The obesity epidemic has hit the liver. About 20% to 30% of Americans have excess fat in the liver, and the problem is widespread throughout the world. The fat accumulation is often benign, but it can progress to a condition called nonalcoholic steatohepatitis, or NASH, that features inflammation and swollen cells. NASH often leads to fibrosis, or scarring that can result in cirrhosis, liver failure and death. Why some people with excess fat in their livers develop NASH remains uncertain, but researchers and doctors are optimistic because more than 20 potential NASH treatments are under development or in testing. Two large clinical trials of possible NASH drugs are due to start this year. In a previous clinical trial, one of the treatments, obeticholic acid, reduced the amount of fibrosis, a first for a liver drug.

To read the full story, see the 3 July issue of Science.