Nose as Early Alarm: Immune-Driven Olfactory Breakdown in Alzheimer’s
New research links the initial signs of Alzheimer’s to brain immune cells (microglia) destroying scent-related connections between the olfactory bulb and locus coeruleus, driven by membrane changes on neurons; evidence from mice, human tissue, and PET scans suggests smell loss could serve as an early diagnostic cue and support earlier treatment with amyloid-beta antibodies.