Study could lead to injections that replicate brain benefits of exercise

‘It could help the very elderly or someone who has had a brain injury or stroke to improve cognition’

Scientists have found that an injection of molecules derived from blood can replicate the benefits of exercise in mice brains, an advance that may lead to new treatments for improving cognition in Alzheimer’s disease patients.

The study, published recently in the journal Nature Communications, discovered that platelets, the tiny cells behind blood clotting, secrete a protein that rejuvenates nerve cells in aged mice in a similar way to physical exercise.

“We know exercise increases the production of new neurons in the hippocampus, the part of the brain important for learning and memory, but the mechanism hasn’t been clear,” study co-author Odette Leiter from the University of Queensland in Australia said.

“Our previous research has shown platelets are involved, but this study shows platelets are actually required for this effect in the aged mice,” Dr Leiter said.

In the study, scientists focussed on the biological compounds exerkines released into the bloodstream during exercise and believed to stimulate exercise-induced response in the brain.

They found that the molecule exerkine CXCL4/Platelet factor 4 or PF4 released from platelets after exercise results in regenerative and cognitive improvements when injected into aged mice.

“We show that platelets are activated by exercise and are required for the exercise-induced increase in hippocampal precursor cell proliferation in aged mice,” scientists wrote in the study.

Researchers believe the new findings can have “significant implications” for the development of drug interventions for age-related cognitive decline such as seen in conditions like Alzheimer’s disease.

“For a lot of people with health conditions, mobility issues or of advanced age, exercise isn’t possible, so pharmacological intervention is an important area of research,” Tara Walker, another author of the study, said.

“We can now target platelets to promote neurogenesis, enhance cognition and counteract age-related cognitive decline,” Dr Walker said.

In the next step, scientists hope to test the response in Alzheimer diseased mice, before moving towards human trials.

Scientists however caution that any future therapeutic developed based on the study may not be a replacement for exercise.

“But it could help the very elderly or someone who has had a brain injury or stroke to improve cognition,” Dr Walker said.

“Together, these findings highlight the role of platelets in mediating the rejuvenating effects of exercise during physiological brain ageing,” researchers added.