GFAP and Parkinson disease: A postmortem study also showed that levels of TRPV1, CNTF, and GFAP (a marker of astrogliosis) were significantly higher in the substantia nigra of patients with PD than controls, as well as in GFAP+ astrocytes of patients with PD; a significant difference in the expression of these proteins in the cortex was not noted (Nam et al., 2015).