If applied to human embryos, the discovery could aid in the understanding of human fertility, and developmental abnormalities, and provide a new path for developing lab-grown tissues or organs for transplantation.
A team of scientists from the United Kingdom and the United States has generated “synthetic” mouse embryos that developed a brain, a spinal cord, and beating heart tissue in the laboratory without the requirement for a fertilized egg or uterus.
It is comparable to a breakthrough revealed earlier this month by an Israeli team. Together, the achievements have the potential to revolutionize our knowledge of one of the greatest challenges in biology: how a few cells organize into life.
If applied to human embryos, the discovery could contribute to a greater understanding of human fertility, and developmental abnormalities, and offer a novel way to generate lab-grown tissues or organs for donation.
However, the application of this technology to human embryos would create significant ethical and legal concerns.
How we begin our lives is the central subject being addressed in the lab. Professor Magdalena Zernicka-Goetz of Caltech in Pasadena, California, and Cambridge University in the United Kingdom explains.
To build synthetic embryos, or “embryoids,” scientists extracted three types of stem cells from a mouse embryo that would usually form all the necessary tissues for a developing fetus.
They next put the cells into an artificial growth media, which consisted of nutrients in a flask that rotated.
The stem cells spontaneously developed into embryos.
Prof. Zernicka-Goetz asserts that the few successful embryos “are essentially indistinguishable from natural embryos in many instances.”
The embryos only matured for eight and a half days, which is roughly half of a mouse’s normal gestation length.
However, the technology should remain incredibly significant as a means of creating early embryos for studying early development without using animals.
The team is currently hard at work on a human embryo model, but they emphasize that it is still a ways off. Significant distinctions exist between early mouse development and early human development.
Having a synthetic human embryo, however, could be a significant step forward for the research of fertility and common developmental diseases.
According to Prof. Zernicka-Goetz, the majority of human babies are lost in the very early stages of life, and 20 to 70 percent of IVF attempts fail.
Donated human embryos are scarce and frequently of low quality, therefore a “model” embryo generated in a laboratory could assist address numerous problems.
The team proposes synthetic embryoids that reproduce only a single component of an early human embryo, such as the heart or the tissue that develops the placenta. Failure at implantation is a leading cause of IVF pregnancy failure.
In “regenerative” medicine, synthetic human embryos could also be used to generate new tissues or organs. Such tissues could be a perfect match for the recipient if produced from the patient’s stem cells.
However, generating synthetic human embryos would necessitate a change in the current law in the United Kingdom, which does not permit the growth of embryos from stem cells.
The law of the United Kingdom prohibits the cultivation of human embryos in the laboratory beyond 14 days. This occurs before the majority of the significant developmental processes are observed in these mouse embryos.
According to experts, the discussion of these legal and ethical problems should commence sooner rather than later in light of this most recent demonstration.
Prof. Alfonso Martinez Arias of the Universitat Pompeu Fabra in Barcelona, who was not involved in the study, thinks that the findings indicate that similar experiments with human cells will be conducted in the future and will eventually produce similar outcomes.
“This should prompt questions of the ethics and societal effect of these studies before they are conducted,” he added.
