Mechanisms underlying the influence of the gastrointestinal tract environment on probiotic efficacy

目前的证据表明，肠道微生物通过对宿主防御和免疫系统的影响而在宿主健康中发挥重要作用，益生菌在这方面受到了极大的关注。然而，由于效果和结果的不同，通过战略性使用饮食和给药方式有效地翻译和应用当前关于益生菌的知识的尝试引起了争议。这种变化对有效利用益生菌的潜力提出了挑战。必须解决目前关于益生菌在胃肠道(GI)中行为的知识差距，以应对这一挑战。这项研究计划的目的是确定胃肠道中的关键元素如何影响益生菌的活性及其对免疫系统的影响。胃肠道是一个复杂的环境，有许多因素可能导致益生菌效力的变化。一个基本的问题是，先前存在的胃肠道微生物群落如何影响益生菌的活动，这一因素可能对个体之间的反应差异做出很大贡献。能够影响细胞信号和基因表达的食物成分提供了另一个可能影响胃肠道益生菌功效的因素。用于在饮食中输送益生菌的乳制品和大豆食品含有几种这样的成分，如某些维生素、脂肪酸、多肽，对于大豆，还包括植物化学物质。这项研究将确定这些胃肠道因素，包括肠道微生物群落的变化，对益生菌作用于免疫系统的能力的影响。在细胞活性、信号和基因表达水平上研究这种关系的机制将澄清益生菌的影响，并导致对利用益生菌的最佳方法的新见解。

Current evidence indicates essential roles for gut microbes in host health through effects on host defense and the immune system, and probiotics receive much attention in this regard. However, attempts to effectively translate and apply current knowledge about probiotics through strategic use of diet and administration modalities have generated controversy, due to variation in effects and outcomes. Such variation poses a challenge to effectively harnessing the potential of probiotics. Gaps in current knowledge about behavior of probiotics in the gastrointestinal (GI) tract must be addressed to meet this challenge. The objective of this research program is to determine how key elements in the GI tract influence the activity of probiotics and their resultant impact on the immune system. The GI tract is a complex milieu with many factors potentially contributing to variation in probiotic efficacy. One fundamental question is how the pre-existing GI tract community of microbes influence the activity of probiotics, a factor that could contribute greatly to variation in response between individuals. Food components with the ability to influence cell signaling and gene expression provide another element that could influence probiotic efficacy in the GI tract. Dairy and soy foods used to deliver probiotics in the diet contain several such components, such as certain vitamins, fatty acids, peptides, and in the case of soy, phytochemicals. This research will determine the impact of these GI tract elements including, variation in the gut microbial community, on the ability of probiotics to act on the immune system. Examining the mechanisms underlying this relationship at the level of cell activity, signalling and gene expression will clarify probiotic effects and lead to new insight into the best ways to utilize probiotics.