Spinal injury researchers find a sweet spot for stem cell injections
As they do in many areas of medicine, stem cells hold great potential in treating injured spinal cords, but getting them where they need to go is a delicate undertaking. Scientists at the University of California San Diego (UCSD) are now reporting a breakthrough in this area, demonstrating a new injection technique in mice they say can deliver far larger doses of stem cells and avoid some of the dangers of current approaches.
The research focuses on the use of a type of stem cell known as a neural precursor cell, which can differentiate into different types of neural cells and hold great potential in repairing damaged spines. Currently, these are directly injected into the primary cord of nerve fibers called the spinal parenchyma.
“As such, there is an inherent risk of (further) spinal tissue injury or intraparechymal bleeding,” says Martin Marsala, professor in the Department of Anesthesiology at UCSD School of Medicine.
In experiments on rodents, Marsala and his team have demonstrated a safer and less invasive approach. The scientists instead injected the stem cells in between a protective layer around the spine called the pial membrane and the superficial layers of the spinal cord, a region known as the spinal subpial space.
“This injection technique allows the delivery of high cell numbers from a single injection,” says Marsala. “Cells with proliferative properties, such as glial progenitors, then migrate into the spinal parenchyma and populate over time in multiple spinal segments as well as the brain stem. Injected cells acquire the functional properties consistent with surrounding host cells.”
Following these promising early results, the scientists are hopeful that stem cells injected in this way could one day greatly accelerate healing and improve the strength of cell-replacement therapies for several spinal neurodegenerative disorders, including spinal traumatic injury, amyotrophic lateral sclerosis and multiple sclerosis. But first will come experiments on larger animal models closer to the human anatomy in size, which will help them fine tune their technique for the best results.
“The goal is to define the optimal cell dosing and timing of cell delivery after spinal injury, which is associated with the best treatment effect,” says Marsala.
The research was published in the journal Stem Cells Translational Medicine.