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Certain biomedical news items inevitably hit the headlines. Two that have done so recently have been the possibility of a head transplant, and the cloning of genetically identical monkeys. Why do issues like this catch people's attention, and why are they newsworthy?
Each pushes the boundaries of what we think should or should not be done. Each has a science fiction aura, and over the years have featured in science fiction writings.
The trouble is that stories like these, paint science in a very bleak light. They also suggest that scientists are irresponsible, have no moral compass, and are set on destroying everything we hold dear.
The cloning of the monkeys is by far the more important of the two stories, since it has demonstrated that cloning can be accomplished in primates. The cloning of Dolly, the sheep, in 1997 was itself a remarkable advance in developmental biology and has been followed by the cloning of about two dozen other species. These [advances] have led to increased understanding of the differentiation of cells, and a host of biotechnological innovations in the production of new pharmaceuticals.
The cloning of genetically identical primates is a major development. By combining these procedures with gene-editing tools, it may prove possible to create genetically engineered models of human disorders such as Parkinson's. Scientifically speaking, this is a major achievement, in spite of the very large number of unsuccessful attempts. Inevitably, there are also a large number of pertinent ethical queries.
Alongside these positive vistas are the negative ones raised by the prospect of human reproductive cloning. These were debated at length around the year 2000, as people worried about a world in which we could create our own identical twins.
It emerged that the concerns were largely unfounded, since there are few substantial reasons for doing so. Examples discussed included parents looking for a sibling to be a compatible tissue donor for a child dying from leukaemia, and of infertile couples wanting to have genetically related children. There are, however, less problematic ways of accomplishing the same ends.
Over the past few years, an Italian neuroscientist, Sergio Canavero, has been making grandiose claims about his ability to graft a living person's head on to a donor body. Not surprisingly, this has evoked an enormous amount of interest, most of it critical, especially from neuroscientists who regard it as both outlandish and not scientifically feasible.
There are also huge ethical issues that have been barely addressed. It is even uncertain whether this should be described as a head transplant or a body transplant.
Canavero's optimism and enthusiasm are unbounded. He revels in the limelight. Indeed, he has named his procedure HEAVEN; it will solve all problems and lead to a life of glorious bliss! He imagines head transplantation leading to life extension, with younger blood from donor bodies being infused into older donor heads.
Before dismissing these procedures out of hand, Canavero does have some expertise in this area, since he and Ren Xiaoping have transplanted a head on to a corpse. It is this experience that will be used to move to a living human paralysed from the neck down.
The technical challenges are formidable: sustaining life after the head is severed; the feasibility of spinal cord reconnection and the restoration of motor and sensory functions; immune rejection; and psychological adaptation. The evidence from animal studies is either non-existent or very limited, even in mice. There are no long-term survival statistics from animals to show expected survival rates, a piece of evidence usually regarded as essential before embarking on major surgery in humans.
The psychological effects are unknown. The only evidence available at present comes from the small number of face and hand transplants. While the evidence from these is mixed, the failure and rejection in some cases are salutary, pointing to difficulties with accepting the new face or hand as one's own.
The far more dramatic head transplant procedure will undoubtedly have repercussions for the individual's sense of self. Is this my body? Who am I?
The ethical problems are legion, ranging from consent to cost, from whether the procedure will benefit the patient, to determining who is the patient - the head or the body? The lack of basic scientific knowledge throws doubt on the ethical legitimacy of the surgery. There is even the question of whether cutting off a head constitutes murder!
The final take-home message is to be sceptical when presented with claims made by individuals who enjoy the gruesome and the bizarre, and continually seek the headlines. This is not where serious science is at, and this is not the sort of work that usually leads to major beneficial developments in medicine.
-Gareth Jones is an emeritus professor of anatomy at the University of Otago.