For example, the phosphodiesterase-4 inhibitor ASP9831 lowered alanine transaminase (ALT) levels, necroinflammation and fibrosis in both an acute hepatitis model and a methionine and choline deficient (MCD) diet NASH model, by selectively inhibiting activated macrophages and Kupffer cells. Here, GPT is linked to metabolic dysfunction-associated steatohepatitis.