Randomized trial of exercise effect on intrahepatic triglyceride content and lipid kinetics in nonalcoholic fatty liver disease.
Nonalcoholic fatty liver disease (NAFLD) and alterations in hepatic lipoprotein kinetics are common metabolic complications associated with obesity. Lifestyle modification involving diet-induced weight loss and regular exercise decreases intrahepatic triglyceride (IHTG) content and very low density lipoprotein (VLDL) triglyceride (TG) secretion rate. The aim of this study was to evaluate the weight loss-independent effect of following the physical activity guidelines recommended by the Department of Health and Human Services on IHTG content and VLDL kinetics in obese persons with NAFLD. Eighteen obese people (body mass index [BMI]: 38.1 ± 4.6 kg/m(2)) with NAFLD were randomized to 16 weeks of exercise training (45%-55% VO(2peak) , 30-60 minutes × 5 days/week; n = 12) or observation (control; n = 6). Magnetic resonance spectroscopy and stable isotope tracer infusions in conjunction with compartmental modeling were used to evaluate IHTG content and hepatic VLDL-TG and apolipoprotein B-100 (apoB-100) secretion rates. Exercise training resulted in a 10.3% ± 4.6% decrease in IHTG content (P < 0.05), but did not change total body weight (103.1 ± 4.2 kg before and 102.9 ± 4.2 kg after training) or percent body fat (38.9% ± 2.1% before and 39.2% ± 2.1% after training). Exercise training did not change the hepatic VLDL-TG secretion rate (17.7 ± 3.9 μmol/min before and 16.8 ± 5.4 μmol/min after training) or VLDL-apoB-100 secretion rate (1.5 ± 0.5 nmol/min before and 1.6 ± 0.6 nmol/min after training).


CONCLUSIONS
Following the Department of Health and Human Services recommended physical activity guidelines has small but beneficial effects on IHTG content, but does not improve hepatic lipoprotein kinetics in obese persons with NAFLD.
Center for Human Nutrition, Washington University School of Medicine, St. Louis, MO; Atkins Center of Excellence in Obesity Medicine, Washington University School of Medicine, St. Louis, MO; Division of Gastroenterology, Washington University School of Medicine, St. Louis, MO.
Shelby
S
Sullivan
Erik P
EP
Kirk
Bettina
B
Mittendorfer
Bruce W
BW
Patterson
Samuel
S
Klein
D000328:Adult; D000410:Alanine Transaminase / Q000097:blood; D001823:Body Composition; D015444:Exercise; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005234:Fatty Liver / Q000378:metabolism*; D005260:Female; D006801:Humans; D007700:Kinetics; D008055:Lipids / Q000097:blood*; D008099:Liver / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D065626:Non-alcoholic Fatty Liver Disease; D014280:Triglycerides / Q000032:analysis*
D005230:Fatty Acids, Nonesterified; D008055:Lipids; D014280:Triglycerides; D000410:Alanine Transaminase