by Ruth Stirton and David Lawrence
It is widely acknowledged that there is a nationwide shortage of organs for transplantation purposes. In 2016, 400 people died whilst on the organ waiting list. Asking for donors is not working fast enough. We should explore all avenues to alleviate this problem, which must include considering options that appear distasteful. As the world gets safer, and fewer young people die in circumstances conducive to the donation of their organs, there is only so much that increased efficiency in collection (through improved procedures and storage) can do to increase the number of human organs available for transplantation. Xenotransplantation – the transplantation of animal organs into humans – gives us the possibility of saving lives that we would certainly lose otherwise.
There are major scientific hurdles in the way of transplanting whole animal organs into humans, including significant potential problems with incompatibility and consequent rejection. There is, however, useful similarity between human and pig cells, which means that using pigs as the source of organs is the most likely to be viable. Assuming, for the moment, that we can solve the scientific challenges with doing so, the bigger issue is the question of whether we should engage in xenotransplantation.
A significant challenge to this practice is that it is probably unethical to use an animal in this way for the benefit of humans. Pigs in particular have a relatively high level of sentience and consciousness, which should not be dismissed lightly. Some would argue that animals with certain levels of sentience and consciousness – perhaps those capable of understanding what is happening to them – have moral worth and are entitled to respect and protection, and to be treated with dignity. It is inappropriate to simply use them for the benefit of humanity. Arguably, the level of protection ought to correlate to the level of understanding (or personhood), and thus the pig deserves a greater level of protection than the sea cucumber. The problem here is that the sea cucumber is not sufficiently similar to the human to be of use to us when we’re thinking about organs for transplantation purposes. The useful animals are those closest to us, which are by definition those animals with more complex brains and neural networks, and which consequently attract higher moral value.
The moral objection to using animals in this way arises because of their levels of cognition. This moral objection would disappear if we could prevent the animals ever developing the capacity for consciousness: they would never become entities capable of being harmed. If we were able to genetically engineer a brainless pig, leaving only the minimal neural circuits necessary to maintain heart and lung function, it could act as organic vessel for growing organs for transplantation. The objection based on the use of a conscious animal disappears, since this entity – it’s not clear the extent to which is it possible to call it an animal – would have no consciousness. It is correspondingly difficult to ground an objection in the undignified treatment of the entity. Arguments relying on dignity imply that there is a conscious entity that is entitled to be treated with respect. Since this engineered pig has no capacity to possess consciousness or even cognition at all, it is difficult to argue that it is capable of possessing any dignity in this sense, that can or should be protected. Since the sentience and consciousness has been prevented, the vessel is more akin to an agricultural field than it is to a ‘normal’ pig. There is no sense in which we would object to a ploughed field being sown with crops. It is equally difficult to see how we could object to this vessel made of organic matter which happens to be shaped like a pig being used to grow organs.
This brings us to another scientific hurdle. While pig organs are likely to be the most compatible with the human body, they are not necessarily ideal, and many people may not be able to handle non-human organs. The next stage is to use the organic vessel as a host to grow human organs from induced pluripotent stem cells. The iPSCs have no consciousness or sentience that attracts moral value. Nor does the organic vessel. It is simply a complex collection of organic matter, grown in a machine that happens to be made of similar materials, that is more compatible with the protection of human life. If organs were grown from iPSCs that were HLA tissue typed to the individual patient then organs would be perfectly matched and rejection would be even less likely to occur. Experimentation into chimeric organisms that can do just this are underway and are increasingly successful, albeit in sentient creatures.
However, this process is still less than perfect. Using a vessel that originated from pig matter is not the ideal growing medium for human organs. It would be much more likely to be successful if the vessel came from human tissue matter. We can apply the same reasoning as for our pig vessel, with an escalation. The respect and moral value that human beings attract is due to their capacity for consciousness and feelings – the elements of personhood. We nurture consciousness and intelligence, and we protect the ability to develop consciousness once an entity with the capacity to develop consciousness comes into being. If we were able to genetically engineer brainless humans, then the reasons behind these protections no longer apply. The object – it is not possible to call it a human being since it has no consciousness – has no capacity for consciousness, nor did it have the potential for capacity for consciousness since it would not have been created except in these circumstances. It is at best, similarly to the vessel of pig origin, a collection of organic matter that happens to be shaped like a member of the species Homo sapiens. The organs grown within this vessel would be the most compatible with patients, and would help to alleviate the organ shortage crisis.
In relation to both types of vessel there are challenges to be overcome with the growing phase. They would have to be grown using ectogenesis, outside of the womb. A living ‘mother’, whether pig or human, would be caused a great deal of pain and suffering through gestating a brainless foetus. Furthermore, pregnancy itself is not without its physical risks, irrespective of any mental anguish that might be suffered. Ultimately, it is not necessary to use human persons to host the organ growth vessels since the development of the Biobag, an external womb that has been used to continue gestating premature lambs. It is within the realms of possibility that organic matter of human origin could be grown within the Biobag, and this would also avoid some of the criticisms levelled at ectogenesis regarding parental bonds.
The transplantable organ shortage is critical. It is imperative to find new means of procuring organs in the context of an ageing population. It is important to continue to encourage the population to sign up to donation registers, and to pursue research into how chimeras – human/animal hybrids – can reduce immunological rejection rates. But we must recognise that our initial distaste may be preventing us from implementing other solutions that may be more effective and more efficient. There is no good reason to ascribe any particular value to meat that has never – and could never have – suffered, regardless of its appearance or genetic origin. If we can do an immense good, by reducing suffering and saving the lives of the 400 people a year who die in the UK waiting for a transplant, all whilst not causing any harm or disrespect to another creature, is it right that some sense of discomfort should prevent us from doing so? We say no, discomfort is not a good enough reason. Further, if we were to follow this path, it is imperative to do it in the way that has the most chance of success, the creation of genuine human organs which will avoid all the scientific issues of xenotransplantation. It is not enough to grown organs in brainless animals. We should go further and grow human organs in organic vessels of human origin.
We do not suggest that this is the only solution or even the right one. However, the organic vessel of human origin serves to illustrate that even those methods we may have dismissed out of hand are no longer necessarily repugnant nor even morally problematic.
Ruth Stilton is a Lecturer in Health Care Law at the University of Sussex, and David Lawrence is a Postdoctoral Fellow at Newcastle University. This post first appeared on the Journal of Medical Ethics Blog.