Researchers at Chalmers University of Technology in Sweden and the University of Auckland in New Zealand have developed a groundbreaking bioelectric implant that restores movement in rats after injuries to the spinal cord. This breakthrough offers new hope for an effective treatment for humans suffering from loss of sensation and function due to spinal cord injury.
A recent report from the World Health Organization, WHO, estimates that approximately 15 million people worldwide live with spinal cord injuries. The spinal cord is made up of numerous nerve fibres that transmit signals between the brain and the rest of the body. When damaged, the connection between the brain and body is shattered, often resulting in loss of sensation and function, and in severe cases, paralysis.
“Unlike a skin wound, which typically heals on its own, the spinal cord does not regenerate effectively, making these injuries devastating and currently incurable,” says Maria Asplund, Professor of Bioelectronics at Chalmers University of Technology.
Asplund is, together with Darren Svirskis, University of Auckland, senior author of a study recently published in Nature Communications.
Before birth, and to a lesser extent afterwards, naturally occurring electric fields play a vital role in early nervous system development, encouraging and guiding the growth of nerve fibers along the spinal cord. The researchers are now harnessing this same electrical guidance system in the lab.
“We developed an ultra-thin implant designed to sit directly on the spinal cord, precisely positioned over the injury site in rats,” says Bruce Harland, senior research fellow, University of Auckland, and one of the lead researchers of the study.
The device delivers a carefully controlled electrical current across the injury site.
“The aim is to stimulate healing so people can recover functions lost through spinal cord injury,” says Professor Darren Svirskis, University of Auckland.
In the study, researchers observed how electrical field treatment improved the recovery of locomotion and sensation in rats with spinal cord injury. The findings offer renewed hope for individuals experiencing loss of function and sensation due to spinal cord injuries.
“Long-term, the goal is to transform this technology into a medical device that could benefit people living with life-changing spinal-cord injuries,” says Maria Asplund.
The study presents the first use of a thin implant that delivers stimulation in direct contact with the spinal cord, marking a groundbreaking advancement in the precision of spinal cord stimulation.
“This study offers an exciting proof of concept showing that electric field treatment can support recovery after spinal cord injury,” says doctoral student Lukas Matter, Chalmers University of Technology, the other lead researcher alongside Harland.
Unlike humans, rats have a greater capacity for spontaneous recovery after spinal cord injury, which allowed researchers to compare natural healing with healing supported by electrical stimulation.
After four weeks, animals that received daily electric field treatment showed improved movement compared with those who did not. Throughout the 12-week study, they responded more quickly to gentle touch.
“This indicates that the treatment supported recovery of both movement and sensation,” Harland says.
“Just as importantly, our analysis confirmed that the treatment did not cause inflammation or other damage to the spinal cord, demonstrating that it was not only effective but also safe,” Svirskis says.
The next step is to explore how different doses, including the strength, frequency, and duration of the treatment, affect recovery, to discover the most effective recipe for spinal-cord repair.
