An Italian neuroscientist who wants to perform the world’s first human head transplant next year is claiming to have conducted radical spinal cord experiments on mice, rats, and a dog. Experts say the results are vague and incomplete, and that talk of human head transplants are grossly premature.
In a series of papers published in Surgical Neurology International, neurosurgeon Sergio Canavero describes recent experiments using a chemical called polyethylene glycol, or PEG, which his team is using to reconnect severely damaged spinal cords. Accompanying video shows a mouse dragging itself across the floor, and a rat and dog in various stages of recovery.
In one of the experiments, Canavero, with the help of C-Yoon Kim from Konkuk University in Seoul, severed the spinal cord of 16 mice. PEG was injected into the injured areas of half of the mice, while the other half received a saline solution. Four weeks after the surgery, five of the eight mice in the PEG group had regained some mobility, while the other three died. None of the mice in the control group were able to move afterwards. The chemical works by reconnecting the two fused ends of the spinal cord —a meticulous healing process that involves thousands of neurons.
In a second experiment with similar results, rats were given a juiced-up version of PEG that uses graphene nanoribbons—an electrically conductive material—that serves as a scaffold along which neurons can grow. Unfortunately, the results of this experiment were incomplete because a flood in the lab killed four of the five rats treated with new-and-improved PEG.
For the experiment on the dog, the researchers severed about 90 per cent of its spinal cord. Two weeks later, the dog was able to drag its hind legs, and after the third week it was able to walk, grab objects, and wag its tail. No other dog was experimented on, which means there were no controls. This was basically a single case study.
But as New Scientist reports, experts aren’t impressed by the experiments, complaining about the small sample sizes, the absence of controls in the dog experiment, and insufficient evidence proving that the canine’s spinal cord was damaged to the degree reported.
These objections are serious given that Canavero wants to perform a human head transplant next year. A Russian man suffering from a degenerative disease has already volunteered for the procedure, and a hospital in Vietnam has said it’ll make its facility available for the controversial surgery. Assuming it happens.
Despite these recent animal studies, there’s no compelling evidence to believe that a human head transplant will work, or that it’ll endow the Russian patient with a body that’s superior or longer-lasting than the one he currently has. Earlier this year, the same team reportedly performed a head transplant on a monkey, but the results weren’t published.
Given the inexplicably short timelines that these researchers have imposed upon themselves, it’s clear they’re rushing into this. Realistically, it takes about a decade or more for lab experiments to translate into actual practice. If these maverick researchers aren’t careful, they could actually kill this desperate young man. [Surgical Neurology International I, II, III, IV, New Scientist]