Brain tissue study sheds light on how exercise can fight dementia
A new post-mortem brain tissue study is offering clues as to how exercise in old age can improve brain health and prevent cognitive decline. The research found late-life physical activity was associated with higher levels of presynaptic proteins, molecules previously found to support healthy brain functions.
It is, of course, no newsflash to suggest exercise can help keep your brain healthy. For years scientists have consistently found physical activity can improve cognitive function, particularly in elderly subjects experiencing the early stages of Alzheimer’s and dementia.
But exactly how exercise can improve brain health and prevent cognitive decline is still a bit of a mystery. Several animal studies have pointed to certain mechanisms that may be playing a role but validating those findings in humans can prove challenging.
This new research focused on a collection of proteins known to play a role in maintaining healthy synaptic functions. A study published last year reported a correlation between high levels of these presynaptic proteins and reduced accumulations of toxic proteins associated with neurodegeneration and cognitive decline.
The prior study tracked levels of these presynaptic proteins in spinal fluid from living elderly subjects and in post-mortem brain tissue samples. The new research set out to investigate whether physical activity could be linked to presynaptic protein levels in the brain.
Over 400 brain tissue samples were analyzed. The tissue samples came from the Rush Memory and Aging Project, a long-term brain health study tracking the health of elderly subjects in their final years.
The findings reveal a significant correlation between physical activity in late-life and increased levels of presynaptic proteins. Kaitlin Casaletto, a neuropsychologist working on both studies, says the findings validate the hypothesis that maintaining synaptic health in one’s senior years may be key to staving off age-related dementia.
“In older adults with higher levels of the proteins associated with synaptic integrity, this cascade of neurotoxicity that leads to Alzheimer’s disease appears to be attenuated,” says Casaletto. “Taken together, these two studies show the potential importance of maintaining synaptic health to support the brain against Alzheimer’s disease.”
William Honer, from the University of British Columbia and senior author on the new study, has previously found high levels of presynaptic proteins in post-mortem brain tissue to correlate with strong cognitive function in later life. In this study Honer was surprised to find physical activity linked to a broad spread of these beneficial proteins across the entire brain, and not just in the hippocampus, a brain region commonly considered the center of memory function.
“It may be that physical activity exerts a global sustaining effect, supporting and stimulating healthy function of proteins that facilitate synaptic transmission throughout the brain,” says Honer.
Ultimately, this new study offers just one small piece in a larger puzzle as researchers develop ways to maintain cognitive health in later life. Casaletto says these findings indicate improving synaptic functioning through physical exercise may be one way to help stave off age-related dementia.
“Our work is the first that uses human data to show that synaptic protein regulation is related to physical activity and may drive the beneficial cognitive outcomes we see,” says Casaletto. “Maintaining the integrity of these connections between neurons may be vital to fending off dementia, since the synapse is really the site where cognition happens. Physical activity – a readily available tool – may help boost this synaptic functioning.”
The new study was published in the journal Alzheimer’s & Dementia.