Scientists claim to have developed the first stages of a human embryo-like organism without the use of sperm, eggs, or a womb.
The ’embryo model’ even produces hormones that can result in a positive pregnancy test.
However, the embryo’s goal is to give an ethical means of monitoring early human development. Synthetic embryos would not be allowed to develop beyond a few weeks.
The embryonic embryo undergoes remarkable alterations within the first 14 days after an egg is fertilized by a sperm. Myriad developmental problems and birth defects can occur at this point, although the source of these is unknown.
The first two weeks are also a common time for miscarriage.
‘It’s a black box, and that’s not a cliche – our knowledge is really limited,’ co-author Professor Jacob Hanna of the Weizmann Institute of Science told the BBC.
Advancements in understanding early human development
Teams all over the world are racing to create better ways to comprehend this critical period. A team from the University of Cambridge and the California Institute of Technology developed synthetic embryos using only stem cells earlier this year.
The team described their discoveries as the first ‘full’ embryo model, one that mimics critical cells and structures throughout the first two weeks of development and was published in the journal Nature.
‘This is really a textbook image of a human day-14 embryo, [which] hasn’t been done before,’ said Professor Hanna.
‘It closely mimics the development of a real human embryo, particularly the emergence of its exquisitely fine architecture.’
The researchers utilized a chemical cocktail to ‘coax’ the stem cells into changing into four critical embryonic cells: epiblasts, trophoblasts, hypoblasts, and extraembryonic mesoderm cells.
These were then allowed to develop until they reached the size of a two-week-old embryo following fertilization.
‘An embryo is self-driven by definition, we don’t need to tell it what to do,’ said Professor Hanna. ‘We must only unleash its internally encoded potential.
‘It’s critical to mix in the right kinds of cells at the beginning, which can only be derived from naive stem cells that have no developmental restrictions.
Once you do that, the embryo-like model itself says “Go!”.
In many nations, the legal limit for normal embryo research is 14 days.
A promising step for research and beyond
However, these ’embryo models’ are not legally considered embryos and therefore not subject to the same restrictions as embryos.
According to the experts, this approach could aid in determining the reasons for various birth abnormalities and types of infertility.
It could potentially lead to novel methods of producing transplant organs and provide a way around trials that cannot be performed on live embryos, according to the team.
Professor Alfonso Martinez Arias, from the Department of Experimental and Health Sciences at Pompeu Fabra University in Spain, commented on the study, saying he expected it to raise ethical concerns, but that it was a “most important piece of research.”
He said: “The work from the Hanna lab just published has, for the first time, achieved a faithful construction of the complete structure from stem cells, in vitro, thus opening the door for studies of the events that lead to the formation of the human body plan.”