Before birth, all of us start out as a collection of stem cells: the building blocks that can become the more specialized cells that make up our tissues and organs. But it turns out that even adults maintain stem cells that could help injured tissues repair themselves.
The neural stem cells that populate the brain are the ones that neuroscientist Cindi Morshead wants to tap into. Morshead, professor of anatomy and surgery at the University of Toronto, is trying to identify and characterize these cells.
“What’s special about [stem cells] is that they can make all the different cell types, depending on the tissue that they’re in,” explains Morshead. “So if they’re in the brain, the stem cells can make brain cells; if they’re in the liver, the liver stem cells can make liver cells.”
Liver tissue is famously able to regenerate on its own under many circumstances, even allowing eligible living donors to grow their livers back to 90 percent of their original size after having an entire lobe removed for transplant. But patients with brain damage need help to mobilize their brain stem cells.
“There’s a whole bunch of different pockets of stem cells in the body, and the idea is we can activate them so that we can induce them to repair an injured tissue. We don’t want to just change what’s going on in the disease, we want to actually repair the body, and use our own body to do that.”
Morshead is repurposing drugs that are already used in the clinic for other diseases, like type II diabetes, to stimulate brain stem cells in young brains after a neonatal injury.
“We’ve been able to show that if you stimulate resident brain stem cells with drugs that are already in the clinical setting, we can get the brain to repair itself after a neonatal injury, or in a young brain.”
Despite this success, she still has more questions about whether the same results will still apply in older brains.
“We’ve made a really promising investment in trying to figure out how we can activate cells through age,” says Morshead. “They change during aging. They change after injury. So it’s not enough to know a stem cell can do x. We have to know, can a stem cell from an early-born brain do x? And will that change in an old-age brain?”
Stem cells have the potential to offer real cures for injuries where we currently only have the the option to treat symptoms. Activating these building blocks of development could one day restore function to the injured brain.