Therapy to mend parts of the brain damaged by strokes has moved a step closer, thanks to research at Monash University’s Australian Regenerative Medicine Institute (ARMI) and the Florey Neuroscience Institutes (FNI).
Scientists, James Bourne and Jihane Homman-Ludiye, of ARMI, and Tobias Merson, of FNI, have discovered precursor cells in the visual processing region of the brains of young marmoset monkeys which can form new brain cells in a culture dish.
The work, published recently in the journal, PLoS One, raises the possibility of new therapies for victims of brain injuries such as stroke.
Commenting on the work, Stem Cells Australia's Professor Martin Pera said "These results, which point strongly to the existence of stem cells in the primate cortex, have important implications for understanding normal brain function and add to a growing body of evidence that stem or progenitor cells may participate in the repair of injuries to this critical region of the brain."
The team isolated a type of cell from the brain tissue of two-week-old marmoset monkeys, which have similar brains to humans.
They exposed the cells to various combinations of growth factors – proteins that promote cell proliferation – to see if the cells would multiply and form neurons in the culture dish.
Some of the cells started to multiply to form clusters of cells called neurospheres – the forerunners of mature brain cells – when treated with two specific growth factors. This puts them in a class of cells called neural progenitors. Like stem cells, these cells can convert into specialist cells to form various tissues.
It was once thought that our full complement of brain cells was fixed at birth. That view has been toppled in recent decades with the discovery of stem cells in the human brain that can form new neurons in adulthood, said Dr Merson, a neuroscientist.
But until now, those cells have been thought to be limited to two regions of the brain, including the hippocampus, which is involved in memory and learning.
The team’s breakthrough suggests that cells with the ability to form new neurons after birth are much more widespread in the brain. The cells under investigation in this latest research were isolated from the primary visual cortex, the brain structure at the back of the head involved in the processing of stimuli from the eyes. “This structure is very big in humans and other primates and is often affected by brain injury,” Dr Bourne said.
“Our results support the view that this region of the brain has the potential to generate new neurons at later stages than once thought,” Dr Merson said. “We were surprised at how easily we were able to generate the proliferating neurospheres. We were able to propagate them, and keep them in culture for up to a year.”
He said other regions of the brain involved in sensory processing could harbour similar cells.
The scientists plan further research to see if the production of new neurons after birth occurs naturally in the primary visual cortex, and whether the mechanism could be activated after injury.
“It could be plausible to manipulate the progenitor cells to produce more neurons,” Dr Bourne said.