The Gut Microbiota in Mild Cognitive Impairment in Community‐Dwelling Older Adults in Taiwan

Abstract

AbstractBackgroundRecent microbial studies of Alzheimer’s disease and mild cognitive impairment (MCI) have focused on the alterations of gut microbiota in cognitively impaired patients. However, related research remains limited and varies with analytical pipelines. This study aims to examine biodiversity and the differential abundance of gut flora in MCI.MethodThe study sample of 96 older adults was derived from a community‐based prospective cohort study, the Epidemiology of Mild Cognitive Impairment in Taiwan (EMCIT). Among them, 31 were ascertained as MCIs, matched with 65 cognitively normal individuals on age, gender and community. Fecal samples were analyzed by Illumina sequencing of the V3‐V4 regions of the 16S rRNA gene. The divisive amplicon denoising algorithm 2 (DADA2) pipeline was applied to the production of the amplicon sequence variant (ASV) table, and the SILVA database 138.1 was used to assign taxonomies.ResultThere is no significant difference in alpha‐ and beta‐ diversity between MCI and cognitively normal adults after adjusting for age, gender, community, education and hypertension. (Fig. 1). However, the results of linear discriminant analysis (LDA) effect size (LEfSe) showed a differential abundance of ASVs between two groups. Increased abundance of several genera within Firmicutes phylum and reduced abundance of Ruminococcus, Butyricimonas, Oxalobacter are associated with MCI. A ROC curve using these microbial genera of interest can distinguish MCI patients from controls with AUC = 84%. (Fig. 2)ConclusionCompared with cognitively normal older adults, the gut microbiota of older adults with MCI identified from the community was significantly altered, particularly manifesting in enriched genera from the Firmicutes phylum and decreased abundance of genera Ruminococcus, Butyricimonas, Oxalobacter.