Researchers at the University of California San Diego School of Medicine have successfully implanted grafts of neural stem cells straight into spinal cord injuries in mice and documented their functionality in mimicking the animals' existing neuronal network after growing and filling the place of injury, a new study reports.
This stem cell breakthrough might be what patients who are living with spinal cord injury are waiting for.
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Restoring lost functions with stem cells
According to the press release, nearly 18,000 people in the U.S. suffer from spinal cord injury and 294,000 people live with it. Whether it is a permanent paralysis or diminished physical function, researchers were trying their hand at restoring these lost functions using stem cells lately.
Previous research also done by the team of researchers had shown that neural stem cell grafts improved functioning in SCI animal models. However, how that was happening was a mystery to the scientists.
The study's first author Steven Ceto stated, "We knew that damaged host axons grew extensively into (injury sites), and that graft neurons, in turn, extended large numbers of axons into the spinal cord, but we had no idea what kind of activity was actually occurring inside the graft itself."
What they didn't know, however, was whether if host and graft axons were making functional connections.
Researchers used recent technological developments
In order to solve this, the researchers used recent technology and were able to stimulate and record the activity of neuron populations with light rather than electricity, enabling them to see the connections.
They saw that graft neurons acted like the neural networks of the normal spinal cord even when there was an absence of direct stimulation.
To further the research, the team stimulated regenerating exons from the mice's brain and found that "some of the same spontaneously active clusters of graft neurons responded robustly." This meant that these networks receive functional synaptic connections from inputs that typically cause movement, also being activated by light touch and pinches.
They were found to be functional
Ceto said, "We showed that we could turn on spinal cord neurons below the injury site by stimulating graft axons extending into these areas.
"Putting all these results together, it turns out that neural stem cell grafts have a remarkable ability to self-assemble into spinal cord-like neural networks that functionally integrate with the host nervous system. After years of speculation and inference, we showed directly that each of the building blocks of a neuronal relay across spinal cord injury are in fact functional."
The team is now working to further enhance the functional connectivity of stem cell grafts and trying to move their stem cell graft approach into clinical trials. According to the researchers, a therapy might be achieved within a decade.
The study was published in Cell Stem Cell.