CHICAGO, July 11 (Xinhua) -- Researchers at the University of Michigan (UM) have designed nanoparticles that intercept immune cells on their way to the spinal cord, and redirect them away from the injury. Those that reach the spinal cord have been altered to be more pro-regenerative.
The researchers have demonstrated the approach in mice, with the nanoparticles enhancing healing by reprogramming the aggressive immune cells, an "EpiPen" for trauma to the central nervous system, which includes the brain and spinal cord, according to a news release posted on UM's website on Thursday.
With no drugs attached, the nanoparticles reprogram the immune cells with their physical characteristics: a size similar to cell debris and a negative charge that facilitates binding to immune cells. In theory, their non-pharmaceutical nature avoids unwanted side effects.
With fewer immune cells at the trauma location, there is less inflammation and tissue deterioration. Immune cells that do make it to the injury are less inflammatory and more suited to supporting tissues that are trying to grow back together.
"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," said Lonnie Shea, a professor of biomedical engineering.
"The immune system underlies autoimmune disease, cancer, trauma, regeneration -- nearly every major disease," Shea said. "Tools that can target immune cells and reprogram them to a desired response have numerous opportunities for treating or managing disease."
Trauma of any kind kicks the body's immune response into gear. In a normal injury, immune cells infiltrate the damaged area and clear debris to initiate the regenerative process.
The central nervous system, however, is usually walled off from the rough-and-tumble of immune activity by the blood-brain barrier. A spinal cord injury breaks that barrier, letting in overzealous immune cells that create too much inflammation for the delicate neural tissues. That leads to the rapid death of neurons, damage to the insulating sheaths around nerve fibers that allow them to send signals, and the formation of a scar that blocks the regeneration of the spinal cord's nerve cells.
The research has been published in the current issue of Proceedings of the National Academy of Sciences.