Electron microscopic analysis of FHUVECs and MHUVECs. ( A) FHUVECs have little smooth endoplasmic reticulum (SER), abundant lysosomes (L) and a normal cytoplasmic membrane (CM). M and N indicate the mitochondria and nucleus, respectively. (B) MHUVECs have abundant autophagic vacuoles (V) in different stages of digestion and a CM with many blebs. M and N indicate the mitochondria and nucleus, respectively. (A) Magnification × 6,900, scale bars: 2 mm. (B) Magnification × 9,000, scale bars: 2 mm.