The human intestinal ecosystem is characterized by a complex interplay between different microorganisms and the host. The high variation within the human population further complicates the quest toward an adequate understanding of this complex system that is so relevant to human health and well-being. To study host-microbe interactions, defined synthetic bacterial communities have been introduced in gnotobiotic animals or in sophisticated in vitro cell models. This review reinforces that our limited understanding has often hampered the appropriate design of defined communities that represent the human gut microbiota. On top of this, some communities have been applied to in vivo models that differ appreciably from the human host. In this review, the advantages and disadvantages of using defined microbial communities are outlined, and suggestions for future improvement of host-microbe interaction models are provided. With respect to the host, technological advances, such as the development of a gut-on-a-chip system and intestinal organoids, may contribute to more-accurate in vitro models of the human host. With respect to the microbiota, due to the increasing availability of representative cultured isolates and their genomic sequences, our understanding and controllability of the human gut "core microbiota" are likely to increase. Taken together, these advancements could further unravel the molecular mechanisms underlying the human gut microbiota superorganism. Such a gain of insight would provide a solid basis for the improvement of pre-, pro-, and synbiotics as well as the development of new therapeutic microbes.

中文翻译：

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使用定义的微生物群落来模拟人类肠道中的宿主-微生物相互作用。

人类肠道生态系统的特征在于不同微生物与宿主之间复杂的相互作用。人口中的高度变异进一步加剧了对充分理解这一与人类健康和福祉息息相关的复杂系统的追求。为了研究宿主与微生物之间的相互作用，已将定义的合成细菌群落引入了致生菌动物或复杂的体外细胞模型中。这篇评论强调了我们有限的理解常常阻碍了代表人类肠道微生物群的明确社区的适当设计。最重要的是，一些社区已应用于与人类宿主明显不同的体内模型。在这篇评论中，概述了使用定义的微生物群落的利弊，并提供了未来改进宿主-微生物相互作用模型的建议。关于宿主，技术上的进步，例如芯片上肠系统和肠道类器官的发展，可能有助于建立更准确的人类宿主体外模型。关于微生物群，由于代表性培养分离物及其基因组序列的可用性增加，我们对人类肠道“核心微生物群”的理解和可控性可能会增加。综上所述，这些进展可进一步揭示人类肠道微生物群超生物的分子机制。这种见识的积累将为改善益生元，益生元和合生元以及开发新的治疗性微生物提供坚实的基础。