Key BBB proteins that had robust expression in CAA(−) vessels were significantly decreased in CAA(+) vessels (Supplementary Fig. 2), including OCLN (MCI: 2.7-fold decrease, p = 2.03 × 10–2; AD: not detected), TJP1 (also known as zona occludens-1; ZO-1; MCI: 2.7-fold decrease, p = 4.45 × 10–3; AD: 1.7-fold decrease, p = 1.76 × 10–3), and SLC2A1 (also known as GLUT1; MCI: 2.2-fold, p = 0.059; AD: 1.7-fold, p = 0.030). This evidence concerns the gene OCLN and Alzheimer disease.