Akkermansia muciniphila and Alzheimer's Disease: Mechanisms, Evidence and Translational Potential.

Akkermansia muciniphila (A. muciniphila) is a bacterium that breaks down mucus and is studied for its effects on metabolism and the immune system. Studies show that it affects Alzheimer's disease (AD) by protecting the gut barrier, reducing inflammation, and influencing communication between the immune system, the brain, and mitochondria. This review summarizes mechanistic, preclinical, and translational evidence connecting A. muciniphila to AD, including products such as short-chain fatty acids (SCFAs), and structural or secreted proteins including Amuc_1100 and extracellular vesicles (AmEVs). We also discuss differences between bacterial strains, differences in research methods, and findings that change under different conditions, which make the results harder to interpret. Animal studies suggest neuroprotective effects, but clinical evidence is still limited. Clinical use will need human studies at the strain level, confirmation in humanized models, and early trials using biomarkers to test safety and causal effects.