Researchers have identified nerve cells that are essential for helping paralysed people regain their ability to walk, making this a breakthrough in the treatment of spinal cord injuries.
Nine patients who took part in an ongoing Swiss trial to help paralysed people regain movement contributed to the findings.
With the use of implants that electrically stimulate spinal neurons that control lower-body mobility, all nine individuals quickly regained their ability to stand and walk.
According to the latest research, a particular group of cells in the lower spine appear to be required for that movement recovery to take place.
According to specialists, it is hoped that the discovery will contribute to the improvement of electrical stimulation therapy and, eventually, aid in the development of even more advanced methods to enable paralysed individuals regain complicated mobility.
According to the American Association of Neurological Surgeons, as many as 450,000 persons in the United States are currently coping with a spinal cord injury. Younger than 30-year-old males make up the majority of those injured, and traffic accidents or acts of violence are frequently to fault.
The communication between the brain and the spinal nerves below the level of the injury is essentially cut off by spinal cord injuries.
But those nerve cells aren’t dead; they’re just inactive. And for many years, scientists have been researching epidural electrical stimulation (EES) as a technique to stimulate those neurons and provide paralysed individuals some degree of mobility.
Electrodes that send electrical currents to the spinal cord’s neurons are implanted during EES. An implanted pulse generator is attached to the electrodes in the abdomen.
According to Eiman Azim, a researcher at the Salk Institute in La Jolla, California, who examines the mechanics underpinning human movement, EES has been used as a pain therapy for 50 years.
Researchers later discovered that EES also has an impact on mobility. Over the past ten years or more, many research teams have employed EES in conjunction with rigorous physical therapy to aid a limited number of paralysed patients in regaining some degree of standing and walking abilities.
Azim claimed that the Swiss team has been “making tremendous advances” in the direction of the strategy recently.
For instance, they have created electrodes that precisely target the spinal cord’s “dorsal root” areas, which regulate trunk and leg movement. Additionally, they have included advanced technology that stimulates nerves in a way that more closely resembles how the brain would carry out the task.
The team, which includes members from the University of Lausanne and Swiss Federal Institute of Technology, reported on its three most recent patients earlier this year. The patients, all men between the ages of 29 and 41, had spinal cord injuries that prevented them from feeling or moving their legs.
In 2020, surgery was performed on everyone to implant the EES hardware. The implants were used in conjunction with software that enables patients and physical therapists to create stimulation programmes that are semi-automated and permit a range of movements. These programmes can be run independently by users using a tablet and tiny remote controls that wirelessly connect to the pulse generator.
After recuperating from surgery, those three patients were able to stand and walk with assistance right away.
Along the way, the Swiss team made an unusual discovery: Some of their nine patients were still able to walk when the electrical stimulation was switched off, which, according to Azim, suggests that the neurons involved in walking have undergone a “reorganisation.”
In order to learn more, the researchers used lab mice to mimic several of the key aspects of EES in people who have suffered spinal cord injuries. They were able to focus their attention on a group of neurons known as Vsx2 neurons that they believe to be “important” for the restoration of walking in EES patients.
When lab mice were given EES, “silencing” the neurons prevented them from regaining their ability to walk; activating the neurons allowed the mice to move again.
What transpires in the spinal cord during stimulation was the question posed by this investigation. said Azim. That is a huge black box.
The restored function in these nine patients was praised as “excellent” by Dr. Greg Nemunaitis, director of spinal cord injury rehabilitation at the Cleveland Clinic in Ohio.
In addition, he added that until a “cure” is established, the identification of “recovery-organizing neurons” in mice is “a first step in understanding and boosting function in humans.”
In the near future, according to Azim, the research on these crucial neurons might contribute in improving EES.
In the future, he suggested, a better comprehension of how EES promotes mobility recovery could aid in the creation of even more advanced treatments. According to Azim, technology is progressing to the point where it may eventually be safe to reach the spinal cord and “rebuild” broken circuits.
It’s not just a fantasy, he insisted.
The journal Nature published the findings online on November 9.
A summary of spinal cord damage can be found at the American National Institute of Neurological Disorders and Stroke.
SOURCES: Greg Nemunaitis, MD, director of spinal cord injury rehabilitation at Cleveland Clinic, and professor at Case Western Reserve University School of Medicine, Cleveland, Ohio; Eiman Azim, PhD, associate professor at Salk Institute for Biological Studies, La Jolla, California