Myocardial triglyceride content and epicardial fat mass in human obesity:: Relationship to left ventricular function and serum free fatty acid levels
Myocardial triglyceride content and epicardial fat mass in human obesity:: Relationship to left ventricular function and serum free fatty acid levels
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DOI：
10.1210/jc.2006-0584
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发表时间：
2006-11-01
影响因子：
5.8
通讯作者：
Iozzo, Patricia
中科院分区：
文献类型：
--
作者：
Kankaanpaa, Mikko;Lehto, Hanna-Riikka;Iozzo, Patricia
背景和目的：异位脂肪聚集在心肌壁及其周围与肥胖性心脏病的发病机制有关。我们评估了9名男性(5名瘦，4名中度肥胖)的心肌和心外膜脂肪、左心室(LV)功能和代谢危险因素。方法：用质子磁共振波谱测定间隔内心肌脂肪百分比。通过三次收缩和舒张期测量来评估重复性。磁共振成像测定左心室参数及心外膜脂肪含量。结果：肥胖者的心肌脂肪(2.1+/-0.5vs.0.8+/-0.1，P=0.03)和心外膜脂肪(120+/-33vs.55+/-12g，P=0.08)明显高于瘦肉者。丙氨酸转氨酶中值高于中位数的个体，心肌脂肪增加了4倍。重复测定心肌脂肪百分比的变异系数在收缩和舒张期分别为17=3和23±3%。心肌脂肪与游离脂肪酸(r=0.76；P=0.017)、心外膜脂肪(r=0.69；P=0.042)、腰臀比(r=0.7；P=0.035)呈正相关，且与左心室功呈正相关。心外膜脂肪与外周血管阻力(正相关)和心脏指数(负相关)相关。游离甘油三酯水平与左心室重量(r=0.72；P=0.030)、前向功(r=0.74；P=0.023)显著相关。结论：中度肥胖者心肌内及周围甘油三酯蓄积显著，且与游离脂肪酸暴露、全身异位脂肪增多及外周血管阻力有关。这些变化先于左室负荷过重和肥厚。
Context and Objective: Ectopic fat accumulation within and around the myocardial wall has been implicated in the pathogenesis of heart disease in obesity. We evaluated myocardial and epicardial fat, left ventricular (LV) function, and metabolic risk factors in nine (five lean, four moderately obese) men.Methods: Myocardial fat percent was quantified in the septum by proton magnetic resonance spectroscopy. Reproducibility was assessed by triplicate systolic and diastolic measurements. LV parameters and epicardial fat were determined by magnetic resonance imaging. Waist-to-hip ratio and liver enzymes (alanine transaminase) were used as surrogate markers of visceral and liver fat contents.Results: Myocardial fat (2.1 +/- 0.5 vs. 0.8 +/- 0.1, P = 0.03) and epicardial fat (120 +/- 33 vs. 55 +/- 12 g, P = 0.08) were higher in obese than lean subjects. Individuals with above-median alanine transaminase values had a 4-fold elevation in myocardial fat. The coefficient of variation of repeated myocardial fat percent determinations was 17 = 3 and 23 +/- 3% in systole and diastole, respectively. Myocardial fat was correlated with free fatty acid (FFA) levels (r = 0.76; P = 0.017), epicardial fat (r = 0.69; P = 0.042), and waist-to-hip ratio (r = 0.70; P = 0.035), and it showed a tendency to associate positively with LV work. Epicardial fat was associated with peripheral vascular resistance (positively) and the cardiac index (negatively). FFA levels were significantly correlated with LV mass (r = 0.72; P = 0.030) and forward work (r = 0.74; P = 0.023).Conclusions/Interpretation: The accumulation of triglyceride in and around the myocardium of moderately obese individuals is significant, and it is related to FFA exposure, generalized ectopic fat excess, and peripheral vascular resistance. These changes precede LV overload and hypertrophy.