Exercise Training Reduces Liver Fat and Increases Rates of VLDL Clearance But Not VLDL Production in NAFLD

Area of Science:

• Hepatology
• Metabolic Research
• Exercise Physiology

Background:

• Nonalcoholic fatty liver disease (NAFLD) is often reduced by exercise, even without calorie restriction.
• Previous studies indicate supervised exercise training in NAFLD does not alter total very low-density lipoprotein (VLDL) kinetics.

Purpose of the Study:

• To investigate the impact of exercise training on intrahepatocellular fat (IHCL).
• To determine the effect of exercise on the kinetics of large triglyceride (TG)-rich VLDL1 and smaller, less-TG-rich VLDL2 particles.

Main Methods:

• A 16-week randomized controlled trial involving 27 sedentary NAFLD patients.
• Intervention groups included supervised moderate-intensity aerobic exercise or conventional lifestyle advice (control).
• VLDL1 and VLDL2 triglyceride (TG) and apolipoprotein B (apoB) kinetics were assessed using stable isotopes pre- and post-intervention.

Main Results:

• The exercise group showed a 31% increase in maximal oxygen uptake and a significant reduction in IHCL (19.6% to 8.9%).
• Exercise training increased VLDL1-TG and apoB fractional catabolic rates (clearance) and VLDL1-apoB production rate.
• No significant changes in maximal oxygen uptake or IHCL were observed in the control group. Plasma TG levels remained unchanged in both groups.

Conclusions:

• Enhanced clearance of VLDL1 particles likely contributes to the observed reduction in liver fat following 16 weeks of exercise in NAFLD patients.
• Longer duration or higher-intensity exercise interventions may be necessary to influence plasma TG and VLDL production rates.