Alzheimer's research links brain immune cells and bacterial signature

International research published in Nature Medicine identified that the behavior of microglia, the brain's resident immune cells, may be a decisive factor in whether Alzheimer's pathology leads to dementia. The study, involving scientists from VIB, KU Leuven, the UK Dementia Research Institute and Muna Therapeutics, compared brain tissue from elderly patients with Alzheimer's, from older individuals with typical Alzheimer's lesions but preserved cognition, and from cognitively healthy centenarians. Using single‑cell sequencing and spatial transcriptomics, they observed distinct microglial activation states associated with resilience.

Parallel research highlighted a bacterial “signature” linked to Alzheimer's, showing that alterations in oral and gut microbiota—particularly the presence of Porphyromonas gingivalis and other gram‑negative pathogens—correlate with neuroinflammation, amyloid accumulation and cognitive decline. These findings suggest that microbial biomarkers could aid early detection and that targeting the microbiome may become a preventive strategy.