Gut bacteria metabolite linked to Alzheimer’s progression in new study

A study published in Nature Communications has identified imidazole propionate (ImP), a metabolite produced by certain gut bacteria, as a potential link between gut health and the progression of Alzheimer’s disease. The research indicates that ImP can weaken the blood-brain barrier, allowing it to enter the brain where it exacerbates the accumulation of amyloid beta plaques and tau protein phosphorylation.

Analysis of 1,196 cognitively healthy adults showed that higher blood levels of ImP correlated with worse cognitive test scores, higher levels of Alzheimer’s biomarkers, and faster cognitive decline over time. The participants, with a mean age of 61.2 years, were monitored for changes in pTau-217 and neurofilament light chain (NfL), both of which serve as indicators of neuronal damage.

Experiments on genetically modified mice confirmed that ImP administration worsened disease signs. In these models, the metabolite led to increased amyloid beta plaques and tau abnormalities, alongside heightened reactions from astrocytes, the cells responsible for protecting and maintaining the brain.

Federico Rey, a professor of bacteriology at the University of Wisconsin and co-author of the study, noted that while ImP-producing bacteria are present in many healthy people, they are not usually abundant. However, the concentration of ImP in the bloodstream appears to be influenced by a combination of factors, including age, sex, genetics, diet, and metabolic health.

Researchers suggest that targeting ImP itself, rather than eliminating the bacteria, may be a viable therapeutic approach. They compare this strategy to the use of statins for cholesterol, proposing that an inhibitor capable of reducing ImP concentration in the blood could one day help mitigate Alzheimer’s risk without disrupting the broader microbiome.