pyruvate consumed (13.9 pmol/embryo per hour). Oxygen was also consumed in the absence of exogenous substrates. Lactate appeared in the incubation medium with pyruvate (0.47 mM) as sole exogenous substrate at a rate of 12.1 pmol/embryo per hour, at a similar rate (10.85 pmol/embryo per hour) in the presence of 1 mM glucose and 0.47 mM pyruvate, and at 2.25 pmol/embryo per hour in the absence of exogenous substrates, suggesting that a high proportion of the pyruvate taken up by early human embryos is converted to lactate. Pyruvate uptake in the presence of UK5099, a pyruvate transport inhibitor, was reduced to 10% of control values, consistent with the presence of the monocarboxylate carrier in the human embryo plasma membrane.

No abstract