Department of Medicine, Section of Cardiology, Boston University School of Medicine, Boston, Massachusetts, USA.
Obesity (Silver Spring). 2010 Jun;18(6):1116-21. doi: 10.1038/oby.2009.363. Epub 2009 Oct 29.
Storage of lipid in ectopic depots outside of abdominal visceral and subcutaneous stores, including within the pericardium and liver, has been associated with obesity, insulin resistance, and cardiovascular risk. We sought to determine whether anatomically distinct ectopic depots were physiologically correlated and site-specific effects upon cardiovascular function could be identified. Obese subjects (n = 28) with metabolic syndrome but without known atherosclerotic disease and healthy controls (n = 18) underwent magnetic resonance imaging (MRI) and proton MR spectroscopy (MRS) to quantify pericardial and periaortic lipid volumes, cardiac function, aortic compliance, and intrahepatic lipid content. Fasting plasma lipoproteins, glucose, insulin, and free-fatty acids were measured. Pericardial and intrahepatic (P < 0.01) and periaortic (P < 0.05) lipid volumes were increased in obese subjects vs. controls and were strongly and positively correlated (P <or= 0.01) but independent of BMI (P = NS) among obese subjects. Intrahepatic lipid was associated with insulin resistance (P < 0.01) and triglycerides (P < 0.05), whereas pericardial and periaortic lipid were not (P = NS). Periaortic and pericardial lipid positively correlated to free-fatty acids (P <or= 0.01) and negatively correlated to high-density lipoprotein (HDL) cholesterol (P < 0.05). Pericardial lipid negatively correlated to cardiac output (P = 0.03) and stroke volume (P = 0.01) but not to left ventricular ejection fraction (P = 0.46). None of the ectopic depots correlated to aortic compliance. In conclusion, ectopic storage of lipid in anatomically distinct depots appeared tightly correlated but independent of body size. Site-specific functional abnormalities were observed for pericardial but not periaortic lipid. These findings underscore the utility of MRI to assess individual differences in ectopic lipid that are not predictable from BMI.
脂肪在腹部内脏和皮下储存以外的异位储存，包括在心包和肝脏内，与肥胖、胰岛素抵抗和心血管风险有关。我们试图确定解剖上不同的异位储存是否在生理上相关，是否可以确定对心血管功能的特定部位影响。患有代谢综合征但无已知动脉粥样硬化疾病的肥胖受试者（n = 28）和健康对照者（n = 18）接受磁共振成像（MRI）和质子磁共振波谱（MRS）检查，以定量心包和主动脉旁脂质体积、心脏功能、主动脉顺应性和肝内脂质含量。测量空腹血浆脂蛋白、葡萄糖、胰岛素和游离脂肪酸。与对照组相比，肥胖受试者的心包内和肝内（P < 0.01）和主动脉旁（P < 0.05）脂质体积增加，并且在肥胖受试者中强烈且呈正相关（P < 0.01），但与 BMI 无关（P = NS）。肝内脂质与胰岛素抵抗（P < 0.01）和甘油三酯（P < 0.05）相关，而心包和主动脉旁脂质则不相关（P = NS）。主动脉旁和心包脂质与游离脂肪酸呈正相关（P < 0.01），与高密度脂蛋白（HDL）胆固醇呈负相关（P < 0.05）。心包脂质与心输出量（P = 0.03）和每搏输出量（P = 0.01）呈负相关，但与左心室射血分数（P = 0.46）无关。这些异位储存均与主动脉顺应性无关。总之，在解剖上不同的储存部位储存异位脂肪似乎紧密相关，但与体型无关。心包脂质存在特定部位的功能异常，但主动脉旁脂质则没有。这些发现强调了 MRI 用于评估 BMI 无法预测的异位脂质个体差异的实用性。
