- Researchers developed an injection that appears to prevent paralysis in mice with spinal cord injuries.
- They hope it can also prevent or reverse paralysis in humans.
- The treatment uses “dancing molecules” to repair and regenerate cells.
Samuel Stupp did not expect many surprises inside his laboratory after a 40-year career as a scientist. But something magical happened recently: His research team at Northwestern University developed an injection that appeared to prevent mice with spinal cord injuries from becoming paralyzed.
A paper published last week in the journal Science outlines how the first of its kind works – a complex process involving dancing molecules, electrical signals and growing blood vessels.
“It’s the most important paper I’ve ever written because I’ve never so deeply integrated so many pieces of science,” Stupp, a professor at Northwestern, told Insider.
At present, no existing treatments can reverse paralysis – and spinal cord injuries do not heal on their own. So patients rely on anti-inflammatory drugs and physiotherapy to relieve pain and repair injuries in small ways.
Stupp’s therapy, on the other hand, has the potential to prevent people with severe spinal cord injuries from becoming paralyzed – provided the results of his mouse study also apply to humans. Eventually, he said, a new version of the same treatment could help people regain the feeling or movement after the paralysis has already occurred.
‘Dancing molecules’ help instruct cells in repairing and regenerating themselves
A spinal cord injury either damages or disrupts axons – the long tails of neurons (nerve cells) that carry electrical signals that instruct the body to feel or move. After an injury, scar tissue often builds up, preventing axons from regenerating, which is why people become permanently paralyzed.
Stupps therapy not only reduced scar tissue but also regenerated axons in mice. It also reformed myelin – a fatty layer that covers axons, like insulation around electrical wires – that helps axons grow. In addition, it signaled the body to produce blood vessels, which are necessary for cells to repair themselves.
Mice with spinal cord injuries in the study were able to walk again within four weeks of receiving the treatment.
The drug is administered as a liquid injection the day after an injury occurs. This fluid contains tiny fibers – each of which consists of hundreds of thousands of molecules bound together. As soon as the fluid touches the spinal cord tissue, these fibers form a gel.
“Our small fibers collapse together into a network or matrix that resembles natural tissue,” Stupp said. “This is probably part of why it is so safe and biocompatible and so efficient – because cells see an environment that is very similar to what they normally see.”
Once the therapy is introduced to the body, it is ready to perform its main function: to instruct cells to repair and regenerate themselves. Stupp’s research team programmed the molecules to move or “dance” by mutating their amino acid chains. It increased the chances of the molecules coming in contact with cell receptors, the proteins that receive the body’s electrical signals.
“The molecules inside the small fibers are very dynamic,” Stupp said. “They can reversibly jump out of the fiber and get back into the fiber. They just dance around.”
By touching cell receptors, the molecules trigger axons to regenerate, myelin to reform and blood vessels to grow. The more the molecules danced, the more successful the treatment seemed to be in preventing paralysis.
Researchers hope to study the drug in human trials next time
The dancing molecules are “a true discovery for any kind of therapy for disease,” Stupp said. Eventually, he said, they could be used to regenerate tissues in other parts of the central nervous system. It suggests that similar drugs may help treat stroke or neurodegenerative diseases such as Parkinson’s and Alzheimer’s.
But first, Stupp must demonstrate that spinal cord treatment works in humans. Humans are not mice, so the results of successful animal experiments are often not translated into humans.
Stupp plans to submit its research to the Food and Drug Administration in early 2022, he said. Provided the FDA approves it, Stupp said he hopes the drug can go directly to trials in humans – perhaps in people with severe spinal cord injuries for whom no other treatments are available.
He is optimistic that the drug would be safe in humans, he added, as it mainly consists of compounds found naturally in the body, such as lipids and amino acids. It is also biodegradable, which means that the body easily breaks it down.
“The therapy is basically gone in a few weeks,” Stupp said. “It is biodegradable into nutrients for the cell.”
The treatment appears to have a long-lasting effect, Stupp added – although the researchers only observed mice for 12 weeks after the injection.
“I see no reason why it would not be permanent,” he said.