Yamashita Haruyo, Bharadwaj Kalyani G, Ikeda Shota, Park Tae-Sik, Goldberg Ira J
Dept. of Medicine, Columbia University, New York, NY 10032, USA.
Am J Physiol Endocrinol Metab. 2008 Sep;295(3):E705-13. doi: 10.1152/ajpendo.90338.2008. Epub 2008 Jul 22.
Fatty acids (FAs) are acquired from free FA associated with albumin and lipoprotein triglyceride that is hydrolyzed by lipoprotein lipase (LpL). Hypertrophied hearts shift their substrate usage pattern to more glucose and less FA. However, FAs may still be an important source of energy in hypertrophied hearts. The aim of this study was to examine the importance of LpL-derived FAs in hypertensive hypertrophied hearts. We followed cardiac function and metabolic changes during 2 wk of angiotensin II (ANG II)-induced hypertension in control and heart-specific lipoprotein lipase knockout (hLpL0) mice. Glucose metabolism was increased in ANG II-treated control (control/ANG II) hearts, raising it to the same level as hLpL0 hearts. FA uptake-related genes, CD36 and FATP1, were reduced in control/ANG II hearts to levels found in hLpL0 hearts. ANG II did not alter these metabolic genes in hLpL0 mice. LpL activity was preserved, and mitochondrial FA oxidation-related genes were not altered in control/ANG II hearts. In control/ANG II hearts, triglyceride stores were consumed and reached the same levels as in hLpL0/ANG II hearts. Intracellular ATP content was reduced only in hLpL0/ANG II hearts. Both ANG II and deoxycorticosterone acetate-salt induced hypertension caused heart failure only in hLpL0 mice. Our data suggest that LpL activity is required for normal cardiac metabolic compensation to hypertensive stress.
脂肪酸(FAs)来源于与白蛋白结合的游离脂肪酸以及被脂蛋白脂肪酶(LpL)水解的脂蛋白甘油三酯。肥大的心脏会将其底物利用模式转变为更多地利用葡萄糖,而减少对脂肪酸的利用。然而,脂肪酸在肥大的心脏中可能仍然是重要的能量来源。本研究的目的是探讨LpL衍生的脂肪酸在高血压性肥大心脏中的重要性。我们在对照小鼠和心脏特异性脂蛋白脂肪酶基因敲除(hLpL0)小鼠中,观察了血管紧张素II(ANG II)诱导高血压2周期间的心脏功能和代谢变化。ANG II处理的对照(对照/ANG II)心脏中的葡萄糖代谢增加,使其达到与hLpL0心脏相同的水平。对照/ANG II心脏中与脂肪酸摄取相关的基因CD36和脂肪酸转运蛋白1(FATP1)降低至hLpL0心脏中的水平。ANG II并未改变hLpL0小鼠中的这些代谢基因。对照/ANG II心脏中LpL活性得以保留,且与线粒体脂肪酸氧化相关的基因未发生改变。在对照/ANG II心脏中,甘油三酯储备被消耗,达到与hLpL0/ANG II心脏相同的水平。仅在hLpL0/ANG II心脏中细胞内ATP含量降低。ANG II和醋酸脱氧皮质酮-盐诱导的高血压均仅在hLpL0小鼠中导致心力衰竭。我们的数据表明,LpL活性是心脏对高血压应激进行正常代谢补偿所必需的。