Scientists have used stem cells and a soup of nerve-friendly chemicals to not just bridge a damaged spinal cord but actually regrow the circuitry needed to move a muscle, helping partially paralyzed rats walk.
Years of additional research is needed before such an experiment could be attempted in people.
But the work marks a tantalizing new step in stem cell research that promises to one day help repair damage from nerve-destroying illnesses such as Lou Gehrig's disease, or from spinal cord injuries.
The Hopkins experiment isn't the first to use stem cells to help paralyzed rodents move. But previous work bridged damage inside the spinal cord that blocked nerve cells from delivering their ''move'' messages to muscles, sort of like fixing the circuit that brings electricity to a fan.
The new work essentially installs new wiring: replacing motor neurons -- specialized nerve cells for movement -- that have died to make a new circuit that grows neuronal connections out of the spinal cord and down to a leg muscle.
...The paralysis wasn't completely gone, but six months after treatment, 11 of the 15 animals could bear weight, take steps and push away with the affected leg.
Of the roughly 4,000 new motor neurons generated in the rats' spinal cords, about 120 reached the muscle, and 50 were electrically active, further testing showed.
The next step, to start this summer: Redoing the experiment in pigs, to see if new neurons can be enticed to grow connections over the longer distances needed to reach from a pig's spinal cord to its leg.
Let's see how long Bush's policy of only funding research on existing stem cell lines holds up when people see a cure for paralysis on the horizon. It's even more awkward when you consider how many paraplegics and quadriplegics Bush has single-handedly created with his unnecessary war.
On the other hand, those wheelchairs are mighty comfortable...