Researchers in the United States have developed an injectable therapy that harnesses ‘dancing molecules’ to repair tissue after severe spinal cord injuries, which is said to have the potential to cure paralysis.
In a new study, researchers at Northwestern University administered a single injection to tissues surrounding the spinal cords of paralysed mice.
Just four weeks later, the animals regained the ability to walk.
By sending bioactive signals to trigger cells to repair and regenerate, the breakthrough therapy dramatically improved severely injured spinal cords in five key ways:
- The severed extensions of neurons, called axons, regenerated;
- scar tissue, which can create a physical barrier to regeneration and repair, significantly diminished;
- myelin, the insulating layer of axons that is important in transmitting electrical signals efficiently, reformed around cells;
- functional blood vessels formed to deliver nutrients to cells at the injury site;
- more motor neurons survived.
After the therapy performs its function, the materials biodegrade into nutrients for the cells within 12 weeks and then completely disappear from the body without noticeable side effects.
This is the first study in which researchers controlled the collective motion of molecules through changes in chemical structure to increase a therapeutic’s efficacy.
“Our research aims to find a therapy that can prevent individuals from becoming paralyzed after major trauma or disease,” said Northwestern’s Samuel I. Stupp, who led the study.
“For decades, this has remained a major challenge for scientists because our body’s central nervous system, which includes the brain and spinal cord, does not have any significant capacity to repair itself after injury or after the onset of a degenerative disease.
“We are going straight to the FDA to start the process of getting this new therapy approved for use in human patients, who currently have very few treatment options.”
According to the National Spinal Cord Injury Statistical Center, nearly 300,000 people are currently living with a spinal cord injury in the United States.
Less than three per cent of people with complete injury ever recover basic physical functions, and approximately 30 per cent are re-hospitalised at least once during any given year after the initial injury, incurring significant lifetime health care costs per patient.
“Currently, there are no therapeutics that trigger spinal cord regeneration,” said Stupp, an expert in regenerative medicine.
“I wanted to make a difference on the outcomes of spinal cord injury and to tackle this problem, given the tremendous impact it could have on the lives of patients.
“Also, new science to address spinal cord injury could have impact on strategies for neurodegenerative diseases and stroke.”
The science behind Stupp’s new breakthrough therapeutic is tuning the motion of molecules, so they can find and properly engage constantly moving cellular receptors.
Injected as a liquid, the therapy immediately gels into a complex network of nanofibres that mimic the extracellular matrix of the spinal cord.
By matching the matrix’s structure, mimicking the motion of biological molecules and incorporating signals for receptors, the synthetic materials are able to communicate with cells.
“Receptors in neurons and other cells constantly move around,” Stupp said. “The key innovation in our research, which has never been done before, is to control the collective motion of more than 100,000 molecules within our nanofibres.
“By making the molecules move, ‘dance’ or even leap temporarily out of these structures, known as supramolecular polymers, they are able to connect more effectively with receptors.”
While the new therapy could be used to prevent paralysis after major trauma as well as from diseases, Stupp believes the underlying discovery — that “supramolecular motion” is a key factor in bioactivity — can be applied to other therapies and targets.
“The central nervous system tissues we have successfully regenerated in the injured spinal cord are similar to those in the brain affected by stroke and neurodegenerative diseases, such as ALS, Parkinson’s disease and Alzheimer’s disease,” Stupp said.
“Beyond that, our fundamental discovery about controlling the motion of molecular assemblies to enhance cell signalling could be applied universally across biomedical targets.”
