A hormone already valued for its role in appetite suppression and weight loss appears to moonlight as a guardian of the liver, according to new research published in Cell Metabolism by a team at McMaster University. The hormone, GDF15, activates a previously unknown pathway connecting the brain to the liver that suppresses inflammation and slows the buildup of scar tissue, even when body weight and food intake stay unchanged.
The findings matter because millions of people worldwide live with metabolic dysfunction-associated steatohepatitis, or MASH, a severe form of fatty liver disease tied to obesity and diabetes. Newer weight-loss medications have improved outcomes for many patients, but researchers have repeatedly observed that liver inflammation can persist even after substantial weight loss, suggesting the drugs are not addressing every mechanism driving the disease.
A Brain-to-Liver Signal
Senior author Gregory Steinberg said the pathway operates independently of the appetite effects GDF15 is best known for. "GDF15 activates a natural brain-to-liver signaling pathway that helps suppress liver inflammation and reduce fibrosis," he said. First author Dongdong Wang described the cellular effect in more granular terms.
GDF15 helps reprogram liver cells to reduce inflammation and scarring. It shifts immune cells into a more protective and less active state.
Dongdong Wang, first author, McMaster University
According to the McMaster release, the hormone triggers a nervous-system signal that releases glucocorticoids, steroid hormones that dampen liver inflammation and limit fibrosis progression without altering food intake or body weight in the models tested. Rather than treating liver damage as a downstream consequence of obesity, the pathway suggests the liver has its own dedicated hormonal defense system that could, in principle, be targeted directly.
The research was conducted primarily in mouse models, and the authors caution that human studies are needed to confirm whether the same brain-to-liver circuit is strong enough to produce meaningful clinical benefit. The work was funded by Canadian public research agencies, with additional support from Novo Nordisk, a maker of GLP-1 weight-loss drugs with a direct commercial interest in liver-related complications of obesity treatment.