1. Introduction
NAFLD, NASH, metabolic dysfunction
NONALCOHOLIC FATTY LIVER DISEASE, NONALCOHOLIC STEATOHEPATITIS (NASH), LIVER FIBROSIS, CHRONIC LIVER DISEASE
Background and Aims: Exercise remains a key component of nonalcoholic fatty liver disease (NAFLD) treatment. However, mechanisms underpinning the improvements in NAFLD seen with exercise are unclear. Exercise improved liver fat and serum biomarkers of liver fibrosis in the NASHFit trial. We investigated exercise’s mechanism of benefit by conducting a post hoc analysis of these data to determine the relationship between serum fibroblast growth factor (FGF) 21, which is implicated in NAFLD development, and exercise. Methods: In the 20 wk NASHFit trial, patients with nonalcoholic steatohepatitis (NASH) were randomized to receive moderate-intensity aerobic exercise training or standard clinical care. Mediterranean-informed dietary counseling was provided to each group. Change in serum FGF21 was measured after an overnight fast. Results: There was a significant improvement in serum FGF21 with exercise training compared to standard clinical care (Globally, nonalcoholic fatty liver disease (NAFLD) is a leading cause of chronic liver disease and affects between 25% and 30% of the world population [In the absence of a regulatory-agency-approved drug therapy, lifestyle modification through dietary change and increased physical activity remain the most effective treatment for NAFLD and NASH [Fibroblast growth factor (FGF) 21 is a hepatokine that regulates carbohydrate, lipid, and energy metabolism [Exercise training may also impact the FGF21–adiponectin axis, where an elevation in this ratio is observed in patients with NAFLD and indicative of metabolic dysfunction. In fact, FGF21/adiponectin ratio has been proposed as a NAFLD biomarker [In the NASHFit trial, aerobic exercise training was shown to improve liver fat, serum biomarkers of liver fibrosis, as well as cardiorespiratory fitness [