Weight loss surgery alters fatty liver disease genes

Research has shown that weight loss surgery can benefit obese individuals in ways that go beyond shedding pounds, for example by causing early remission of type 2 diabetes. Now scientists have found that the surgery can also reverse the symptoms of fatty liver disease. The findings, which are to be published online on August 6 in the Cell Press journal Cell Metabolism, are derived from research on liver samples in normal and obese patients—some with fatty liver disease and some without fatty liver disease. The results provide another example of the DNA-altering effects of weight loss surgery.

Nonalcoholic (NAFLD)—which includes a spectrum of liver disorders in people with obesity and type 2 diabetes—is the most common chronic liver disorder in industrialized countries. NAFLD has emerged as one of the dominant types of liver disease worldwide and effects one in three Americans.

In an experimental tour de force, researchers analyzed liver samples from 27 obese individuals with different stages of NAFLD, 18 healthy obese individuals without liver disease, and 18 normal-weight individuals without liver disease. Methylation—a chemical modification on DNA that regulates gene expression—was altered on various genes in patients with NAFLD. The expression levels of nine of these genes—which code for key enzymes involved in metabolism and insulin signaling—were also different from those seen in healthy individuals. Furthermore, binding sites for proteins that affect gene expression were enriched in the liver disease patients' genes.

Dr. Joseph Hampe and his colleagues also found that when they compared patients' before and after weight loss surgery, the NAFLD-associated methylation changes were partially reversible. The findings demonstrate that changes the chemical properties of DNA, thereby affecting gene expression.

"These DNA modifications may point to the first steps in the evolution of the disease and may thus direct future research," says senior author Dr. Hampe of University Hospital Dresden, Germany. "In the very long term, they may lead to new therapeutic options."

More information: Cell Metabolism, Ahrens et al.: "DNA methylation analysis in non-alcoholic fatty liver disease suggests distinct disease-specific and remodelling signatures after bariatric surgery." dx.doi.org/10.1016/j.cmet.2013.07.004

Related Stories

NAFLD increases the risk of early atherosclerotic lesions

Apr 26, 2013

A study presented today at the International Liver Congress 2013 – which evaluated the relationship between non-alcoholic fatty liver disease (NAFLD), early predictors of atherosclerosis and the 10-year Framingham risk ...

Discovery of gene involved in fatty liver disease

Apr 24, 2013

An international research consortium led by CIC bioGUNE has discovered the involvement of a gene in the development of non-alcoholic fatty liver disease (NAFLD). Although the gene concerned (SLC2A1) had never previously been ...

Recommended for you

Malaysia reports first Asian death from MERS virus

5 hours ago

A Malaysian man who went on a pilgrimage to Saudi Arabia has become the first death in Asia from Middle East respiratory syndrome, while the Philippines has isolated a health worker who tested positive for the deadly coronavirus.

Philippines quarantines man over MERS fears

5 hours ago

Philippine health authorities said Wednesday they have quarantined a Filipino who arrived from the Middle East because he tested positive for the deadly MERS virus.

User comments