Yesterday: Faecalibacterium prausnitzii depleted in Parkinson's disease.
Today: the same bacterium, a different brain disease ... Alzheimer's.
In Alzheimer's, its depletion triggers a completely different chain — one that targets the blood-brain barrier and drives neuroinflammation from the inside.
Here's the science 👇
#Alzheimers #GutBrainAxis
F. prausnitzii has been identified as depleted in Alzheimer's patients across multiple human cohort studies.
Ueda et al. 2021 (Cell Reports Medicine) identified specific F. prausnitzii strains as candidate targets for gut microbiome-based intervention in Alzheimer's-type dementia.
Depletion correlates with worse MMSE cognitive scores — the standard clinical test for dementia severity.
The AD mechanism is different from Parkinson's.
↓ F. prausnitzii
→ ↓ butyrate
→ HDAC inhibition lost
→ NF-kB pathway hyperactivated in microglia
→ TNF-alpha, IL-1beta, IL-6 elevation
→ accelerated amyloid-beta deposition
→ tau hyperphosphorylation
Butyrate also maintains claudin-5, the blood-brain barrier tight junction protein. When F. prausnitzii falls, the BBB becomes permeable to peripheral inflammation.
A 2025 study (Molecular Brain) examined butyrate's role in the BBB transport of Alzheimer's amyloid-beta peptides directly.
In germ-free mice colonized with butyrate-deficient microbiomes, key BBB proteins were altered — consistent with increased amyloid accumulation.
Butyrate production is significantly reduced in AD patients and correlates with cognitive decline.
Worth noting for your own research lens.
Emerging evidence suggests gut microbiome differences — including F. prausnitzii abundance — may partly explain sex differences in Alzheimer's risk.
Women carry approximately two-thirds of the global Alzheimer's burden. The gut-brain axis is increasingly implicated as one contributing pathway.
This is early-stage but scientifically credible. [EMERGING]
Same dietary levers as in PD — because the same bacterium responds to the same inputs:
✓ High dietary fiber (inulin, FOS, resistant starch)
✓ Jerusalem artichoke, chicory root, leeks, asparagus
✓ Mediterranean diet pattern
✓ Polyphenol-rich foods
No approved F. prausnitzii supplement exists. Clinical trials in development.
NOTE: Probiotics carry real risks for immunocompromised individuals, the elderly, and children. Always consult your doctor
Tomorrow: this same bacterium in a completely different context.
Not a brain disease. Aging itself.
Centenarian studies are revealing that people who live past 100 have something in common — and F. prausnitzii is part of the story.
Follow @Neuroscope_mp for Part 3.
#Alzheimers #Dementia #GutBrainAxis #Neuroscience #Microbiome
If you missed yesterday’s thread on Parkinson’s, here it is 👇
Today, we’re covering how the exact same bacteria affect Alzheimer’s through a totally different pathway.
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