Brivanlou et al.

Womb-in-a-dish allows study of human embryos

Embargoed until: Publicly released:

We now have a clearer idea of how a fertilised egg grows beyond its first week, thanks to US, UK and French scientists who have managed to create lab conditions that mimic the womb. Until now, human embryos haven't survived beyond seven days in the lab because they've needed to attach to the uterus wall to develop further - but two papers have revealed that it's now possible if the early embryo can attach to something similar in the lab dish. However, the researchers still don't know what happens at 14 days because it is illegal to keep growing embryos in the lab beyond this time.

Journal/conference: Nature, Nature Cell Biology

Organisation/s: The Rockefeller University, USA; Cambridge University, UK

Media Release

From: Springer Nature

Early development of human embryos tracked in culture

The early stages of development of the human embryo are studied in culture for up to 10–13 days in two separate studies published in Nature and Nature Cell Biology this week. Both studies show that, even in a petri dish, human embryos can self-organize — a process involving cell divisions and shape rearrangements — and that the changes they undergo are similar to those that occur in the presence of maternal cues.

Although very early stages of human embryo development have been studied before, so far it has been challenging to keep human embryos in a petri dish past the seventh day of development, when they usually implant into the womb. Ali Brivanlou and colleagues, writing in a paper published in Nature, and Magdalena Zernicka-Goetz and colleagues, writing in a separate paper in Nature Cell Biology, have shown that the human embryo can self-organize in a petri dish. Using a technique previously developed by the second set of authors for culturing mouse embryos, both groups report various events taking place up to 10–13 days of development, from the formation of the blastocyst — an embryo stage in which cell divisions are underway — to the post-implantation stage, which occurs after the embryo has adhered to the wall of the womb, or, in this case, an attachment substrate. These observations highlight developmental differences between mouse and human embryos, including cell-type specification and tissue organization.

In accordance with internationally recognised guidelines, the experiments were concluded before 14 days into development or the formation of a line of cells known as the primitive streak. In a Comment piece published in Nature this week, Insoo Hyun, Amy Wilkerson and Josephine Johnston explain that the 14-day rule has been effective at permitting research on embryos within strict constraints in part because, until now, it has been technologically challenging for scientists to break it. They stress that this rule was “never intended to be a bright line denoting the onset of moral status in human embryos.” Instead, they write, it is “a public-policy tool designed to carve out a space for scientific inquiry and simultaneously show respect for the public’s diverse views on research on human embryos.”  Any decision to revise the rule in light of the evolving science and its potential benefits must depend on how well the proposed changes can achieve these two chief goals, the authors argue. They recommend that any future processes of consensus-building involve experts, policy makers, patients and concerned citizens.

The last paragraph of this press release refers to a Nature Comment piece, not a Nature research paper. Comment pieces are topical, authoritative Op-Eds pertaining to scientific research and its ramifications.

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  • Springer Nature
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Expert Reaction

These comments have been collated by the Science Media Centre to provide a variety of expert perspectives and reflect independent opinion on this issue. Feel free to use these quotes in your stories. Views expressed are the personal opinions of the experts named. They do not represent the views of the SMC or any other organisation unless specifically stated.

Assoc Prof Michael Legge, Department of Biochemistry, University of Otago

Whilst animal models (primarily the mouse) have been valuable in understanding pre-implantation and post-implantation embryo development, they are limited to the embryological time frame of embryogenesis (20 days in mice). To fully understand the developmental programme of human embryos it is necessary to transfer the techniques and knowledge from animal embryos to human embryos.

Taking inā€vitro embryo development up to 14 days will significantly enhance the understanding of cellular decision making and programming for specific cell lineages, understanding cell migration and the role of embryonic stem cell biology in making those decisions.

When this approach is combined with the newer ‘gene-editing’ techniques it will provide a powerful developmental biology analytical system to understand how early gene signaling influences normal development, and will provide a greater insight in understanding how abnormalities develop during embryogenesis.

New Zealand’s stance on embryo research

Human embryo research is governed by the Human Assisted Reproductive Technology Act (2004), which allows, in principle, research on human embryos up to 14 days with appropriate ethical approval. Two committees resulted from the Act, the Advisory Committee on Assisted Reproductive Technology (ACART) primarily responsible for setting policy, guidelines and advice to government ministers and the Ethics Committee on Assisted Reproductive Technology (ECART) with the overarching responsibility of ethical approval of reproductive technology procedures that are not an established procedure, which includes any embryo research.

Currently in New Zealand suitable guidelines for human embryo research have not been formulated although research is clearly stated in the Act and decisions relating to establishing guidelines are awaiting ministerial direction.

Last updated: 03 Nov 2016 8:12pm

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