Chassaing Benoit, Raja Shreya M, Lewis James D, Srinivasan Shanthi, Gewirtz Andrew T
Center for Inflammation, Immunity and Infection, Institute for Biomedical Sciences, Georgia State University, Atlanta, Georgia.
Digestive Diseases Division, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia.
Cell Mol Gastroenterol Hepatol. 2017 Apr 13;4(2):205-221. doi: 10.1016/j.jcmgh.2017.04.001. eCollection 2017 Sep.
Mucoid structures that coat the epithelium play an essential role in keeping the intestinal microbiota at a safe distance from host cells. Encroachment of bacteria into the normally almost-sterile inner mucus layer has been observed in inflammatory bowel disease and in mouse models of colitis. Moreover, such microbiota encroachment has also been observed in mouse models of metabolic syndrome, which are associated low-grade intestinal inflammation. Hence, we investigated if microbiota encroachment might correlate with indices of metabolic syndrome in humans.
Confocal microscopy was used to measure bacterial-epithelial distance of the closest bacteria per high-powered field in colonic biopsies of all willing participants undergoing cancer screening colonoscopies.
We observed that, among all subjects, bacterial-epithelial distance was inversely correlated with body mass index, fasting glucose levels, and hemoglobin A. However, this correlation was driven by dysglycemic subjects, irrespective of body mass index, whereas the difference in bacterial-epithelial distance between obese and nonobese subjects was eliminated by removal of dysglycemic subjects.
We conclude that microbiota encroachment is a feature of insulin resistance-associated dysglycemia in humans.
覆盖上皮的黏液样结构在使肠道微生物群与宿主细胞保持安全距离方面起着至关重要的作用。在炎症性肠病和结肠炎小鼠模型中，已观察到细菌侵入通常几乎无菌的内层黏液层。此外，在与低度肠道炎症相关的代谢综合征小鼠模型中也观察到了这种微生物群的侵入。因此，我们研究了微生物群的侵入是否可能与人类代谢综合征的指标相关。
使用共聚焦显微镜测量所有愿意参加癌症筛查结肠镜检查的参与者的结肠活检组织中每个高倍视野下最接近细菌的细菌与上皮的距离。
我们观察到，在所有受试者中，细菌与上皮的距离与体重指数、空腹血糖水平和糖化血红蛋白呈负相关。然而，这种相关性是由血糖异常的受试者驱动的，与体重指数无关，而通过去除血糖异常的受试者，肥胖和非肥胖受试者之间细菌与上皮距离的差异被消除。
我们得出结论，微生物群的侵入是人类胰岛素抵抗相关血糖异常的一个特征。
