Interaction between gut microbiota and Alzheimer's disease: Re-analysis of the same sample

Background Alzheimer's disease (AD) is a neurodegenerative disease causing memory and cognitive dysfunction, and it is well established that the gut microbiota has an important effect on AD. Objective In this study, we aimed to identify evidence in AD affecting the abundance of gut microbiota, analyzing age and post-disease, with the expectation of discovering new gut microbiota combinations for diagnostic purposes. Methods We initially retrieved 219 samples from five studies in the GMrepo, and after screening, 86 samples collected from the same location were retained, with 98 species of gut microbiota at the genus level. Results It was found that Clostridium , Ruminococcus , Roseburia , and Faecalibacterium were enriched in AD. We confirmed that AD altered the evenness of gut microbiota and validated the AD-induced significant changes in gut microbiota. For the impact of age on disease, we identified the most sensitive age group for AD detection by gut microbiota and the relevant species. When analyzing the association between AD and sex, we found that sex had no effect on the overall bacterial distribution, but in the subgroup analysis by sex, we identified significantly relevant species that could serve as diagnostic targets. Conclusions This study investigated the interaction between gut microbiota and AD utilizing an online free database and revealed a series of significant associations between the two. In the future, further emphasis should be placed on the identification of key bacteria and their associated genes to determine the relative causality of gut microbiota and AD.