These synthetic embryo models exhibit all the characteristic structures and compartments found at this developmental stage, including the placenta, yolk sac, chorionic sac, and other external tissues crucial for dynamic and adequate growth, as stated by the researchers.
To craft this human embryo model, designed to resemble a textbook image of a human day-14 embryo, the scientists meticulously transformed stem cells into four distinct cell types: epiblast, hypoblast, extraembryonic mesoderm, and trophoblast. These four cell types were then mixed in a precise ratio, with epiblast cells forming the embryo, trophoblast cells becoming the placenta, hypoblast cells supporting the yolk sac, and extraembryonic mesoderm cells contributing to overall embryo development.
“This is the first embryo model that has structural compartment organization and morphological similarity to a human embryo at day 14,” affirmed Prof. Jacob Hanna, the lead researcher, in an interview with The Guardian. At the two-week mark, these cell clusters measured approximately half a millimeter in width.
This innovative achievement holds vast potential for various applications, including the study of the effects of medicines on real human embryos. Currently, many clinical trials exclude pregnant women, limiting our understanding of how medications affect developing embryos. Additionally, researchers envision the creation of embryos using the skin cells of patients facing medical challenges.
Prof. Hanna explained, “Grow the model embryos for a month or so, and they will start to develop organs that can be used as a source of cells to transplant into the patients.” However, he emphasized that ethical considerations must be taken into account, raising questions about whether individuals have the right to use their own skin cells to generate embryos for life-saving medical purposes. Researchers would also ensure that any model embryo created for donor tissue purposes would be genetically modified to prevent the development of a brain or nervous system.The research findings have been published in the scientific journal Nature, marking a significant milestone in the field of synthetic embryology.