title: Exercise training improves cutaneous microvascular function in nonalcoholic fatty liver disease.
abstract: The leading causes of mortality in nonalcoholic fatty liver disease (NAFLD) relate to cardiovascular disease (CVD). The contribution of nitric oxide (NO) to endothelial function, a surrogate of CVD risk, is currently unknown in NAFLD. We hypothesize that NO-mediated cutaneous microvessel function would be impaired in NAFLD compared with controls and that exercise would enhance microvessel function compared with conventional care. Thirteen NAFLD patients (aged 50 ± 3 yr, BMI 31 ± 1 kg/m²) and seven controls (48 ± 4 yr, 30 ± 2 kg/m²) were studied. NAFLD patients were randomized to either 16 wk of exercise or conventional care. Cutaneous microvessel function was examined using laser Doppler flowmetry combined with intradermal microdialysis of N(G)-monomethyl-l-arginine to assay the NO dilator response to local forearm heating. Magnetic resonance imaging and spectroscopy quantified abdominal and liver fat, respectively, and cardiorespiratory fitness was assessed. Differences in NO contribution to cutaneous blood flow between NAFLD and control individuals and between interventions were analyzed using general linear modeling. NO contribution to cutaneous blood flow was similar between NAFLD and controls (P = 0.47). Cardiorespiratory fitness was greater following exercise training compared with conventional care. NO contribution to cutaneous blood flow in response to heating at 42°C was 20.4% CVCmax (95% CI = 4.4, 36.4) greater following exercise training compared with conventional care (P = 0.02). Exercise training improves cutaneous microvascular NO function in NAFLD patients. The benefit of exercise training compared with conventional care strongly supports a role for exercise in the prevention of CVD in NAFLD.
authors: Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom.
authors: Christopher J A
authors: CJ
authors: Pugh
authors: Daniel J
authors: DJ
authors: Cuthbertson
authors: Victoria S
authors: VS
authors: Sprung
authors: Graham J
authors: GJ
authors: Kemp
authors: Paul
authors: P
authors: Richardson
authors: A Margot
authors: AM
authors: Umpleby
authors: Daniel J
authors: DJ
authors: Green
authors: N Timothy
authors: NT
authors: Cable
authors: Helen
authors: H
authors: Jones
mesh_terms: D000328:Adult; D002318:Cardiovascular Diseases / Q000453:epidemiology / Q000378:metabolism / Q000517:prevention & control*; D005081:Exercise Therapy / Q000379:methods*; D005234:Fatty Liver / Q000453:epidemiology / Q000378:metabolism / Q000503:physiopathology*; D005260:Female; D006358:Hot Temperature; D006801:Humans; D017078:Laser-Doppler Flowmetry; D008297:Male; D008833:Microcirculation / Q000502:physiology*; D008875:Middle Aged; D065626:Non-alcoholic Fatty Liver Disease; D010101:Oxygen Consumption / Q000502:physiology; D012307:Risk Factors; D040242:Risk Reduction Behavior; D012867:Skin / Q000098:blood supply*; D016896:Treatment Outcome
keywords: cutaneous microvessel function; exercise; exercise training; microvascular function; nitric oxide; nonalcoholic fatty liver disease