Figure 5. ECV transfer Aβ across the BBB into the brain parenchyma.

HBMEC transfected with pT-CD63-GFP were exposed to 100 nM Aβ (1–40) HiLyte AlexaFluor647 for 48 h, followed by isolation of ECV from cell culture media. 2.5×10⁷ ECV were infused into the mouse brain via the internal carotid artery. Control mice were infused with saline. Analyses were performed 1 h post infusion by confocal microscopy; DAPI or Hoechst staining (blue) visualizes the nuclei. A) CD63-GFP positive ECV were associated with the isolated brain microvessels. Scale bar: 50 µm. B) Co-localization of CD63-GFP (green), Aβ (1–40) HiLyte AlexaFluor647 (yellow), and CD31 (endothelial marker, red) in the brain sections indicate association of CD63-GFP and Aβ with brain capillaries (arrows on the enlarged right panel). C) Brain sections were analyzed as in (B), indicating partial localization of Aβ in brain parenchyma and not associated with brain microvessels (arrowheads on the enlarged area), after an apparent crossing the BBB. Scale bar on B and C: 50 µm.