How obesity impairs mental capacity

April 24, 2019

How obesity impairs mental capacity
Being overweight is not only a problem with metabolism, with the heart and vessels, it is also a problem with the brain. It is known that people with obesity deteriorate mental abilities, and with age they are more likely to develop dementia and other disorders associated with the brain.

There are many medical works devoted to the relationship of overweight and weakening of cognitive functions, but only in recent years, researchers have begun to understand exactly how obesity harms the brain.

Experiments on animals have shown that microglia need to blame for this; they need microglial cells that perform immune functions in the brain, protecting nerve tissue from infections and clearing it from unnecessary and dangerous molecular cell debris.

It turned out that in obesity, microglial cells eat up on the neurons the so-called dendritic spines - special protrusions on the cell membrane, where the dendritic process is ready to form a connection-synapse with another neuron. In other words, microglia reduces the number of potential interneuronal contacts, and, consequently, the number of potential neural chains. And as we know, cognitive functions - memory, ability to learn, etc. - directly depend on the ability of nerve cells to form synapses.

Researchers at Princeton University have demonstrated that if you prohibit microglia from biting outgrowths on dendrites, it helps to improve cognitive functions, despite being obese. Elise Cope (Elise Cope) and her colleagues suppressed the activity of microglial cells in different ways: either with special substances or with the help of genetic modification, when the gene encoding the receptor was turned off in microglia cells, through which microglia looked for dendrites for feeding.

And, as stated in an article in the Journal of Neuroscience, mice with obesity, with which all this was done, normally passed tests for memory, then like fat mice, in which microglia were not suppressed, memory deteriorated. The authors of the work emphasize that microglia harmed the brain, regardless of what kind of food a mouse was fat - overweight itself was important. Obviously, some peculiarities of metabolism in an obese organism cause microglial cells to show unnecessary activity, and in the future it is necessary to understand what exactly irritates microglia during obesity.

In general, microglia cells, when something starts to go wrong with them, can cause a lot of trouble. We once wrote that Alzheimer's disease develops with the connivance of microglia, and a year ago Cell Metabolism published an article stating that microglial cells themselves can be one of the causes of obesity, forcing more to eat.

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