Aerobic exercise could have the final say on fatty livers

July 29, 2020

Science Daily/Trinity College Dublin

A new study from Trinity College Dublin highlights that fitness may be a more important clinical endpoint for improvement in patients with fatty liver diseases during exercise trials, rather than weight loss. The findings have been published today (Tuesday, 28th July 2020) in the medical journal Alimentary Pharmacology and Therapeutics.

Metabolic associated fatty liver disease (MAFLD) is a condition characterised by a build up of fat in the liver. The liver is central to a suite of vital processes in the body including digestion, blood clotting and energy production.

If left untreated, MAFLD can lead to serious complications like liver fibrosis (scarring), cirrhosis, liver failure and liver cancer, as well as cardiovascular and metabolic issues. Risk factors for developing MAFLD include type 2 diabetes and obesity. The global estimated prevalence of MAFLD is 25%, making it the leading cause of chronic liver disease worldwide, and is quickly becoming the leading cause of cirrhosis and liver cancer in liver transplant candidates in the western world.

Up to now, due to the lack of approved pharmacological interventions, treatment has been a combination of prescribed weight loss and physical activity, with a weight loss target of 7-10% being the primary treatment endpoint. There is some evidence that exercise training alone without significant weight loss can reduce liver fat content (assessed using non-invasive methodologies such as transient elastography and ultrasound) in MAFLD patients. However, the independent effects of exercise alone on biopsy-measured outcomes (the gold standard for diagnosing and assessing MAFLD) have been unknown.

This new study highlights that increased fitness, the result of aerobic exercise participation, may be a more important clinical endpoint for improvement in MAFLD patients during exercise trials, rather than weight loss.

In Ireland and worldwide, MAFLD is a silent epidemic. In Ireland, there is currently no national screening programme for the disease, so the true prevalence in Ireland is unknown. However, St James's Hospital, Dublin, where the study took place, now has over 1000 patients on their own database, with the numbers growing year on year.

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. The study also demonstrates that improvements in biopsy-measured liver outcomes were significantly related to improvements in fitness levels. The study also found however, that when patients were followed up longitudinally, none of the benefits of the exercise intervention were sustained.

The study is unique in that it used repeat biopsies in MAFLD patients during an exercise-only intervention. 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. This study is also the first to relate improvements on liver biopsies with improvements in fitness, suggesting a potential interrelationship between the two outcomes.

Dr Philip O'Gorman, Department of Physiotherapy, Trinity College said:

"The benefits of exercise training on both liver and cardiometabolic outcomes for these patients is 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. This study clearly demonstrates the clinical benefit of exercise in MAFLD in as little as 12 weeks and shows the clinical benefit of improving cardiorespiratory fitness, which is increasingly being considered a 'clinical vital sign.'

Worryingly, there is little to no exercise referral systems in place within hospital departments and beyond throughout the healthcare system in Ireland. However, as our results have shown, the lack of sustainability of the benefits of exercise in MAFLD is concerning and there is an urgent unmet need to enable patients to continually engage in exercise therapy in the community setting. A systems-based approach whereby clinicians can refer patients to exercise specialists in the community is required for long-term benefits of exercise to be sustained."

https://www.sciencedaily.com/releases/2020/07/200729114728.htm

Obesity crisis blamed for a rise in fatty liver disease amongst young adults

January 15, 2020

Science Daily/University of Bristol

One in five young people have fatty liver disease (steatosis), with one in 40 having already developed liver scarring (fibrosis), research published today [15 January] has found. The study, published in The Lancet Gastroenterology & Hepatology, is the first to attempt to determine the prevalence of fatty liver disease and fibrosis in young healthy adults in the UK.

Fatty liver disease is a condition in which fats build up in the cells of the liver. It is broadly split into non-alcoholic fatty liver disease (NAFLD), which is usually seen in people who are overweight or obese, and alcohol related fatty liver disease, which is associated with harmful levels of drinking. If left untreated both can lead to fibrosis (scarring of the liver) and in severe cases eventually cirrhosis of the liver, which is irreversible. Worldwide NAFLD affects approximately a quarter of adults in developed countries.

The research, conducted by Dr Kushala Abeysekera and researchers from the University of Bristol, looked at data collected from 4,021 participants of the Children of the 90s study also known as Avon Longitudinal Study of Parents and Children (ALSPAC). Based in Bristol, participants from the health study -- who had previously been assessed for NAFLD as teenagers using ultrasound -- were invited for assessment using transient elastography with FibroScan as part of the Focus @24 clinic.

Researchers first looked at those participants who did not report harmful alcohol consumption and found that one in five had non-alcoholic fatty liver disease. On widening the data to include all participants, they again found that over 20 per cent displayed evidence of fatty liver and one in 40 had already developed fibrosis, with those participants who had both fatty liver and harmful alcohol use at greatest risk of liver scarring. As a comparison, at 17 years of age, 2.5 per cent of participants had moderate to severe levels of fatty liver, whilst at the age of 24 this number had increased to 13 per cent.

Dr Abeysekera, Honorary Lecturer in the Bristol Medical School: Population Health Sciences, explained: "Children of the 90s data has highlighted the potential importance of liver health amongst young adults. This age group remains a blind spot for clinicians, as they are typically considered a "healthy" age group that are rarely studied. If the obesity epidemic and culture of alcohol abuse aren't tackled nationally, we may see increasing numbers of patients presenting with end-stage liver disease, and at earlier ages.

"It is important to note that whilst we identified that 20 per cent of the cohort had fatty liver -- only a small percentage of the individuals will go on to develop cirrhosis (irreversible liver scarring), and the vast majority of participants should be fine if they manage their diet and exercise appropriately."

The next steps will be to take a closer look at how environmental and genetic factors may lead to individuals developing non-alcoholic fatty liver disease earlier in life.

https://www.sciencedaily.com/releases/2020/01/200115191527.htm