There is a growing body of evidence that suggests skeletal muscle cells secrete proteins into the blood during exercise, which can have a regenerative effect on the brain, according to a National Institutes of Health blog.
An NIH-supported study found that levels of the protein cathespin B rise in the blood of people who exercise regularly. In mice tested in the study, brain cells treated with the protein also exhibited molecular changes associated with the production of new neurons.
The findings, published in Cell Metabolism, are from a team of researchers led by Hyo Youl Moon and Henriette van Praag of NIH’s National Institute on Aging. The researchers found that blood levels of the enzyme rose after the mice ran regularly for two weeks or more, suggesting that running results specifically in production of cathepsin B in muscle and leads to its secretion into the bloodstream.
To see if their findings were also valid in humans, the researchers compared cathepsin B levels in people after four months of regular exercise on a treadmill to those who didn’t exercise. The study, which was conducted in Germany and involved about 40 healthy young adults, showed a significant increase in blood cathepsin B levels with regular fitness training, according to the NIH blog.
The researchers hope to continue learning about how cathepsin B makes its way into the brain and influences the development of new neural connections once there, according to the blog.
“This paper provides a convincing mechanism that involves running-induced increases in a particular protein — cathepsin B — that appears to promote neurogenesis by enhancing expression of a growth factor — BDNF — in the brain,” said neuroscientist Paul Frankland of the University of Toronto, who was not involved in the study, in a June 23 article on The Scientist website. “This is a long chain of events, from exercise to muscle to brain to cognition, but the authors do a great job at demonstrating each of the links.”
Another new study shows that strenuous exercise seems to beneficially change how certain genes work inside the brain, at least in mice, according to a June 15 article in The New York Times.
The study was published in June in the journal eLIFE. Researchers with New York University’s Langone Medical Center and other institutions believe that exercise boosts the body’s production of a substance called brain-derived neurotrophic factor, or BDNF, which is a protein that scientists sometimes refer to as “Miracle-Gro” for the brain, according to the article. BDNF helps neurons to grow and remain vigorous and also strengthens the synapses that connect neurons, allowing the brain to function better. Low levels of BDNF are associated with cognitive decline in both people and animals.
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For more information on exercise is beneficial, check out the continuing education webinar, “Exercise is medicine.”