Exploring the Alteration of Firmicutes and Bacteroides in  Preclinical Alzheimer’s Disease  — The Association Specialists
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Exploring the Alteration of Firmicutes and Bacteroides in  Preclinical Alzheimer’s Disease  (22060)

Sithara Dissanayaka 1 2 , Thilini Jayasinghe 3 , Hamid Sohrabi 2 4 5 , Stephanie Rainey-Smith 2 5 , Karen Scott 6 , Ralph Martins 1 2 4 , Binosha Fernando 1 2
  1. Centre of Excellence for Alzheimer's Disease Research and Care , School of Medical and Health Sciences , Edith Cowan University, Nedlands, WA, Australia
  2. Alzheimer’s Research Australia, Nedlands, WA, Australia
  3. The University of Sydney, Camperdown, NSW, Australia
  4. Department of Biomedical Sciences, Macquarie University , Sydney, NSW, Australia
  5. Murdoch University, Murdoch, WA, Australia
  6. University of Aberdeen, Aberdeen, UK

 

 

 

Alzheimer's disease is a progressive neurodegenerative disorder characterized by memory loss and significant behavioral changes. Recent studies emphasize the pivotal role of gut dysbiosis in AD pathogenesis, with notable alterations in the gut microbiome observed in individuals with AD or mild cognitive impairment. However, the specific changes in microbiota during the preclinical stages of AD, defined by cerebral amyloidosis without cognitive impairment, are not well understood. This study seeks to address this critical gap in knowledge.

All study participants (17 CU Aβ+ and 54 CU Aβ-) were selected from highly characterised cohorts and underwent Pittsburg compound B-positron emission tomography. The taxonomic composition of faecal samples was examined through metagenomic analysis.

 The analysis revealed differences in microbial taxa abundances between the CU Aβ+ and CU Aβ- groups. At the phylum level, Bacteroidetes were more abundant in the CU Aβ+ group, while Firmicutes predominated in the CU Aβ- group. At the genus level, Bacteroides (phylum Bacteroidetes) showed high abundance in both groups. At the species level, Faecalibacterium prausnitzii and Bacteroides vulgatus had higher relative abundances in the CU Aβ- group, whereas Bacteroides copri (phylum Bacteroidetes) was more prevalent in the CU Aβ+ group.

These findings suggest that dysbiosis in Firmicutes and Bacteroides phyla may indicate an imbalance of beneficial and harmful gut bacteria in preclinical AD. Identifying these microbiota shifts may provide insights into early therapeutic targets for managing AD progression and may assist in preclinical AD diagnosis. A deeper understanding of the relationship between gut microbiota and AD is needed.