After undergoing surgery to transplant cells from his nose to his spinal cord, a paralyzed man from Poland is able to walk again.
The procedure effectively provided a "bridge" over the injury site so nerve cells - encouraged by the special nose cells - could regrow across the scar tissue.
Darek Fidyka was left paralyzed from the chest down after suffering stab wounds to his back in 2010. After 19 months of treatment at a Polish hospital, his doctors say he has recovered some voluntary movement and some sensation in his legs.
Mr. Fidyka is continuing to improve further than predicted - he is able to drive and live more independently.
The news brings hope to some of the 3 million people worldwide living with spinal injury. It is thought the success of the procedure may be partly due to the fact the injury was a "clean cut." It may not be suitable for patients with more complicated spinal injuries.
The breakthrough represents decades of pioneering work for Geoffrey Raisman, a professor in the Institute of Neurology at University College London in the UK. In 1969, he discovered that damaged nerve cells can form new connections, and in 1985, he identified that a type of nose cell - called an olfactory ensheathing cell (OEC) - allows nerve fibers to regenerate into the brain.
These and other discoveries led Prof. Raisman and his team to believe it would one day be possible to regenerate nerve fibers in spinal cords damaged by injury.
Nose cells encouraged spinal nerve cells to grow across a nerve graft 'bridge'
When the spinal cord is damaged, scar tissue forms at the injured site and stops nerve fibers from regrowing. Prof. Raisman had the idea the nerve fibers might regrow if they had a bridge across the scar.
There followed many painstaking years of searching for the right materials to produce such a bridge. He and his team focused on the nerve cells responsible for sense of smell because they are the only type of nerve cell known to regenerate. They believed OECs helped to clear the way for the nerve cells to regrow.
They undertook and published animal studies where they transplanted OECs from the nose into injured spinal cords to stimulate the regrowth of nerve cells in rats with paralyzed limbs.
These studies attracted worldwide interest, including that of Pawel Tabakow, assistant professor in Neurosurgery at Wroclaw Medical University in Poland, who began corresponding with Prof. Raisman and then invited him and his team to Poland.
In 2013, they reported how they safely transplanted nasal OECs into the spinal cords of three paraplegic patients who showed "neurological improvement."
Mr. Fidyka was a recipient of this treatment. In the first of two operations, the surgeons removed one of his olfactory bulbs from high up in his nose and grew the OECs in culture.
Two weeks later, using about 100 micro-injections on either side of the site, they transplanted the cultured OECs into his severed spinal cord, using a strip of nerves from his ankle to bridge the gap.
The idea was to use the OECs to spur the spinal nerve fibers to regrow across the gap, using the ankle nerve grafts as a bridge.
Mr. Fidyka has continued with 5 hours a day of intensive rehabilitation under the careful management of Prof. Tabakow and his team, who have refined and optimized the treatment after visiting many spinal injury projects around the world.
'A historic change' for people disabled by spinal cord injury
In a BBC Panorama program, "To Walk Again," broadcast today, Mr. Fidyka says:
"I knew it would be difficult, and it would last long - but I always shut out the thought that I could be in a wheelchair for the rest of my life, so I was always set to fight hard."
Prof. Raisman says, "We believe that this procedure is the breakthrough which - as it is further developed - will result in a historic change in the currently hopeless outlook for people disabled by spinal cord injury."
He says they are currently raising funds so the English and Polish teams can continue to work together and verify the benefits of the approach with more patients.
The research behind the treatment was funded by the Nicholls Spinal Injury Foundation (nsif) and the UK Stem Cell Foundation.
Nsif was founded by David Nicholls after his son, Daniel - an 18-year-old from the UK on his gap year in Australia - was left paralyzed from the neck down after he dived into a wave on Bondi Beach in Sydney in 2003. Mr. Nicholls, who promised his son he would not give up until a cure had been found, says:
"Prof. Geoffrey Raisman and Dr. Pawel Tabakow's breakthrough marks the first step. The scientific information relating to this significant advancement will be made available to other researchers around the world so that together we can fight to finally find a cure for this condition which robs people of their lives."