Exercise and fat accumulation in the human liver

Division of Endocrinology, Diabetes, and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA.
Current opinion in lipidology (Impact Factor: 5.8). 12/2010; 21(6):507-17. DOI: 10.1097/MOL.0b013e32833ea912
Source: PubMed

ABSTRACT Fat accumulation in the liver is strongly associated with metabolic dysfunction. Regular exercise improves many cardiometabolic risks factors; however, its effect on intrahepatic triglyceride (IHTG) content remains elusive. This article summarizes available data regarding the effects of exercise on IHTG.
Several but not all observational studies report negative associations of habitual physical activity and cardiorespiratory fitness with IHTG and the prevalence of fatty liver. Aerobic exercise training in combination with hypocaloric diet reduces IHTG by a considerable amount (20-60%), even when weight loss is mild (<5%); hence weight loss per se may not be a critical factor. Longitudinal studies involving exercise training without dietary restriction and no weight loss demonstrate that increased cardiorespiratory fitness and reduced intra-abdominal adiposity are not invariably associated with liver fat depletion, whereas relatively large exercise-induced reductions in IHTG content (20-40%) can occur even in the absence of changes in body weight, body composition, or visceral adipose tissue. Although the majority of studies have examined aerobic training, resistance exercise has also been shown to be inversely associated with the prevalence of fatty liver in humans and effectively reduces IHTG content in animals.
Exercise does hold promise as an effective treatment for hepatic steatosis; this field of research is still in its infancy, and there is much more to be learned.

  • Source
    Dataset: mnfr1966
  • [Show abstract] [Hide abstract]
    ABSTRACT: Object The objective of this study was to determine the effects of a standardized fat rich meal and subsequent exercise on liver fat content by 1H MRS and on liver adenosine triphosphate (ATP) content by 31P MRS in healthy subjects. Materials and methods Hepatic 1H and proton decoupled 31P MRS were performed on nine healthy subjects on a clinical 3.0 T MR imager three times during a day: after (1) an overnight fast, (2) a following standardized fat rich meal and (3) a subsequent exercise session. Blood parameters were followed during the day to serve as a reference to MRS. Results Liver fat content increased gradually over the day (p = 0.0001) with an overall increase of 30 %. Also γ-NTP changed significantly over the day (p = 0.005). γ-NTP/tP decreased by 9 % (p = 0.019, post hoc) from the postprandial to the post-exercise state. Conclusion Our study shows that in vivo MRS can depict short lived physiological changes; entering of fat into liver cells and consumption of ATP during exercise can be measured non-invasively in healthy subjects. The physiological state may have an impact on fat and energy metabolite levels. Hepatic 1H and 31P MRS studies should be performed under standardized conditions.
    MAGMA Magnetic Resonance Materials in Physics Biology and Medicine 06/2014; 28(1). DOI:10.1007/s10334-014-0450-7 · 1.35 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Triglyceride (TG) is an important source of fuel during endurance exercise. Lipolysis of adipose tissue and intramuscular triacylglycerol oxidation increases during exercise. In compare with moderate-intensity exercise, high-intensity exercise decreases fat oxidation. For many years it has been debated whether triacylglycerols located in the muscle are utilized during exercise because conflicting results have been appeared. To conduct this research, 8 (eight) male mouse were taken as samples and four mouse were divided into two groups as control (sedentary life) and experimental (routine exercise in treadmill). After one month of close supervision, the mouse were seizured and collect the sample (liver, epidedymal adipose tissue, skeletal muscle) for further experiment. We analyzed the sample and estimate the TG (triglycerides) content from the sample with standard GPO-POD method. In this study, we found that compare with sedentary mouse, exercise group slightly increased liver weight and epididymal adipose tissue TG whereas gastrocnemius muscle weight increased significantly because of exercise induced muscle storage. On the other hand, in compare with body weight, epididymal adipose tissue weight and gastrocnemius muscle TG decreased significantly. There is no alteration in liver weight of both group. Finally, we demonstrate that exercise increased the skeletal muscle weight of trained mice and decreased the TG accumulation in gastrocnemius skeletal muscle and this findings is inversely correlated with insulin resistance.