We are on the cusp of transplanting pig kidneys into humans, writes Louis M. Profeta MD on LinkedIn.
Whilst ‘cusp’ can be a fluid term in medical research, used to denote anything from one year to a decade, in this case, pig to human xenotransplants might be carried out as early as 2018.
For anyone currently waiting for a kidney transplant, or those who will need one in the future, this is an ostensibly good, if not borderline miraculous, breakthrough.
NHS statistics put the number of people waiting for kidney transplants in the UK at just over 5,000 (as of March 2015). Of those, a percentage will receive a kidney that works; a percentage will receive a kidney that fails and a third group will die before they ever receive a kidney at all.
If the current research comes good on its promises, we shall soon be able to modify porcine kidneys to make them almost indistinguishable from human kidneys. This will make immunosuppressant drugs redundant and facilitate a future in which any pig kidney, from any pig, can be transplanted into any human with success.
Exciting? Yes. Groundbreaking? Certainly. But whilst the science behind pig to human transplants is clear, the risk factors, and morality, remain murky.
The received wisdom is that transplantation is a cure for organ failure. It is not. A transplant is a merely a treatment for the condition, albeit a very effective one in a great many cases.
Once organ failure patients have received a new organ (or ‘graft’), they run the gauntlet of rejection, whether it comes in minor, treatable episodes or one, catastrophic bout.
All transplant patients will lose their graft eventually and that is before you consider the risks associated with sustained exposure to immunosuppressants – side effects like cancer and osteoporosis, which are both common.
We know about these risks because successful human to human transplants have been carried out across the world for the last 67 years and the science and technology is continually getting more and more advanced.
The outcomes and side effects of transplants using pig kidneys are not yet known.
Even at this early stage, concerns are being raised about the potential impact of porcine endogenous retroviruses (PERVs) that are inherently carried by pigs in dormant states.
Would these viruses become active in a human host? If so, how might they manifest? And would the effects of PERVs be more malicious than simply staying in organ failure?
No doubt the same doctors who have led this pioneering research are working to negate and ultimately eliminate the possible risks of PERVs. Yet for a treatment to be approved by the Medicines and Healthcare Products Regulatory Agency (MHRA), and for a treatment to be socially palatable, it must be more than just medically useful. It must be sustainable and it must be ethical.
We are setting a thought-provoking favourite precedent by creating – creating, not breeding – genetically modified organisms solely in order to harvest them for their body parts.
This is, of course, precisely what we breed pigs for now, except we eat rather than transplant their innards. Is there even an argument to be made about pigs that save lives, when we are already breeding them to line our stomachs?
We must shift the argument from the quality of human life to the quality of life these pigs will have. Pigs bred ethically for their meat enjoy a good quality of life in conditions that have been agreed as necessary for porcine happiness: space to roam, food they like to eat, companionship etc.
The discourse around rearing pigs for transplant is a little less comforting. The pigs must be kept in ‘sterile conditions’ and there is talk of huge processing farms where hundreds of donor pigs will be produced. It sounds disconcerting at best, cruel at worst.
A kidney failure patient would have to be desperate to accept a kidney from a pig raised in inhumane conditions and summarily disposed of, all in the name of maintaining the human race.
This presents a problem, however. Because after three years on dialysis, which is the average waiting time for UK kidney failure patients, most are desperate for a new organ.
Just because we can… does that mean we should?
The idea of engineering living, breathing, desirous organisms in order to harvest their organs must be addressed, now, before the hope offered by pig xenotransplants becomes too strong and the demand too great.
Opposition will likely come from animal rights groups and scrutiny from ethics boards and the medical community. The voices with the most gravitas, however, come from the people who will benefit most: the kidney recipients.
These are coincidentally the people with the least power. The elation, the sheer, unbridled relief that comes with medical breakthroughs of this kind, can muddy the waters of what is actually involved.
Kidney failure is grim. No one with any experience of the condition would wish it on their greatest enemy.
But is the solution to breed another species for donation, then death?