Paralysis from spinal cord injuries could be prevented through an ‘EpiPen’ injection of nanoparticles, which can prevent the body’s immune system from overreacting to trauma.
University of Michigan researchers have designed nanoparticles which intercept immune cells on their way to the spinal cord, redirecting them away from the injury. Fewer immune cells at the trauma location should lead to less inflammation and tissue deterioration.
Those that do reach the spinal cord have been altered to be more pro-regenerative, as the nanoparticles reprogram the immune cells to have a size similar to the cell debris and a negative charge that facilitates binding to immune cells. This makes them more suited to supporting tissues that are trying to grow back together.
The researchers have thus far trialled the technology only in mice, but hope the new technique can be used to prevent paralysis in humans.
University of Michigan professor of biomedical engineering Lonnie Shea said: “In this work, we demonstrate that instead of overcoming an immune response, we can co-opt the immune response to work for us to promote the therapeutic response.”
In a normal injury, immune cells infiltrate the damaged area and clear debris to initiate regeneration of the trauma site. The spinal cord houses the central nervous system, which is walled off from immune activity by the blood-brain barrier. When that barrier breaks, overzealous immune cells can create too much inflammation for the delicate neural tissues, leading to the rapid death of neurons.
This neuron death damages the insulating sheaths around nerve fibres that allow them to send signals, and the formation of a scar that blocks the regeneration of the spinal cord’s nerve cells. All of this can induce loss of function below the level of the injury.
Previously, clinicians have attempted to offset this immune response through injecting steroids such as methylprednisolone into the spine. This practice has been largely discredited as it has been known to induce severe complications such as sepsis, gastrointestinal bleeding and blood clots.
University of Michigan research fellow Jonghyuck Park said: “Hopefully, this technology could lead to new therapeutic strategies not only for patients with spinal cord injury but for those with various inflammatory diseases.”