In a recent study conducted by a collaborative team comprising researchers from UCLA, the Swiss Federal Institute of Technology, and Harvard University, a critical element in restoring functional activity following spinal cord injuries has been unveiled. Their investigation focused on the importance of regrowing specific neurons to their natural target areas for effective recovery, as opposed to random regrowth.
Initially, in a 2018 Nature publication, this team had identified a treatment approach capable of stimulating axon regrowth – the minuscule fibers that facilitate communication between nerve cells – after spinal cord injuries in rodents. Although this approach successfully regenerated axons across severe spinal cord lesions, achieving meaningful functional recovery remained a significant challenge.
In their latest study, published in Science, the researchers sought to determine if orchestrating the regeneration of axons from specific subpopulations of neurons to their native target regions could lead to substantial functional restoration in mice with spinal cord injuries. To achieve this, they employed advanced genetic analysis to identify the nerve cell groups responsible for enhancing walking abilities following partial spinal cord injuries.
Their findings revealed that merely regenerating axons from these nerve cells across spinal cord lesions without precise guidance had no impact on functional recovery. However, when the approach was refined to include the use of chemical signals to attract and steer the regeneration of these axons towards their natural target region in the lumbar spinal cord, significant improvements in walking ability were observed in a mouse model of complete spinal cord injury.
Dr. Michael Sofroniew, a professor of neurobiology at UCLA’s David Geffen School of Medicine and a senior author of the study, emphasized the significance of their research, stating, “Our study offers valuable insights into the intricacies of axon regeneration and the prerequisites for meaningful recovery following spinal cord injuries.” He stressed the importance of not only regenerating axons across injury sites but also actively guiding them to their natural destinations for substantial neurological restoration.
The authors of the study suggest that grasping how to reconnect specific subpopulations of neurons with their natural target areas holds great potential for developing therapies to restore neurological functions in larger animals and ultimately in humans. They acknowledge the challenges of promoting regeneration over longer distances in non-rodent species, requiring strategies with intricate spatial and temporal features.
Nevertheless, they remain optimistic that implementing the principles outlined in their research “will establish the foundation for achieving substantial repair of injured spinal cords and may accelerate recovery after other types of central nervous system injuries and diseases.”