New pig-human hybrid embryos could be used to grow transplantable organs and tissues

pig human chimera stem cells embryo
Salk Institute

Scientists for the first time have created an embryo that is part human and part pig as part of a groundbreaking experiment that published this week in the biochemistry journal Cell. This incredible chimera was developed by a team of researchers from the Graduate School of Agriculture and Department of Advanced Bioscience at Kindai University in Japan. Heralded as one of the most successful chimeras to date, the experiment is a leap forward for the field of regenerative medicine, which is searching for ways to produce human organs using animal models.

The complicated procedure involves the injection of human induced pluripotent stem (iPS) cells into a developing pig blastocyst. These iPS cells are a type of stem cell that has been created from an adult cell and has the ability to differentiate into a variety of cell types including neuronic, cardiac, pancreatic and more. In the procedure developed by the Kindai team, a laser beam was used to make an opening in the outer membrane of a pig blastocyst cell. The channel was wide enough for a needle to deliver the human iPS cells into the matrix of the developing embryo. The resulting hybrid cell was then implanted into a female pig (sow) and allowed to develop for four weeks.

After a month of in situ development, the embryo was harvested and analyzed. It was found that a small fraction of the pig embryo was composed of human cells. The human stem cells that were present had grown into precursor cells capable of eventually developing into heart cells, liver cells, and neurons.

Though researchers cautioned that the results were “highly inefficient,” the experiment hold promise as a model to better understand human embryonic and stem cell development as well as explore human disease progression. These results also may lead to the future use of farm animals as a host for growing transplantable human tissues. The future application of the technology may provide organs suitable for transplant and could help lessen the worldwide organ shortage that currently exists.