Can GLP-1 mimic drugs improve liver health in patients with diabetes?

This review looked at whether medications similar to the GLP-1 hormone can improve liver health for people with type 2 diabetes (T2D) and fatty liver disease. It found that these medications can improve liver health and reduce fat in the liver.

As many as 60% of people with T2D also develop non-alcoholic fatty liver disease (NAFLD). This condition involves an excessive build-up of fat stores within the liver. Over time, the liver can become inflamed and develop scar tissue (cirrhosis). NAFLD reduces the liver’s ability to function normally. NAFLD is connected to both obesity and T2D.

T2D involves resistance to the hormone insulin. Insulin resistance can increase free fatty acids, cholesterol, and other lipids (oily compounds) in the blood. The liver is responsible for clearing these lipids. However, the liver stores these fatty acids as triglycerides (fat). So insulin resistance can contribute to NAFLD.

Diets high in the sugar fructose can also contribute to NAFLD. Unlike glucose, fructose is broken down by the liver. Fructose is commonly found in fruit, honey, and many root vegetables.

GLP-1 receptor agonists (GLP-1-RAs) are a group of medications including exenatide (Byetta) and liraglutide (Victoza). These medications are similar to glucagon-like peptide 1 (GLP-1), which the gut releases after eating. Like the natural hormone, GLP-1-RAs reduce appetite and aid the pancreas in releasing insulin. GLP-1-RAs can reduce body weight. Additionally, GLP-1 may improve blood lipid levels. It is not clear whether GLP-1-RAs can improve liver health for people with NAFLD and T2D.

This review used data from 8 studies with 1,454 patients with both T2D and NAFLD. 

The amount of fat in the liver was measured using ultrasound and magnetic resonance imaging (MRI). Medications similar to GLP-1 significantly reduced fat in the liver. High alanine aminotransferase (ALT) in the blood can indicate damage to the liver. GLP-1-RAs significantly improved ALT tests of liver function.

GLP-1-RAs improved waist circumference and the amount of abdominal fat. Fat in the abdomen is connected to T2D, NAFLD, and heart disease. These medications also improved blood glucose control.

People using GLP-1-RAs had less inflammation of fatty tissue. This was measured by the amount of adiponectin, a protein in fatty tissue. GLP-1-RAs improved inflammation more than other medications including insulin, metformin (Glucophage), or gliptins such as linagliptin (Tradjenta). 

This review found that GLP-1-RAs improved liver health for people with T2D and NAFLD.

There are several treatment options for T2D and NAFLD. Other studies have found that SGLT2 inhibitors, such as empagliflozin (Jardiance), may also reduce fat in the liver.