Rifaximin eases amyloid pathology in APP/PS1 mice by reshaping gut bile acids
- A non-absorbed antibiotic, given orally for two months to aged APP/PS1 mice, improved memory and lowered amyloid burden, neuroinflammation and synaptic loss.
- It shifted gut microbiota composition and cut several primary and secondary bile acids, while raising tryptophan metabolism and serum serotonin.
- The authors read the benefit as acting through the microbiome–bile acid–serotonin axis rather than through any drug exposure in the brain.
💡 Points Based on the abstract
A drug that never leaves the gut cannot be doing target engagement in the brain, so the model carries the whole argument: one dose, one transgenic strain, male mice only. Hepatic encephalopathy patients already take rifaximin for years, which is the cheap natural experiment. A cognition signal in that cohort, or a germ-free or bile-acid-sequestrant control here, would tell me whether this is mechanism or microbiome noise.