In line with previous observations in mouse models and human AD patients (Bergen et al, 2015; Brkic et al, 2015b), 6 h after AβO injection claudin‐5 (Cldn5) expression was significantly downregulated in WT mice but not in TNFR1−/− mice (Fig 6D). This evidence concerns the gene CLDN5 and Alzheimer disease.