Exercise training improves cutaneous microvascular function in nonalcoholic fatty liver disease

Area of Science:

• Cardiovascular Science
• Hepatology
• Exercise Physiology

Background:

• Cardiovascular disease (CVD) is a leading cause of mortality in nonalcoholic fatty liver disease (NAFLD).
• The role of nitric oxide (NO) in endothelial function, a marker for CVD risk, is not well understood in NAFLD.
• This study investigated NO-mediated microvessel function in NAFLD and the impact of exercise.

Purpose of the Study:

• To determine if NO-mediated cutaneous microvessel function is impaired in NAFLD patients compared to controls.
• To assess whether exercise training improves microvessel function more than conventional care in NAFLD.
• To explore the relationship between exercise, cardiorespiratory fitness, and microvascular function in NAFLD.

Main Methods:

• Compared cutaneous microvessel function using laser Doppler flowmetry and microdialysis in 13 NAFLD patients and 7 controls.
• NAFLD patients were randomized to 16 weeks of exercise or conventional care.
• Assessed NO dilator response to local heating, body composition via MRI, and cardiorespiratory fitness.

Main Results:

• Baseline NO contribution to cutaneous blood flow was similar between NAFLD patients and controls.
• Cardiorespiratory fitness significantly improved with exercise training compared to conventional care.
• Exercise training led to a significant improvement in NO-mediated cutaneous microvascular function (20.4% greater CVCmax, P=0.02).

Conclusions:

• NO-mediated microvascular function is not initially impaired in NAFLD patients compared to controls.
• Exercise training significantly enhances NO-mediated microvascular function in NAFLD patients.
• Exercise demonstrates a beneficial role in preventing CVD in the NAFLD population.