Palmitoleic acid is elevated in fatty liver disease and reflects hepatic lipogenesis
Palmitoleic acid is elevated in fatty liver disease and reflects hepatic lipogenesis
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DOI：
10.3945/ajcn.114.092262
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发表时间：
2015-01-01
影响因子：
7.1
通讯作者：
Parks, Elizabeth J.
中科院分区：
文献类型：
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作者：
Lee, Joseph J.;Lambert, Jennifer E.;Parks, Elizabeth J.
背景：生物化学证据已经将脂肪酸（FA）合成的协调控制与硬脂酰辅酶A去饱和酶-1（SCD 1）的活性联系起来。血浆三酰甘油FA中16：1 n-7与16：0 [SCD 1（（16））]的比率已被用作反映肝脏SCD 1（（16））活性的指标，并已被提议作为FA合成的生物标志物，尽管这种用途尚未通过与同位素测量的从头脂肪生成（DNLMeas）进行比较来验证。在这项代谢的横断面调查中，24名超重的成年人，他们可能有DNL升高，摄入D2 O 10 d后，用磁共振波谱法测定肝脏脂肪（LF）。极低密度脂蛋白（VLDL）-三酰甘油和血浆游离FA [非酯化脂肪酸（NEFA）]通过气相色谱法分析FA组成结果：在所有受试者中，VLDL-三酰甘油16：1 n-7显著高于对照组（P < 0. 05），而VLDL-三酰甘油16：1 n-7显著高于对照组（P < 0. 05）。与DNLMeas相关（P < 0.01）（r = 0.56），肝脂（r = 0.53），脂肪胰岛素抵抗（r = 0.56）;与SCD 1（（16））指数显示类似的正相关性，NEFA的模式与VLDL-三酰甘油的模式相呼应。与低LF受试者相比（3.1 ± 2.7%; n=11），高LF受试者（18.4 +/- 3.6%; n=13）显示VLDL-三酰甘油16：1 n-7摩尔百分比高45% 16%的受试者18：2n-6较低（P < 0.01（P = 0.01），27%的受试者使用已发表的DNL指数评估DNL较高（比例为16：0至18：2n-6; P = 0.03），这通过DNLMeas同位素证实（增加2.5倍; P < 0.01）。与16：0的饮食相比，低量的饮食中的VLDL-三酰甘油16：1 n-7对应于一个更强的信号升高DNL.Conclusion：目前的数据提供支持使用的VLDL-三酰甘油16：1 n-7摩尔百分比作为生物标志物升高肝脂肪时，同位素的使用是不可行的，但是，需要更大规模的验证性研究。
Background: Biochemical evidence has linked the coordinate control of fatty acid (FA) synthesis with the activity of stearoyl-CoA desaturase-1 (SCD1). The ratio of 16:1n-7 to 16:0 [SCD1((16))] in plasma triacylglycerol FA has been used as an index to reflect liver SCD1((16)) activity and has been proposed as a biomarker of FA synthesis, although this use has not been validated by comparison with isotopically measured de novo lipogenesis (DNLMeas).Objective: We investigated plasma lipid 16:1n-7 and FA indexes of elongation and desaturation in relation to lipogenesis.Design: In this cross-sectional investigation of metabolism, 24 overweight adults, who were likely to have elevated DNL, consumed D2O for 10 d and had liver fat (LF) measured by magnetic resonance spectroscopy. Very-low-density lipoprotein (VLDL)-triacylglycerols and plasma free FA [nonesterified fatty acids (NEFAs)] were analyzed by using gas chromatography for the FA composition (molar percentage) and gas chromatography-mass spectrometry and gas chromatography-combustion isotope ratio mass spectrometry for deuterium enrichment.Results: In all subjects, VLDL-triacylglycerol 16:1n-7 was significantly (P < 0.01) related to DNLMeas (r = 0.56), liver fat (r = 0.53), and adipose insulin resistance (r = 0.56); similar positive relations were shown with the SCD1((16)) index, and the pattern in NEFAs echoed that of VLDL-triacylglycerols. Compared with subjects with low LF (3.1 +/- 2.7%; n=11), subjects with high LF (18.4 +/- 3.6%; n=13) exhibited a 45% higher VLDL-triacylglycerol 16:1n-7 molar percentage (P < 0.01), 16% of subjects had lower 18:2n-6 (P = 0.01), and 27% of subjects had higher DNL as assessed by using a published DNL index (ratio of 16:0 to 18:2n-6; P = 0.03), which was isotopically confirmed by DNLMeas (increased 2.5-fold; P < 0.01). Compared with 16:0 in the diet, the low amount of dietary 16:1n-7 in VLDL-triacylglycerols corresponded to a stronger signal of elevated DNL.Conclusion: The current data provide support for the use of the VLDL-triacylglycerol 16:1n-7 molar percentage as a biomarker for elevated liver fat when isotope use is not feasible; however, larger-scale confirmatory studies are needed.