The benefits of exercise can be shared by blood transfer, according to research in mice. Sedentary mice given an injection of plasma from active mice experience more brain cell growth and less inflammation. And a protein that seems to be behind some of the effects could potentially be developed into an 鈥渆xercise mimetic鈥�.
Exercise is good for your body and brain 鈥� we know it can reduce inflammation, lower the risk of various diseases and improve our ability to think and learn. Zurine De Miguel at Stanford University in California and her colleagues wondered if exercise might exert these benefits through factors in the blood.
To find out, the team compared mice that were able to exercise with a running wheel with a separate group of mice that weren鈥檛 able to exercise. After 28 days, the mice that were free to exercise had more new brain cells than the sedentary mice.
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The team then took blood plasma from the mice that had exercised and injected it into a group of sedentary mice. Another group of sedentary mice were injected with plasma from equally sedentary mice.
An injection of 鈥渞unner plasma鈥� seemed to confer some of the benefits of exercise to the sedentary mice. These mice had significant increases in the number of new brain cells, for example. They also performed better in tests of learning and memory than mice that were given 鈥渃ontrol plasma鈥� from other sedentary mice.
Reduces inflammation
Something in runner plasma appears to change the way genes work. The team found 1974 genes that were affected in the mice depending on which blood plasma they were given. This appears to alter the level of proteins in a way that reduces inflammation in the body and brain.
鈥淚 love the idea personally, because I鈥檝e always hated running, and now I can get somebody to do it for me,鈥� jokes Richard Faragher at the University of Brighton, UK, who wasn鈥檛 involved in the study.
One protein seems to be especially beneficial. When clusterin was removed from the runner plasma, the benefits were reduced. And when the team looked at clusterin levels in a group of 20 people with a form of mild cognitive impairment known as who were put on an exercise programme, they found that clusterin levels increased with exercise. In these individuals, the level of clusterin in their blood correlated with their endurance.
Could clusterin be used to develop an 鈥渆xercise-in-a-pill鈥� treatment? 鈥淭hat might be hoping for too much,鈥� says Faragher. It鈥檚 unlikely that all the myriad effects of exercise could be replicated with a single protein, he says.
Lorna Harries at the University of Exeter, UK, agrees. When you exercise, you have more muscle to take up glucose, less fat, and less insulin resistance 鈥� all of which contribute to better health and potentially longer life. And clusterin might be exerting its effects via other proteins, she says.
But a treatment based on clusterin might still provide benefits for people who aren鈥檛 able to exercise, Faragher says. 鈥淚magine, for example, you are an older person with crippling arthritis,鈥� he says. 鈥淭here, an exercise mimetic might be very useful.鈥�
bioRxiv
