Rodent of the Week: Secondhand smoke damages liver

The dangers of inhaling secondhand smoke are accumulating. A study published today in the Journal of Hepatology found that long-term exposure to secondhand smoke can cause nonalcoholic fatty liver disease in mice.

Fatty liver disease -- which is an abnormal buildup of fat in the liver -- is a growing problem in the United States. It can be caused by chronic, heavy drinking. But in nonalcoholics, it's most often linked to obesity. The condition can lead to liver dysfunction and is thought to contribute to metabolic syndrome and cardiovascular disease.

Researchers at UC Riverside exposed mice to secondhand cigarette smoke for a year in the lab. They found the smoke affected two key substances that regulate fat metabolism. The smoke inhibited the activity of a kinase (adenosine monophosphate kinase) which then caused an increase of a protein called sterol regulatory element-binding protein that leads to more fatty acid production in the liver.

Identifying these two molecules could give researchers new targets to develop drugs that can reverse fat buildup in the liver, said the lead author of the study, Manuela Martins-Green.

More studies are needed to confirm the relationship between tobacco smoke and liver injury in humans, said Drs. Arian Mallat and Sophie Lotersztajn, in an editorial accompanying the study.

[F]indings from a large survey of U.S. adolescents indicate that passive and active smoke exposure are strong independent predictors of the presence of the metabolic syndrome. These observations indirectly suggest that tobacco use may indeed enhance non-alcoholic fatty liver disease, the hepatic hallmark of the metabolic syndrome.

People with fatty liver disease should stop smoking and avoid secondhand smoke, they said.

-- Shari Roan

Top photo courtesy of Advanced Cell Technology, Inc.

Bottom photo: The top slide shows fatty liver cells in mice exposed to secondhand smoke while the lower image shows the cells of mice exposed to smoke-free air. Credit: UC Riverside.

Comments

[Symposier]

It sounds like a car accident when the pilot suvives with less injuries but his co-driver dies or survives with more complications than the driver. It is very interesting that physicians found that tobacco can also affect the liver. There is more information available for physicians at Symposier site on the consequences of smoking and other medical topics.