Fresh research from the United States has revealed that the ability to breathe has been restored to mice with spinal cord injuries. The scientists who have carried out this research have described the breakthrough as a medical first.

Some patients with damaged spinal cords need ventilators as they are unable to breathe on their own. However, a recent report in the journal Nature showed that a nerve graft, coupled with a protein, could restore breathing.

Human trials could begin soon, which the charity Spinal Research said could be "potentially life-changing" for patients with spinal injuries.

Damage at the top of the spinal cord, around the neck, can interrupt messages to the diaphragm - a layer of muscle in the abdomen involved in breathing. The spinal cord is notoriously resistant to repair. Techniques such as nerve grafts, which doctors have successfully applied to the arms and legs, had previously shown limited results with the spinal cord.

Once the spinal cord has been damaged it is scarred, like any other part of the body, and those scars, acting together with molecules, prevent nerves repairing and forming new connections. This results in paralysis and other problems, including breathing, for the patient.

Nerve graft across the scars in the spinal cord

The researchers at Cape Western Reserve University in Cleveland, Ohio used a nerve graft to form a bridge across the scars in the spinal cord, and at the same time injected an enzyme which attacked the inhibitory molecules. Three months later, tests showed that the mice that had received the treatment had recovered 80-100% of breathing function.

Researchers on the project explained that the use of the enzyme helps to get the nerve fibres out and then allows them to reconnect. Once that has happened the spinal cord was apparently able to begin working again, and restore functional breathing patterns to the mice. It is hoped to begin trials in humans, and are also investigating whether bladder function can be restored, which can be lost when the lower spine is damaged.

Dr Mark Bacon, from the charity Spinal Research, said:"Long distance regeneration has remained quite elusive in the field of spinal cord injury repair, so to achieve this and at the end of it establish functional connections that actually do something useful - restore breathing - is remarkable.

"It is potentially life-changing if this or similar techniques can be translated to the clinic."

Paralysed from the chest down following a road traffic accident

This news of spinal cord regeneration comes a few months after a US man who was paralysed from the chest down following a road traffic accident received electrical stimulation of his spinal cord, allowing him to stand for the first time since 2006.

Rob Summers, from Oregon, was a keen baseball player and in 2006 was part of the team which won the College World Series. However that summer he was injured in a hit and run accident and his spinal cord was damaged. Messages from the brain, which travel down the spinal cord, were blocked and Rob was paralysed.

Using radical new techniques, doctors at the University of California surgically implanted 16 electrodes into Rob’s spine. He was then trained daily in trying to stand, walk and move his legs, while electrical pulses were sent to the spinal cord. Within days he was able to stand independently and eventually he could control his legs and step, with assistance, for short periods of time. Rob was able to voluntarily move his toes, hips, knees and ankles and also walk on a treadmill while being supported.

In most spinal cord injuries only a small amount of the tissue is damaged so many nerve cells remain. These cells pick up signals from the legs and respond automatically, the signals which allow a healthy person to stand still or walk without actively thinking about it. It is this process the doctors were trying to tap into.

However, following a spinal injury the nerve cells need help to transmit signals from the brain, in this case precise electric stimulation was used to mimic those signals.

More patients are being lined up to further test the treatment

The researchers at the University of California explained that the electric stimulation mimics a message from the brain to start moving and changes the "mood" of the spinal cord so that it is able to hear the information which is coming in from the legs and respond. This, coupled with intensive training, allowed Rob to stand or walk while supported on a treadmill.

The researchers admitted however to having "no idea" about how the brain was also able to gain direct control of the toes, knee and hips. They speculate that some nerve cells are being reactivated or maybe more of them are being created, allowing signals from the brain to pass down the spinal cord. As a result, Rob was also able to regain other functions such as bladder, bowel and blood pressure control.

This study has proved that electrical stimulation works in one person. Four more patients in the US are being lined up to further test the treatment.

Experts in the UK have warned that victims of spinal cord injury should not believe that they can be cured. A professor from the Institute of Neurology at University College London, said: "This one case is interesting, and from one of the leading groups in the world. To what extent this procedure could in the future provide a further and sustained improvement cannot be judged on the basis of one patient.

"From the point of view of people currently suffering from spinal cord injury, future trials of this procedure could add one more approach to getting some benefit. It is not and does not claim to be a cure."

Offers hope to those who have suffered paralysis

Alastair Elliot, a solicitor specialising in Spinal Injuries with Thompsons Solicitors in the South West said: “This is quite mind blowing research for those of us who are involved and work closely with those suffering from spinal cord injuries. Whilst this research is very much in it’s infancy, it offers hope to those who have suffered paralysis at whatever level.

“Research from the UK shows that there are approximately 800 spinal cord injuries in the UK each year, of which roughly half are in the neck. Sadly the majority of those injuries are as a result of road traffic accidents, with the majority of victims being young men aged between 17 and 25. The majority of those suffering spinal cord injury will have some degree of impaired breathing. Research such as that highlighted above shows that medical science is advancing rapidly, and offering injured people fresh insight into their conditions. “