When doctors refer to a "complete spinal cord injury," they mean that there has been a total severance of the spinal cord at some point in the neck or back. The gap prevents the brain from communicating with any part of the body connected below it. Unfortunately, these injuries have long been considered intractable, with no way to restore the communication and an extremely limited chance for improvement in the patient.
Now, however, researchers have found a three-part cocktail that can coax one type of spinal nerve to grow across the gap of a complete spinal cord injury in rodents. The nerves were then able to take on electrical communication from the brain, although physical therapy would still be needed to for the patient's body to re-learn how to use the newly-healed spine.
The research was published on Aug. 29 in the journal Nature. The neurobiologists involved stress that the research is at an early stage. The research proves the concept that the three-pronged approach works for one of the types of neurons that make up the spinal cord, but it is likely that other approaches will be needed for other types of neurons. Therefore, we shouldn't be expecting new treatments anytime soon. Still, it's an exciting development.
The researchers combined a group of chemicals known to promote nerve cell growth, a structural protein called laminin, and chemical "lures" meant to draw growing nerve cells to the right location. The three-part approach was effective at growing propriospinal neurons. These neurons are known for their ability to sometimes restore nerve signaling in partial spinal cord injuries.
Using the three-part approach, the researchers were able to draw "an unprecedented amount" of propriospinal neurons across the gap of a complete spinal cord injury, and the axons of the propriospinal neurons were fully able to pass electrical signals.
"As far as scientific impact, it is a good leap," said a Cleveland Clinic researcher who was not involved in the study.
Bridging the injury gap is just the start. While some electrical signals were able to pass from the brain to the neurons on the other side of the gap, the animals weren't immediately able to use the previously silent muscles. Just as babies don't walk simply because their nerves are whole, the healed mice and rats need training and engaging the regenerating axons through repetition.
We stress again that a great deal of work needs to be done before human treatments can be developed. The next step in the research is to find out "if we can, with rehabilitation training, reboot the whole system."