Michael S. Dauber, M.A., GBI Visiting Scholar
Luhan Yang and members of her research team at eGenesis have taken a crucial step in growing organs in animals that may be used to provide organs for therapeutic transplants in humans, according to a study published in Science Magazine on Thursday, August 10th. Researchers involved in the study used CRISPR, a genetic editing technique, to “knock out” 25 genes that cause porcine endogenous retroviruses (sometimes referred to as “PERV genes”) that make ordinary pig organs unsuitable for transplants because PERVs can infect human transplant recipients. The result was the birth of 37 baby pigs without PERV genes.
The move comes at a time when CRISPR experiments are becoming increasingly popular. Last week, a team led by Shoukhrat Mitalipov published the results of the first successful attempt to modify human embryos using CRISPR by American scientists in Nature. The researchers successfully deleted a gene responsible for several fatal heart conditions.
While the results are a significant step in developing techniques for growing organs suitable for human transplantation, scientists must still travel a long road before any human patients will receive such organs. Researchers will need to determine whether or not organs from pigs developed using CRISPR can be safely and effectively transplanted into other animals first. Another hurdle is the cost and complexity of the technique: Yang’s experiments with her team involved embryos produced through cloning, an expensive technique that is not always completely effective: indeed, in Yang’s study, only a few of the cloned embryos were viable. However, Yang and her team hope that her pigs will be able to produce PERV-free offspring through traditional modes of reproduction, which would greatly reduce the cost and resources required to make pig-to-human transplantation systems possible.
Using CRISPR to create offspring solely for the purposes of harvesting organs raises serious ethical questions, however. According to some writers, pigs “come with less ethical baggage than, say, chimps or baboons,” making them more appealing to many researchers, bioethicists, clinicians, and patients as subjects for an organ harvesting system. They key in evaluating this intuition largely depends on what one thinks gives an organism “moral status.” Moral status is the property that makes it the case that we need to consider a being’s interests and welfare when deciding to act. So, for example, if a rock doesn’t have moral status, there’s nothing morally wrong with stepping on it. Stepping on a living creature with moral status, however, would be morally wrong in many everyday situations.
In claiming that pigs come with “less ethical baggage,” individuals suggest that pigs have lower moral status than some other species. By some theories, this makes sense: many individuals think that moral status arises from cognitive intelligence, and pigs are not intelligent to the same degree as human beings. There is strong evidence to suggest that chimps and baboons are more intelligent than pigs as well.
However, many believe there are other factors that contribute to moral status. For example, Peter Singer argued in his influential book, Animal Liberation, that a creature’s ability to feel pleasure and pain is a significant component for determining moral status. While he also incorporates considerations such as intelligence and cognitive ability, the fact that pigs can feel pain means we must think seriously about whether or not it is morally right to farm them in order to harvest their organs.
The situation becomes trickier when we consider the fact that we already farm animals on an industrial scale for food consumption. Is there something additionally morally wrong about farming an animal to harvest its organs for transplantation, rather than for consumption? Would more animals need to be killed in order to procure enough organs for patients, or would scientists be able to use CRISPR to produce animals that would be used both for meat and for organ transplants?
These are complex ethical and practical question that will take years to fully answer. Even if we ordinarily do consume animals for food, animal rights activists like Singer still believe such practices are morally wrong, and, by extension, harvesting organs from animals might be wrong as well. But would harvesting organs really be morally similar to killing animals for food? One of the most powerful arguments that animal rights activists give is that we do not, in fact, need to eat meat to survive. In potential organ harvesting cases, those organs might be the only way to save some human lives, which makes harvesting substantially different than killing animals for food.
Nevertheless, a system in which scientists can grow organs in labs without slaughtering animals would be morally preferable. It is quite possible that scientists will one day be able to grow thousands of organs in labs without harming any animals at all. Unfortunately, it is likely that developing such techniques will still require many animals to be killed in experiments. As such research moves forward, it is essential that we think seriously about the interests of animals used in research, the harm we do to them for the sake of medical progress, and the ways we can ensure that such experiments are pursued as humanely and ethically as possible.