Talk:Week 1
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Cite this page: Hill, M.A. (2024, April 25) Embryology Week 1. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Talk:Week_1 |
2012
Atlas of Human Embryology: from Oocytes to Preimplantation Embryos
Human Reproduction
Volume 27 suppl 1 August 2012
http://humrep.oxfordjournals.org/content/27/suppl_1.toc
2010
Dynamic changes in gene expression during human early embryo development: from fundamental aspects to clinical applications
Assou S, Boumela I, Haouzi D, Anahory T, Dechaud H, De Vos J, Hamamah S. Hum Reprod Update. 2010 Aug 17. [Epub ahead of print] PMID 20716614
The first week of human embryonic development comprises a series of events that change highly specialized germ cells into undifferentiated human embryonic stem cells (hESCs) that display an extraordinarily broad developmental potential. The understanding of these events is crucial to the improvement of the success rate of in vitro fertilization. With the emergence of new technologies such as Omics, the gene expression profiling of human oocytes, embryos and hESCs has been performed and generated a flood of data related to the molecular signature of early embryo development. METHODS In order to understand the complex genetic network that controls the first week of embryo development, we performed a systematic review and study of this issue. We performed a literature search using PubMed and EMBASE to identify all relevant studies published as original articles in English up to March 2010 (n = 165). We also analyzed the transcriptome of human oocytes, embryos and hESCs. RESULTS Distinct sets of genes were revealed by comparing the expression profiles of oocytes, embryos on Day 3 and hESCs, which are associated with totipotency, pluripotency and reprogramming properties, respectively. Known components of two signaling pathways (WNT and transforming growth factor-beta) were linked to oocyte maturation and early embryonic development. CONCLUSIONS Omics analysis provides tools for understanding the molecular mechanisms and signaling pathways controlling early embryonic development. Furthermore, we discuss the clinical relevance of using a non-invasive molecular approach to embryo selection for the single-embryo transfer program.
Life-giving caspases: revealing new roles during mouse embryo preimplantation development
Int J Dev Biol. 2010;54(5):857-65.
Busso D, Dominguez C, Perez-Acle T, Moreno RD.
Department of Physiology, Facultad de Ciencias Biologicas, Pontificia Universidad Catolica de Chile, Santiago, Chile. dbusso@bio.puc.cl Abstract Caspases, cystein proteases traditionally related to programmed cell death, have recently been found to be involved in vital processes such as cell proliferation, adhesion and differentiation. Although caspases are expressed in mouse embryos before the blastocyst stage, their role is unclear, since apoptosis does not occur significantly before implantation. In this work, we have used mouse preimplantation development as a model to evaluate the existence of non-lethal caspase activities. The use of specific caspase inhibitors during in vitro embryo culture showed that caspase 8 activity, but not caspase 2 or 9, was relevant for development. The inhibition of caspase 8 affected the compaction of morulae and the progression to the blastocyst stage. In agreement with these results, caspase 8 was expressed in mouse embryos, as shown by indirect immunofluorescence and RT-PCR. An in silico approach was used to find putative caspase targets expressed in mouse preimplantation embryos. Large-scale management of sequence data from mouse embryos was used to predict caspase substrates by tools matrix-based on known cleavage sites. A total of 510 potential caspase targets expressed in mouse embryos were identified by this procedure. The functional characterization of these proteins by Gene Onthology associations showed that many of these putative caspase targets were previously related to non-apoptotic functions and only 63 had been previously reported to be actually cleaved by caspases. Interestingly, eleven knockout mice models for caspase substrates identified in our work, i.e. catenin alpha and beta, geminin, pescadillo, calpain-2, have preimplantation lethal phenotypes. This work supports the involvement of caspases in vital functions during mouse preimplantation development and proposes a model in which the regulated cleavage of caspase substrates could account for this role.
PMID 20336607
http://www.intjdevbiol.com/paper.php?doi=10.1387/ijdb.092921db
2009
Human embryonic stem cell lines derived from single blastomeres of two 4-cell stage embryos
Geens M, Mateizel I, Sermon K, De Rycke M, Spits C, Cauffman G, Devroey P, Tournaye H, Liebaers I, Van de Velde H.
Hum Reprod. 2009 Nov;24(11):2709-17. Epub 2009 Jul 24.
BACKGROUND: Recently, we demonstrated that single blastomeres of a 4-cell stage human embryo are able to develop into blastocysts with inner cell mass and trophectoderm. To further investigate potency at the 4-cell stage, we aimed to derive pluripotent human embryonic stem cells (hESC) from single blastomeres.
