June 7, 2010
Blood Cholesterol Regulated By The Brain
A US study conducted in mice suggests the amount of cholesterol that circulates through the bloodstream is partially regulated by the brain, which counters previous beliefs that it is solely controlled by what we eat and by cholesterol production in the liver.
The study, carried out by a research team at the University of Cincinnati, found that a hunger hormone called ghrelin in the brain of mice acts as the "remote control" for cholesterol traveling around the body.
The researchers said levels in the blood rise because signals from the brain prompt the liver to store less cholesterol. They find 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 the levels of cholesterol circulating in the blood.
The findings need to be replicated in humans, the researchers said, in order to open up new ways of potentially treating high cholesterol.
We have long thought that cholesterol is exclusively regulated through dietary absorption or synthesis and secretion by the liver," study leader Professor Matthias Tschoep told BBC News.
"Our study shows for the first time that cholesterol is also under direct 'remote control' by specific neurocircuitry in the central nervous system," he 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," Fotini Rozakeas, a cardiac nurse at the British Heart Foundation, told BBC News in an interview.
Rozakeas said the findings could potentially open up new ways of treating and controlling cholesterol levels in humans, which would be great news for people with heart and circulation problems.
Much more research is needed before the mechanisms at play are fully understood, she said.
"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," said Rozakeas.
The sutdy is published in Nature Neuroscience.
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