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16 HEALTH AND LABORATORY MAGAZINE

EMBRYOS

WERE PRODUCED

WITHOUT USING

SPERM AND EGGS!

The embryos lasted longer

than anticipated.

An egg meets a sperm organs, has proved far mouse embryos from day 5 that sustain the developing For Hanna and other
– that’s a necessary first more difficult. to day 11. embryo,” Hanna says. stem cell and embryonic
step in life’s beginnings. In development researchers,
embryonic development “Until now, in most studies, In the new study, the team Soon after being mixed the study presents a new
research, it’s also a com- the specialized cells were set out to grow a synthetic together inside the device, arena: “Our next challenge
mon first step. However, in often either hard to pro- embryo model solely from the three groups of cells is to understand how stem
a new study, researchers duce or aberrant, and they naïve mouse stem cells convened into aggre- cells know what to do –
from the Weizmann Insti- tended to form a mishmash that had been cultured gates, the vast majority how they self-assemble
tute of Science have grown instead of well-structured for years in a petri dish, of which failed to develop into organs and find their
synthetic embryo models tissue suitable for trans- dispensing with the need properly. But about 0.5 way to their assigned spots
of mice outside the womb plantation. We managed to for starting with a fertilized percent – 50 of around inside an embryo. And
by starting solely with stem overcome these hurdles by egg. This approach is ex- 10,000 – went on to form because our system, unlike
cells cultured in a petri dish. unleashing the self-organi- tremely valuable because spheres, each of which a womb, is transparent, it
That means they are grown zation potential encoded in it could, to a large extent, later became an elongat- may prove useful for mod-
without the use of fertilized the stem cells.” bypass the technical and ed, embryo-like structure. eling birth and implantation
eggs. This method opens ethical issues involved in Since the researchers had defects of human embry-
new horizons for studying Hanna’s team built on two the use of natural embryos labeled each group of os.”
how stem cells form various previous advances in his in research and biotech- cells with a different color,
organs in the developing lab. One was an efficient nology. Even in the case of they were able to observe In addition to helping
embryo. It may also one method for reprogramming mice, certain experiments the placenta and yolk reduce the use of animals
day make it possible to stem cells back to a naïve are currently unfeasible sacs forming outside the in research, synthetic em-
grow tissues and organs state – that is, to their because they would require embryos and the model’s bryo models might in the
for transplantation using earliest stage – when they thousands of embryos, development proceeding future become a reliable
synthetic embryo models. have the greatest potential whereas access to models as in a natural embryo. source of cells, tissues, and
to specialize into differ- derived from mouse em- These synthetic models organs for transplantation.
“The embryo is the best ent cell types. The other, bryonic cells, which grow in developed normally until “Instead of developing
organ-making machine described in a scientific lab incubators by the mil- day 8.5 – nearly half of the a different protocol for
and the best 3D bioprint- paper in Nature in March lions, is virtually unlimited. mouse 20-day gestation growing each cell type –
er – we tried to emulate 2021, was the electroni- – at which stage all the for example, those of the
what it does,” says Prof. cally controlled device the Before placing the stem early organ progenitors kidney or liver – we may
Jacob Hanna of Weiz- team had developed over cells into the device, the re- had formed, including a one day be able to create
mann’s Molecular Genetics seven years of trial and searchers separated them beating heart, blood stem a synthetic embryo-like
Department, who headed error for growing natural into three groups. In one, cell circulation, a brain with model and then isolate the
the research team. mouse embryos outside which contained cells in- well-shaped folds, a neural cells we need. We won’t
the womb. The device tended to develop into em- tube and an intestinal tract. need to dictate to the
Hanna explains that keeps the embryos bathed bryonic organs themselves, When compared to natural emerging organs how they
scientists already know in a nutrient solution inside the cells were left as they mouse embryos, the syn- must develop. The embryo
how to restore mature of beakers that move were. Cells in the other two thetic models displayed itself does this best.”
cells to “stemness.” In fact, continuously, simulating the groups were pretreated for a 95 percent similarity in
pioneers of this cellular way nutrients are supplied only 48 hours to overex- both the shape of internal Reference: “Post-Gastru-
reprogramming won a by material blood flow to press one of two types of structures and the gene lation Synthetic Embryos
Nobel Prize in 2012. How- the placenta, and closely genes: master regulators expression patterns of Generated Ex Utero from
ever, going in the opposite controls oxygen exchange of either the placenta or different cell types. The Mouse Naïve ESCs”, 1 Au-
direction, that is, causing and atmospheric pressure. the yolk sac. “We gave organs seen in the models gust 2022, Cell.
stem cells to differentiate In the earlier research, the these two groups of cells a gave every indication of
into specialized body cells, team had successfully used transient push to give rise being function DOI: 10.1016/j.
not to mention form entire this device to grow natural to extraembryonic tissues cell.2022.07.028