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【bio-news】长链脂肪并不一定更好
Researchers have uncovered why some dietary fats, specifically long-chain fats, such as oleic acid (found in olive oil), are more prone to induce inflammation. Long-chain fats, it turns out, promote increased intestinal absorption of pro-inflammatory bacterial molecules called lipopolysaccharides (LPS). This study appears in the January issue of JLR.
While dietary fats that have short chains (such as those found in milk and cheese products) can be absorbed directly into the bloodstream from the intestines, long-chain fats need to be first packaged by the intestinal cells into large particles known as chylomicrons (large complexes similar to HDL and LDL particles). Erik Eckhardt and colleagues at the University of Kentucky wondered whether some unwanted LPS particles, routinely shed by the bacteria that inhabit the human gut, might also be sneaking in the chylomicrons.
Their hypothesis turned out to be correct; when they treated cultured human intestinal cells with oleic acid they observed significant secretion of LPS together with the chylomicron particles, a phenomenon that was not observed when the cells were treated with short-chain butyric acid. Similar findings were found in mouse studies; high amounts of dietary oleic acid, but not butyric acid, promoted significant absorption of LPS into the blood and lymph nodes and subsequent expression of inflammatory genes.
Eckhardt and colleagues believe these findings may pave the way for future therapies for Crohn's disease and other inflammatory bowel disorders. In addition, they note that this study once again highlights the importance of the diverse bacteria that call our intestines home.
From the article: “Chylomicrons promote intestinal absorption of lipopolysaccharides” by Sarbani Ghoshal, Jassir Witta, Jian Zhong, Willem de Villiers and Erik Eckhardt
研究者们最近发现了某些膳食脂肪，如油酸（在橄榄油中发现的），更容易引起炎症的原因。实验表明，长链脂肪酸更容易促使小肠吸收促炎症细菌因子，这种因子被称为脂多糖(LPS)。该研究发表于一月刊的JLR杂志。
短链膳食脂肪（如牛奶和芝士中的脂肪）能够被小肠直接吸收并进入血液系统，而长链脂肪则要先被小肠细胞包装成被称为乳糜粒脂蛋白的大分子复合体（类似于HDL和LDL的大分子复合体）。肯塔基大学的Erik Eckhardt及其同事认为，某些经常由人类肠道内细菌携带的不良LPS复合物，可能也被组装进入乳糜粒脂蛋白。
实验证明他们的假说是正确的。他们用油酸处理培养的人类小肠细胞，能够很明显的观察到LPS与乳糜粒脂蛋白复合体共同分泌，而如果用短链的丁酸处理就不能观察到这个现象。该结果证实，LPS能明显的被血液吸收并转运，然后造成炎症基因的表达。
Eckhardt及其同事们认为，他们的发现可能为未来治疗克隆氏病和其它肠道感染疾病找到一条新路。此外，他们还指出这项研究再一次说明，在人类肠道中居住的不同种类细菌的重要性。
原文链接: http://www.jlr.org/cgi/content/full/50/1/90
通讯作者: Erik Eckhardt, Department of Internal Medicine, University of Kentucky, Lexington. 电话: 859 323 4933 * 81741; email: eeckh2@uky.edu
注释: 本论文的评论文章可在以下网址下载 http://www.jlr.org/cgi/content/full/50/1/1 [标签:content1][标签:content2]
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作者:admin@医学,生命科学 2011-04-15 17:11
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