It is not the first time that the focus has been physical activity as a factor that delays or prevents diseases such as Alzheimer’s. But now a team of scientists has gone one step further trying to find out what systemic biomarkers can measure the effects of exercise on brain function and how they can be linked to relevant metabolic responses.
Learning and memory were positively correlated with the change in the levels of a substance that is generated when doing sports
The hypothesis on which the research carried out at the University of Wisconsin-Madison, published under the title ‘Pilot Study on Aerobic Exercise and Cognitive Health (REACH)’ in the journal ‘Frontiers in Endocrinology’, is that three specific biomarkers, involved in learning and memory, would increase in older adults after exercise training and would be correlated with cognition and metabolomic markers of brain health.
To address this question, Dr. Henriette van Praag, from the Florida Atlantic University Charles E. Schmidt School of Medicine, and Dr. Ozioma Okonkwo, from the Wisconsin Alzheimer’s Disease Research Center and the Department of Medicine of the University of Wisconsin-Madison, and colleagues examined these three biomarkers: myokine cathepsin B (CTSB), a substance that is secreted from the muscle into the circulation after exercise; brain-derived neurotrophic factor (BDNF), which is a key protein in enhancing synaptic connections in the brain, and the klotho, a hormone that slows down aging.
The researchers performed a metabolomic analysis on blood samples from 23 adults asymptomatic late-middle-aged patients with familial and genetic risk of Alzheimer’s. The mean age of the sample was 65 years and 50% were women.
The participants were divided into two groups: one who did habitual physical activity (UPA) and another who did improved physical activity (EPA). The EPA group underwent 26 weeks of supervised treadmill training. Blood samples were taken for both groups at the start of the study and after 26 weeks.
The results yielded a clue. There was a positive association between the CTSB (which was the substance that is produced after exercising), cognition and substantial modulation of lipid metabolites involved in the dementia. This supports the hypothesis of the beneficial effects of exercise training on brain function and brain health in asymptomatic individuals at risk of Alzheimer’s disease.
Plasma CTSB levels increased after this 26-week structured aerobic exercise training in older adults at risk for this condition. Verbal learning and memory were positively correlated with the change in the levels of this substance, but it was not related to the levels of the protein BDNF or the hormone klotho. Therefore, the authors believe that CTSB may be useful as a marker to know the cognitive changes that occur in hippocampal function after exercising in people at risk of dementia.
The researchers also highlighted that multiple lipid metabolites relevant to Alzheimer’s were modified by exercise in a way that may be neuroprotective. Although the serum klotho did not change, was associated with cardiorespiratory fitness.
“Human studies often use expensive, low-throughput brain imaging and are impractical for large population studies. Systemic biomarkers that can measure the effect of exercise interventions on Alzheimer’s-related outcomes quickly and at low cost they could be used to inform disease progression and to develop new therapeutic targets, “added Van Praag.