16S rRNA Next Generation Sequencing Analysis Shows Bacteria in Alzheimer's Post-Mortem Brain

Area of Science:

• Neuroscience
• Microbiology
• Genetics

Background:

• Alzheimer's disease (AD) involves amyloid-beta and neurofibrillary tangles, with neuroinflammation as a key pathological factor.
• The brain's historically assumed microbial privilege is being re-evaluated, especially concerning neurodegenerative conditions.
• Microbial invasion of the central nervous system is increasingly considered a potential trigger or contributor to neurodegeneration.

Purpose of the Study:

• To investigate the presence and abundance of bacterial species in Alzheimer's disease brain tissue.
• To compare bacterial populations in Alzheimer's-affected brains versus cognitively normal brains.
• To explore the potential role of microbial incursion in Alzheimer's pathogenesis.

Main Methods:

• Utilized 16S ribosomal gene-specific Next-Generation Sequencing (NGS).
• Analyzed bacterial species content from both frozen and formaldehyde-fixed brain tissue sections.
• Compared bacterial profiles between a cohort of Alzheimer's disease cases and cognitively unimpaired controls.

Main Results:

• Detected an increased abundance of bacterial populations in Alzheimer's disease brain tissue compared to normal brain tissue.
• Provided evidence challenging the concept of a sterile central nervous system in the context of Alzheimer's disease.
• Identified specific bacterial signatures associated with Alzheimer's pathology.

Conclusions:

• The findings suggest a significant association between bacterial presence and Alzheimer's disease pathology.
• Microbial incursion may play a more substantial role in neurodegenerative diseases than previously thought.
• Further research is warranted to elucidate the causal relationship between bacteria and Alzheimer's disease progression.