Human monkey chimeric embryos created using stem cells
Researchers in China and the USA have successfully grown chimeric embryos for up to 20 days by integrating human stem cells into primate embryos.
Researchers in China and the USA have successfully grown chimeric embryos for up to 20 days by integrating human stem cells into primate embryos. Though this research does raise ethical concerns, it has the potential to provide new insights into developmental biology and evolution, and address the shortage in donor organs. The study has been published in Cell.
The ability to grow the cells from one species within an organism of another species offers a powerful tool for medical research. The potential implications are wide and could advance our understanding in human development, disease progression, aging and provide platforms for drug evaluation and organ transplantation.
“As we are unable to conduct certain types of experiments in humans, it is essential that we have better models to more accurately study and understand human biology and disease,” commented senior author Juan Carlos Izpisua Belmonte, a professor in the Gene Expression Laboratory at the Salk Institute for Biological Science (CA, USA). “An important goal of experimental biology is the development of model systems that allow for the study of human diseases under in vivo conditions.”
Researchers previously hoped that growing human cells in pig tissue might address the shortage of available organs to transplant. However, the contribution of human cells to the organs generated were fairly low, which could be due to the large evolutionary distance between the two species. This led Belmonte and his team to investigate chimera formation in a more closely related species.
They hoped that by better understanding the molecular pathways involved in interspecies communication between human and macaque cells, they could ultimately improve the integration of human cells into more hosts that are more evolutionarily distant, such as pigs.
In this study, the team tagged human pluripotent stem cells with a fluorescent protein and injected them into 6-day-old macaque embryos. They observed that the human stem cells survived and integrated with better relative efficiency than in the previous experiments using pig tissue.
To identify the molecular communication pathways between the two species, the investigators performed transcriptome analysis on both the human and macaque cells from the embryos. They observed that cells from chimeric tissue had distinct transcriptomic profiles from controls, and discovered several novel or strengthened communications pathways in the chimeric cells.
Further understanding of this molecular communication in chimeric organisms could allow researchers an unprecedented glimpse into the early stages of human development. Chimeric organisms could also be used to generate cells and organs for transplantations in host species that are more appropriate for various reasons. Further, these organisms could provide a new platform to study how specific diseases arise, as well as to test efficacy of drug compound, as chimeric models might reveal more applicable results that better affect responses in humans.
An accompanying Preview in Cell outlines the ethical considerations surrounding this study. Belmonte notes that “it is our responsibility as scientists to conduct our research thoughtfully, following all the ethical, legal, and social guidelines in place.” He adds that before beginning this work, “ethical consultations and reviews were performed both at the institutional level and via outreach to non-affiliated bioethicists. This thorough and detailed process helped guide our experiments.”
Link: https://www.regmednet.com/human-monkey-chimeric-embryos-created-using-stem-cells/
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