Bacterial extracellular vesicles (BEVs) are nano-size particles secreted by bacteria that carry various bioactive components. These vesicles are thought to provide a new window into the mechanisms by which bacteria affect their hosts, but their fundamental proprieties within human remain poorly understood. Here, we developed a single-vesicle analytical platform that enabled BEV detection in complex biological samples of host. Using this platform, we found the presence of BEVs in the host circulation and they were mainly derived from gut microbes. We showed that the levels of circulating BEVs in humans significantly increased with aging due to an age-related increase in intestinal permeability. Significantly different levels of BEVs in blood were also found in patients with colorectal cancer and colitis. Together, our study provides new insights into circulating BEV biology and reveals their potential as a new class of biomarkers.

中文翻译：

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循环细菌细胞外囊泡的单颗粒分析揭示了它们的生物发生、血液变化以及与肠道屏障的联系

细菌细胞外囊泡（BEV）是细菌分泌的纳米级颗粒，携带各种生物活性成分。这些囊泡被认为为了解细菌影响宿主的机制提供了一个新的窗口，但它们在人类体内的基本特性仍然知之甚少。在这里，我们开发了一个单囊泡分析平台，可以在宿主的复杂生物样品中检测 BEV。利用这个平台，我们发现宿主循环中存在 BEV，它们主要来源于肠道微生物。我们发现，由于肠道通透性随年龄增长而增加，人体循环 BEV 水平随着年龄的增长而显着增加。结直肠癌和结肠炎患者的血液中 BEV 水平也存在显着差异。总之，我们的研究为循环 BEV 生物学提供了新的见解，并揭示了它们作为一类新型生物标志物的潜力。