The Potential of the Combination of CRISPR/Cas9 and Pluripotent Stem Cells to Provide Human Organs from Chimaeric Pigs

Abstract

Clinical organ allotransplantation is limited by the availability of deceased human donors. However, the transplantation of human organs produced in other species would provide an unlimited number of organs. The pig has been identified as the most suitable source of organs for humans as organs of any size would be available. Genome editing by RNA-guided endonucleases, also known as clustered regularly interspaced short palindromic repeat (CRISPR/Cas9), in combination with induced pluripotent stem cells (iPSC), may have the potential to enable the creation of human organs from genetically-modified chimaeric pigs. These could potentially provide an unlimited supply of organs that would not be rejected by the recipient’s immune system. However, substantial research is needed to prove that this approach will work. Genetic modification of chimaeric pigs could also provide useful models for developing therapies for various human diseases, especially in relation to drug development.

Recent advances in understanding xenotransplantation: implications for the clinic

“…A final potential alternative to xenotransplantation lies with blastocyst complementation, though it is also in its relative infancy [88-91]. In this highly-innovative approach, the genes for an organ, e.g., the lung, are deleted in the pig, which then in embryonic life receives human pluripotent cells from which a human lung is generated.…”

Recent Progress in Xenotransplantation, with Emphasis on Virological Safety

“…When gene editing was performed using the zinc finger nuclease (ZFN), the expression of ZFN was very high, inducing a toxic effect when the nucleases were cutting in multiple sites and destabilizing the genome [99]. When the Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR-associated (CRISPR/Cas9) technology [100][101][102] was used, a breakthrough was achieved. Sixtytwo PERV proviruses were knocked-out in immortalized PK-15 pig cells [103].…”

Ethical Issues in Genome Editing using Crispr/Cas9 System

“…CRISPR/Cas 9 in combination with induced pluripotent stem cells may have the potential to enable the creation of human organs in chimeric pigs, with the possibility of having an unlimited supply of organs not rejected by the immune system of human recipient [30]. In conjunction with blastocyst complementation, the technique CRISPR/Cas9 may produce multigene mutations of essential regulators of vascular and lymphatic tissues in the desired organ, making it ready for transplantation.…”

“…Chimeras have raised ethical concerns over their risk and on the violation of the order of nature, producing moral confusion on how to treat the organism, as animal or human? [30,49,50]. For some, chimeric embryos possess the potential to develop organisms with human-derived cells or tissue, which may affect the identity of the human species, affecting its dignity.…”