You knew that in response to a fat-rich diet, immune cells in the brain, and in particular those of the hypothalamus, trigger a process that leads to overweight and obesity?
Research has shown that a cerebral region called the mid-basal hypothalamus (MBH) contains groups of neurons whose task is to match food intake and energy expenditure, but this delicate balance is crushed by a high intake of fat, with Resulting in increased weight, however, it was not possible to identify the mechanisms underlying this phenomenon.
But in this study Suneil Koliwad and colleagues have now discovered that weight gainers are microglia cells, that is, the cellular complex of the immune system present in the brain, whose population expands through fat.
Excess fat leads the microglia cells to trigger an inflammatory response, which in turn is responsible for the failure of MBH to function well. Inflammation then causes recall from the bloodstream of other immune cells that, once in the hypothalamus, become microglia cells, aggravating inflammation and reflecting the imbalance between food intake and energy expenditure in a cycle difficult to arrest.
The researchers also found that the administration to the mice of an experimental drug
Able to block inflammation at the microglia level was eating less guinea pigs, by 15 percent, gaining less weight by 20 percent than mice not treated with the drug and fed with the same diet.
According to Koliwad, the fact that the microglia has evolved the ability to trigger increased appetite and weight in response to a high-fat diet might have an evolutionary explanation. "Fat is the most concentrated form of calories that human beings from the remote past could consume. When they could get a meal after a long period of fasting, it was important that the microglia signal their presence to the hypothalamus neurons so that these Stimulate the appetite as much as possible ".
In the present world, where there isn't scarcity of fatty foods, this ancient mechanism, which was only rarely activated, became counterproductive: chronic activation of microglia due to continued fat consumption ends up leading to overweight and obesity.