A pioneering treatment has allowed paralysed dogs to regain some movement. The results have raised hopes that the method will work in people too. So far, nine dogs paralysed in road accidents or by spinal disc injuries have been treated by veterinary surgeons Robin Franklin and Nick Jeffery of the University of Cambridge. Within a month, all regained the ability to make jerky movements in their hind legs, Jeffery told a meeting in Birmingham, UK, this week, although they are only slowly gaining the ability to support their own weight.
Many different approaches to treating spinal injuries are being explored, but promising results in small animals such as rats have often not been repeated in larger animals. That is one of the reasons why the dog results are exciting, says Geoffrey Raisman of the Institute of Neurology at University College London, one of the pioneers of the method used by the Cambridge team. “I think that these findings in dogs are directly relevant to the human situation,” he says. “Of course, we can’t know for sure without doing the work but it is a very good indicator that we can expect the same effects. We are hoping to start similar trials in humans within a couple of years.”
In Australia, three patients have already been treated using the same method (New Scientist, 12 July 2002, p 18). But the results will not be revealed until 2007. Jeffery agrees the results seen in the nine dogs are encouraging, but says a full recovery may require a combination of methods. “It is exceedingly improbable that one simple intervention alone will permit full recovery of locomotor activity after this type of extremely severe spinal cord injury,” he cautions.
His team is one of several studying the use of specialised cells called olfactory ensheathing glia cells, OEG cells, found in the back of the nose, are support cells for the only nerve cells in the central nervous system capable of constant regeneration. For the Cambridge study, OEG cells were collected by opening the skulls of the dogs. The cells were multiplied in the lab and then injected into the damaged part of the spinal cord.
As well as regaining some movement, the dogs also seemed to recover some sensation below the injury site. Three of the dogs can warn their owners when they have a full bladder, Jeffery says, though they have not regained control. There are no signs that the dogs have regained a proper pain response, but neither do they appear to suffer pain from the severed nerve, a potential side effect of the treatment. Franklin is looking for an alternative source of OEG cells, as three of the nine dogs have suffered seizures as a result of the surgery. The team has found a form of stem cell in the nasal mucosa that can be turned into OEGs in the lab. These cells can be collected by inserting a simple swab into the nose. The Australian team is using a similar approach.
A trial of another spinal injury treatment in dogs hit the headlines in December. Injections of a chemical called PEG appeared to greatly boost recovery (New Scientist, 11 December 2004, p 9). However, PEG has to be injected within 48 hours of an injury. By contrast, all nine dogs treated at Cambridge had been paralysed for at least three months without showing any sign of recovery.
April 26, 2005
Original web page at New Scientist