Free Access Articles
Validation of next-generation sequencing for comprehensive chromosome screening of embryos
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).Ectogenesis: what could be learned from novel in-vitro culture systems?
Early mammalian development consists of two distinct phases separated by the event of implantation. Whereas much has been discovered about developmental mechanisms prior to implantation, the inability to culture and follow in real time cell behaviour over the period of implantation means that the second phase has not been explored in as much detail. Recently, a novel in-vitro culture system was described that permits continuous culture and time-lapse observations through the peri- and early post-implantation stages.Modelling a risk classification of aneuploidy in human embryos using non-invasive morphokinetics
This study determined whether morphokinetic variables between aneuploid and euploid embryos differ as a potential aid to select euploid embryos for transfer. Following insemination, EmbryoScope time-lapse images from 98 blastocysts were collected and analysed blinded to ploidy. The morphokinetic variables were retrospectively compared with ploidy, which was determined following trophectoderm biopsy and analysis by array comparative genomic hybridization or single-nucleotide polymorphic array. Multiple aneuploid embryos were delayed at the initiation of compaction (tSC; median 85.1 hours post insemination (hpi); P = 0.02) and the time to reach full blastocyst stage (tB; median 110.9 hpi, P = 0.01) compared with euploid embryos (tSC median 79.7 hpi, tB median 105.9 hpi).Temperature gradients in female reproductive tissues
Deep body temperature in mammals is generally but incorrectly regarded as uniform. Alterations of temperature in oviducts and preovulatory Graafian follicles may play a vital role in gamete maturation, fertilization and early embryonic development. At a molecular level, the conformation of regulatory proteins is susceptible to changes in temperature. Deviation from physiological temperature during IVF procedures could thereby exert a profound influence on patterns of gene expression as the embryonic genome unfolds during early cleavage stages and act to generate specific anomalies.Oocyte developmental competence and embryo development: impact of lifestyle and environmental risk factors
Oocyte development is the end result of a sophisticated biological process that is hormonally regulated and produced by highly specialized cellular lines that differentiate in early embryo/fetal development. Embryo development is initially regulated by maternal transcripts until replaced by embryonic genomic expression. Then, an assortment of hormones and local environmental factors in various concentrations along the reproductive tract (e.g. fallopian tube, endometrial lining) provide the protection, nutrients and means of communication for the embryo to implant and develop.
