Page URL:

Stem cells form human tissue that behave like early-stage embryos

22 March 2021
Appeared in BioNews 1088

For the first time, researchers have successfully developed models of early-stage human embryos using stem cells.

Two research groups have reported the development of new human blastocyst cell models, called blastoids. Until now, only later stage embryo models have been successfully cultured in vitro using stem cells. The models could help advance the study of miscarriage and birth defects, which are largely attributed to events at early stages of development.

'We're very excited,' remarked Dr Jun Wu, from the University of Texas Southwestern Medical Centre, and senior author of one study. 'Studying human development is really difficult, especially at this stage of development. It's essentially a black box,' he added.

Blastocysts are the first cluster of cells that form when a fertilised egg cell divides. After seven or eight days, the blastocyst implants on the uterine wall, and from here can develop into a fetus. Current research relies on small numbers of donated human embryos, and mouse models.

The two separate studies were published in the journal Nature, alongside preprints of two further studies reporting similar results that have not yet been peer-reviewed (see bioRxiv and bioRxiv). Both teams cultivated three-dimensional models of blastocysts in a dish, using human cells. Dr Wu's group (see Nature) used two types of human pluripotent stem cells (hPSCs) – originating from human embryos, or adult cells that had been induced to return to a stem-cell like state. In contrast, the second group (see Nature), led by Professor Jose Polo at Monash University in Melbourne, Australia, used induced pluripotent stem cells (iPSCs) derived from adult skin cells.

Each team obtained similar results, and found that cells self-organised into blastoids in vitro after culturing for six to eight days. Importantly, the blastoids resembled natural blastocysts in size and shape, and sequencing revealed that they were also genetically very similar. Furthermore, both groups were able to coax blastoids to 'implant' on artificial plastic sheets that resembled the uterus lining. However, based on mouse studies, the authors do not predict blastoids will have the capacity to develop into viable embryos.

Despite not being natural human blastocysts, neither team allowed the blastoids to grow beyond the equivalent of a 14-day old embryo, following strict rules issued by the International Society for Stem Cell Research (ISSCR). It is not clear whether the artificial models must adhere to these rules, and the ISSCR is due to release updated guidelines in May.

The advance has been heralded as a breakthrough by experts in the developmental biology field. 'The research provides an important new cell model to investigate human early development, which could lead to a better understanding of infertility and early pregnancy loss,' said Dr Peter Rugg-Gunn, group leader at the Babraham Institute in Cambridge who was not involved in the studies.

Both research groups acknowledged the need for further protocol optimisation, with both high variability and only ten to 20 percent efficiency of blastoid formation reported in each study. Despite this, the authors believe the potential benefits of the models are promising.

Professor Polo concluded: 'The capacity to work at scale, we think, will revolutionise our understanding of these early stages of human development.'

13 September 2021 - by Purvi Shah 
Researchers in Japan have successfully demonstrated the development of functional sperm cells that developed into fertile offspring from pluripotent embryonic stem cells, in mice...
1 June 2021 - by BioNews 
A conversation between Sandy Starr and Professor Robin Lovell-Badge (deputy director and chair of trustees respectively at the Progress Educational Trust) about the latest guidelines of the International Society for Stem Cell Research...
1 June 2021 - by Sandy Starr 
The International Society for Stem Cell Research has published wide-ranging new guidelines, covering a number of contentious areas of research and clinical practice...
10 May 2021 - by David O'Rourke 
Human blastocysts have been created in a simple, efficient way from stem cells grown in a lab...
4 May 2021 - by Bethany Muller 
Cells in synthetic mouse embryos have been shown to have gene expression profiles resembling those of the three initial cell lines of a mammalian embryo: the trophectoderm, epiblast and endoderm...
21 October 2019 - by Dr Jennifer Frosch 
US researchers have generated novel early embryo models – called blastoids – from mouse stem cells and implanted them into surrogate mice...
7 January 2019 - by Emma Laycock 
'Science marches on' was the third session of the Progress Educational Trust (PET)'s Annual Conference 'Make Do or Amend: Should We Update UK Fertility and Embryo Law?'. The session focused on the key scientific developments within embryo research asking: where are we now, what can we learn from past battles and, most importantly, where are we going?...
8 May 2018 - by Ewa Zotow 
Scientists have created synthetic embryos in mice using stem cells rather than sperm or egg cells.
to add a Comment.

By posting a comment you agree to abide by the BioNews terms and conditions

Syndicate this story - click here to enquire about using this story.