Fig 1: Astrocytic p-tau in CTE is primarily age-related and subpial, while neuronal p-tau is associated with RHI exposure. (A) Scatter plot of the log-transformed neuronal and astrocytic p-tau densities compared to age demonstrate a linear relationship between age and neuronal p-tau density (p < 0.0001, ß = 0.343) and astrocytic p-tau density (p = 0.0014, ß = 0.324), n = 149. (B) Comparison of log-transformed neuronal and astrocytic p-tau densities and years of RHI exposure demonstrate an association between neuronal (p = 0.0005, ß = 0.199) but not astrocytic p-tau density (p = 0.329, ß = 0.094) with years of RHI exposure. Only individuals who played American football were used for the RHI exposure analysis, n = 137. (C) Representative image of AT8, MAP2, and GFAP immunolabeling, left row, top to bottom. Right panel showing representative image of subpial astrocytic p-tau in a 69-year-old individual with high-stage CTE. White box indicates inset of left column, white arrows indicate cells with GFAP and AT8 colocalization. Scale bar = 10 µm and 250 µm. (D, E) Percentage of neuronal, subpial astrocytic, and parenchymal astrocytic p-tau densities separated by CTE stage (D) and decade of age (E) demonstrating the association of astrocytic p-tau with age but not CTE stage. Bar graphs represent mean ± standard error of the mean.