Obesity and the gut microbiome: pathophysiological aspects
Obesity and the gut microbiome: pathophysiological aspects
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DOI：
10.1515/hmbci-2013-0063
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发表时间：
2014-01-01
影响因子：
1
通讯作者：
Bradlow, H. Leon
中科院分区：
文献类型：
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作者：
Bradlow, H. Leon
虽然有大量文献将肥胖描述为乳腺癌和许多其他癌症的风险因素，但大体上还没有建立起因果关系。如果这项研究仅限于乳腺癌风险，有人认为绝经后女性性激素形成的增加起到了一定作用。众所周知，肥胖与慢性低度炎症有关，但过去没有提供过这种联系的理由。肠道微生物群虽然已知是巨大的，但在过去并不被认为是身体中的新陈代谢角色。现在，人们认识到情况就是这样。最近的研究发现，肥胖与肠道微生物群的变化有关。在肥胖个体中，两种主要细菌-类杆菌和细菌-的相对比例发生了变化，后者在肥胖中占主导地位，并导致脱氧胆酸和脂多糖(LPS)等代谢内毒素的形成增加。肥胖者表现为肠壁粘液中阿克曼氏菌浓度下降，导致粘液变薄，肠道衬里变弱，并允许其他细菌群(如脂多糖)形成的代谢内毒素进入血液，导致与肥胖相关的慢性炎症。微生物群组的变化导致更有效地产生能量的细菌菌株的增加，从而导致肥胖增加。在小鼠中，研究表明，将肥胖小鼠盲肠的肠道细菌菌群引入无菌小鼠会导致肥胖增加，食物消耗减少，而从瘦小鼠引入细菌菌群则会导致体重减轻。这增加了一种诱人的可能性，即操纵肠道微生物群可以促进人类减肥或预防肥胖。
While there is a large volume of literature describing a role for obesity as a risk factor for breast cancer and many other cancers, in the main a causal relationship has not been established. If the study is limited to breast cancer risk, it has been suggested that the increase in sex steroid formation that occurs in postmenopausal women plays a role. Obesity is known to be associated with chronic low grade inflammation, but no reason for this association has been offered in the past. The gut microbiome, while known to be enormous, has not in the past been considered as a metabolic role player in the body. This is now recognized to be the case. Recent studies have found the obesity is correlated with an alteration in the gut microbiome. In obese individual there is a change in the relative proportions of the two major classes of bacteria - bacteroides and firmacutes - with the latter dominant in obesity and resulting in the formation of increased amounts of metabolic endotoxins like deoxycholic acid and lipopolysaccharides (LPS). Obese individuals show a decrease in the concentration of Akkermansia muciniphila in the mucus that lines the intestinal wall, resulting in thinner mucus and a weakened intestinal lining and permitting metabolic endotoxins formed by other bacterial flora like LPS to enter the blood steam and cause the chronic inflammation associated with obesity. The change in the microbiome profile results in increases in bacterial strains that are more efficient at generating energy, leading to increased obesity. In mice, it has been shown that introducing gut bacterial flora from the cecum of obese mice into germ-free mice results in increased obesity with lesser food consumption while the reverse, introducing bacterial flora from lean mice results in a loss in weight. This raises the attractive possibility that manipulating the gut microbiome could facilitate weight loss or prevent obesity in humans.