Brain regulates cholesterol in blood, study suggests
The amount of cholesterol circulating in the bloodstream is partly regulated by the brain, a study in mice suggests.
It counters assumptions that levels are solely controlled by what we eat and by cholesterol production in the liver.
The US study in Nature Neuroscience found that a hunger hormone in the brain acts as the "remote control" for cholesterol travelling round the body.
Too much cholesterol causes hardened fatty arteries, raising the risk of a heart attack.
The research carried out by a US team at the University of Cincinnati found that increased levels of the hunger hormone ghrelin in mice caused the animals to develop higher levels of blood-circulating cholesterol.
Levels in the blood rise because signals from the brain prompt the liver to store less cholesterol, the researchers said.
It is known that ghrelin inhibits a receptor in the brain in its role in regulating food intake and energy use.
In a separate experiment, they found that blocking this receptor in mice also increased levels of cholesterol in the blood.
The researchers said the finding needs to be replicated in humans but potentially opens up a new way of treating high cholesterol.
Study leader Professor Matthias Tschoep said: "We have long thought that cholesterol is exclusively regulated through dietary absorption or synthesis and secretion by the liver.
"Our study shows for the first time that cholesterol is also under direct 'remote control' by specific neurocircuitry in the central nervous system."
Fotini Rozakeas, cardiac nurse at British Heart Foundation, said: "This interesting study on mice shows for the first time that blood cholesterol levels can be directly controlled by signals transmitted from the brain to the liver where cholesterol is formed.
"This could potentially open up new forms of treatment to control cholesterol levels, which would be great news for people with heart and circulation problems."
She stressed that much more research would be needed before the mechanisms at play were fully understood.
"In the meantime, people should reduce the amount of saturated fat in their diet, take part in regular physical activity and, in some cases, take prescribed medicines such as statins, to keep their cholesterol levels under control."