By Anayelly Medina
This post was written as part of a class assignment from students who took a neuroethics course with Dr. Rommelfanger in Paris in Summer 2016.
The Chimera is a Greek mythological fire-breathing monstrosity composed of multiple animal parts with the head of a lion, the body of a goat, and the tail of a snake. Not surprisingly, in the realm of science, chimera is also the name given to an organism or embryo containing a mixture of cells from two species. Recently, the world has learned of the current research efforts being made towards growing human organs in other animals, specifically pigs [2,3,4,5]. From these efforts, the human-pig chimera has been developed and so have ethical questions concerning the process and outcomes of this research.
According to the United Network for Organ Sharing, in the United States, about 22 people die each day while waiting for an organ transplant. This shortage of organ transplants has played a role in fueling researchers’ interests in developing alternative methods to solve this problem. One proposed method , by Pablo Ross, involves creating a human-pig chimera embryo, inserting it into the uterus of a pig, allowing it to develop, and having an end result of the growth of a human organ as the chimera develops. The process of creating the chimera, in this case one that will potentially develop a human pancreas, first involves removing the DNA in a pig embryo that would allow it to grow a pig pancreas. This removal process is conducted through a gene editing technique known as CRISPR. The CRISPR process involves utilizing a protein molecule such as CAS9 to cut out the targeted DNA section from a DNA strand. The CAS9 enzyme includes a guide RNA (gRNA) that matches up to the target DNA section and removes it. The removal of the pig’s DNA section creates what is called a “niche” (void) in the DNA strand; human induced pluripotent stem cells, or iPS, are then injected into the embryo when it’s just a few cells in a petri dish . Researchers then hope that these injected human stem cells will take advantage of the void in the DNA and result in the development of a pig fetus growing a human pancreas. This human organ would then be compatible with a human patient from whom the iPS cells are derived, reducing the risk of organ rejection by the body. The potential ability to grow human organs inside of other animals in order to solve the organ donor/transplant shortage seems like a proposal without faults. Nevertheless, the future of this technology could lead to the purposeful growth of a human brain in a different species. Purposefully growing a human brain in a different species would raise a multitude of questions regarding their placement/personhood on the human/ animal scale. Furthermore, there are questions surrounding the ethics of such a procedure that must be addressed.
|The mythical chimera, courtesy of Flickr user Eric Parker|
Another main concern of this research involves the process of inserting human genes into the pig embryo but then having some of these genes migrate into the developing pig’s brain. The concern is that this migration of human stem cells into the brain of the animal could result in chimeras acquiring a cognitive state  and make them more human . Once again, the deontological issue of determining what side of the human/nonhuman side these animals are on arises. As stated by Imam, “mental condition is an intrinsically human experience” ; if these chimeras were to develop a cognitive state, what would occur in terms of continuing with the procedure? Would these chimeras now hold autonomy? Researchers, such as Lowe, offer a solution, stating that “with every organ we will look at what's happening in the brain and if we find that it's too human like, then we won't let those fetuses be born" . Lowe’s proposed solution has its own issues. At what point in the developmental stage are these chimeras considered to hold a cognitive state (if a human brain were to show signs of development). Ultimately, the old question of what “counts” as life arises once again. Furthermore, when considering humans, according to Farah, we wouldn’t sacrifice one healthy human for five life-saving organs ; if these chimeras were to develop a cognitive state, would such a notion hold true for them as well?
The concern surrounding these ethical issues, especially that of altering cognitive function, is evident through the National Institute of Health’s (NIH) refusal to fund this research in the United States  [Ed. note: this may be changing]. In other locations, such as the UK, guidelines for research involving animals containing human genetic material have already been established. Finally, what must also be considered in this research are the rights of the animals since the procedure requires surgical techniques and alterations of their genetic code that are yet to be fully understood. In addition, if such a technique were to function, then the development of organ farms would also be concerning to both humans and animals. The possible development of “organ farms” would raise further questions regarding the ethics of creating a new market for human organs.
1. Farah, M. 2015. An Ethics Toolbox for Neurotechnology. 86: 34-37.
2. Imam, J. 2016. Human organs grown in pigs may help transplant patients, scientists say. Cable News Network (CNN). June 9. Available at: http://edition.cnn.com/2016/06/09/health/human-organs-chimera-irpt/index.html (accessed June 11, 2016).
3. Regalado, A. 2016. Human-animal chimeras are gestating on U.S. Research Farms. MIT Technology Review. January 6. Available at: https://www.technologyreview.com/s/545106/human-animal-chimeras-are-gestating-on-us-research-farms/ (accessed June 11, 2016).
4. Stein, R. 2016. In Search For Cures, Scientists Create Embryos That Are Both Animal And Human. NPR. May 18. Available at: http://www.npr.org/sections/health-shots/2016/05/18/478212837/in-search-for-cures-scientists-create-embryos-that-are-both-animal-and-human (accessed June 12, 2016).
5. Walsh, F. 2016. US bid to grow human organs for transplant inside pigs. BBC News. June 6. Available at: http://www.bbc.com/news/health-36437428 (accessed June 12, 2016).
Medina, Anayelly. (2016). The Ethical Implications of Harvesting Human Organs from Pigs. The Neuroethics Blog. Retrieved on , from http://www.theneuroethicsblog.com/2016/08/the-ethical-implications-of-harvesting.html