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Updated: Nov 18, 2025
Microbiota Analysis Using Two-step PCR and Next-generation 16S rRNA Gene Sequencing
Published on: October 15, 2019
The oral microbiome and inflammation in mild cognitive impairment
Irene Yang1, Robert Adam Arthur2, Liping Zhao3
1Emory University, Nell Hodgson Woodruff School of Nursing, 1520 Clifton Road NE Room 424, Atlanta, GA 30322, United States of America.
Abstract:
Inflammation and immune mechanisms are believed to play important roles in Alzheimer's disease pathogenesis. Research supports the link between poor oral health and Alzheimer's disease. Periodontal disease and dental caries represent the two most common infections of the oral cavity. This study focused on a precursor to Alzheimer's disease, mild cognitive impairment (MCI). Using 16S rRNA sequencing, we characterized and compared the oral microbiome of 68 older adults who met the criteria for MCI or were cognitively normal, then explored relationships between the oral microbiome, diagnostic markers of MCI, and blood markers of systemic inflammation. Two taxa, Pasteurellacae and Lautropia mirabilis were identified to be differentially abundant in this cohort. Although systemic inflammatory markers did not differentiate the two groups, differences in five cerebrospinal fluid inflammatory mediators were identified and had significant associations with MCI. Because inflammatory markers may reflect CNS changes, pursuing this line of research could provide opportunities for new diagnostic tools and illuminate mechanisms for prevention and mitigation of Alzheimer's disease.
Insights
This study found specific oral bacteria linked to mild cognitive impairment (MCI), a precursor to Alzheimer's disease. These findings suggest potential new diagnostic tools and prevention strategies for Alzheimer's disease.
Area of Science:
- Neuroscience
- Microbiology
- Immunology
Background:
- Alzheimer's disease (AD) pathogenesis involves inflammation and immune responses.
- Poor oral health, including periodontal disease and dental caries, is linked to increased Alzheimer's disease risk.
- Mild cognitive impairment (MCI) is a recognized precursor stage to Alzheimer's disease.
Purpose of the Study:
- To investigate the oral microbiome composition in individuals with MCI compared to cognitively normal controls.
- To explore the relationship between oral microbiome profiles, MCI diagnostic markers, and systemic inflammation.
- To identify potential microbial and inflammatory biomarkers for early detection of MCI.
Main Methods:
- 16S rRNA sequencing was employed to analyze the oral microbiome.
- The study included 68 older adults, categorized as MCI or cognitively normal.
- Cerebrospinal fluid (CSF) and blood samples were analyzed for inflammatory mediators.
Main Results:
- Two oral bacterial taxa, Pasteurellacae and Lautropia mirabilis, were found to be differentially abundant in the MCI group.
- No significant differences in systemic inflammatory markers were observed between MCI and control groups.
- Five CSF inflammatory mediators showed significant differences and associations with MCI status.
Conclusions:
- Specific alterations in the oral microbiome are associated with mild cognitive impairment.
- Cerebrospinal fluid inflammatory mediators, not systemic markers, correlate with MCI.
- Further research into oral microbiome and CNS inflammation may yield novel diagnostic and therapeutic targets for Alzheimer's disease prevention and mitigation.
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