Research conducted by the Medical Centre of Georgia, Georgia Regents University, has shown how regular exercise can have a impactful effect on the reversal of cognitive impairment as a result of conditions such as diabetes and obesity.
The work was published in the scientific journal The Journal of Neuroscience.
Previous research has enlightened scientists to the effects of these conditions on the brain, showing that diabetes, for example, has been linked to increasing the incidence of Alzheimer’s, with some members of the scientific community labeling the neurodegenerative condition “type three diabetes.”
The research team was tasked to investigate what effect fat, as well as the diabetes-related inflammation of the hippocampus, had on the reduced cognitive ability.
The tests involved genetically manipulated mice that were bred to include genes that typically express increased fat deposition and diabetes.
The researchers discovered a surprising immune reaction as a result: the mice showed high levels of inflammatory cytokines, tiny proteins responsible in cell signaling, that often alert the immune system of potential pathogens, allowing the body to mount an appropriate and targeted response.
These results lead the team to believe that these cytokines actually view excess adipose tissue as an external pathogen, explaining the high levels found in the tests.
Speaking to the news release of their findings on Eureka Alert!, Dr. Alexis Strachan, who worked on the study, explained that “These obese diabetic mice have very high levels of inflammatory cytokines and I think it’s because their bodies are reacting to the invasion of fat into tissues […]”.
These cytokines thus view fat as a chronic and long term condition, resulting in the levels of interleukin-1 beta, produced by the cytokines, and inflammation to remain high for a long period of time.
As a result, the obese mice showed reductions in the efficacy of the blood-brain barrier, which usually protects the organ, making it more susceptible to the compound interleukin-1 beta.
Inside the brain, interleukin-1 beta has an interesting effect on the microglial cells of the brain. These cells typically support the brain and central nervous system, helping clear pathogens and form the primary active immune defence mechanism of these organs.
However, in the presence of interleukin-1 beta, these immune cells become “predatory,” according to the press release, making the normally helpful microglial cells begin to eat away at the synapses between neurons, causing a breakdown in communications.
The scientists however were able to reverse the effects by making their murine test subjects hit the gym.
After being placed on a treadmill and running between five and ten kilometers per week over a period of three months, the mice began showing significant decreases in interleukin-1 beta levels. A similar result was concluded once 15-20% of their weight was surgically removed.
Dr. Stranhan was keen to suggest that exercise was the best method in order to improve cognitive ability; however, he did concede that surgical removal of fat could be a viable and important option in individuals that finding moving complicated, particularly the elderly.
The next step for the researchers is to assess the effects in diet-induced obesity rather than genetically enhanced obesity as seen in the experiment, as this would correlate much more closely to the human model being currently observed in the modern world.
What other studies would you like to see exercise and brain function investigated, for example the correlation between regular sports and test result scores in teenagers?