GFAP and Alzheimer disease: GFAP elevation is associated with astrocytic activation. NfL is elevated in dopaminergic neuronal injury and progression of motor and non-motor decline. sTREM2 indicates microglial activation in the substantia nigra, while YKL-40 and S100B reflect ongoing glial-driven inflammation and BBB dysfunction. These markers parallel those in AD, highlighting common pathways of degeneration.