Originally published June 15, 2023 4:00 pm PDT
In a monumental scientific development, researchers have reportedly constructed synthetic human embryos from stem cells, bypassing the requirement for eggs or sperm.
This pioneering step could offer significant insights into genetic diseases and the biological roots of recurrent miscarriages, according to the scientists.
However, this groundbreaking work also brings about complex ethical and legal concerns, as these lab-cultivated entities are currently not covered under existing laws in the United Kingdom and the majority of other countries.
The lab-created structures lack a pulsating heart or early brain formation but do consist of cells that would usually contribute to the formation of the placenta, yolk sac, and embryo.
Prof Magdalena Żernicka-Goetz, from the University of Cambridge and the California Institute of Technology, revealed the developments in a plenary speech at the International Society for Stem Cell Research’s yearly meeting in Boston.
Żernicka-Goetz explained, “We can create human embryo-like models by the reprogramming of [embryonic stem] cells.”
Yet, these synthetic embryos aren’t anticipated to have any immediate clinical application.
It is currently illegal to insert them into a woman’s womb, and it remains undetermined if these structures can develop beyond the initial stages of human growth.
These synthetic embryos could allow scientists to investigate the so-called “black box” period of development, which is usually inaccessible due to the legal limit of 14 days for cultivating embryos in a lab.
Understanding this period of development is said to be valuable for researchers to understand how developmental issues can occur without requiring the use of early-stage embryos.
Robin Lovell-Badge, head of stem cell biology and developmental genetics at the Francis Crick Institute in London, stated that the creation of these models can “gain an awful lot of information about how we begin development, what can go wrong, without having to use early embryos for research.”
The full specifics of the research conducted by the Cambridge-Caltech lab are yet to be published.
Still, Żernicka-Goetz discussed the cultivation of these synthetic embryos to a stage slightly beyond what would be 14 days of development in a natural embryo.
She proudly stated before her talk, “Our human model is the first three-lineage human embryo model that specifies amnion and germ cells, precursor cells of egg and sperm. It’s beautiful and created entirely from embryonic stem cells.”
The speed of these scientific advances in synthetic embryology has overtaken existing legal frameworks, prompting scientists worldwide to begin crafting voluntary guidelines for work with these synthetic embryos.
Lovell-Badge pointed out, “If the whole intention is that these models are very much like normal embryos, then in a way they should be treated the same. Currently in legislation they’re not. People are worried about this.”
One major query remains: could these synthetic structures, theoretically, develop into fully grown organisms?
Past attempts with synthetic embryos from mouse cells did not result in the birth of live animals.
A similar experiment with monkey cells led to early signs of pregnancy but no further development.
Lovell-Badge concluded, “That’s very difficult to answer. It’s going to be hard to tell whether there’s an intrinsic problem with them or whether it’s just technical.”
He further stressed the need for more comprehensive legislation given this uncertainty.
