The world鈥檚 first human spinal cord transplant has been carried out in Russia. This is said to have involved removing a damaged segment of a person鈥檚 spinal cord, three years after the injury, and replacing it with a section from a brain-dead donor.
Although the recipient is said to be doing well, the operation has drawn concern from some researchers, who question whether it will work and are concerned that it may even leave the individual worse off.
at the Second Affiliated Hospital of Guangxi University of Chinese Medicine in China, who led the surgery, told New 女生小视频 that the operation took place last week at the Sklifosovsky Institute for Emergency Medicine in Moscow.
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Ren says the surgery was performed on an adult with a complete spinal cord injury that occurred from external trauma three years earlier. This usually causes paralysis and loss of physical sensation below the site of the injury. However, it isn鈥檛 known what part of the spinal cord was injured in this individual.
Further details are limited, but Ren says the surgery involved the use of polyethylene glycol (PEG) 鈥� a kind of biological glue 鈥� alongside microsurgical techniques to fuse the ends of the donor segment to the recipient鈥檚 own spinal cord.
鈥淲e have informed the patient of every potential risk and surgical outcome, and the patient鈥檚 current condition is good,鈥� says Ren. 鈥淥ur Russian team will later release a document describing the surgery.鈥�
鈥淭his is a Sputnik moment for spinal cord injury,鈥� says at Harbin Medical University in Heilongjiang province, China, who has previously published papers with Ren .
But some question whether the operation will really help the recipient. 鈥淚鈥檓 concerned for the patient鈥檚 safety as they likely will be much worse off after this procedure, given the need to recover from a substantial surgery, with very little benefit,鈥� says at the University of Southampton, UK. She also warns of a high risk of infection.
The major problem with repairing spinal cord injuries is restoring communication between the brain and the neural circuits below the injury. Spinal cord cells don鈥檛 divide and regrow, and after injury, damaged areas degrade further.
For many years, Ren, Canavero and others have been developing a procedure involving bringing freshly cut spinal cord surfaces together and applying PEG in an attempt to fuse the fibres across the junction 鈥� like placing clumps of dry spaghetti end to end and hoping some fibres meet.
, who is also at the Sklifosovsky Institute for Emergency Medicine, has done similar work on pigs, but wasn鈥檛 involved in the human transplant. He previously told New 女生小视频 that this proposed 鈥渇usion鈥� approach is based on joining nerves together, rather than generating new nerve cells or encouraging fibres to grow across a lesion. This, in theory, is followed by 鈥渘europlastic reorganisation鈥�, where the brain and spinal cord adapt to the new connections, which wouldn鈥檛 have functioned together before.
There has been and dogs, as well as pigs, using this technique. Some protocols involve adding drugs to reduce inflammation or support nerve health, plus electrical stimulation of spinal circuits.
However, reconnecting a freshly severed spinal cord is different to repairing an injury experienced years before or integrating a donated segment of spinal cord.
Andrews says that for a transplant to functionally integrate, the surgery would have to include molecules that promote tissue healing. It would also need factors that neutralise molecules in and around the spinal cord that act as a natural brake on nerve fibre growth and other factors that induce growth between the donor tissue and the recipient鈥檚 spinal cord. 鈥淓ven then, the chance of regeneration and functional recovery would be, in my opinion, zero,鈥� says Andrews.
She also has doubts over the animal evidence underpinning the surgery. 鈥淥n the whole, I don鈥檛 believe these studies have been done rigorously enough, and the results don鈥檛 relate to what is neurologically possible.鈥�
at Newcastle University, UK, says there is some data showing that , and he can imagine a situation where a transplanted segment of spinal cord tissue might provide some growth factors to support regeneration of severed nerve fibres. But he says that researchers traditionally use because 鈥渋t is very difficult to get two adult pieces of nervous system to join together in a functional way鈥�.
He adds that he hopes supporting evidence for the surgery will be available for peer review as soon as possible. 鈥淭here are many people living with spinal cord injury and they deserve clarity, transparency and honesty about the prospects and outcomes of any new therapies that are being trialled.鈥�
