A) Increased global expression of astrocytic water channel Aquaporin-4 (AQP4) was observed in cases with Alzheimer’s disease (AD, n = 10) over aged control cases (n = 16), but not in cases of mixed dementia consisting of AD and vascular pathologies (n = 7). B) While no significant group differences in perivascular localization of AQP4 expression was observed, the AD group had a qualitative reduction in perivascular localization of AQP4 compared to mixed dementia cases (p = 0.08). ANOVA with Bonferroni correction, *p < 0.05, **p < 0.01.