A breakthrough in embryology showcased the potential to generate a monkey embryo from embryonic stem cells, a development highlighted in a recent article in Cell Stem Cell. Biologists have long struggled to understand the earliest steps of fetal growth, including how the fertilized egg begins division and forms both the body’s organs and the placenta. Ethical considerations restrict direct experiments on human embryos, which has, in turn, limited certain avenues of research. In the past, researchers demonstrated that mouse embryos could be derived from stem cells, but mice are not perfect models for human development due to evolutionary distance.
Recently, a team led by Liu Zhen of the Shanghai Neuroscience Institute in Shanghai, China, reported progress by creating monkey embryos that closely resemble humans in both anatomy and genetics. The team worked with stem cells from the cynomolgus macaque (Macaca fascicularis) to explore the early developmental process. A key focus was to map the signaling molecules produced by the female reproductive system and the embryo as it begins to divide. This information guided the formulation of a specialized nutrient medium designed to reset the developmental programming of stem cells already present in embryos or umbilical cord blood. The aim was to coax these cells into forming structures that approximate the blastocyst stage, an early stage in which a few days of development determine the future embryo and supportive tissues.
Using these reprogrammed cells, researchers created blastoids, synthetic counterparts to the blastocyst, which normally arises in the first two weeks of pregnancy. When these blastoids were placed into the wombs of female monkeys, they underwent a trajectory similar to natural embryogenesis, proceeding toward the gastrula stage and attaching to the uterine lining. This attachment marks the earliest sense of pregnancy, as the embryo begins to establish a connection with the mother’s body and establish the foundations for growth. The scientists now aim to push these models further toward stages where more complex organ structures would be present, with the broader goal of understanding developmental barriers and potential infertility treatments. The research holds promise for shedding light on why some pregnancies fail and how early developmental events influence later outcomes.
While these advances open new avenues for studying early development, they also prompt careful consideration of ethical boundaries and regulatory oversight. The work emphasizes cautious progression, ensuring that scientific goals align with societal values and safety standards while expanding knowledge that could ultimately influence reproductive medicine and fertility therapies, with a focus on human health benefits that can be responsibly realized in the future.
previous experiment showedThe disappearing balloon trick can’t fool the monkeys.