High Fat Diet Could Lead to Liver Damage

A high fat diet in mice may cause a fatty liver according to new research published in November's issue of Hepatology. It is believed that high fat in a diet could kill the T cells in the fatty liver, exaserbating a simple fatty liver (steatosis) into a more threatening fatty liver with inflammation (steatohepatitis).

Although researchers know that nonalcoholic fatty liver disease can progress and vary in intensity, the actual progression of the disease is not fully known. Current knowledge suggests that two conditions must be present for it to develop: excess fat in the diet and general overeating and inflammation or stress related to T cells in the organ.

Even though a fatty liver is often associated with excessive alcohol consumption, for this study researchers focused on those fatty livers caused by metabolic syndromes such as diabetes, hypertension, and dyslipidemia. There have been multiple known causes, ranging from drugs, nutritional deficiencies, and even HIV. For nonalcoholic fatty liver disease, symptoms vary from hepatic steatosis to cirrhosis of the organ, which can be fatal.

The study focused on the specific T cells that regulate the organ called tregs. It is believed that when these T cells cease to regulate as efficiently it can leave the liver open to even more damage if the organ is exposed to another risk factor.

For the mice in the study, obesity was induced through a high fat diet. The high fat diet caused steotosis and insulin resistance, similar side affects of obesity and a high fat diet in humans. Then the mice were injected with a substance to cause inflammation. A control group of mice were fed a normal diet with the correct levels of fat, but also received injections to cause inflammation.

The livers of the mice were then examined for the levels of T cells present. The researchers found that the level of T cells decreased, leaving the organ open to other sources of inflammation. For mice with a high fat diet, the damage to the liver was much more severe. The high fat diet mice also had T cells that were half the level of the other group of mice.

Interestingly enough, the T cells in the liver increased once the mice were taken off the high fat nutrition and fed a normal diet. This emphasizes the fact the effects of a high fat diet on the liver may be reversible in the early stages.

SOURCES:

John Wiley & Sons, Inc, "High-fat diet makes mice susceptible to liver injury" Eurekalert