Division of Endocrinology, Diabetology and Clinical Nutrition, University Hospital of Bern, Inselspital, Bern, Switzerland.
PLoS One. 2013 Aug 14;8(8):e70865. doi: 10.1371/journal.pone.0070865. eCollection 2013.
Intrahepatocellular (IHCL) and intramyocellular (IMCL) lipids are ectopic lipid stores. Aerobic exercise results in IMCL utilization in subjects over a broad range of exercise capacity. IMCL and IHCL have been related to impaired insulin action at the skeletal muscle and hepatic level, respectively. The acute effect of aerobic exercise on IHCL is unknown. Possible regulatory factors include exercise capacity, insulin sensitivity and fat availability subcutaneous and visceral fat mass).
To concomitantly investigate the effect of aerobic exercise on IHCL and IMCL in healthy subjects, using Magnetic Resonance spectroscopy.
Normal weight, healthy subjects were included. Visit 1 consisted of a determination of VO2max on a treadmill. Visit 2 comprised the assessment of hepatic and peripheral insulin sensitivity by a two-step hyperinsulinaemic euglycaemic clamp. At Visit 3, subcutaneous and visceral fat mass were assessed by whole body MRI, IHCL and IMCL before and after a 2-hours aerobic exercise (50% of VO(2max)) using ¹H-MR-spectroscopy.
Eighteen volunteers (12M, 6F) were enrolled in the study (age, 37.6±3.2 years, mean±SEM; VO(2max), 53.4±2.9 mL/kg/min). Two hours aerobic exercise resulted in a significant decrease in IMCL (-22.6±3.3, % from baseline) and increase in IHCL (+34.9±7.6, % from baseline). There was no significant correlation between the exercise-induced changes in IMCL and IHCL and exercise capacity, subcutaneous and visceral fat mass and hepatic or peripheral insulin sensitivity.
IMCL and IHCL are flexible ectopic lipid stores that are acutely influenced by physical exercise, albeit in different directions.
ClinicalTrial.gov NCT00491582.
肝细胞内（IHCL）和肌细胞内（IMCL）脂质是异位脂质储存库。有氧运动可导致运动能力广泛的受试者利用 IMCL。IMCL 和 IHCL 分别与骨骼肌和肝脏水平的胰岛素作用受损有关。急性有氧运动对 IHCL 的影响尚不清楚。可能的调节因素包括运动能力、胰岛素敏感性和脂肪供应（皮下和内脏脂肪量）。
使用磁共振波谱法同时研究有氧运动对健康受试者 IHCL 和 IMCL 的影响。
纳入正常体重的健康受试者。第 1 次就诊包括在跑步机上确定 VO2max。第 2 次就诊包括通过两步高胰岛素正葡萄糖钳夹法评估肝和外周胰岛素敏感性。在第 3 次就诊时，使用 1H-MR 光谱法在 2 小时有氧运动（50%的 VO2max）前后评估皮下和内脏脂肪量、IHCL 和 IMCL。
18 名志愿者（12 名男性，6 名女性）入组本研究（年龄 37.6±3.2 岁，平均值±SEM；VO2max 53.4±2.9 mL/kg/min）。2 小时有氧运动导致 IMCL 显著减少（-22.6±3.3%，与基线相比）和 IHCL 增加（+34.9±7.6%，与基线相比）。IMCL 和 IHCL 的运动诱导变化与运动能力、皮下和内脏脂肪量以及肝或外周胰岛素敏感性之间没有显著相关性。
IMCL 和 IHCL 是灵活的异位脂质储存库，它们会受到身体活动的急性影响，尽管影响方向不同。
ClinicalTrials.gov NCT00491582。
