Scientists from the University of Michigan have created a device that can mass-produce human embryo-like structures, according to a recent NPR report. The synthetic, living objects closely resemble a primitive form of human embryos.
Scientists from the University of Michigan have created a device that can mass-produce human embryo-like structures, according to a recent NPR report. The synthetic, living objects closely resemble a primitive form of human embryos.
The research has been acknowledged “as an important advance for studying the earliest days of human embryonic development. But it also raises questions about where to draw the line in manufacturing ‘synthetic’ human life,” quotes the NPR article.
This isn’t the first time synthetic embryos have been created. Multiple scientists in the past have created such “embryoids”, such as molecular biologist Ali Brivanlou and a team of scientists from Rockefeller University. The team “used human embryonic stem cells to develop living models of human embryos that could be studied in the laboratory. The three-dimensional model of a human epiblast had the size, cell orientation and gene expression roughly equivalent to a day 10 human epiblast.”
Brivanlou disclosed to NPR that “we came up with a model of human embryos that are developed outside of the womb and is not the product of the sperm and the eggs but is the product of human embryonic stem cells that self-organize into complicated structures.”
The so-called embryoids serve as an alternative to embryos, but have raised ethical dilemmas of how long the entities should be allowed to develop. At the 15-day mark, embryos begin to show what is known as the “primitive streak”, thus the controversial 14-day rule is currently common practice.
The rule “is used in science policy and regulation to limit research on human embryos to a maximum period of 14 days after their creation or to the equivalent stage of development that is normally attributed to a 14‐day‐old embryo . . . In biological terms, the 15th day of embryo development is the point when the primitive streak forms: that is, the beginning of gastrulation when three layers of germ cells differentiate. The 14th day is therefore notable, because the embryo is then individuated and can no longer become a twin. Consequently, the 14th day has, until recently, represented a natural and convenient biological turning point at which to restrict any further research on embryos,” details an article in EMBO Molecular Medicine.
The University of Michigan team clarified in their ethics statement that “the embryonic-like sacs lack the primitive endoderm and the trophoblast, and thus cannot form yolk sac and placenta, respectively. Therefore, these embryonic-like tissues do not have human organismal form or potential. Furthermore, all experiments were terminated by no later than day 4 invitro. All protocols used in this work with hPSCs to model early post-implantation human embryo development, including the development of embryonic-like sacs and specifications of hPGCLCs and primitive streak-like cells, have been approved by the Human Pluripotent Stem Cell Research Oversight Committee at the University of Michigan, Ann Arbor.”
This new research has expanded the realm of possibilities in the field by developing a process that can mass-produce embryoids. Jianping Fu, leader of the research and associate professor of biomedical engineering at the University of Michigan, told NPR that “this new system allows us to achieve a superior efficiency to generate these human embryo-like structures.” He added that the development is “‘an exciting new milestone for this emerging field’ that should significantly improve the ability of scientists to study early human development.”
Such human embryo-like structures have a lot of potential to open what we call the so-called black box of human development,” he added, which returns to the principle of the 14-day rule. The NPR article goes on to describe that “he’s referring to the first few weeks after a sperm fertilizes an egg, when the embryo is inside a woman’s body and hard to study. A long-standing guideline bars scientists from conducting research on embryos in their labs beyond 14 days of development for ethical reasons.”
Brivanlou added that “it’s a major advance in the knowledge of early human development. We’re opening up windows to aspects of development that we have never seen before. This knowledge is really the Holy Grail of human embryology.”
Each of Fu’s devices are silicone squares in which researchers place “either human embryonic stem cells or induced pluripotent stem cells” into four wells. The scientists then add chemicals that stimulate growth. “Each device can produce about a dozen embryoids in just a few days, Fu says, and that enables the scientists to produce hundreds of the structures by using many of the devices simultaneously.”
The research is not free of controversy, however, as Insoo Hyun, a bioethicist at Case Western Reserve University and Harvard Medical School suggests. “This team needs to be very careful not to model all aspects of the developing human embryo, so that they can avoid the concern that this embryo model could one day become a baby if you put it in the womb.”
Fu responds to such ideas by conveying that “I understand that there may be people sensitive when you see that you can massively produce organized embryonic structures. People will be concerned. I understand that. I guess we are pushing the boundary. But I want to make 100% clear that we have no intention of trying to generate a synthetic structure [that] looks like a complete human embryo. We have zero intention to do that.”
