Additive effect of distant Lewy bodies and tau seeds injections on nigral degeneration in macaques.

The influence of Lewy body (LB) and tau co-pathologies is increasingly acknowledged as putatively affecting neurodegeneration and clinical phenotypes. Here, we injected rhesus macaques with LB fractions or/and tau seeds derived from patients brains into distinct brain areas connected to the mesencephalon. Compared to control macaques, we observed increased mesencephalic staining of pathological α-synuclein and tau, as well as nigrostriatal dopaminergic neuronal loss, with a cumulative effect of co-pathology.