图片来源：the-scientist.com

　　肠道微生物组对机体健康非常关键，但一项对小鼠进行的研究却发现，在涉及胰岛素敏感性和肥胖症上，肠道微生物组或许并不像科学家们认为的那样。

　　近日，一项刊登在国际杂志NatureMedicine上的研究论文中，来自瑞士日内瓦大学的科学家通过研究表示，没有肠道菌群的动物或许会表现出更好的葡萄糖耐受性和胰岛素敏感性，而且还会表现出低脂肪低体重指数的情况。

　　研究者Mirko Trajkovski说道，尽管利用高剂量抗生素治疗肥胖并不切实际，主要是由于抗生素耐受性出现的风险，但我们仍然像开发出一种可替代的方法来抑制或修饰微生物菌群，从而鉴别出对这种现象负主要责任（抗生素耐受性）的确切细菌；文章中研究者及其同事对小鼠进行研究，首先利用抗生素剔除消除肠道的菌群或者在无菌环境中饲养小鼠，随后给予小鼠高脂肪饮食，当正常小鼠变得肥胖时，无菌小鼠还可以依然保持苗条，同时还会产生更多的米色脂肪（beige fat），即一种可以燃烧机体能量的脂肪组织。

　　研究结果表明，无菌小鼠机体中存在高水平的特定细胞因子，而抑制这种特殊信号或许就会损伤抗生素诱导的皮下脂肪褐变过程，同时还会抑制肠道菌群剔除小鼠的葡萄糖表型。后期研究中研究人员还将进行更为深入的研究来开发治疗肥胖等疾病的新型疗法。

　　doi:10.1038/nm.3994

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Microbiota depletion promotes browning of white adipose tissue and reduces obesity

　　Nicolas Suárez-Zamorano, Salvatore Fabbiano, Claire Chevalier, Ozren Stojanovi , Didier J Colin, Ana Stevanovi , Christelle Veyrat-Durebex, Valentina Tarallo, Dorothée Rigo, Stéphane Germain, Miroslava Ilievska, Xavier Montet, Yann Seimbille, Siegfried Hapfelmeier &Mirko Trajkovski

　　Brown adipose tissue (BAT) promotes a lean and healthy phenotype and improves insulin sensitivity1. In response to cold or exercise, brown fat cells also emerge in the white adipose tissue (WAT; also known as beige cells), a process known as browning2, 3, 4. Here we show that the development of functional beige fat in the inguinal subcutaneous adipose tissue (ingSAT) and perigonadal visceral adipose tissue (pgVAT) is promoted by the depletion of microbiota either by means of antibiotic treatment or in germ-freemice. This leads to improved glucose tolerance and insulin sensitivity and decreased white fat and adipocyte size in lean mice, obese leptin-deficient (ob/ob) mice and high-fat diet (HFD)-fed mice. Such metabolic improvements are mediated by eosinophil infiltration, enhanced type 2 cytokine signaling and M2 macrophage polarization in the subcutaneous white fat depots of microbiota-depleted animals. The metabolic phenotype and the browning of the subcutaneous fat are impaired by the suppression of type 2 cytokine signaling, and they are reversed by recolonization of the antibiotic-treated or germ-free mice with microbes. These results provide insight into the microbiota-fat signaling axis and beige-fat development in health and metabolic disease.