Aging May Impact Our Immune System’s Ability To Respond to Spinal Cord Injury

An age-related decline in our body’s immune response to spinal cord injuries has been highlighted by new research that sheds light on new approaches for enhancing patient recovery. The study reveals insights into the immune system's diminished reaction to such injuries over time and emphasizes the crucial role of membranes bordering the spinal cord in initiating an immune response. Researchers hope that the study findings could be used to improve the outlook for patients with spinal cord injury, especially those affected in later life.           

Poor prognosis for spinal cord injury   

Dr. Andrea Francesca M. Salvador, a study co-author and researcher at the University of Virginia School of Medicine, said, “Our findings suggest in aging, there is an impairment in how the immune response is initiated and resolved, compared to young people. Hopefully, our results can help identify points of intervention and druggable targets that can improve recovery and address long-term consequences of injury, such as pain.”

Understanding spinal cord injuries is an urgent task. The current prognosis for patients includes potentially devastating and lifelong effects. The extent and location of the injury alter outcomes, but patients may experience mobility loss, loss of bowel control, chronic pain, sexual dysfunction or spasms. Part of the reason for this set of grim outcomes is a lack of understanding of how the body responds to these injuries.

The senior author of the paper, Professor Jonathan Kipnis, made a significant advance in this area in 2015, identifying for the first time vessels connecting the brain and immune system. This revelation effectively challenged the notion that the brain was isolated from the immune system. The field of neuroimmunology, exploring the relationship between the immune system and the brain, has only advanced in the years since.

Lymphatic “patches”

The study conducted by Salvador, Kipnis and their collaborators specifically identified the critical role of meninges – made up of layers of membranes filled with cerebrospinal fluid – in the immune response to spinal cord injuries. They found that previously unknown meningeal lymphatic "patches" formed above the injury site. These patches’ function is unclear, but the researchers speculate that they could be involved in cellular programs of tissue recovery and repair.

The team also looked at how immune cells respond to spinal cord injuries. This revealed that young lab mice had a stronger immune response and a better recovery from injury, suggesting that targeting specific immune cells could potentially enhance recovery after spinal cord injury.

Kipnis, now a professor at Washington University School of Medicine in St. Louis, looked to the future of the field, stating, "This is an exciting finding and one which may indeed lead to new therapeutic approaches for spinal cord injury patients. We are now collaborating with clinicians in the hope to better understand what is happening in human patients and how our findings could be translated to make a real difference.” 

Reference: Salvador AFM, Dykstra T, Rustenhoven J, et al. Age-dependent immune and lymphatic responses after spinal cord injury. Neuron. 2023. doi: 10.1016/j.neuron.2023.04.011

This article is a rework of a press release issued by the University of Virginia. Material has been edited for length and content.