Metabolic associated fatty liver disease (MAFLD) is the most prevalent chronic liver disease worldwide. It is recognized as the liver disease component of metabolic syndrome, which is mainly related to insulin resistance and genetic susceptibility.
In the absence of approved pharmacological therapies, lifestyle interventions are the key to treatment of MAFLD, with current guidelines recommending a weight loss of 7–10% to achieve optimum benefit. Exercise is known to be beneficial for the treatment and prevention of many chronic inflammatory diseases such as cancer, type 2 diabetes, arthritis, and cardiovascular disease. Yet, the role exercise plays in the treatment of MAFLD remains unclear.
Researchers from Trinity College Dublin sought to determine exercise’s impact on MAFLD improvement and found that fitness may be a more important clinical endpoint than weight loss.
The findings have been published in Alimentary Pharmacology and Therapeutics in a paper entitled, “Improvement in histological endpoints of MAFLD following a 12‐week aerobic exercise intervention.”
The researchers sought to determine the effects of 12 weeks of moderate‐to‐vigorous intensity aerobic exercise, without prescribed dietary modifications, on histological endpoints of MAFLD.
“Lifestyle interventions are the primary treatment for metabolic (dysfunction) associated fatty liver disease (MAFLD). However, the histological and cardiometabolic effects of aerobic exercise in MAFLD remain unclear,” noted the researchers.
The Trinity study is the first to demonstrate significant improvements in biopsy-measured liver outcomes in a MAFLD cohort following an exercise-only intervention, without clinically significant weight loss. Improvements in biopsy-measured liver outcomes were significantly related to improvements in fitness levels. However, the study found that when patients were followed up longitudinally, none of the benefits of the exercise intervention were sustained.
Only two previous studies have been conducted using repeat biopsies in exercise-only trials, but these studies had significant methodological limitations. These studies used low-intensity resistance exercise and lacked exercise supervision, which may have led to non-significant changes on liver biopsy outcomes.
The main findings were: 12 weeks of aerobic exercise produced significant histological improvements in hepatic fibrosis and hepatocyte ballooning; 12 weeks of aerobic exercise significantly improved estimated cardiorespiratory fitness, markers of central obesity and fat mass, without the prescribed weight loss target of 7‐10%.
Philip O’Gorman, PhD, department of physiotherapy, Trinity College, and lead author of the study explained: “The benefits of exercise training on both liver and cardiometabolic outcomes for these patients are very clear. Our findings suggest that there is an urgent need to better transition exercise into the community setting for these patients as the benefits of exercise intervention were not sustained longitudinally.”
Gorman also noted that results have shown that there is an urgent unmet need to enable patients to continually engage in exercise therapy in the community setting. A systems-based approach where clinicians can refer patients to exercise specialists is required for long-term benefits of exercise to be sustained.