There has been a lot of media coverage on the recent claims by Dr. Sergio Canavero that he has successfully transplanted the head of a monkey on to a donor body of another monkey. This story, originally posted by the New Scientist, has since gone viral with some touting miracle cures for paralysis, while others have publicly expressed outrage and disgust. As pointed out by the New Scientist, this is not science, or at the least, not yet. Until the veil of secrecy concerning the conduct of this study is made transparent – no formal conclusions can be made and one can only speculate in regards to the quality of the experiment that was performed. Moreover, as this work still has to pass through the peer-review process, it remains unclear whether this is simply an attempt at publicity. As Arthur Caplan, a New York University bioethicist told New Scientist:
It’s science through public relations. When it gets published in a peer reviewed journal I’ll be interested. I think the rest of it is BS”
So far, the only evidence that Dr Canavero has produced is a picture of a monkey which appears to have had a head/body transplant, as well as a short video of a mouse moving around (despite significant impairments), which also appears to have a transplant (but how long did they live for? When Dr Canavero’s colleague Dr Xiaoping Ren of China’s Harbin Medical University carried out similar head transplants in mice in 2015 they all died within a few minutes of being revived after surgery). While the monkey “fully survived the procedure without any neurological injury of whatever kind”, according to Canavero, it was euthanized after 20 hours for “ethical reasons”. The media storm surrounding this story appears to play up to the researcher’s aims – to find financial backing to continue his research and then move it into humans.
Two pieces of information in the article by the New Scientist bear scrutiny. The first is that Canavero is quoted as saying “this experiment, which repeats the work of Robert White in the US in 1970, demonstrates that if the head is cooled to 15°C, a monkey can survive the procedure without suffering brain injury.” Second, Sam Wong, author of the article in the New Scientists stated “they connected up the blood supply between the head and the new body, but did not attempt to connect the spinal cord.” Careful reading highlights a simple fact, this study is not novel in any regard – this is a replication of the work by Robert White and is quite simply a “head transplant”. Thus, the same criticisms that were levied in regards to the original experiment by Robert White apply here. As Stephen Rose, director of brain and behavioural research at Open University can be quoted as saying in 2001:
This is medical technology run completely mad and out of all proportion to what’s needed. It’s entirely misleading to suggest that a head transplant or a brain transplant is actually really still connected in anything except in terms of blood stream to the body to which it has been transplanted. It’s not controlling or relating to that body in any other sort of way. It’s scientifically misleading, technically irrelevant and scientifically irrelevant, and apart from anything else a grotesque breach of any ethical consideration. It’s a mystification to call it either a head transplant or a brain transplant. All you’re doing is keeping a severed head alive in terms of the circulation from another animal. It’s not connected in any nervous sense.”
And so, it is worth reflecting at this juncture on the moral and ethical issues surrounding this controversial procedure. Let us assume for a moment that this procedure is in fact feasible. In the original studies by Robert White and Vladimir Demikov, it was made clear that these experiments were lethal for the animal. Simply put, while the head of the animal was capable of “seeing, hearing, tasting, smelling”; none of the other regulatory processes were intact (e.g. breathing) as there was no control over the donor body. Furthermore, like many tissue transplants, rejection of the donor body from the immune system is a large possibility, immunorejection was after all the cause of death in the monkey whose head Dr White transplanted in 2001. Indeed, Canavero has yet to demonstrate any kind of proof of principle with regeneration of nervous tissue with any meaningful metric of control of the donor body.
Perhaps the most interesting insight into Canavero’s thinking comes from a quotation in the New Scientist article where he says:
Gene therapy has failed. Stem cells, we’re still waiting. Even if they come now, for these patients there is no hope. Tetraplegia can only be cured with this. Long term, the body decays, organs decay. You have to give them a new body because even if you take care of the cord, you’re going nowhere.”
These remarks by Canavero are somewhat naive as both gene therapy and stem cell therapy have made substantial advances in recent years, with many therapies now in clinical trials. Furthermore, the claim that “Tetraplegia can only be cured with this [head transplant]” flies in the face of evidence from recent successful animal and clinical trials on a variety of innovative therapies for paralysis, including epidural stimulation, intraspinal microstimulation, neuroprosthesis, and stem cell therapy.
While there is mounting evidence from studies in rodents that the polyethylene glycol (PEG) implantation approach favored by Canavero may be able to promote repair of injured spinal cord and recovery of motor function in paralyzed limbs, his casual dismissal of the work of other scientists – while often simultaneously citing their work in support of his own approach – exemplifies his arrogance. He would be better off lending his expertise to the work of others who are exploring the potential for PEG in spinal cord repair, work that has the potential to benefit millions of people, but instead appears set on a self-aggrandizing PR campaign in support of an approach that if successful – which seems highly unlikely even if the surgery is a technical success – can only benefit a tiny number of people…potentially at the cost of depriving many other transplant patients of much needed organs.
The reality, however, remains that the procedure exposes the patient (be it mouse, monkey or human) to far greater risks compared to the potential benefits. But these issues are not unknown to Dr. Canavero. Indeed, as can be seen here (scroll to see response), and in what can only be described as derision and a willful skirting of the law, Dr. Canavero remains set to push forward with his ideas regardless of the consequences. For these reasons we have the gravest of reservations about the course being followed by Dr. Canavero and his colleagues, and call on them to halt this research until a full independent review of the scientific evidence and impact on potential patients can be undertaken.
Jeremy Bailoo and Justin Varholick
The opinions expressed here are our own and do not necessarily reflect the interests of the the University of Bern or the Division of Animal Welfare at the University of Bern.