METHODS: Four 4-cell stage embryos were split on Day 2 of preimplantation development and the 16 blastomeres were individually cultured in sequential medium. On Day 3 or 4, the blastomere-derived embryos were plated on inactivated mouse embryonic fibroblasts (MEFs).
RESULTS: Ten out of sixteen blastomere-derived morulae attached to the MEFs, and two produced an outgrowth. They were mechanically passaged onto fresh MEFs as described for blastocyst ICM-derived hESC, and shown to express the typical stemness markers by immunocytochemistry and/or RT-PCR. In vivo pluripotency was confirmed by the presence of all three germ layers in the teratoma obtained after injection in immunodeficient mice. The first hESC line displays a mosaic normal/abnormal 46, XX, dup(7)(q33qter), del(18)(q23qter) karyotype. The second hESC line displays a normal 46, XY karyotype.
CONCLUSION: We report the successful derivation and characterization of two hESC lines from single blastomeres of four split 4-cell stage human embryos. These two hESC lines were derived from distinct embryos, proving that at least one of the 4-cell stage blastomeres is pluripotent.
PMID 19633307
http://humrep.oxfordjournals.org/content/24/11/2709.long
© The Author 2009. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please email: journals.permissions@oxfordjournals.org The online version of this article has been published under an open access model. Users are entitled to use, reproduce, disseminate, or display the open access version of this article for non-commercial purposes provided that: the original authorship is properly and fully attributed: the Journal and Oxford University Press are attributed as the original place of publication with the correct citation details given: if an article is subsequently reproduced or disseminated not in its entirety but only in part or as a derivative word this must be clearly indicated.
2008
Genomic RNA profiling and the programme controlling preimplantation mammalian development
Bell CE, Calder MD, Watson AJ. Mol Hum Reprod. 2008 Dec;14(12):691-701. Epub 2008 Nov 29.
Preimplantation development shifts from a maternal to embryonic programme rapidly after fertilization. Although the majority of oogenetic products are lost during the maternal to embryonic transition (MET), several do survive this interval to contribute directly to supporting preimplantation development. Embryonic genome activation (EGA) is characterized by the transient expression of several genes that are necessary for MET, and while EGA represents the first major wave of gene expression, a second mid-preimplantation wave of transcription that supports development to the blastocyst stage has been discovered. The application of genomic approaches has greatly assisted in the discovery of stage specific gene expression patterns and the challenge now is to largely define gene function and regulation during preimplantation development. The basic mechanisms controlling compaction, lineage specification and blastocyst formation are defined. The requirement for embryo culture has revealed plasticity in the developmental programme that may exceed the adaptive capacity of the embryo and has fostered important research directions aimed at alleviating culture-induced changes in embryonic programming. New levels of regulation are emerging and greater insight into the roles played by RNA-binding proteins and miRNAs is required. All of this research is relevant due to the necessity to produce healthy preimplantation embryos for embryo transfer, to ensure that assisted reproductive technologies are applied in the most efficient and safest way possible.
PMID 19043080
http://molehr.oxfordjournals.org/content/14/12/691.long
Special Issue: Emerging Technologies for the Assessment of Gametes and Embryos - The OMICS
http://molehr.oxfordjournals.org/content/14/12.toc
http://creativecommons.org/licenses/by-nc/2.0/uk/
Selective single blastocyst transfer study: 604 cases in 6 years
J Hum Reprod Sci. 2008 Jan;1(1):10-4.
Sadasivam N, Sadasivam NM. Source Department of Infertility Medicine, Maaruthi Medical centre and Hospitals, Erode, Tamilnadu, India. Abstract AIM: To evaluate the credibility of single blastocyst transfer (SBT) method in selected group of patients. SETTINGS AND DESIGN: Retrospective analysis of SBT cases based on computerized data in a private Fertility research centre. MATERIALS AND METHODS: A total of 604 cases of SBTs, done during June 2000 to June 2006, have been analyzed retrospectively to assess the credibility of the method as a method of choice in selective high fertile group of patients. Women between 28 and 42 years have been included in the retrospective analysis, who had adequate number of eggs for fertilization, between 6 and 12. RESULTS AND CONCLUSIONS: Grade I blastocyst transfer resulted in 46.6% of clinical pregnancy and grade II blastocyst transfer resulted in 17.4% of clinical pregnancy rates. Overall pregnancy rate was 64%. Pregnancy loss, as early and late fetal wastages, was 11.06%.
PMID 19562057 PMCID: PMC2700678
