2023-05-17 17:24:03
A team of Garvan Institute of Medical Investigation has discovered a group of brain cells that stimulates appetite when there is a prolonged excess of energy in the body, such as the excessive accumulation of fat in obesity.
The researchers found that these cells not only produced the appetite-stimulating molecule NPY, but also made the brain more sensitive to the molecule, further stimulating the appetiteo.
“These cells trigger changes in the brain that make it more sensitive even at low NPY levels when there is a surplus of energy in the body in the form of excess fat, which drives appetite during obesity,” explains Herbert Herzog. , lead author of the study.
“Our study addresses a long-standing question of how appetite is controlled in obesity and may take the development of therapies in a new direction.”
The research has been published in the journal «Cell Metabolism».
Obesity is a major public health problem and a disease that affects more than one in 10 adults and increases a person’s risk of developing other chronic conditions, such as diabetes or heart disease. Although there are many factors that can influence the development of obesity – excessive accumulation of adipose tissue in the body – eating patterns and levels of physical activity are key factors.
“Our brain has intricate mechanisms that detect the amount of energy stored in our body and adjust our appetite accordingly. One way to do this is through the NPY molecule, which the brain naturally produces in response to stressful situations, such as hunger, to stimulate eating,” explains Herzog.
“When the energy we consume is less than what we expend, the brain produces higher levels of NPY. When we take in more energy than we expend, NPY levels drop and we feel less hungry. However, when there is a prolonged energy surplus, such as excess body fat in obesity, NPY continues to stimulate appetite even at low levels. We wanted to understand why.”
In mouse models of obesity, the researchers investigated the brain cells called neurons that produce NPY and found that, surprisingly, 15% of them were different: they did not turn off NPY production during obesity.
When there is a prolonged energy surplus, such as excess body fat in obesity, NPY continues to stimulate appetite even at low levels.
“We found that, under conditions of obesity, appetite was driven primarily by NPY produced by this subset of neurons. These cells not only produced NPY, but also sensitized other parts of the brain to produce additional receptorsThey are “docking stations” for the molecule.
“When the energy we consume is less than what we expend, our brain produces higher levels of NPY. When our energy intake exceeds our energy output, NPY levels drop and we feel less hungry. However, when there is a prolonged energy surplus, such as excess body fat in obesity, NPY continues to stimulate appetite even at low levels. We wanted to understand why.”
In mouse models of obesity, the researchers investigated the brain cells called neurons that produce NPY and found that, surprisingly, 15% of them were different: they did not turn off NPY production during obesity.
What we have discovered is a vicious cycle that alters the body’s ability to balance its energy intake with energy storage.
“We found that, under conditions of obesity, appetite was driven primarily by NPY produced by this subset of neurons. These cells not only produced NPY, but also sensitized other parts of the brain to produce additional receptors or ‘docking stations’ for the molecule, further increasing appetite,” says Professor Herzog.
“What we have discovered is a vicious cycle that alters the body’s ability to balance its energy intake with energy storage and favors the development of obesity.”
“Our brain is programmed to resist lack of energy or weight loss, since it sees it as a threat to our survival and sets in motion mechanisms that increase our appetite so that we look for food. As we have now discovered, this occurs even when we have excess energy stored in the body,” explains Professor Herzog.
The researchers say their discovery opens up the possibility of blocking additional, more sensitized NPY receptors as a new approach to developing anti-obesity drugs.
‘Our discovery helps us better understand the brain mechanisms that interfere with balanced energy metabolism and how they can be acted upon to improve health,’ says Professor Herzog.
#brain #cells #direct #appetite #obesity