Division of Endocrinology and Metabolism, Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria.
PLoS One. 2012;7(12):e50077. doi: 10.1371/journal.pone.0050077. Epub 2012 Dec 3.
AIMS/HYPOTHESIS: Recent evidence suggests a link between myocardial steatosis and diabetic cardiomyopathy. Insulin, as a lipogenic and growth-promoting hormone, might stimulate intramyocardial lipid (MYCL) deposition and hypertrophy. Therefore, the aim of the present study was to investigate the short-term effects of insulin therapy (IT) on myocardial lipid content and morphology in patients with T2DM.
Eighteen patients with T2DM were recruited (age 56 ± 2 years; HbA1c: 10.5 ± 0.4%). In 10 patients with insufficient glucose control under oral medication IT was initiated due to secondary failure of oral glucose lowering therapy (IT-group), while 8 individuals did not require additional insulin substitution (OT-group). In order to assess MYCL and intrahepatic lipid (IHLC) content as well as cardiac geometry and function magnetic resonance spectroscopy (MRS) and imaging (MRI) examinations were performed at baseline (IT and OT) and 10 days after initiation of IT. Follow up measurements took place 181 ± 49 days after IT.
Interestingly, basal MYCLs were 50% lower in IT- compared to OT-group (0.41 ± 0.12 vs. 0.80 ± 0.11% of water signal; p = 0.034). After 10 days of IT, an acute 80%-rise in MYCL (p = 0.008) was observed, while IHLC did not change. Likewise, myocardial mass (+13%; p = 0.004), wall thickness in end-diastole (+13%; p = 0.030) and concentricity, an index of cardiac remodeling, increased (+28%; p = 0.026). In the long-term MYCL returned to baseline, while IHCL significantly decreased (-31%; p = 0.000). No acute changes in systolic left ventricular function were observed.
CONCLUSIONS/INTERPRETATION: The initiation of IT in patients with T2DM was followed by an acute rise in MYCL concentration and myocardial mass.
目的/假设：最近的证据表明心肌脂肪变性与糖尿病心肌病之间存在关联。胰岛素作为一种促脂和促生长的激素，可能会刺激心肌内脂质（MYCL）沉积和肥大。因此，本研究的目的是探讨胰岛素治疗（IT）对 T2DM 患者心肌脂质含量和形态的短期影响。
招募了 18 名 T2DM 患者（年龄 56±2 岁；HbA1c：10.5±0.4%）。在口服药物治疗血糖控制不佳的 10 名患者中（IT 组），由于口服降糖治疗继发失败而开始胰岛素治疗，而另外 8 名患者不需要额外的胰岛素替代（OT 组）。为了评估 MYCL 和肝内脂质（IHLC）含量以及心脏几何形状和功能，在基线（IT 和 OT）和开始 IT 后 10 天进行磁共振光谱（MRS）和成像（MRI）检查。随访测量在 IT 后 181±49 天进行。
有趣的是，与 OT 组相比，IT 组的基础 MYCL 降低了 50%（0.41±0.12%与 0.80±0.11%的水信号；p=0.034）。在 10 天的 IT 后，观察到 MYCL 的急性增加 80%（p=0.008），而 IHLC 没有变化。同样，心肌质量增加了 13%（p=0.004），舒张末期的壁厚度增加了 13%（p=0.030），以及心脏重构的指标——向心性增加了 28%（p=0.026）。在长期内，MYCL 恢复到基线水平，而 IHLC 显著降低（-31%；p=0.000）。未观察到收缩期左心室功能的急性变化。
结论/解释：在 T2DM 患者中开始 IT 后，MYCL 浓度和心肌质量会急性增加。
