Lim Soo, Son Kyu R, Song In C, Park Ho S, Jin Cheng J, Jang Hak C, Park Kyong S, Kim Young-Bum, Lee Hong K
Department of Internal Medicine, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
Obesity (Silver Spring). 2009 Jan;17(1):188-95. doi: 10.1038/oby.2008.486. Epub 2008 Oct 23.
Intrahepatic or intramuscular lipid (IHL/IML) content has been reported to be correlated with insulin resistance. Visceral fat has also been shown to be associated with insulin resistance. Thus, we investigated whether IHL/IML or visceral fat content is more closely associated with insulin resistance. Twenty Sprague-Dawley rats were divided into two groups based on regular chow diet (RCD) or high-fat diet (HFD; 40% fat). The insulin-sensitivity index (ISI) was determined by euglycemic glucose clamp study, the amount of visceral fat by computed tomography (CT), and the IHL/IML content by magnetic resonance spectroscopy (MRS). Weight, food, and water intake, physical activity, energy expenditure, lipid profile, adiponectin, and high-sensitivity C-reactive protein (hsCRP) levels were measured. At the study end point, visceral fat, and the IHL/IML content were higher in the HFD group than in the RCD group. The IHL/IML content was more highly correlated with ISI than was visceral fat amount. Stronger correlations were also found between adiponectin or hsCRP level and IML/IHL content than visceral fat, especially in the HFD group. Furthermore, the IHL/IML content was significantly associated with the ISI in the multiple regression models but visceral fat was not. There was clear discrimination between RCD and HFD groups in scatter plots of IML/IHL against the ISI, but substantial overlap in that of visceral fat against the ISI. This result suggests that IHL/IML contents are closely related with insulin resistance or atherosclerosis and is a better metabolic index of insulin sensitivity than the visceral fat.
据报道，肝内或肌肉内脂质（IHL/IML）含量与胰岛素抵抗相关。内脏脂肪也已被证明与胰岛素抵抗有关。因此，我们研究了IHL/IML或内脏脂肪含量是否与胰岛素抵抗的关系更为密切。将20只Sprague-Dawley大鼠根据常规饲料饮食（RCD）或高脂饮食（HFD；40%脂肪）分为两组。通过正常血糖葡萄糖钳夹研究确定胰岛素敏感性指数（ISI），通过计算机断层扫描（CT）测定内脏脂肪量，通过磁共振波谱（MRS）测定IHL/IML含量。测量体重、食物和水摄入量、身体活动、能量消耗、血脂谱、脂联素和高敏C反应蛋白（hsCRP）水平。在研究终点，HFD组的内脏脂肪和IHL/IML含量高于RCD组。IHL/IML含量与ISI的相关性高于内脏脂肪量与ISI的相关性。脂联素或hsCRP水平与IML/IHL含量之间的相关性也比与内脏脂肪的相关性更强，尤其是在HFD组。此外，在多元回归模型中，IHL/IML含量与ISI显著相关，但内脏脂肪与ISI不相关。在IML/IHL与ISI的散点图中，RCD组和HFD组有明显区分，但在内脏脂肪与ISI的散点图中有大量重叠。这一结果表明，IHL/IML含量与胰岛素抵抗或动脉粥样硬化密切相关，并且是比内脏脂肪更好的胰岛素敏感性代谢指标。
