Animal experiments confirmed that the identified group of neurons can indeed guide the recovery period and in the future will become the basis for the development of new methods of treatment for people with severe spinal cord injuries.
In 2018, scientists found that for the first time Nerve stimulation Near the site of injury, i.e. epidural electrical stimulation (EES) – can relieve pain in people afterward Spinal cord injuries And the Restore the ability to walk. However, although this method was one of the few with significant clinical effects, it was not entirely clear what the underlying neurological mechanisms were.
To explore the mechanistic basis of this therapy, neuroscientists at the Swiss Federal Institute of Technology in Lausanne followed nine paralyzed patients who underwent a five-month EES regimen combined with fPhysiotherapy and rehabilitation. Six patients with spinal cord injuries retained residual sensation in their legs, and three patients were completely paralyzed from the waist down. During the treatment, the team mapped neuronal activity in each of the test subjects.
It was noted that along with the improvement of the condition of the musculoskeletal system and Restore the ability to walk The level of nerve activity decreased near the site of injury. This was not surprising to the research team, because, as they explain, the same thing happens in the brain during learning.
When a person learns a task, the same thing happens in their brain: as they progress, fewer and fewer neurons are activated.
says Dr. Gregoire Courtine, who led the study.
He explains that after a spinal cord injury, when a patient begins treatment and their body begins to respond to it, a lot of “chaotic activity” occurs in their body. However, over time, the rehabilitation process causes this activity to begin to regulate: certain types of neurons increase their activity, while others lose it completely.
These findings indicated to the researchers that there may be a subset of neurons responsible for coordinating recovery from severe spinal cord injuries. They decided to test this hypothesis on mice.
They inflicted trauma on the animals similar to that experienced by the patients, and then rehabilitated them in the same way. It turns out that applying the rat version of EES to paralyzed individuals resulted in the same suppression of activity of a specific group of neurons that occurred in humans.
The researchers then measured gene expression in the neurons of the mice’s spinal tissue and divided them accordingly. Using a machine learning algorithm, they were able to map changes in gene expression that corresponded to stages of recovery for human patients.
Ultimately, they were able to identify a previously unknown subpopulation of excitatory neurons (that is, neurons that connect motor and sensory neurons) that have the potential to take over after injury. They were located in intermediate lamellae Spinal Cord cottony, and on their surface they presented two genetic markers: Vsx2 and Hoxa10.
When scientists in the lab deactivated these cells, the mice lost again The ability to walk And restore it only after the next activation of neurons. However, in animals without spinal cord injury, cell silencing had no effect—suggesting that it only becomes necessary after injury.
The SCVsx2/Hoxa10 population of neurons does not appear to be required for walking in healthy individuals, but is essential for recovery from spinal injuries. Our experiments confirmed that their presence is a prerequisite for restoring the ability to walk after paralysis.
– confirms scientists from Lausanne.
According to the authors, the hope that this discovery will bring relief to people with spinal injuries is very high.
Over time, this could lead to the development of new and effective treatment options and to provide a better quality of life for people with all types of spinal cord injuries.
The researchers believed.
Source: Niezalezna.pl, PAP
