Fig. 6

Abundant vesicles in arteriole cells of human CNS might indicate transcytotic activity. Caveolae vesicles in arteriole endothelial and smooth muscle cells are evident in 3D EM reconstruction of human cortical tissue [14]. a, b Transmission electron microscopy images of a CNS arteriole and capillary. Pseudo-colors highlight cell types: smooth-muscle (green), endothelium (purple), pericyte (yellow), astrocyte end-foot (blue), red blood cell (red), Scale bar 10 µm. a’, b’, Magnification of the boxed area in the left panel. a’ Abundant vesicles in aEC’s (blue ovals) and aSMCs (red ovals). c, Example of multiple vesicles (pseudo labeled in magenta) in aSMCs. d Quantification showing significant higher vesicular density in aECs than in cECs (n = 5 arterioles and 5 capillaries). SMC Smooth-muscle cell, EC Endothelial cell, AC Astrocyte, P Pericyte, L lumen. Scale bar 1 µm. Data are mean ± s.e.m. ** p < 0.05 (two tailed Mann–Whitney U- test)