Impact of assisted oocyte activation on morphokinetics of early human embryos

While the fertilising spermatozoon supplies the active centre directing the human zygote's first mitotic division, the relative contributions of the sperm head and tail (as well as the importance of the sperm's general structural integrity) to subsequent developmental processes remain incompletely studied. The sperm nucleus contains paternal chromatin necessary for restoration of a diploid genome, but the functional role of the sperm tail (either attached or dissected) in early human embryonic growth is not known. In this investigation using oocytes donated by in vitro fertilisation patients, human oocytes were injected with isolated sperm heads (n = 73), isolated sperm flagella (n = 11) or both (dissected sperm heads + free sperm tails, n = 26). The formation of bipronucleate zygotes was recorded for each method. Among oocytes surviving injection with isolated sperm heads, 44 of 66 (67%) formed two pronuclei. Of oocytes receiving only sperm tails, 2 of 11 (18%) displayed two pronuclei, but a single polar body was evident in both cases. When dissected spermatozoa parts (head + tail) were jointly injected, 12 of 26 (46%) developed two pronuclei. From embryos resulting from each of these three fertilisation regimes, blastomere biopsies were obtained and subjected to multiprobe fluorescent in situ hybridisation (FISH) analysis to detect mosaicism or aneuploidy arising from these experimental treatments. Only embryos with growth sufficient to permit sampling of at least two blastomeres were evaluated, and FISH analysis was successful in 25 of 29 (86%) embryos tested. Of 12 embryos derived from injection of an isolated sperm head, only one was normal diploid; the remaining 11 were mosaic. Both embryos resulting from injection of an unattached sperm tail were mosaic. Of 11 embryos generated from oocyte injection with sperm head + tail segments, 10 (91%) were mosaic and only one was normal diploid. Results from this study show that injection of isolated sperm segments can permit oocyte activation and bipronuclear formation. However, a high rate of mosaicism in human embryos originating from disrupted sperm or sperm components suggests that more than a ‘sum of parts’ is needed for later development. The structural integrity of the intact fertilising spermatozoon appears to contribute to normal human early embryogenesis.

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Fertilization Narratives in the Art of Gustav Klimt, Diego Rivera and Frida Kahlo: Repression, Domination and Eros among Cells

Leonardo ◽

10.1162/leon_a_00166 ◽

2011 ◽

Vol 44 (3) ◽

pp. 221-227 ◽

Cited By ~ 2

Author(s):

Scott F. Gilbert ◽

Sabine Brauckmann

Keyword(s):

20Th Century ◽

Human Embryos ◽

Diego Rivera ◽

Frida Kahlo ◽

Embryo Formation ◽

Human Fertilization ◽

Gustav Klimt ◽

The Universe ◽

Early Human

Fertilization narratives are powerful biological stories that can be used for social ends, and 20th-century artists have used fertilization-based imagery to convey political and social ideas. In Danae, Gustav Klimt used an esoteric stage of early human embryos to indicate successful fertilization and the inability of government repression to stifle creativity. In Man, Controller of the Universe, Diego Rivera painted a mural of a man controlling an ovulating ovary, depicting Trotsky's view that society will rationally regulate human fertilization. His former wife, Frida Kahlo, refuted this view in Moses: Nucleus of Creation, wherein she painted images of fertilization and embryo formation as the ultimate acts of erotic consummation and generation.

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Comparison of gene expression in fresh and frozen–thawed human preimplantation embryos

Reproduction ◽

10.1530/rep-12-0047 ◽

2012 ◽

Vol 144 (5) ◽

pp. 569-582 ◽

Cited By ~ 31

Author(s):

Lisa Shaw ◽

Sharon F Sneddon ◽

Daniel R Brison ◽

Susan J Kimber

Keyword(s):

Gene Expression ◽

Expression Profiles ◽

Expression Patterns ◽

Developmental Expression ◽

Preimplantation Embryos ◽

Human Embryos ◽

Molecular Events ◽

Reliable Source ◽

Human Preimplantation Embryos ◽

Early Human

Identification and characterisation of differentially regulated genes in preimplantation human embryonic development are required to improve embryo quality and pregnancy rates in IVF. In this study, we examined expression of a number of genes known to be critical for early development and compared expression profiles in individual preimplantation human embryos to establish any differences in gene expression in fresh compared to frozen–thawed embryos used routinely in IVF. We analysed expression of 19 genes by cDNA amplification followed by quantitative real-time PCR in a panel of 44 fresh and frozen–thawed human preimplantation embryos. Fresh embryos were obtained from surplus early cleavage stage embryos and frozen–thawed embryos from cryopreserved 2PN embryos. Our aim was to determine differences in gene expression between fresh and frozen–thawed human embryos, but we also identified differences in developmental expression patterns for particular genes. We show that overall gene expression among embryos of the same stage is highly variable and our results indicate that expression levels between groups did differ and differences in expression of individual genes was detected. Our results show that gene expression from frozen–thawed embryos is more consistent when compared with fresh, suggesting that cryopreserved embryos may represent a reliable source for studying the molecular events underpinning early human embryo development.

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The sperm centriole: its inheritance, replication and perpetuation in early human embryos

Human Reproduction ◽

10.1093/humrep/11.2.345 ◽

1996 ◽

Vol 11 (2) ◽

pp. 345-356 ◽

Cited By ~ 134

Author(s):

A.H. Sathananthan ◽

S.S. Ratnam ◽

S.C. Ng ◽

J.J. Tarin ◽

L. Gianaroli ◽

...

Keyword(s):

Human Embryos ◽

Early Human

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Topographical studies of the liver in early human embryos

Journal of Nippon Medical School ◽

10.1272/jnms1923.26.7_641 ◽

1959 ◽

Vol 26 (7) ◽

pp. 641-658

Author(s):

Norio Sankawa

Keyword(s):

Human Embryos ◽

Early Human

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Protocol for controlled modeling of human epiblast and amnion development using stem cells

10.21203/rs.2.11520/v1 ◽

2019 ◽

Cited By ~ 2

Author(s):

Yi Zheng ◽

Jianping Fu

Keyword(s):

Stem Cells ◽

Primordial Germ Cells ◽

Primitive Streak ◽

Human Embryos ◽

Vitro Fertilization ◽

Human Embryology ◽

Post Implantation ◽

Advance Knowledge ◽

Early Human

Abstract Due to the inaccessibility of post-implantation human embryos and the restriction on in-vitro fertilization (IVF) embryos cultured beyond 14 days, the knowledge of early post-implantation human embryogenesis remains extremely limited. Recently, we have developed a microfluidic in-vitro platform, based on human pluripotent stem cells (hPSCs), which is capable of recapitulating several key developmental landmarks of early human post-implantation embryonic development, including lumenogenesis of the epiblast (EPI), amniogenesis, and specification of primordial germ cells (PGCs) and of primitive streak (PS) cells. Given its controllability and reproducibility, the microfluidic platform provides a powerful experimental platform to advance knowledge of human embryology and reproduction. This protocol describes the preparation of the microfluidic device and its implementation for modeling human post-implantation epiblast and amnion development using hPSCs.

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