Cholesterol levels in the bloodstream are not regulated solely by what we eat and by the production of this substance in the liver. According to research published in the journal Nature Neuroscience , the real person responsible for controlling the amount of cholesterol in the blood is a hormone called ghrelin , which regulates hunger in the brain.
The finding, say the authors of the research, from the University of Cincinnati (USA), could lead to the development of new drugs targeting this hormone to control cholesterol levels.
Cholesterol is a fatty substance that occurs naturally and is necessary for the body. However, in excess it can lead to atherosclerosis , the accumulation of deposits in the arteries, and increase the risk of cardiovascular diseases, such as heart attack and stroke. In humans two types of cholesterol are distinguished: low-density lipoprotein or LDL (“bad” cholesterol because it is responsible for the accumulation of plaques in the arteries) and high-density lipoprotein or HDL .
Remote cholesterol monitoring
“For a long time we have long thought that cholesterol is exclusively regulated by the absorption of food or the synthesis and secretion carried out by the liver”, says Professor Matthias Tschop, co-author of the work. “Our study shows for the first time that cholesterol is also ‘remotely controlled’ by specific neural circuits in the central nervous system ,” he adds.
It is known that the ghrelin hormone is responsible for inhibiting a receptor in the hypothalamus, called MC4R , which is very important for the regulation of food consumption and caloric energy expenditure. In their tests with mice, the researchers found that an increase in ghrelin levels caused the animals to develop high levels of cholesterol in the blood due to a reduction in the absorption of cholesterol in the liver. To test the relationship, the scientists studied mice that had the MC4R receptor deleted or blocked in the nervous system. The experiment showed an increase in cholesterol levels, suggesting that MC4R is the central element in this “remote control” of cholesterol.
While these findings have yet to be confirmed in humans, they could potentially lead to a new way of treating high cholesterol.
