(CN) — Memory improvements in older mice injected with the cerebrospinal fluid of young mice show the potential rejuvenating properties of the stuff for the aging brain, according to a study published Wednesday in the journal Nature.
The study could shed light on potential treatments to slow brain aging and decrease the risk of dementia and neurodegenerative disease.
Cerebrospinal fluid, or CSF, is part of the immediate environment of the brain — providing brain cells with nourishing compounds including nutrients, signaling molecules and growth factors — but its role in brain aging is not well understood.
Its protein composition changes with human aging, marked by an increase in inflammatory proteins and a decrease in growth factors. Whether those changes in CSF contribute to age-related cognitive decline is unknown.
Tony Wyss-Coray of the department of neurology and neurological sciences at Stanford University’s School of Medicine and his international colleagues tested the potential rejuvenating properties of CSF by taking the fluid from 10-week-old mice and putting it into the brains of 18-month-old mice.
The treatment improved memory function of the older animals, according to the study.
“This strengthens the notion that studying CSF, the medium that has adapted to the unique needs of the brain, holds the potential to expand understanding of the brain’s intricate mechanisms and cellular interactions,” the researchers wrote.
“Our results suggest that targeting hippocampal myelination through factors present in young CSF might be a therapeutic strategy to prevent or rescue cognitive decline associated with ageing and neurodegenerative diseases.”
Young CSF is shown to increase the stimulation of the largest population of stem cells in the aged brain called oligodendrocyte precursor cells — which have the potential to regenerate brain cells known as oligodendrocytes — as well as myelin, a fatty material that protects nerve cells, within the hippocampus memory center of the brain.
The study authors looked at signaling pathways activated by young CSF to determine the mechanisms underlying the effects on memory function.
They found a transcription factor known as SRF brings about the effects of young CSF on the oligodendrocyte precursor cells. Expression of that factor is shown to decrease in the hippocampus of older mice, according to the study.
Expression of a growth factor known as Fgf17, which is also shown to decrease in older mice, could induce SRF signaling. The growth factor was found to be a potential rejuvenating factor for the aging brain.
Infusion of the growth factor into older mice reproduces the effects seen with infusion of young CSF, according to the researchers, including oligodendrocyte precursor cell proliferation and improving memory function.
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