Gut-derived imidazole propionate linked to Alzheimer’s biomarkers and cognitive decline

Researchers investigated whether imidazole propionate (ImP), a gut bacterial metabolite, is associated with Alzheimer’s-related pathology and cognitive decline. The Nature Communications study combined mouse experiments with an observational analysis of blood samples from almost 1,200 participants in the Wisconsin Registry for Alzheimer’s Prevention and Wisconsin Alzheimer’s Disease Research Center studies. Human outcomes included dementia-related biomarkers and cognitive performance over time.

Higher circulating ImP concentrations were associated with biomarkers of abnormal protein accumulation and impaired neuronal function. Participants with the highest ImP levels also experienced faster cognitive decline. In mice, ImP reaching the brain increased abnormal beta-amyloid and tau accumulation. A genetic variant carried by approximately 43% of study participants was associated with substantially higher circulating ImP; researchers hypothesized that it may affect renal clearance of the compound.

These findings identify ImP as a potential therapeutic research target, not an established clinical marker or treatment target. The human associations do not establish causality, and the supplied university news account provides no effect estimates, confidence intervals, or details of confounder adjustment. No evidence is reported that lowering ImP prevents dementia or slows decline in humans. Because bacteria produce ImP from histidine, an essential amino acid, the findings do not support eliminating histidine-containing foods. Support included government and Wisconsin Partnership Program grants.