Cholesterol levels regulated by gut bacteria
24 February 2013
The metabolism of cholesterol in the human body is regulated by
bacteria in the small intestine, according to research at the
Sahlgrenska Academy, University of Gothenburg, Sweden. These
findings may be important for the development of new drugs for
It is well established that cholesterol is the major risk factor
for cardiovascular disease. Cholesterol, which is mainly synthesized
in the body but also obtained from dietary sources, is converted to
bile acids in the liver, which are then secreted into the intestine
and either removed from the body or recycled back to the liver.
The influence of gut bacteria on human health and disease is a
rapidly expanding research area. The research group at Sahlgrenska
Academy is a leader in this field and is investigating how gut
bacteria are linked to lifestyle diseases such as obesity, diabetes
and cardiovascular disease.
In a study published in the journal Cell Metabolism, the
group show that gut bacteria reduce bile acid synthesis in the liver
by signalling through a specific protein, known as the FXR receptor,
in the small intestine.
"Drugs that reduce cholesterol levels have, in recent years,
greatly reduced deaths from cardiovascular disease. Our study is a
step forward because we have shown how gut bacteria regulate the
formation of bile acids from cholesterol," says Sama Sayin, medical
doctor and PhD student at the Sahlgrenska Academy, and the study's
The FXR receptor not only affects cholesterol metabolism but is
also involved in the body's sugar and fat metabolism.
‘If future research can identify the specific bacteria that
affect FXR signaling in the gut, this could lead to new ways to
treat diabetes and cardiovascular disease’, says Fredrik Bäckhed,
professor at the Sahlgrenska Academy, who led the study.
The article ‘Gut microbiota regulates bile acid metabolism by
reducing the levels of tauro-betamuricholic acid, a naturally
occurring FXR antagonist’ is published in Cell Metabolism on
February 5. The study is a collaboration with researchers from VTT
in Finland, the Karolinska Institute and AstraZeneca in Mölndal.
Sayin S et al. Gut Microbiota Regulates Bile Acid
Metabolism by Reducing the Levels of Tauro-beta-muricholic Acid, a
Naturally Occurring FXR Antagonist. Cell Metabolism Volume 17, Issue
2, 225-235, 5 February 2013.