"Well, it doesn't seem to be working. I don't see any real change in pain behavior in any of the groups," said Shiga, a visiting scholar at University of California San Diego School of Medicine, apologetically, as he walked into the office of his supervisor, Wendy Campana, PhD, professor in the Department of Anesthesiology and Program in Neuroscience.
But, to Campana's surprise, he continued, almost as an after-thought.
"Although ... some rats are actually really moving."
The difference for those rats was this: Before delivering them into the spinal cord injury site, Shiga and Campana had conditioned stem cells with a modified form of tissue-type plasminogen activator (tPA), a drug commonly used to treat non-hemorrhagic stroke.
Findings - December - Scientific - Reports
Their findings are published December 17, 2019 in Scientific Reports.
tPA is used to break up blood clots, allowing blood to more freely flow back into the brain following a stroke. But tPA is also a naturally occurring enzyme known to boost neuron growth and dampen inflammation. So the researchers used an enzymatically inactive form of tPA, still anti-inflammatory and pro-neuron growth but without effect on blood clotting, which could be a dangerous side effect in a person not having a stroke.
Dish - Researchers - TPA - Progenitor - Cells
In a laboratory dish, the researchers added the modified tPA to neural progenitor cells -- the precursors to neurons. They had generated these pre-neurons from induced pluripotent stem cells, a special kind of stem cell that can be derived from a person's skin cells. After 15 minutes, the researchers transferred either tPA-conditioned or unconditioned neural progenitor cells to the injury site in a rat model of severe spinal cord injury.
Two months after treatment, the researchers found 2.5-fold more tPA-conditioned neural progenitor cells than unconditioned cells still present in the rats. What's more, the tPA-conditioned cells had begun specializing into full-fledged neurons, with axons (branches) emerging from the site...
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