Aging Gut-Brain Interactions: Pro-Inflammatory Gut Bacteria Are Elevated in Fecal Samples from Individuals Living with Alzheimer’s Dementia

<b>Background/Objectives</b>: Alzheimer’s disease (AD) is the most common form of dementia, characterized by an irreversible decline in cognitive function. The pathogenesis of several neurodegenerative disorders has been linked to changes in the gut microbiota, transmitted through the gu...

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Main Authors: Alison I. C. Donaldson, Claire L. Fyfe, Jennifer C. Martin, Ellen E. Smith, Graham W. Horgan, Phyo K. Myint, Alexandra M. Johnstone, Karen P. Scott
Format: Article
Language:English
Published: MDPI AG 2025-03-01
Series:Geriatrics
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Online Access:https://www.mdpi.com/2308-3417/10/2/37
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author Alison I. C. Donaldson
Claire L. Fyfe
Jennifer C. Martin
Ellen E. Smith
Graham W. Horgan
Phyo K. Myint
Alexandra M. Johnstone
Karen P. Scott
author_facet Alison I. C. Donaldson
Claire L. Fyfe
Jennifer C. Martin
Ellen E. Smith
Graham W. Horgan
Phyo K. Myint
Alexandra M. Johnstone
Karen P. Scott
author_sort Alison I. C. Donaldson
collection DOAJ
description <b>Background/Objectives</b>: Alzheimer’s disease (AD) is the most common form of dementia, characterized by an irreversible decline in cognitive function. The pathogenesis of several neurodegenerative disorders has been linked to changes in the gut microbiota, transmitted through the gut-brain axis. <b>Methods</b>: We set out to establish by case-control study methodology whether there were any differences in the composition and/or function of the gut microbiota between older resident adults in care homes with or without an AD diagnosis via analysis of the microbial composition from fecal samples. <b>Results</b>: The microbial composition, determined by 16S rRNA gene profiling, indicated that AD sufferers had significantly increased proportions of <i>Escherichia/Shigella</i> and <i>Clostridium_sensu_stricto_1</i>, and significantly decreased proportions of <i>Bacteroides</i>, <i>Faecalibacterium</i>, <i>Blautia</i>, and <i>Roseburia</i> species. The increase in potentially pro-inflammatory bacteria was consistent with slightly higher concentrations of calprotectin, a biomarker of gut inflammation. Fecal concentrations of most microbial metabolites measured were similar across groups, although participants with AD had significantly increased proportions of the branched-chain fatty acid, iso-butyrate, and lower overall concentrations of total short chain fatty acids. <b>Conclusions</b>: Participants with Alzheimer’s disease have several key differences within their gut microbiota profile, in contrast to care home residents without Alzheimer’s disease. The altered microbiome included both compositional and functional changes linked to poorer health and gut inflammation.
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spelling doaj-art-bc848b18556543f9a9750afb12003d4c2025-08-20T03:13:54ZengMDPI AGGeriatrics2308-34172025-03-011023710.3390/geriatrics10020037Aging Gut-Brain Interactions: Pro-Inflammatory Gut Bacteria Are Elevated in Fecal Samples from Individuals Living with Alzheimer’s DementiaAlison I. C. Donaldson0Claire L. Fyfe1Jennifer C. Martin2Ellen E. Smith3Graham W. Horgan4Phyo K. Myint5Alexandra M. Johnstone6Karen P. Scott7Institute of Applied Health Sciences, School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Aberdeen AB25 2ZD, UKThe Rowett Institute, School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Aberdeen AB25 2ZD, UKThe Rowett Institute, School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Aberdeen AB25 2ZD, UKCentre for Genome Enabled Biology and Medicine, University of Aberdeen, 23 St Machar Drive, Aberdeen AB24 3FX, UKBiomathematics and Statistics Scotland (BioSS), Aberdeen AB25 2ZD, UKInstitute of Applied Health Sciences, School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Aberdeen AB25 2ZD, UKThe Rowett Institute, School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Aberdeen AB25 2ZD, UKThe Rowett Institute, School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Aberdeen AB25 2ZD, UK<b>Background/Objectives</b>: Alzheimer’s disease (AD) is the most common form of dementia, characterized by an irreversible decline in cognitive function. The pathogenesis of several neurodegenerative disorders has been linked to changes in the gut microbiota, transmitted through the gut-brain axis. <b>Methods</b>: We set out to establish by case-control study methodology whether there were any differences in the composition and/or function of the gut microbiota between older resident adults in care homes with or without an AD diagnosis via analysis of the microbial composition from fecal samples. <b>Results</b>: The microbial composition, determined by 16S rRNA gene profiling, indicated that AD sufferers had significantly increased proportions of <i>Escherichia/Shigella</i> and <i>Clostridium_sensu_stricto_1</i>, and significantly decreased proportions of <i>Bacteroides</i>, <i>Faecalibacterium</i>, <i>Blautia</i>, and <i>Roseburia</i> species. The increase in potentially pro-inflammatory bacteria was consistent with slightly higher concentrations of calprotectin, a biomarker of gut inflammation. Fecal concentrations of most microbial metabolites measured were similar across groups, although participants with AD had significantly increased proportions of the branched-chain fatty acid, iso-butyrate, and lower overall concentrations of total short chain fatty acids. <b>Conclusions</b>: Participants with Alzheimer’s disease have several key differences within their gut microbiota profile, in contrast to care home residents without Alzheimer’s disease. The altered microbiome included both compositional and functional changes linked to poorer health and gut inflammation.https://www.mdpi.com/2308-3417/10/2/37brainAlzheimer’s diseasegut-brain axisfecal microbiota
spellingShingle Alison I. C. Donaldson
Claire L. Fyfe
Jennifer C. Martin
Ellen E. Smith
Graham W. Horgan
Phyo K. Myint
Alexandra M. Johnstone
Karen P. Scott
Aging Gut-Brain Interactions: Pro-Inflammatory Gut Bacteria Are Elevated in Fecal Samples from Individuals Living with Alzheimer’s Dementia
Geriatrics
brain
Alzheimer’s disease
gut-brain axis
fecal microbiota
title Aging Gut-Brain Interactions: Pro-Inflammatory Gut Bacteria Are Elevated in Fecal Samples from Individuals Living with Alzheimer’s Dementia
title_full Aging Gut-Brain Interactions: Pro-Inflammatory Gut Bacteria Are Elevated in Fecal Samples from Individuals Living with Alzheimer’s Dementia
title_fullStr Aging Gut-Brain Interactions: Pro-Inflammatory Gut Bacteria Are Elevated in Fecal Samples from Individuals Living with Alzheimer’s Dementia
title_full_unstemmed Aging Gut-Brain Interactions: Pro-Inflammatory Gut Bacteria Are Elevated in Fecal Samples from Individuals Living with Alzheimer’s Dementia
title_short Aging Gut-Brain Interactions: Pro-Inflammatory Gut Bacteria Are Elevated in Fecal Samples from Individuals Living with Alzheimer’s Dementia
title_sort aging gut brain interactions pro inflammatory gut bacteria are elevated in fecal samples from individuals living with alzheimer s dementia
topic brain
Alzheimer’s disease
gut-brain axis
fecal microbiota
url https://www.mdpi.com/2308-3417/10/2/37
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