The steady increase in life-expectancy of world population, coupled to many genetic and environmental factors (for instance, pre- and post-natal exposures to environmental neurotoxins), predispose to the onset of neurodegenerative diseases, whose prevalence is expected to increase dramatically in the next years. Recent studies have proposed links between the gut microbiota and neurodegenerative disorders such as Alzheimer's and Parkinson's diseases. Human body is a complex structure where bacterial and human cells are almost equal in numbers, and most microbes are metabolically active in the gut, where they potentially influence other target organs, including the brain. The role of gut microbiota in the development and pathophysiology of the human brain is an area of growing interest for the scientific community. Several microbial-derived neurochemicals involved in the gut-microbiota-brain crosstalk seem implicated in the biological and physiological basis of neurodevelopment and neurodegeneration. Evidence supporting these connections has come from model systems, but there are still unsolved issues due to several limitations of available research tools. New technologies are recently born to help understanding the causative role of gut microbes in neurodegeneration. This review aims to make an overview of recent advances in the study of the microbiota-gut-brain axis in the field of neurodegenerative disorders by: (a) identifying specific microbial pathological signaling pathways; (b) characterizing new, advanced engineered tools to study the interactions between human cells and gut bacteria.

世界人口预期寿命的稳步增长，加上许多遗传和环境因素（例如，产前和产后接触环境神经毒素），容易发生神经退行性疾病，预计其患病率将在2020年急剧增加。未来几年。最近的研究提出肠道微生物群与阿尔茨海默病和帕金森病等神经退行性疾病之间的联系。人体是一个复杂的结构，其中细菌和人体细胞的数量几乎相等，并且大多数微生物在肠道中代谢活跃，它们可能影响其他靶器官，包括大脑。肠道微生物群在人脑发育和病理生理学中的作用是科学界日益关注的领域。几种参与肠道-微生物群-大脑串扰的微生物衍生的神经化学物质似乎与神经发育和神经退行性变的生物学和生理学基础有关。支持这些联系的证据来自模型系统，但由于可用研究工具的一些限制，仍然存在未解决的问题。最近诞生的新技术有助于了解肠道微生物在神经退行性疾病中的致病作用。本综述旨在通过以下方式概述神经退行性疾病领域微生物群-肠-脑轴研究的最新进展：（a）确定特定的微生物病理信号通路；(b) 表征新的、先进的工程工具来研究人体细胞和肠道细菌之间的相互作用。