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The Fertility Show


 

Human embryos grown in lab for 13 days – longest time ever

09 May 2016

By Julianna Photopoulos

Appeared in BioNews 850

Scientists from the UK and US have grown human embryos in the lab for 13 days after fertilisation – the longest ever recorded. This is beyond the stage when embryos would normally implant in the womb, but just before the 14-day legal limit in the UK.

'We can now, for the very first time, study human development at this very critical stage of our lives, at the time of implantation,' Professor Magdalena Zernicka-Goetz, who led the UK research at Cambridge University, told the Guardian.

The longest that human embryos had previously been grown in the lab was nine days, though seven days was far more common.

The research, published in Nature and Nature Cell Biology, promises new insights into early human development that could help determine the causes of miscarriages and infertility, and help create improved progenitor stem cell lines.

'Implantation is a milestone in human development as it is from this stage onwards that the embryo really begins to take shape and the overall body plan are decided. It is also the stage of pregnancy at which many developmental defects can become acquired. But until now, it has been impossible to study this in human embryos. This new technique provides us with a unique opportunity to get a deeper understanding of our own development during these crucial stages and help us understand what happens, for example, during miscarriage,' said Professor Zernicka-Goetz.

Adapting her team's previous work on mouse embryos, the scientists chemically mimicked the womb and found that immediately after the implantation stage, the three cell types that comprise the blastocyst reorganise into a new formation.

'The stem cells in the epiblast that will form the future body have the remarkable ability to self-organise themselves and create a cavity that represent the basic structure of the early post-implantation human embryo,' said Professor Zernicka-Goetz.

This reoganisation process, occurring through cell–cell interactions rather than through programmed cell death as previously thought, was similar to what was observed in mouse embryos. However, the culture method also revealed significant differences between human and mouse embryos, such as the genes expressed and the structure.

'With this work, we can really appreciate the differences between human and mouse, and across all mammals,' said Dr Ali Brivanlou of the Rockefeller University, who led the US research. 'Because of the variations between species, what we learn in model systems is not necessarily relevant to our own development, and these results provide crucial information we couldn't learn elsewhere.'

While the ability to grow an embryo in vitro for 13 days is an exciting breakthrough, the achievement raises ethical and policy considerations. At least 12 countries, including the UK, do not allow experiments on human embryos that are older than 14 days, and some scientists are already calling for the decades-old rule to be revisited (see this week's BioNews comment).

'This limit was chosen more than 20 years ago as it was thought to represent the first point when individuality is assigned and twinning no longer possible,' said Professor Daniel Brison of the University of Manchester. 'However, given the potential benefits of new research in infertility, improving assisted conception methods, and in early miscarriage and disorders of pregnancy, there may be a case in the future to reconsider this.'

Both Professor Zernicka-Goetz and Dr Brivanlou told Nature News that they doubt their embryos would survive much beyond the 14-day mark because work in mice suggests that further developed embryos need an unknown mix of hormones and nutrients from the mother to survive. They are starting to run experiments with embryos from non-human primates and cows, in order to learn more.

Robin Lovell-Badge, a geneticist at the Francis Crick Institute in London who was not involved in the research, said: 'Proposing to extend the 14-day limit might be opening a can of worms, but would it lead to Pandora's box, or a treasure chest of valuable information? This is not a question to be left to scientists alone.'

The Nuffield Council on Bioethics has announced that it will review this issue.

RELATED ARTICLES FROM THE BIONEWS ARCHIVE

23 January 2017 - by Anna Leida 
A recent YouGov poll has shown that almost half of the general public is in favour of legalising research on embryos up to 28 days old...
19 December 2016 - by Giulia Cavaliere 
It's not enough to just talk about the benefits of extending the 14-day rule, we must also consider the views of those who believe that human embyros are persons...
19 December 2016 - by Dr Cathy Herbrand 
Baroness Mary Warnock was the first speaker at this year's Progress Educational Trust Annual Conference. She is best known for The Warnock report, which was written more than 30 years ago and has shaped legislation in the UK and around the world...
05 December 2016 - by Annabel Slater 
An extension to the 14-day human embryo research rule will be proposed at the annual Progress Educational Trust conference on 7 December...
24 October 2016 - by Anneesa Amjad 
In this podcast, Radiolab presenter Molly Webster explores the origins of the 14-day rule – the internationally agreed two-week time constraint on growing embryos in a lab...

09 May 2016 - by Julian Hitchcock 
The advances of Magdalena Zernicka-Goetz, the opportunities to undertake valuable medical research and our changed sense of values all demand that we reappraise the 14-day limit...
03 May 2016 - by Professor Magdalena Zernicka-Goetz 
Although our recent findings on the fate of aneuploid cells in mosaic embryos have indeed been somewhat misrepresented in the press, our findings may still constitute a strand of hope for mothers who have had early test results showing mosaic aneuploidy...
01 February 2016 - by Ayala Ochert 
The Human Fertilisation and Embryology Authority has granted the first licence to a UK researcher to edit the genomes of human embryos...
21 December 2015 - by Wendy Suffield 
At PET's recent conference, Professor Azim Surani claimed that permission to carry out experiments on embryos beyond the 14-day rule could make a huge difference to research. It may be time to review the ethical reasoning behind this time limit...

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Published by the Progress Educational Trust

CROSSING FRONTIERS

Moving the Boundaries of Human Reproduction

Public Conference
London
8 December 2017

Speakers include

Professor Azim Surani

Professor Magdalena Zernicka-Goetz

Professor Robin Lovell-Badge

Sally Cheshire

Professor Guido Pennings

Katherine Littler

Professor Allan Pacey

Dr Sue Avery

Professor Richard Anderson

Dr Elizabeth Garner

Dr Jacques Cohen

Dr Anna Smajdor

Dr Andy Greenfield

Vivienne Parry

Dr Helen O'Neill

Dr César Palacios-González

Philippa Taylor

Fiona Fox

Sarah Norcross


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