Obesity reduces left ventricular strains, torsion, and synchrony in mouse models: a cine displacement encoding with stimulated echoes (DENSE) cardiovascular magnetic resonance study.
Obesity reduces left ventricular strains, torsion, and synchrony in mouse models: a cine displacement encoding with stimulated echoes (DENSE) cardiovascular magnetic resonance study.
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DOI：
10.1186/1532-429x-15-109
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发表时间：
2013-12-31
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影响因子：
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通讯作者：
Fornwalt BK
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文献类型：
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作者：
Kramer SP;Powell DK;Haggerty CM;Binkley CM;Mattingly AC;Cassis LA;Epstein FH;Fornwalt BK
肥胖影响了美国三分之一的成年人，并导致心血管死亡风险增加。虽然这种增加风险的机制尚不清楚，但肥胖的动物模型已经显示出对心脏的直接影响，如脂肪变性和纤维化，这可能会影响心脏功能。然而，在动物模型中，肥胖对心脏功能的影响还没有明确的定义。我们假设饮食诱导的肥胖小鼠减少了左心室(LV)的张力、扭转和同步性。10只12周龄的C57BL/6小鼠被随机分为高脂饮食或低脂饮食。在节食5个月后，小鼠被用7英尺T ClinScan进行成像，使用电影密度方案。采集3个短轴和2个长轴切片，用于测量左心室应变、扭转和同步性。左心室重量增加了15%(p = 0.032)，而容量和射血分数没有变化。肥胖小鼠的心外膜下应变较低，周向应变减少了40%(p = 0.008)，径向应变减少了53%(p = 0.032)，纵向应变有减少19%的趋势(p = 0.056)。相比之下，肥胖小鼠的心内膜下应变在周向略微减少了12%(p = 0.028)，在径向(p = 0.690)或纵向(p = 0.602)上没有差异。峰值扭转减少34%(p = 0.028)。收缩的同步性也降低(p = 0.032)，间隔至侧壁方向的时间延迟。饮食诱导的肥胖减少了小鼠的左心室张力和扭转。心脏应变的减少主要局限于心外膜下，心内膜下的功能相对保留。饮食诱导的肥胖也会导致小鼠模型收缩和肥大的同步性降低。
Obesity affects a third of adults in the US and results in an increased risk of cardiovascular mortality. While the mechanisms underlying this increased risk are not well understood, animal models of obesity have shown direct effects on the heart such as steatosis and fibrosis, which may affect cardiac function. However, the effect of obesity on cardiac function in animal models is not well-defined. We hypothesized that diet-induced obesity in mice reduces strain, torsion, and synchrony in the left ventricle (LV). Ten 12-week-old C57BL/6 J mice were randomized to a high-fat or low-fat diet. After 5 months on the diet, mice were imaged with a 7 T ClinScan using a cine DENSE protocol. Three short-axis and two long-axis slices were acquired for quantification of strains, torsion and synchrony in the left ventricle. Left ventricular mass was increased by 15% (p = 0.032) with no change in volumes or ejection fraction. Subepicardial strain was lower in the obese mice with a 40% reduction in circumferential strain (p = 0.008) a 53% reduction in radial strain (p = 0.032) and a trend towards a 19% reduction in longitudinal strain (p = 0.056). By contrast, subendocardial strain was modestly reduced in the obese mice in the circumferential direction by 12% (p = 0.028), and no different in the radial (p = 0.690) or longitudinal (p = 0.602) directions. Peak torsion was reduced by 34% (p = 0.028). Synchrony of contraction was also reduced (p = 0.032) with a time delay in the septal-to-lateral direction. Diet-induced obesity reduces left ventricular strains and torsion in mice. Reductions in cardiac strain are mostly limited to the subepicardium, with relative preservation of function in the subendocardium. Diet-induced obesity also leads to reduced synchrony of contraction and hypertrophy in mouse models.